oversight

Spent Nuclear Fuel: Options Exist to Further Enhance Security

Published by the Government Accountability Office on 2003-07-15.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

             United States General Accounting Office

GAO          Report to the Chairman,
             Subcommittee on Energy and Air
             Quality, Committee on Energy and
             Commerce, U.S. House of
             Representatives
July 2003
             SPENT NUCLEAR
             FUEL
             Options Exist to
             Further Enhance
             Security




GAO-03-426
                                                 July 2003


                                                 SPENT NUCLEAR FUEL

                                                 Options Exist to Further Enhance
Highlights of GAO-03-426, a report to the        Security
Chairman, Subcommittee on Energy and
Air Quality, Committee on Energy and
Commerce, U.S. House of
Representatives




Spent nuclear fuel, the used fuel
                                                The likelihood of widespread harm from a terrorist attack or a severe
periodically removed from nuclear
power reactors, is one of the most              accident involving commercial spent nuclear fuel is low, according to studies
hazardous materials made by                     conducted by DOE and NRC. Largely because spent fuel is hard to disperse
man. Nuclear power companies                    and is stored in protective containers, these studies found that most terrorist
currently store 50,000 tons of spent            or accident scenarios would cause little or no release of spent fuel, with
fuel at 72 sites in 33 states. That             little harm to human health. Some assessments found widespread harm is
amount will increase through 2010,              possible under certain severe but extremely unlikely conditions involving
when the Department of Energy                   spent fuel stored in storage pools. As part of its ongoing research program
(DOE) expects to open a                         and to respond to increased security concerns, NRC has ongoing and
permanent repository for this                   planned studies of the safety and security of spent fuel, including the
fuel at Yucca Mountain, Nevada.                 potential effects of more extreme attack scenarios, including deliberate
Concerns have been raised since
                                                aircraft crashes.
September 11, 2001, that terrorists
might target spent fuel. GAO
was asked to (1) review federally               While NRC and DOE have found that spent fuel may be relatively safe and
sponsored studies that assessed                 secure, DOE could potentially enhance the security of this fuel through
the potential health effects of a               options such as minimizing the number of shipments and picking up fuel in
terrorist attack or a severe accident           an order that would reduce risk, such as moving older less dangerous fuel
on spent fuel, either in transit or             first. These options could reduce the risk during transport and at some
in storage, and (2) identify options            locations where the fuel is currently stored. However, contractual
for DOE to further enhance the                  agreements between DOE and owners of spent fuel may limit DOE's ability
security of spent fuel during                   to choose among these options. In addition, it is not clear that the benefits
shipping to Yucca Mountain.                     of these measures would justify the potential costs, including a possible
                                                renegotiation of the contracts between DOE and the spent fuel owners.

GAO is recommending that,
as DOE develops its plans for
transporting spent fuel to Yucca
Mountain, it assess potential
options to further enhance the
security and safety of this fuel.

In commenting on GAO’s report,
DOE and NRC generally concurred
with the facts of the report.
DOE noted that the information
on transit was accurate and
well-balanced, while the Nuclear
Regulatory Commission (NRC)
noted that the information provides
a reasonable characterization of
the current understanding of risks
associated with spent fuel storage.
www.gao.gov/cgi-bin/getrpt?GAO-03-426.

To view the full product, including the scope
and methodology, click on the link above.
For more information, contact Robin M.
Nazarro at (202) 512-3841 or
nazarror@gao.gov.
Contents


Letter                                                                                      1
               Results in Brief                                                             2
               Background                                                                   3
               Likelihood of Widespread Harm from Terrorist Attacks or Severe
                  Accidents Involving Spent Fuel Is Low                                    8
               Options May Exist to Further Enhance Security and Safety                   17
               Conclusions                                                                24
               Recommendations for Executive Action                                       24
               Agency Comments and Our Evaluation                                         24
               Scope and Methodology                                                      26

Appendix I     Nuclear Regulatory Commission Requirements for
               Safety and Security of Spent Fuel                                          28



Appendix II    Additional Information on Studies on the Safety and
               Security of Spent Fuel in Transit                                          37



Appendix III   Comments from the Department of Energy                                     42



Appendix IV    Comments from the Nuclear Regulatory Commission                            43



Appendix V     GAO Contact and Staff Acknowledgments                                      45



Table
               Table 1: Potential Health Effects of Fire in a Spent Fuel Pool             14




               Page i                                           GAO-03-426 Spent Nuclear Fuel
Figures
          Figure 1: Locations for Wet and Dry Storage Sites for Commercial
                   Spent Nuclear Fuel and Yucca Mountain, as of April 2003                           6
          Figure 2: Cutaway Graphic of a Spent Fuel Truck
                   Transportation Cask                                                              29
          Figure 3: Spent Fuel Rail Container                                                       30
          Figure 4: Spent Fuel Truck Container on a Trailer                                         30
          Figure 5: A Wet Storage Pool                                                              32
          Figure 6: A Spent Fuel Dry Storage Container                                              35




          Abbreviations

          DOE               Department of Energy
          NRC               Nuclear Regulatory Commission



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          Page ii                                                   GAO-03-426 Spent Nuclear Fuel
United States General Accounting Office
Washington, DC 20548




                                   July 15, 2003

                                   The Honorable Joe Barton
                                   Chairman, Subcommittee on Energy and Air Quality
                                   Committee on Energy and Commerce
                                   House of Representatives

                                   Dear Mr. Chairman:

                                   One of the most hazardous materials made by man is spent nuclear
                                   fuel—the used fuel periodically removed from reactors in nuclear power
                                   plants. Without protective shielding, the fuel’s intense radioactivity can kill
                                   a person exposed directly to it within minutes or cause cancer in those
                                   who receive smaller doses. As the fuel ages, it begins to cool and becomes
                                   less radiologically dangerous—some of the radioactive particles decay
                                   quickly, within days or weeks, while others exist for many thousands
                                   of years. Currently, more than 50,000 tons of commercial spent fuel are
                                   stored at 72 sites at or near nuclear power plants in 33 states. Most of this
                                   nuclear fuel is stored immersed in pools of water designed to cool the fuel,
                                   but some sites also keep older, cooler fuel in “dry storage” units that
                                   generally consist of steel containers placed inside reinforced concrete
                                   vaults or bunkers. Concerns about the security of these sites and their
                                   spent fuel inventories have been raised following the terrorist attacks of
                                   September 11, 2001.

                                   To provide secure, permanent disposal for spent fuel, the President
                                   and the Congress have approved development of a deep underground
                                   repository at Yucca Mountain, Nevada. The Department of Energy (DOE)
                                   is to construct and operate the repository after receiving a license from the
                                   Nuclear Regulatory Commission (NRC). Shipping this fuel from current
                                   storage locations to Yucca Mountain will be managed by DOE, which in
                                   1983 entered into contracts with owners of spent fuel (essentially owners
                                   and operators of nuclear power plants) requiring DOE to take title to and
                                   dispose of this fuel. DOE estimates that 175 shipments per year over
                                   24 years will be required to move the accumulated inventory of spent
                                   nuclear fuel. These shipments have increased public concern about
                                   nuclear security. Recent media reports suggest that if terrorists could
                                   release spent fuel into the environment during transit or from wet or dry
                                   storage sites, particularly near large cities, the human health effects could
                                   be severe.



                                   Page 1                                            GAO-03-426 Spent Nuclear Fuel
                   We agreed with your office to (1) review federally sponsored studies that
                   examined the potential health effects of a terrorist attack or a severe
                   accident involving commercial spent nuclear fuel, either in transit or in
                   storage, and (2) identify options for DOE to enhance the security of
                   spent fuel as it develops its plans to ship the fuel to Yucca Mountain. In
                   conducting our review, we did not assess the reliability of data or the
                   methodologies used in the studies that examined potential health effects.
                   We also did not examine economic or broader environmental effects of
                   terrorist attacks or severe accidents, nor did we examine the effectiveness
                   of certain other safety and security measures, such as the effectiveness of
                   armed guards and intrusion barriers.


                   NRC and DOE studies indicate a low likelihood of widespread harm to
Results in Brief   human health from terrorist attacks or severe accidents involving spent
                   fuel—either in transit or dry or wet storage. Spent fuel is a heavy, ceramic
                   material that is neither explosive nor volatile and resists easy dispersal.
                   Tests to date on shipping containers and dry storage containers have
                   shown that, while they can be penetrated under terrorist and severe
                   accident scenarios, their construction allows little release of spent fuel,
                   with little harm to human health. While release of a large quantity of
                   radioactive material from a wet storage pool is theoretically possible,
                   such a release would require an extremely unlikely chain of events. For
                   example, coolant would have to be drained from pools and the fuel left
                   uncovered for a sustained period. Studies reveal that such an event would
                   be extremely unlikely to occur by accident. To supplement the existing
                   body of work on the safety and security of spent fuel, NRC has
                   commissioned additional studies to address technical uncertainties and
                   respond to heightened security concerns.

                   While NRC and DOE have found that spent fuel may be relatively safe and
                   secure, DOE could potentially enhance the security of this fuel through
                   options such as minimizing the overall number of shipments and picking
                   up fuel in an order that would reduce risk, such as moving older, less
                   dangerous fuel first. DOE’s ability to choose some of these options may be
                   limited by its contracts with the fuel owners. These contracts generally
                   require DOE to pick up increments of spent fuel based on the dates that
                   the owners removed these amounts of fuel from their nuclear power
                   reactors. Taken literally, the contracts would require DOE to pick up small
                   amounts of spent fuel at reactor sites scattered across the country. For
                   example, adhering to the shipping queue for the 12 largest nuclear power
                   utilities would result in roughly 576 shipments. In contrast, revising the
                   contracts to allow DOE to pick up larger quantities of fuel at each site


                   Page 2                                           GAO-03-426 Spent Nuclear Fuel
             could eliminate about 300 of the shipments. The order in which spent fuel
             is shipped could also affect safety and security because certain fuel poses
             more risks based on its age and location. For example, shipping the oldest
             fuel first could enhance security in transit because this fuel is relatively
             less radiologically dangerous. However, DOE cannot unilaterally mandate
             this approach because the contracts allow the fuel owners to decide, once
             their turn in the shipping queue arrives, which increments of fuel from
             which of their nuclear plants will actually be shipped. Under contracts,
             owners could decide, based on operational needs, to ship younger, more
             radioactive fuel out of wet storage pools first before shipping fuel from dry
             storage—this choice could allow a fuel owner to free up needed space in a
             storage pool. We are recommending that, as DOE develops its plans for
             transporting spent fuel to Yucca Mountain, it identify and assess potential
             options to enhance the safety and security of this fuel. Exercising any of
             these options may require renegotiating aspects of its shipping contracts
             with fuel owners if necessary.

             We provided a draft of this report to DOE and NRC for review and
             comment. These agencies generally concurred with the facts of the report.
             DOE noted that the information on transit was accurate and balanced, and
             concurred with our recommendation with one exception. DOE noted that
             the Department of Transportation is conducting a study of the safety and
             security implications of transporting spent fuel by railroad trains that
             haul only spent fuel. DOE explained that it would prefer to wait for the
             outcome of this evaluation rather than duplicate efforts. NRC noted that,
             overall, the report provides a reasonable characterization of the current
             understanding of risks associated with spent fuel storage. NRC raised
             concerns about our references to two NRC studies in our report. NRC
             expressed concern that we needed to further emphasize NRC’s use of
             conservative assumptions in these two reports, such as the assumption
             that a fire in a spent fuel pool would involve 100 percent of the spent fuel
             assemblies in a pool. We revised the report to account for these concerns
             and added preliminary results from NRC’s ongoing work involving risks
             associated with spent fuel pools.


             Fuel for nuclear power plants consists of fingernail-sized pellets of
Background   uranium dioxide, a radioactive compound. The pellets are fitted into
             hollow metal rods, typically constructed of zirconium alloy, and the rods
             are then gas pressurized. The rods are generally 12 to 14 feet in length and
             are bundled together into assemblies. A portion of the assemblies must be
             replaced every 1 to 2 years as the fuel in the reactor expends energy,
             becoming less efficient at producing heat. As part of the process of


             Page 3                                           GAO-03-426 Spent Nuclear Fuel
expending energy during a nuclear reaction, the fuel becomes highly
radioactive and thermally hot. Spent fuel emits radiation as a consequence
of radioactive decay. Barriers such as thick walls, sealed containers, and
water are used to shield individuals from exposure to this radiation.

NRC regulates not only the construction and operation of commercial
nuclear power plants but also the storage, transportation (together with
the Department of Transportation), and disposal of spent fuel. NRC
requires each operating nuclear power plant to have safety and security
programs. For example, NRC requires protective shielding and security
systems, including armed guards, at nuclear power plants. When spent
fuel assemblies are removed from a reactor, they are stored in large
pools of cooling water. These pools are constructed according to NRC’s
requirements, typically with 4- to 6-foot thick steel-lined concrete walls
and floors. Pools are typically 30 to 60 feet long, 20 to 40 feet wide, and
40 feet deep. The location of these pools is dependent on the type of
reactor. Essentially, all commercial power reactors in the United States
are one of two types, either a boiling water reactor or a pressurized water
reactor.1 For most boiling water reactors, the pools are located close to the
reactors, several stories above ground. For pressurized water reactors, the
pools are located in structures outside the reactor building, on the ground
or partially embedded in the ground. Regardless of reactor type, these
pools are required by NRC to be constructed to protect public health
against radiation exposure, even after a natural disaster, such as an
earthquake. The water in the pool is constantly cooled and circulated, and
the fuel assemblies are generally 20 feet below the surface of the water.




1
  A boiling water reactor uses slightly radioactive steam that is generated in the reactor to
drive a turbine that generates electricity. The water is returned to the reactor core where
it is reheated to steam, driving the turbines as the cycle is repeated. Pressurized reactors
send slightly radioactive pressurized water to a steam generator, which creates steam from
nonradioactive water kept separated by tubes. The steam drives the turbine and the slightly
radioactive water returns to the reactor where it is reheated and the cycle repeated.




Page 4                                                     GAO-03-426 Spent Nuclear Fuel
In 1982, through the Nuclear Waste Policy Act, the Congress directed DOE
to construct an underground repository for disposal of spent fuel and
other high-level radioactive waste.2 The Congress amended the act in 1987
and required DOE to only consider Yucca Mountain, Nevada, as a potential
site for a repository.3 In 2002, the President recommended to the Congress,
and the Congress approved, Yucca Mountain as a suitable site for the
development of a permanent high-level waste repository. As we reported
in 2001, for a variety of reasons, DOE is unlikely to open the repository as
planned in 2010.4

Lacking a long-term disposal option now, some nuclear utilities must
move a portion of their spent fuel into dry storage or face shutting down
their plants because their wet pools are reaching capacity. Currently, 25 of
the 72 storage sites use dry storage, and 11 other sites have plans to move
some of their inventory of spent fuel into dry storage. Dry storage facilities
for spent fuel typically consist of steel containers that are placed inside
concrete vaults or bunkers where the fuel is cooled by air rather than
water. These storage systems are required by NRC to be capable of
protecting against radiation exposure and of surviving natural disasters.
Because the move to dry storage is time-consuming and expensive,
utilities are, wherever possible, modifying wet pool storage capacity so
they can store larger quantities of spent fuel in these pools.




2
 This other waste is the result of nuclear activities from DOE—90 percent of the volume of
waste expected to be shipped to the Yucca Mountain repository is expected to be spent
fuel and the other 10 percent is expected to be DOE waste.
3
  Yucca Mountain, Nevada, is located approximately 100 miles northwest of Las Vegas,
Nevada.
4
 U.S. General Accounting Office, Nuclear Waste: Technical, Schedule, and Cost
Uncertainties of the Yucca Mountain Repository Project, GAO-02-191 (Washington, D.C.,
Dec. 21, 2001).




Page 5                                                   GAO-03-426 Spent Nuclear Fuel
Figure 1: Locations for Wet and Dry Storage Sites for Commercial Spent Nuclear Fuel and Yucca Mountain, as of April 2003




                                        Page 6                                               GAO-03-426 Spent Nuclear Fuel
To expose a large number of people to the harmful effects of radiation
from spent fuel, the fuel would have to be released from its protective
containers and dispersed over a wide or densely populated area. However,
unlike many other hazardous materials, spent fuel is a hard, heavy ceramic
material that is neither explosive nor volatile.5 To achieve a wide dispersal,
some portion of the spent fuel assemblies would have to be pulverized into
small particles by an external force—such as a high-speed impact or a
violent explosion—or some portion of the spent fuel assemblies would
have to burn in a sustained, high-temperature fire. According to NRC,
the redundancy and robustness of the designs of the fuel containers
make wide dispersal highly unlikely. In the event of a dispersal, the most
significant health effects would involve persons who inhaled very small
(respirable) particles—10 microns or less in diameter.6 Such particles
would be absorbed into the body and possibly remain there for
many years. In addition, these particles could be deposited on buildings
and the ground where, in the absence of a costly cleanup effort, they could
expose people to elevated levels of radiation.

The transportation of spent fuel to Yucca Mountain—most likely by both
truck and rail, but with a preference for using mostly rail—will be a major
undertaking, spanning 20 to 30 years.7 According to DOE, more than
50,000 tons of the spent fuel have accumulated at 72 sites in 33 states,
many located near urban areas in the Midwest and the East. DOE has
estimated that the accumulated inventory will have grown to 69,000 tons
by 2010 and that moving this volume could require approximately
175 shipments per year over 24 years, relying on a combination of truck
and rail shipments.

For the transportation of spent fuel, NRC has certification and inspection
requirements for shipping containers to ensure that the containers protect


5
  Spent fuel rods recently discharged from a reactor also contain some radioactive gases
that are a by-product of the nuclear fission process—these gases account for a small
fraction of the total quantity of radioactive material in spent fuel rods, but because of the
short half lives of the material, the gases decay quickly and may not be present in older
spent fuel.
6
 A micron is one millionth of a meter in length—by comparison, one micron is about
1/70 the thickness of a human hair.
7
  At the present time, there is no direct rail service to Yucca Mountain and the closest rail
line is 100 miles away. Until a branch rail line is established, intermodal transfer stations
with interim storage may need to be established to transfer shipping containers from rail to
truck for the final trip to Yucca Mountain.




Page 7                                                       GAO-03-426 Spent Nuclear Fuel
                         against radioactive releases under accident scenarios. NRC has certified
                         a number of shipping container designs for use on trucks and rail. The
                         Nuclear Waste Policy Act of 1982, as amended, requires DOE to ship
                         spent nuclear fuel and high-level radioactive waste to Yucca Mountain
                         in containers that have been certified by NRC. The act also requires DOE
                         to notify NRC in advance of spent fuel and high-level radioactive
                         waste shipments.

                         In addition to NRC, the Department of Transportation plays a role in
                         regulating the transportation of spent fuel and other high-level waste. The
                         department’s Research and Special Programs Administration sets certain
                         safety standards for the transportation of hazardous materials, including
                         spent fuel. These standards include, among other things, documentation
                         and labeling of containers, including placards identifying the shipment,
                         and requirements for separating certain radioactive materials while in
                         transit. The Federal Motor Carrier Safety Administration oversees the
                         safety of shipments by highway, and the Federal Railroad Administration
                         oversees the safety of shipments by rail. The U.S. Coast Guard oversees
                         the safety of shipments that may be made by barge.


                         Studies conducted by NRC and DOE have consistently found that the
Likelihood of            likelihood of widespread harm to human health from a terrorist attack or
Widespread Harm          a severe accident involving spent fuel is very low. None of the studies
                         involving the transportation of spent fuel or dry storage of spent fuel
from Terrorist Attacks   identified a scenario resulting in widespread harm—largely because of
or Severe Accidents      the protective containers required by NRC. For example, these studies
                         repeatedly found that transportation containers would be very difficult to
Involving Spent Fuel     penetrate, and in the worst-case scenarios where they may be penetrated,
Is Low                   only a small fraction of the material would be released. Some studies
                         involving spent fuel stored in pools of water found that widespread harm
                         is possible under severe but unlikely accident conditions. Such conditions
                         may include a catastrophic earthquake or a severe but unlikely accident
                         that could uncover the fuel for several hours, possibly allowing it to
                         spontaneously ignite and scatter radioactive material over a wide area.
                         To respond to increased security concerns stemming from the
                         September 11, 2001, terrorist attacks, NRC is further studying the safety
                         and security of spent fuel in transit and in wet or dry storage, including
                         the potential effects of more extreme attack scenarios such as deliberate
                         aircraft crashes.




                         Page 8                                          GAO-03-426 Spent Nuclear Fuel
Shipping Containers   Since the late 1970s, federal studies have examined the effects of both
Protect against       terrorist acts of sabotage and severe accidents involving shipping
Widespread Release    containers for spent fuel. Sabotage studies have sought to determine
                      whether radioactive material could be released from shipping containers
of Fuel in Transit    in specific sabotage scenarios, while accident studies have assessed
                      whether radioactive material could be released in a variety of accidents,
                      and the overall probability of their occurrence. Some of these studies were
                      commissioned by NRC, and others by DOE, and many of them were
                      conducted through DOE’s Sandia National Laboratory and other DOE
                      laboratories. These studies collectively indicate that the construction of
                      the shipping containers helps to limit releases.8 Although NRC is confident
                      in these results, it is sponsoring assessments to further validate computer
                      models and address heightened security concerns.

Sabotage Studies      The most recent sabotage study—conducted by DOE’s Sandia National
                      Laboratory for DOE in 1999—estimated the amounts and characteristics of
                      releases of radioactive materials from truck and rail spent fuel containers
                      subjected to two different types of weapons.9 The results of this study
                      confirmed the findings of earlier studies that armor-piercing weapons
                      could penetrate shipping containers and release small quantities of
                      radioactive material. The study found that, under a worst-case scenario,
                      the weapon could penetrate a shipping container and release a small
                      amount of material—equal to about 0.016 of 1 percent of the spent fuel in
                      the container—as small, respirable particles. These small, respirable
                      particles could become airborne and spread beyond the immediate vicinity
                      of the attack.10

                      A subsequent DOE-sponsored report used the results of the 1999 Sandia
                      National Laboratory study to estimate the human health impact of the




                      8
                       See appendix I for a more detailed description of the NRC-certified spent fuel shipping
                      containers.
                      9
                       Sandia National Laboratory, Projected Source Terms for Potential Sabotage Events
                      Related to Spent Fuel Shipments, SAND 99-0963, a report prepared at the request of the
                      Department of Energy, Albuquerque, N.Mex., June 1999.
                      10
                        Rather than focus on the entire amount of material released, this and other studies
                      focused on the amount of respirable particles—these particles can potentially become
                      airborne, transported to densely populated areas, and inhaled. By comparison, the
                      nonrespirable material would be a more localized problem that could be more easily
                      contained and controlled.




                      Page 9                                                    GAO-03-426 Spent Nuclear Fuel
                   most severe release.11 Using a computer-based analytic model and
                   conservative assumptions, DOE’s contractor found that the predicted
                   release from a truck container would cause about 48 cancer deaths over
                   the long term and that a predicted release from a rail container would
                   cause about 9 cancer deaths over the long term.12 DOE’s contractor’s
                   analysis explained that these cancer deaths should be considered against
                   a backdrop of an expected 1.1 million cancer deaths among the same
                   population expected from other causes. This analysis assumed that the
                   release would occur in an urban area with a population projected to the
                   year 2035 under stable weather conditions. The analysis also assumed that
                   the spent fuel release would contain twice the radioactive content of a
                   typical spent fuel shipment and that there would be no evacuation or
                   cleanup of the affected area for 1 year after the incident.13

                   These studies are the most recent in a series of studies dating back to
                   the 1970s. According to NRC and DOE officials, confidence in the results
                   of these studies has increased significantly as better data and more
                   sophisticated analytic techniques have been used. Appendix II contains a
                   fuller description of the methodology of these recent studies and the
                   results of previous studies.

Accident Studies   Since the 1970s NRC has also sponsored a series of studies examining
                   the risk that spent fuel could be released during transportation accidents.
                   NRC’s most recent assessment of spent fuel transportation accident risks
                   was conducted for NRC by Sandia National Laboratory and was published
                   in 2000.14 The 2000 Sandia National Laboratory study, like preceding
                   accident studies, found that an accidental release of spent fuel in transit
                   is very unlikely and that significant human health impacts are even less
                   likely. The study estimated that in over 99.9 percent of all truck and rail



                   11
                    Jason Technologies Corporation, Transportation Health and Safety
                   Calculation/Analysis Documentation in Support of the Final EIS for the Yucca Mountain
                   Repository, a report prepared at the request of the Department of Energy, Las Vegas, Nev.,
                   December 2001.
                   12
                     The respirable particles include solid particles of spent fuel, radioactive gases released
                   from the fuel rods, and particles of radioactive deposits that accumulate on the exterior of
                   the fuel assemblies.
                   13
                     Appendix II contains a summary of the methodology of both the 1999 Sandia National
                   Laboratory study and the subsequent DOE analysis.
                   14
                    U.S. Nuclear Regulatory Commission, Reexamination of Spent Fuel Shipment Risk
                   Estimates, NUREG/CR-6672, Washington, D.C., March 2000.




                   Page 10                                                    GAO-03-426 Spent Nuclear Fuel
accidents, the shipping container would experience no significant damage,
and no radioactive material would be released. In fact, the analysis found
that only 7 in 100,000 (0.007 of 1 percent) truck accidents and 4 in 100,000
(0.004 of 1 percent) rail accidents would involve spent fuel casks in
impacts or fires that might cause a release of radioactive material. While
this study did not project the human health impacts of particular accident
scenarios, it concluded that the overall risk of human exposure to
accidental releases of spent fuel was far less than that estimated in the
1977 study, which confirmed that NRC’s safety and security regulations
then in place were adequate.

A subsequent DOE-sponsored study used the results of the 2000 Sandia
National Laboratory study to determine the potential health effects of the
estimated quantity of material released.15 DOE’s contractor used the
estimated amount of material released in what DOE determined as the
most severe reasonably foreseeable accident to estimate the number of
latent cancer fatalities that could result from severe accidents while
shipping spent fuel to the Yucca Mountain repository.16 From this study,
DOE concluded that this type of accident—having a probability of
occurring about 2.8 times in 10 million accidents per year—could cause
about 5 long-term latent cancer fatalities—far less than its estimate of
48 latent cancer deaths in the event of a successful sabotage attack with
armor-piercing weaponry. Apart from this type accident, DOE found that
the probability of any deaths due to an accidental release of radiation was
quite small. DOE’s final environmental impact statement for Yucca
Mountain projected that accidents over 24 years of shipping would cause
fewer than 0.001 latent cancer fatalities. In contrast, DOE projected that
these same shipments had a much greater probability of resulting in
deaths due to normal traffic accidents—between 2.3 and 4.9 traffic
fatalities over the same 24-year period.

As with the sabotage studies, these studies of accident scenarios are the
most recent in a series of studies dating back to the 1970s. According to
NRC and DOE officials, confidence in the results of these studies has



15
 Jason Technologies Corporation, Transportation Health and Safety
Calculation/Analysis Documentation in Support of the Final EIS for the Yucca Mountain
Repository, a report prepared at the request of the Department of Energy, Las Vegas, Nev.,
December 2001.
16
  According to DOE, this accident involved a high-temperature, long duration fire that fully
engulfed a rail container.




Page 11                                                    GAO-03-426 Spent Nuclear Fuel
                      increased significantly as better data and more sophisticated analytic
                      techniques have been used. Appendix II contains a fuller description of the
                      methodology of these recent studies and the results of previous studies.

Ongoing and Planned   Although NRC believes that the results of the federally sponsored studies
Assessments           are valid, it has several evaluations ongoing and planned to further assess
                      its security and safety measures. To assess its existing security measures
                      following the September 11, 2001, terrorist attacks, NRC initiated a
                      commissionwide review. As part of this review, NRC commissioned
                      Sandia National Laboratory to examine more severe terrorist attack
                      scenarios involving spent fuel shipping containers. For example, the
                      laboratory will assess the effects of (1) a 20-passenger aircraft loaded with
                      explosives crashing into shipping containers and (2) a sustained attack on
                      these containers using a variety of weapons in combination.

                      As part of an ongoing process to assess its safety measures, NRC has a
                      number of ongoing and planned studies. NRC commissioned Sandia
                      National Laboratory for further validation of computer models used to
                      evaluate the safety of shipping containers. To solicit comments on the
                      scope of its evaluation, NRC held a series of public meetings beginning in
                      1999. It considered comments obtained during these meetings and issued
                      an interim report in 2002 that recommended several additional studies.17
                      Although these studies are still being designed, their preliminary
                      objectives include (1) validating past computer-based predictions of
                      damage to containers resulting from collisions, (2) validating past
                      computer-based predictions of how well containers withstand fires, and
                      (3) identifying the response of fuel pellets, fuel rods, and fuel assemblies in
                      severe impacts. In contrast to past analyses of severe accident scenarios,
                      the studies are to include physical tests of full-scale current model
                      shipping containers. The results of these physical tests will be compared
                      to the predictions of past computer-based analyses and serve to either
                      validate or to correct those results. The studies are also to address some of
                      the technical issues that were not adequately addressed by past accident
                      analyses. For example, while past studies relied on expert judgment to
                      assess the complex chain of variables involved in releasing respirable
                      spent fuel from containers—including fracturing spent fuel rods and
                      pellets—the planned studies will examine these events experimentally.



                      17
                        Sandia National Laboratory, Spent Nuclear Fuel Transportation Package Performance
                      Study Issues Report, NUREG/CR-6768, a report prepared for the Nuclear Regulatory
                      Commission, June 2002.




                      Page 12                                               GAO-03-426 Spent Nuclear Fuel
                            According to NRC officials, the studies are expected to be completed
                            by 2006.


Widespread Release from     NRC studies have reported that a risk of widespread harm to human
Wet Storage Theoretically   health from spent fuel arises from the remote possibility of a sustained
Possible but Unlikely       loss of coolant in a spent fuel pool. Such a loss could potentially lead to a
                            fire that would disperse radioactive material across a wide area. NRC’s
                            most recent published study of this risk, released in 2001, found that,
                            though the potential consequences of such a fire could be severe—nearly
                            200 early fatalities and thousands of latent cancer fatalities—the likelihood
                            of such a fire is low.18 The study estimated that a catastrophic earthquake
                            or a severe but unlikely accident, such as dropping a 100- to 150-ton
                            storage container into the pool, could precipitate a pool fire.

                            The study was conducted to assess the risks associated with accidents
                            at nuclear reactors that have been permanently shut down. According to
                            NRC, once the fuel is removed from the reactors, there is a risk associated
                            with the fuel stored in pools. NRC designed the study with conservative
                            assumptions to identify the most severe possible impact on public health.
                            The study assessed a variety of natural disasters and accidents that could
                            drain coolant and cause a fire. These events included loss of electrical
                            power, which would shut down the pool cooling system; an event that
                            would significantly damage the pool cooling system; a drop of a heavy
                            load, which could damage the pool wall or floor; a severe earthquake;
                            and an accidental aircraft crash. The study found that a catastrophic
                            earthquake and a heavy load drop were the events most likely to
                            significantly damage the pool, leading to sustained loss of coolant and
                            potentially causing a fire.

                            The study then calculated the amount of radioactive material that might
                            be released by a fire and the possible human health effects stemming from
                            exposure to this material. In making these calculations, the study made
                            various conservative assumptions to ensure that NRC identified the most
                            severe consequences possible. For example, the study assumed that a pool
                            fire would involve 100 percent of the spent fuel assemblies in the pool,
                            releasing large amounts of radioactive material into the atmosphere.



                            18
                              U.S. Nuclear Regulatory Commission, Technical Study of Spent Fuel Pool Accident
                            Risk at Decommissioning Nuclear Power Plants, NUREG-1738, Washington, D.C.,
                            February 2001.




                            Page 13                                                GAO-03-426 Spent Nuclear Fuel
                                           Two of the authors of the study noted that it was not certain how many
                                           spent fuel assemblies would actually burn in a fire. The uncertainty in
                                           the amount of radioactive material released depends on the fuel age and
                                           distribution in the pool and the characteristics of the accident scenario.
                                           The authors noted that some spent fuel assemblies might not reach the
                                           high temperatures required to burn and that some of the radioactive
                                           material might remain trapped in the pool or building. Because spent fuel
                                           decays and thus becomes less dangerous over time, the study evaluated
                                           scenarios in which the reactor had been shut down for 30 days, 90 days,
                                           1 year, 2 years, 5 years, and 10 years. For each scenario, the study
                                           evaluated two levels of radioactivity released from the fuel. NRC used the
                                           results of this study to calculate the potential health effects of a fire in a
                                           spent fuel pool. These results are shown in table 1.

Table 1: Potential Health Effects of Fire in a Spent Fuel Pool
                                                                    a                                                                 a
                                   Lower level of radioactivity                                   Higher level of radioactivity
 Time after                      Number of early        Number of latent                        Number of early         Number of latent
 shutdown of reactor                  fatalities         cancer fatalities                            fatalities         cancer fatalities
 30 days                                       2                    3,500                                   200                   15,000
                                                                          b                                                              b
 1 year                                        1                                                              80
                                                                          b                                                              b
 5 years                                       0                                                               1
                                                                          b
 10 years                                      0                                                               0                    7,500
Source: NRC.
                                           a
                                            NRC assumed a low level and a high level of ruthenium in the dispersed spent fuel. Ruthenium,
                                           found in higher levels in recently discharged fuel, is a particularly lethal isotope when dispersed in
                                           small particles.
                                           b
                                            Information not available.


                                           The study noted that the results are based on a natural disaster or an
                                           accident severe enough to lead to a pool fire and that the risk of such an
                                           event occurring is very low. NRC also noted that part of the reason for
                                           the low probability is NRC’s defense-in-depth policy, which states that
                                           NRC establishes requirements to ensure that safety will not be wholly
                                           dependent on any single system. Instead, NRC’s requirements ensure
                                           multiple or redundant safety systems. In the case of the storage pool
                                           studied in the 2001 report, NRC noted that several factors combine to
                                           make a pool fire unlikely, including the robust design of the pool; the
                                           simple nature of the pool support systems; and the long time required to
                                           heat up the fuel, which allows time for operators to respond.19 For


                                           19
                                                See appendix I for a description of the NRC-certified wet storage pools.




                                           Page 14                                                            GAO-03-426 Spent Nuclear Fuel
                              example, according to the 2001 report, heating the least-decayed spent fuel
                              to the ignition point—were it to occur at all—would take hours, perhaps
                              even days. Thus, NRC officials explained that even if a massive loss of
                              coolant occurred, plant operators might still have time to react, depending
                              on the extent of the damage. NRC requires that nuclear power plants have
                              a backup water supply that can cool fuel in case of an accident, so,
                              depending on the extent of damage, plant operators might be able to keep
                              the fuel submerged.

                              The risk of a pool fire is also limited by the ability of some of the fuel to
                              be cooled by simple air ventilation if the coolant drains out. According to
                              NRC, completely draining a pool may allow enough air ventilation among
                              the stored fuel assemblies so that the spent fuel would stay below the
                              ignition point of a self-sustaining fire (about 1,650 degrees Fahrenheit).
                              Furthermore, even if a fire did begin in one assembly, there is considerable
                              uncertainty about whether the fire would spread to other assemblies. A
                              1987 study of spent fuel pools found that spent fuel in pools with fewer
                              assemblies, after being cooled for just a few weeks, would not ignite if
                              subjected to loss of coolant.20 Under the dense storage conditions
                              characterized by most spent fuel pools today, however, air ventilation
                              becomes less effective.

NRC Continues to Study the    To begin addressing some of the uncertainties regarding the risks of
Risks of Storing Spent Fuel   storing spent fuel in wet storage pools, NRC has some ongoing work, and
in Pools                      recently completed some initial evaluations of sabotage attacks on these
                              pools, and has more work planned and ongoing at two DOE national
                              laboratories. Following the terrorist attacks of September 11, 2001, NRC
                              commissioned the U.S. Army Corps of Engineers to examine potential
                              effects of sabotage directed at spent fuel pools. The Corps conducted
                              several computer-based analyses of the potential effects of armor-piercing
                              weapons and high explosives on typical spent fuel pools. The analyses
                              found that the penetration of armor-piercing weapons and high explosives
                              could vary considerably, depending, among other things, on the size of the
                              weapon or explosive and the sophistication of the attacker.

                              NRC is also conducting studies with less conservative assumptions to
                              more realistically evaluate the risks of spent fuel in a drained pool. NRC



                              20
                                Brookhaven National Laboratory, Severe Accidents in Spent Fuel Pools in Support
                              of Generic Safety Issue 82, NUREG/CR-4982, a report prepared for the U.S. Nuclear
                              Regulatory Commission, July 1987.




                              Page 15                                                GAO-03-426 Spent Nuclear Fuel
                         has contracted with Argonne National Laboratory to study the conditions
                         necessary to ignite a pool fire. NRC has also contracted with Sandia
                         National Laboratory for a series of studies to define potential threats, and
                         to identify potential vulnerabilities, regulatory improvements or legislative
                         initiatives to improve security and safety and better protect public health.
                         The studies by Sandia National Laboratory include a review of a variety of
                         terrorist scenarios, including attacks on fuel pools with aircraft and high
                         explosives. According to NRC, preliminary results of these studies indicate
                         that spent fuel may be more easily cooled than has been predicted in some
                         past studies and that off-site radiological releases may be substantially
                         reduced from previous worst-case estimates. Predicted public health
                         effects might also be substantially reduced for the worst scenarios where
                         coolant is lost and recovery actions are not successful in cooling the fuel.


Dry Storage Containers   Dry storage containers, like shipping containers, pose a considerable
Safeguard against        barrier to releasing spent fuel. Used to store spent fuel when it is removed
Widespread Release       from wet storage, dry storage containers are constructed of layers of steel
                         and radiation barriers such as concrete.21 In establishing regulations for
                         dry storage of spent fuel, NRC stated in 1998 that dry storage containers
                         are structurally similar to shipping containers and that the results of
                         sabotage studies on shipping containers could reasonably be applied to
                         dry storage containers. Nevertheless, NRC is continuing to study potential
                         risks of releases from dry storage containers.

                         Studies by DOE and the Corps on dry storage containers have generally
                         reached the same conclusion—that the thick walls of the containers,
                         consisting of an inner steel container and an outer steel or concrete
                         container, could not be penetrated by airplane crashes and would result in
                         no significant release of radiation when attacked with advanced weapons.
                         Two DOE-sponsored reports, released in 1998 and 2001, found that
                         airplane crashes would not penetrate dry storage containers.22 The reports
                         focused on the most penetrating components of the commercial jet
                         aircraft: the engines and landing gear. Both reports concluded that



                         21
                              See appendix I for a description of the of the NRC-certified dry storage containers.
                         22
                           Jason Technologies Corporation and Pacific Northwest National Laboratory, Accident
                         Analysis for Continued Storage, a report prepared for the U.S. Department of Energy,
                         October 27, 1998. Jason Technologies Corporation, An Evaluation of the Consequences of
                         a Commercial Aircraft Crash into the Yucca Mountain Repository, a report prepared for
                         the U.S. Department of Energy, December 2001.




                         Page 16                                                       GAO-03-426 Spent Nuclear Fuel
                               although airplane crashes could damage the containers, no radioactive
                               material would be released. The analysis showed that the containers
                               would break up the airplane, spreading jet fuel over a wide area,
                               causing the jet fuel to dissipate or burn without affecting the spent fuel
                               in the containers.

                               Two other studies, performed in 2001 by the Corps, found that the
                               containers would not release significant amounts of radioactive
                               material when attacked by armor-piercing weapons or high explosives.
                               The study examining the effect of armor-piercing weapons found that the
                               penetration to the containers was very limited. NRC and DOE officials and
                               independent experts told us that, based on a previous analysis and similar
                               studies involving shipping containers, the weapons would not likely cause
                               a significant release. The study examining the effects of high explosives
                               found that the explosives would not completely penetrate the container.
                               The study showed extensive exterior damage, but no penetration to the
                               spent fuel.

NRC Continues to Study Risks   NRC is continuing to study potential risks to dry storage. NRC has
to Dry Storage Containers      contracted with Sandia National Laboratory to assess the vulnerability of
                               dry storage containers to terrorist attacks, including a further analysis
                               of aircraft crashes and the effects of high explosives. In addition, the
                               laboratory will investigate measures to mitigate any vulnerability identified
                               through the assessment.


                               As DOE develops its plans for shipping spent fuel to the Yucca Mountain
Options May Exist to           repository, the agency has several potential options for enhancing the
Further Enhance                security of spent fuel during the Yucca Mountain shipping campaign.
                               Specifically, DOE could potentially minimize its total number of spent
Security and Safety            fuel shipments, ship the fuel in an order that reduces risk, or transport the
                               fuel on railroad trains dedicated exclusively to hauling spent fuel. Not all
                               of these options may be feasible under the terms of DOE’s contracts with
                               spent fuel owners, and some options for shipping in a particular order
                               would conflict with one another.

Minimizing Number of           DOE could enhance the overall security of spent fuel by minimizing the
Shipments                      total number of shipments. Fewer shipments would present fewer
                               potential targets for terrorists and could also enhance safety because there
                               would be fewer chances for an accident. Representatives of the nuclear
                               power industry and nuclear safety experts that we contacted agreed on
                               these points. For example, a representative of a consortium of nuclear
                               utilities told us that shipping spent fuel by rail is preferable to shipment


                               Page 17                                          GAO-03-426 Spent Nuclear Fuel
by truck because spent fuel containers designed for rail can carry about
5 times more spent fuel than truck containers. This larger capacity
translates to fewer shipments overall. Similarly, a frequent critic of the
safety of spent fuel shipments agreed that fewer shipments would be
better, noting that fewer, large shipments are easier to protect and track.
Beyond expressing a preference for shipping spent fuel to Yucca Mountain
mostly by rail, DOE has not yet developed its plans to implement the
shipping campaign.

In addition to providing security advantages, minimizing the number
of shipments by using rail provides safety and efficiency benefits.
According to a 1998 Department of Transportation report, rail was the
safer mode for shipping large amounts of spent fuel.23 The report states
that minimizing trips usually reduces total risk by reducing risks
associated with routine radiation exposure—such as the incidental
exposure experienced by transportation and plant workers while shipping
containers are being prepared—as well as accident-related exposure and
other nonradiation accident consequences.

DOE’s ability to minimize the total number of shipments may be limited
by its contracts with owners of spent fuel. Under the contracts, DOE is to
establish a shipping queue, in which each utility has shipping rights based
on the date and quantity of fuel removed from a reactor. In many cases,
the places in the queue correspond to quantities of spent fuel that would
fill less than three large rail containers—an amount that, according to the
Association of American Railroads, would be a reasonable size for a
single rail shipment. If strictly followed, the queue could result in many
more shipments than necessary. For example, the 12 spent fuel owners
with the largest quantities of spent fuel would make approximately
576 shipments based on the shipping queue.24 On the other hand, if these
12 owners consolidated all their shipments into rail containers and used
3 containers per shipment, they could reduce their total shipments to 479,
a 17 percent reduction. If these same owners consolidated shipments
into 5 rail containers per shipment, which according to DOE is another



23
  Identification of Factors for Selecting Modes and Routes for Shipping High-Level
Radioactive Waste and Spent Nuclear Fuel, U.S. Department of Transportation, Research
and Special Programs Administration, April 1998.
24
  These figures are based on our analysis of DOE’s 1995 Acceptance Priority Ranking
(U.S. DOE Office of Civilian Radioactive Waste Management), the most recent version
published.




Page 18                                                 GAO-03-426 Spent Nuclear Fuel
                              possible option, total shipments could be reduced to 287—a nearly
                              50 percent reduction.


Order in Which Spent          DOE could also enhance security by shipping spent fuel in an order
Fuel Is Shipped Could         that minimizes risk. There are at least three shipping orders that would
Enhance Security              potentially reduce risk: (1) shipping fuel from shutdown nuclear reactors
                              first, reducing the number of sites storing spent fuel; (2) shipping the
                              oldest and least radiologically dangerous fuel first to reduce transportation
                              risk; or (3) shipping fuel from storage pools first, reducing the likelihood
                              of a pool fire. Shipping fuel first from shutdown nuclear reactors would be
                              permissible under DOE’s contracts with fuel owners, but the contracts
                              might preclude the other two options. Further, to some extent, these
                              options conflict with one another. For example, an emphasis on shipping
                              fuel from spent fuel pools first could leave some older fuel in dry storage
                              at current storage facilities. Data are not available to determine which
                              order would provide the greatest risk reduction.

Shipping Fuel from Shutdown   DOE could potentially enhance the overall security of spent fuel by
Reactor Sites First           first shipping fuel currently stored at shutdown nuclear reactor sites.
                              Currently, about 4,100 tons of spent fuel—about 8 percent of the total
                              stored nationwide—are stored at 14 shutdown nuclear reactors.25 Because
                              nine of these sites will not be accumulating additional spent fuel, clearing
                              their spent fuel inventory would eliminate them as potential targets of a
                              terrorist attack.26

                              DOE recognized the potential importance of removing spent fuel from
                              shutdown reactors when it established its contracts for disposal of spent
                              fuel. Although the contracts establish a shipping queue, the contracts
                              allow DOE to override the queue to make an exception for spent fuel
                              from shutdown reactors. Specifically, the contracts provide that,
                              notwithstanding the age of spent fuel, priority may be accorded any spent
                              fuel removed from a civilian nuclear power reactor that has reached the
                              end of its useful life or has been shut down for whatever reason.




                              25
                                In addition to permanently shutdown reactor sites, a limited quantity of spent fuel is
                              stored at an independent storage facility in Morris, Illinois.
                              26
                                   Four of the shutdown reactors are co-located with operating reactors.




                              Page 19                                                     GAO-03-426 Spent Nuclear Fuel
Shipping Oldest Fuel First   DOE could lower the risk of transporting spent fuel by shipping the
                             oldest spent fuel first. Radioactivity emitted by some components of spent
                             fuel declines significantly over comparatively short periods of time.27 For
                                                                                                    60
                             example, one of the more radioactive elements in spent fuel—cobalt —
                             accounts for about 90 percent of the gamma radiation emitted by spent
                             fuel when it is first removed from the reactor.28 However, after about
                                              60
                             25 years, cobalt emits about 3 percent of the gamma radiation it did when
                                                                                                    137
                             first removed from the reactor. Similarly, the radioactivity of cesium , a
                             comparatively volatile element that would be a major component of any
                             accidental or deliberate release, declines by half after 30 years. Shipping
                             older spent fuel first could therefore be preferable in the event of a
                             deliberate or accidental release during transit. For example, a release of
                             spent fuel that is 25 or 30 years old would be a lesser—though still
                             significant—threat to public health than fuel that is only 5 or 10 years old.

                             Analyses performed for DOE’s environmental impact statement for the
                             Yucca Mountain repository illustrate the reduced impact that a release
                             of older spent fuel can have on public health. In the draft environmental
                             impact statement, DOE estimated that a particular release due to a
                             sabotage attack could result in about 16 latent cancer fatalities. This
                             scenario assumed that the shipped fuel was about 23 years old, which is
                             approximately the average age of the inventory of spent fuel. The final
                             environmental impact statement analyzed the same scenario, except that it
                             assumed that the shipped fuel was about 15 years old. This analysis found
                             that such a release would cause about 48 latent cancer deaths—3 times as
                             many as the older fuel. The age of the fuel was one of two major factors
                             that resulted in the higher estimate of latent cancer fatalities in the final
                             statement. DOE noted that the younger, more dangerous fuel, such as
                             spent fuel discharged 5 years or less from a reactor, makes up a small
                             percentage of the total inventory of spent fuel. As a result, the youngest,
                             hottest fuel would be less likely to be shipped or would represent a small
                             fraction of the fuel that is shipped.

                             In discussions on security and safety issues surrounding the proposed
                             shipment of fuel to Yucca Mountain, some state and industry
                             representatives that we contacted also acknowledged the benefits of


                             27
                               Some components of spent fuel remain deadly for thousands or millions of years. For
                                             235
                             example, uranium requires about 704 million years for its radiation output to be cut
                             in half.
                             28
                                  As mentioned previously, gamma radiation can damage critical organs of the body.




                             Page 20                                                    GAO-03-426 Spent Nuclear Fuel
                             shipping older spent fuel first. An analyst under contract with the state
                             of Nevada noted that shipping the oldest fuel first would be the most
                             important factor in protecting public health during transit. Not only would
                             older fuel have lower consequences if released in an accident or a terrorist
                             event, but it also would be safer for transportation workers—drivers and
                             handlers at intermodal transfer points—and the general public. A
                             representative of the National Research Council’s Board on Radioactive
                             Waste Management told us that shipping the oldest fuel first would help
                             minimize potential human health consequences in the event of a release
                             during transit. However, this representative said that if one assumes that
                             the robust shipping containers make a release unlikely, the potential risk
                             reduction associated with the age of the fuel becomes less important.

                             Regardless of the potential transportation-related security benefits, DOE’s
                             contracts with spent fuel owners limit its ability to ship the oldest fuel
                             first. In addition to establishing a shipping queue, the contracts allow each
                             fuel owner discretion to decide which of its spent fuel is actually delivered
                             to DOE, commensurate with the quantity of fuel associated with a
                             particular spot in the queue. For example, the Exelon company—the
                             nation’s largest nuclear power company—has a place in the queue for
                             about 35 tons of spent fuel removed from a reactor located at its plant in
                             Zion, Illinois. When the time comes to ship this fuel to the repository,
                             Exelon may deliver either this fuel or an equal quantity of fuel—possibly
                             much younger and more radioactive fuel—from any of its facilities located
                             at sites in Illinois and sites in Pennsylvania and New Jersey.

                             Because owners have discretion to choose which fuel they will actually
                             ship under the terms of the contract, DOE does not have the ability under
                             the contract to require that oldest fuel be shipped first. Fuel owners will
                             likely select spent fuel for shipment based on their operational needs. For
                             example, representatives of Progress Energy, a fuel owner with reactors in
                             the Southeast, said they would will likely ship from their pools first
                             because their pools are reaching capacity. Similarly, an Exelon official
                             said that shipping from pools first would minimize the need for dry
                             storage facilities.

Shipping Fuel from Densely   As discussed in the first section of this report, a fire in a wet storage pool,
Packed Pools First           while highly unlikely, is theoretically possible. Shipping spent fuel from
                             densely packed spent fuel pools first could have security benefits.
                             Because DOE has not yet opened a permanent repository, spent fuel has
                             accumulated in quantities that pools were not originally designed to
                             contain. NRC officials noted that while a few spent fuel pools have low
                             density in at least part of the pools, nearly all pools are densely packed.


                             Page 21                                            GAO-03-426 Spent Nuclear Fuel
                            These densely packed pools contain as much as 3.5 times more spent
                            fuel on average than the pools were originally designed to store. Reducing
                            the density of spent fuel in the pools would reduce the likelihood of a
                            fire. Recent NRC and independent studies show that lower-density
                            configurations allow for greater spacing between assemblies, which allows
                            air to more efficiently circulate in the event of coolant loss. According
                            to these reports, greater spacing could also help prevent a fire from
                            spreading among assemblies. Also, in the unlikely event of a fire, fewer
                            assemblies in the pool could result in reduced consequences.

                            As noted earlier, DOE’s contracts limit its ability to influence the order in
                            which spent fuel is shipped. Some owners may prefer to ship fuel from
                            densely packed pools first because when the pools reach full capacity, the
                            fuel must be removed or the plant must shut down. To the extent that, as
                            Exelon and Progress Energy officials stated, utilities are likely to ship from
                            their wet pools first, the threat would be reduced earliest at these pools.
                            This would, however, result in a relatively higher threat during transport
                            from relatively younger, more radioactive, spent fuel. It is not clear
                            whether this will be a common preference.


Shipping Fuel on Trains     According to some analysts, DOE could enhance the security of spent
That Haul Only Spent Fuel   fuel shipments by using trains dedicated to carrying only spent fuel.
                            Such trains would typically consist of three to five rail cars, carrying one
                            container of spent fuel per car. A truck shipment can carry 1 to 2 tons of
                            spent fuel. In contrast, depending on the containers used, a 3-car train can
                            carry from 50 to 65 tons of spent fuel and a 5-car train can carry from
                            about 80 to 110 tons of spent fuel. Although dedicated trains could
                            enhance the security and safety of spent fuel shipments, these benefits
                            would have to be weighed against potential drawbacks. The benefits
                            would also have to be weighed against constructing a rail line to Yucca
                            Mountain. Currently, no rail line extends to Yucca Mountain.

                            Advocates of dedicated trains told us that such trains offer two primary
                            security and safety advantages. First, the use of dedicated trains would
                            significantly reduce the exposure of spent fuel shipments to a terrorist
                            attack by significantly shortening the trip duration from its point of origin
                            to the repository. A representative of the Association of American
                            Railroads, which recommended that DOE use dedicated trains for the
                            shipment of spent fuel, explained that a spent fuel shipment from the East
                            Coast to Nevada would take about 3 to 4 days by dedicated rail, while the
                            same trip by regular rail would take about 8 to 10 days. Specifically, spent
                            fuel transported by regular rail would spend significant amounts of time in


                            Page 22                                          GAO-03-426 Spent Nuclear Fuel
rail yards where trains are broken up and reconfigured. While in the rail
yards, spent fuel containers could be stationary targets.

Second, using dedicated trains would ensure that spent fuel was not
shipped with flammable hazardous materials. If spent fuel were released
from its containers in an accident or a terrorist attack, a fire fueled by
flammable materials could spread radioactive material over a wide area.
For example, NRC recently issued an analysis regarding a rail tunnel
fire that occurred in Baltimore in July 2001 that involved more than
28,000 gallons of a flammable solvent. NRC estimated that temperatures as
high as 1,800 degrees Fahrenheit were reached at certain locations in the
tunnel during the course of the fire but found that temperatures averaged
900 degrees in other parts of the fire. NRC studied the potential effects of
this fire on a spent fuel transportation container carrying spent fuel and
concluded that, when subjected to similar fire conditions, the container
would not release radioactive material.29

According to transportation officials we spoke to, dedicated trains can
also have safety and other benefits beyond sabotage prevention. For
example, officials of the Union Pacific Railroad and the Association of
American Railroads said that combining cars carrying fully loaded spent
fuel containers on trains with those carrying other cargo raises operational
and safety issues. Rail cars carrying spent fuel rail containers are
extraordinarily heavy—such a car weighs about 470,000 pounds compared
to about 200,000 pounds for a standard loaded rail car. This weight
differential introduces difficulties in the physical dynamics of a train
carrying spent fuel and other cargo, making derailments more likely.

On the other hand, it is not clear that the advantages of dedicated trains
outweigh the additional costs. In 1980, while considering amendments to
its security regulations, NRC examined the case for requiring dedicated
trains for rail shipments of spent fuel. NRC noted the advantages of
dedicated trains but also noted that dedicated trains are no more capable
of avoiding high-population areas than are regular trains, that a regular
train in a rail yard would be under surveillance by escorts and railroad
police, and that the necessary physical protection measures can be as
easily implemented on regular trains as on dedicated trains. For these and
other considerations, NRC declined to require dedicated trains. Further,



29
 Evaluation of the Effects of the Baltimore Tunnel Fire on Rail Transportation of
Nuclear Fuel. Nuclear Regulatory Commission, January 6, 2003.




Page 23                                                 GAO-03-426 Spent Nuclear Fuel
                      although DOE recognized the possible advantages of shipping spent
                      nuclear fuel by dedicated trains, DOE also concluded in its final
                      environmental impact statement that available information does not
                      indicate a clear advantage for the use of either dedicated trains or general
                      freight service.


                      The events of September 11, 2001, elevated lingering public concerns
Conclusions           about the security of spent fuel, and in particular the security and safety
                      of large-scale shipping of spent fuel. NRC and DOE studies show a low
                      likelihood of widespread harm to human health from terrorist attacks or
                      severe accidents involving spent fuel. Nonetheless, DOE could potentially
                      take a number of measures to further enhance the security and safety of
                      the shipping campaign to Yucca Mountain. It is not clear whether the
                      additional security and safety benefits such measures offer are worth
                      the additional costs and effort—possibly including a renegotiation of
                      contracts that DOE has established with the nation’s utilities—that they
                      would entail. In addition, it is not clear which of these measures—some of
                      which conflict with each other—would provide the greatest safety and
                      security benefit. However, we believe they should be explored.


                      To ensure that all reasonable options to further enhance the security and
Recommendations for   safety of spent fuel in storage at nuclear power plants and in transit are
Executive Action      explored, we recommend that the Secretary of Energy assess the potential
                      benefits and costs of (1) minimizing the total number of shipments of
                      spent fuel by consolidating shipments where possible, (2) shipping spent
                      fuel in an order that further minimizes risk, and (3) emphasizing the use of
                      trains dedicated to hauling spent fuel.

                      We provided DOE and NRC with drafts of this report for review and
Agency Comments       comment. DOE generally concurred with the facts of the report, noting
and Our Evaluation    that the information on transit was accurate and well balanced. DOE also
                      concurred with our recommendations, with one exception. DOE noted
                      that the Department of Transportation was expected to release a study
                      later this year on the safety and security implications of transporting spent
                      fuel by dedicated train. DOE stated that it preferred to wait for the
                      outcome of the study before beginning its own review. DOE also provided
                      technical comments, which we incorporated into the report.

                      NRC also generally concurred with the facts of the report, noting that
                      the information provides a reasonable characterization of the current
                      understanding of risks associated with spent fuel storage. However, NRC


                      Page 24                                          GAO-03-426 Spent Nuclear Fuel
stated that it does not consider the results of its most recently published
studies on spent fuel in a pool and spent fuel in transit, as quoted in the
report, to accurately reflect the consequences of a potential terrorist
attack. Rather, NRC indicated that the studies started with overly
conservative assumptions, resulting in “unrealistically conservative”
results. NRC noted that it is currently conducting studies to assess the
potential consequences of a terrorist attack that use more realistic
assumptions. NRC also noted in its technical comments that preliminary
results from these ongoing studies show that potential consequences may
be far less severe than reported in the current publications.

We revised our report to account for NRC’s preliminary findings from
ongoing work involving the risk associated with spent fuel pools. As our
report states, these findings indicate that risks from spent fuel pools
may be substantially reduced from previous estimates. We used NRC’s
February 2001 report, Technical Study of Spent Fuel Pool Accident Risk
at Decommissioning Nuclear Power Plants, with the understanding that
the report received a high level of scrutiny both within and outside NRC
prior to its publication. As stated in the report, “Preliminary drafts of this
study were issued for public comments and technical reviews in June 1999
and February 2000. Comments from interested stakeholders, the Advisory
Committee on Reactor Safeguards, and other technical reviewers have
been taken into account in preparing this study. A broad quality review
was also carried out at the Idaho National Engineering and Environment
Laboratory, and a panel of human reliability analysis experts evaluated the
report’s assumptions, methods, and modeling.” The report also states that,
based on the comments received, “staff did further analyses and also
added sensitivity studies on evacuation timing to assess the risk
significance of relaxed offsite emergency preparedness requirements
during decommissioning.” Given this level of review, we believe it to be
appropriate to report the results of this study.

NRC also took issue with our use of its report, Reexamination of Spent
Fuel Shipment Risk Estimates. NRC explained that the analyses in this
document are similarly overly conservative. This March 2000 study was
conducted by Sandia National Laboratory at the request of NRC to
reexamine the conclusions reached in previous studies regarding the risks
of spent fuel shipments. As with its February 2001 report, this report also
indicated a high level of review prior to publication. Specifically, the
report mentions a number of individuals who provided comments to the
report, including staff at Sandia National Laboratory, Lawrence Livermore
National Laboratory, and “a number of technical experts at the NRC.”



Page 25                                           GAO-03-426 Spent Nuclear Fuel
              Given the intent of this study and its level of review, we believe it to also
              be appropriate to report the results of this study.


              We performed our review at DOE and NRC headquarters in Washington,
Scope and     D.C., at NRC’s Region III office near Chicago, Illinois, and at DOE’s Yucca
Methodology   Mountain Project office in Las Vegas, Nevada. We visited several sites
              where spent fuel is stored, including operating nuclear power plants, a
              decommissioned nuclear power plant, and independent spent fuel
              storage sites. We conducted our review from April 2002 to June 2003 in
              accordance with generally accepted government auditing standards.

              To determine the potential health effects of a terrorist attack or a severe
              accident involving commercial spent nuclear fuel, we examined a variety
              of federally sponsored studies, primarily conducted or sponsored by DOE
              and NRC. We examined critiques of these studies prepared by a variety of
              groups and individuals. We also spoke to many of the authors of these
              federal studies, authors of critiques of these studies, nuclear energy
              representatives, and other individuals representing a variety of
              backgrounds, including academia and special interest groups.

              To identify options for DOE to enhance the security of spent fuel as it
              develops its plans to ship the fuel to Yucca Mountain, we reviewed
              documents analyzing DOE’s plans and preferred alternatives, including the
              environmental impact statement and many of its supporting documents.
              We also interviewed DOE, NRC, and Department of Transportation
              officials responsible for developing and coordinating safe shipments of
              spent nuclear fuel. We also spoke to state and local government officials in
              a number states, including Nevada; nuclear energy representatives; and a
              variety of groups and individuals representing a spectrum of viewpoints on
              the shipment of spent nuclear fuel.


              As agreed with your office, unless you publicly announce the contents
              of this report earlier, we plan no further distribution of it until 30 days
              from the date of this letter. At that time, we will send copies of this report
              to other interested parties and make copies available to others who
              request them. In addition, the report will be available at no charge on
              GAO’s Web site at http://www.gao.gov/.




              Page 26                                           GAO-03-426 Spent Nuclear Fuel
If you or your staff have any questions about this report, please call me at
(202) 512-3841. Key contributors to this report are listed in appendix V.

Sincerely yours,




Robin M. Nazzaro
Director, Natural Resources
 and Environment




Page 27                                          GAO-03-426 Spent Nuclear Fuel
                            Appendix I: Nuclear Regulatory Commission
Appendix I: Nuclear Regulatory Commission
                            Requirements for Safety and Security of
                            Spent Fuel


Requirements for Safety and Security of
Spent Fuel
                            As the regulating agency responsible for spent fuel, the Nuclear Regulatory
                            Commission (NRC) must adequately protect the public health and safety
                            against accidents or acts of sabotage. To provide this assurance, NRC uses
                            a “defense-in-depth” philosophy. Consistent with this philosophy, NRC
                            designs its safety and security requirements to ensure that public safety
                            and health are not wholly dependent on any single element of the design,
                            construction, maintenance, or operation of a nuclear facility. More
                            specifically, NRC designs multiple or redundant measures to mitigate
                            areas of known risk or to increase confidence in areas of uncertainty.
                            Listed below are some of the primary requirements NRC has recognized as
                            protecting spent fuel while in transit, in wet storage, and in dry storage.


                            NRC requires that transporters of spent fuel (1) contain the fuel in
Requirements for            NRC-certified shipping containers that must meet stringent durability
Preventing Release of       performance requirements and (2) comply with requirements designed
                            to impede an act of sabotage on the fuel.
Spent Fuel in Transit
                            NRC regulations for spent fuel shipping containers dictate that the
                            containers prevent releases of significant amounts of radiation under both
                            normal operating conditions and in hypothetical accident scenarios. The
                            containers include shielding to ensure that persons near a container are
                            not exposed to significant amounts of radiation. In addition, the containers
                            must remain intact after a series of simulated accident conditions,
                            including

                        •   an impact test, in which containers are dropped from 30 feet onto a flat,
                            unyielding surface;
                        •   a puncture test, in which containers are dropped from 40 inches onto a
                            6-inch diameter steel bar at least 8 inches long;
                        •   a fire test, in which containers are engulfed in a 1,475-degree Fahrenheit
                            fire for 30 minutes; and
                        •   an immersion test in which containers are submerged in 3 feet of water for
                            8 hours.

                            The containers must survive each of these tests in succession, without
                            significant levels of surface radiation or release of spent fuel. Containers
                            must also be shown to survive water pressure equivalent to immersion
                            under nearly 670 feet of water for 1 hour.

                            Because of these requirements and the dimensions of the spent fuel
                            assemblies they contain, spent fuel shipping containers are massive and
                            robust. A typical train container is about 25 feet long and 11 feet in



                            Page 28                                           GAO-03-426 Spent Nuclear Fuel
Appendix I: Nuclear Regulatory Commission
Requirements for Safety and Security of
Spent Fuel




diameter, weighs about 100 tons empty, and about 120 tons fully loaded—
thus the container can account for over 80 percent of the total weight of a
shipment. Though truck containers have significantly less capacity than
rail containers, both types have similar basic designs. As figure 2 indicates,
they are generally composed of several layers of shielding material,
totaling about 5 to 15 inches in thickness, including a radiation barrier
consisting of lead or depleted uranium.

Figure 2: Cutaway Graphic of a Spent Fuel Truck Transportation Cask




Page 29                                            GAO-03-426 Spent Nuclear Fuel
                                          Appendix I: Nuclear Regulatory Commission
                                          Requirements for Safety and Security of
                                          Spent Fuel




                                          When in transit, each end of the container is made of material that is
                                          designed to absorb much of the force of an impact. Figures 3 and 4 show a
                                          spent fuel rail container and a truck container, respectively.

Figure 3: Spent Fuel Rail Container




Figure 4: Spent Fuel Truck Container on a Trailer




                                          Page 30                                       GAO-03-426 Spent Nuclear Fuel
                            Appendix I: Nuclear Regulatory Commission
                            Requirements for Safety and Security of
                            Spent Fuel




                            Although the shipping container is the most important component in
                            preventing release and dispersal of spent fuel in transit, NRC also requires
                            transporters of the spent fuel to implement measures designed to further
                            protect spent fuel shipments from sabotage. For example, transporters
                            of spent fuel must ensure that shipments are under surveillance, that
                            arrangements have been made with local law enforcement agencies for
                            their response in the event of an emergency, and that rail and highway
                            routes have been approved by NRC. NRC had also required that armed
                            escorts be either aboard the shipping vehicle or in a following vehicle in
                            areas of high population; NRC has since strengthened the security required
                            of shipments following the September 11, 2001, terrorist attacks.


Requirements for            Spent fuel pool designs must meet specific performance criteria before
Preventing Release of       NRC can issue a license for construction or operation. The requirements
Spent Fuel in Wet Storage   focus on ensuring that the safety features of the pool survive certain
                            natural phenomena or accidents to ensure that, among other things, the
                            pool will retain water and keep the stored fuel sufficiently cool. Spent fuel
                            in wet storage is also protected by the physical security measures in place
                            at the storage site.

                            As part of the licensing process prior to construction and operation,
                            utilities must submit reports that analyze the likelihood of certain natural
                            phenomena, such as earthquakes, hurricanes, floods, and tidal waves.
                            Using probability analyses, historical information, and current information
                            on seismology, geology, meteorology, and hydrology, the utilities must
                            determine the risks of certain types of natural phenomena. Then the
                            utilities must show that the proposed pool designs would survive the most
                            severe natural phenomena or combinations of less severe phenomena
                            expected for that particular area. The utilities must also perform the same
                            exercise for the likelihood and severity of certain accidents, including
                            airplane crashes. For example, pools constructed near airports may have
                            to be designed to withstand certain types of accidental airplane crashes.

                            Consequently, although the specific designs of wet storage pools vary
                            from site to site, they are massive, robust structures. Pools are typically
                            30 to 60 feet long, 20 to 40 feet wide, and 40 feet deep. Pools could nearly
                            hold three semi-truck tractor-trailers parked side-by-side and stacked
                            three deep. The pool is contained by a structure consisting of a 1/8 inch to
                            1/4 inch stainless steel liner, and 4- to 6-foot thick walls of steel-reinforced
                            concrete. Generally, the pools are contained in other buildings. The roofs
                            of some of these buildings may be made from industrial-type corrugated
                            steel. The assemblies, stored vertically in racks, must be immersed at least


                            Page 31                                            GAO-03-426 Spent Nuclear Fuel
Appendix I: Nuclear Regulatory Commission
Requirements for Safety and Security of
Spent Fuel




20 feet below the surface of the water in order to keep the fuel cool and to
provide a sufficient radiation barrier. See figure 5 for a photograph of a
wet storage pool.

Figure 5: A Wet Storage Pool




Spent fuel pools are also protected by the physical security measures in
place at the facilities where they are located. About 95 percent of the spent
fuel inventory is stored in pools, most of which are located at operating
nuclear reactors. The perimeters of these reactor sites are secured by
fences topped with barbed wire, vehicle barriers, and intrusion detection
systems—including perimeter cameras and motion detection technology—
that are monitored 24 hours per day. Access to the building containing the
wet storage pools is impeded by locked steel doors capable of surviving
armed assault and security checkpoints where a person’s identity must be
verified and where security searches take place. Finally, these facilities are
manned by a force of armed guards.

In addition, nuclear power plants are required to coordinate an emergency
response to the site in the event of a terrorist or sabotage event. The
coordination requires contingency plans and joint exercises with local
law enforcement agencies to ensure an adequate and timely response to


Page 32                                          GAO-03-426 Spent Nuclear Fuel
                                Appendix I: Nuclear Regulatory Commission
                                Requirements for Safety and Security of
                                Spent Fuel




                                an event. Since the terrorist attacks of September 11, 2001, NRC has
                                added additional requirements, including additional armed guards and
                                vehicle barriers.


Requirements for                NRC requires that spent fuel in dry storage be stored in containers that
Preventing Release of           protect workers and other nearby persons from significant amounts of
Spent Fuel in Dry Storage       radiation, and that can survive operational accidents at the storage site, as
                                well as extreme meteorological and other natural events. In addition, fuel
                                in dry storage is protected by physical security measures in place at the
                                storage site.

                                Among other things, dry storage containers must be capable of surviving

                            •   a drop test, in which containers are tested by a drop from the height to
                                which it would be lifted to during operations;
                            •   a tip-over test, testing containers against seismic, weather, and other
                                forces or accidents that could knock over 100- to 150-ton containers,
                            •   an explosion test, in which containers are tested against nearby explosions
                                and the resulting pressures created by the blasts;
                            •   a tornado and tornado missile test, in which high winds and tornado
                                missiles are simulated;
                            •   a seismic test, in which containers are tested against the seismic motions
                                that might be expected to occur in its geologic area (certification
                                requirements may differ from region to region);
                            •   a flood test, in which containers are analyzed for floods; and
                            •   a fire test, in which containers are engulfed at temperatures up to
                                1,475 degrees Fahrenheit for 30 minutes.

                                Manufacturers must provide NRC with information on how well a
                                container design meets these performance requirements. NRC does not
                                require physical tests of the containers, but it accepts information derived
                                from scaled physical tests and computer modeling.




                                Page 33                                          GAO-03-426 Spent Nuclear Fuel
Appendix I: Nuclear Regulatory Commission
Requirements for Safety and Security of
Spent Fuel




As with shipping containers, to meet these performance requirements,
certified dry storage containers are massive and robust. A typical dry
storage container consists of a 1-inch thick steel container housing the
spent fuel. At some facilities, the containers are placed horizontally in
garage-sized bunkers constructed of concrete. The concrete protects
nearby workers and the public from radiation. At other facilities, the
container is encased in an outer cask. The outer cask typically is
constructed of steel-reinforced concrete, 18 or more inches thick. Like
the concrete bunkers, the outer cask shields workers and the public from
radiation. The free-standing, upright units, stored on concrete pads, can
weigh from 100 to 150 tons each with nearly 90 percent of that consisting
of the container weight. A dry storage container can store between 7 and
68 assemblies, depending on the size of the container. See figure 6 for an
illustration of a dry storage container.




Page 34                                         GAO-03-426 Spent Nuclear Fuel
Appendix I: Nuclear Regulatory Commission
Requirements for Safety and Security of
Spent Fuel




Figure 6: A Spent Fuel Dry Storage Container




Page 35                                        GAO-03-426 Spent Nuclear Fuel
Appendix I: Nuclear Regulatory Commission
Requirements for Safety and Security of
Spent Fuel




In addition to the physical performance requirements of dry storage
containers, the containers are protected by the physical security measures
in place at the facilities where they are stored. Dry storage containers at
operating nuclear power plants generally benefit from the physical
security measures already in place at the sites. The large majority of spent
fuel in dry storage is located at operating nuclear power plants. For dry
storage containers situated away from a reactor site, NRC requires vehicle
barriers, fences, intrusion detection systems, and guards. The guards are
also able to contact local law enforcement agencies for assistance, if
required. NRC requires that dry storage facilities coordinate response
plans with local law enforcement agencies to ensure assistance can be
readily provided, if needed. In the wake of the September 11, 2001,
terrorist attacks, NRC issued orders to dry storage facility licensees that
required enhanced security measures, including additional protections
against a vehicle bomb threat.




Page 36                                         GAO-03-426 Spent Nuclear Fuel
                   Appendix II: Additional Information on
Appendix II: Additional Information on
                   Studies on the Safety and Security of Spent
                   Fuel in Transit


Studies on the Safety and Security of Spent
Fuel in Transit
                   The human health implications of sabotage events and accidents
                   involving spent nuclear fuel shipments described in the report are based
                   on computer-based engineering and other analytic models that rely, in
                   part, on physical experiments. In addition, these studies are the most
                   recent in a series of studies that date back to the 1970s. According to NRC
                   and DOE, better data and improved analytic tools over the years have
                   significantly enhanced the agencies’ confidence in the results of these
                   studies. This appendix provides an overview of the methodology of the
                   most recent studies, as well as the approach and results of previous
                   studies.


                   Methodology of Most Recent Studies. The 1999 Sandia National
Sabotage Studies   Laboratory study was undertaken at the request of DOE for use in its
                   preparation of an environmental impact statement for the Yucca Mountain
                   repository.1 The study relied on computer models to estimate how the
                   two selected armor-piercing missiles would damage shipping containers.
                   Although no physical tests or experiments were conducted in this study,
                   the study used computer models that were validated using the results of
                   previous studies that included experimental data.

                   Two of the most important factors considered in designing the study were
                   the types of shipping containers and the weapons selected for analysis.
                   For the shipping containers, the study used truck and rail containers
                   considered representative of those that would be used to transport the
                   spent fuel likely to be shipped in the early decades of the 21st Century.
                   NRC’s performance standard for these containers requires that they
                   prevent release of significant amounts of radiation under normal
                   operating conditions and in accident scenarios. For example, radiation
                   levels at the exterior of the container must remain below specified
                   minimal levels after a series of tests to simulate accident conditions,
                   including an impact test, in which the container is dropped from 30 feet
                   onto a flat, unyielding surface.

                   In selecting the weapons used in the analysis, the authors researched the
                   latest information available and chose weapons they believed represented




                   1
                    Sandia National Laboratory, Projected Source Terms for Potential Sabotage Events
                   Related to Spent Fuel Shipments, SAND 99-0963, a report prepared at the request of the
                   Department of Energy, Albuquerque, N.Mex., June 1999.




                   Page 37                                                  GAO-03-426 Spent Nuclear Fuel
    Appendix II: Additional Information on
    Studies on the Safety and Security of Spent
    Fuel in Transit




    the two weapons that would penetrate spent fuel shipping containers, and
    which could also be available to terrorists.2

    To ensure that the analysis would represent the upper limit of possible
    damage, the authors made conservative assumptions, including the
    following:

•   No security measures were in place, such as armed guards who travel with
    spent fuel shipments and who are required to have the capability to
    contact local law enforcement personnel in the event of an attack.
•   The weapons would be employed at a distance from these containers that
    would result in maximum damage to the container and that the weapon
    would strike the container dead center; if the missile were to strike higher
    or lower, it could be deflected by the cylindrical shape of most containers,
    and penetration of the container would be lessened or not occur at all.

    Previous Studies. The 1999 Sandia study is the most recent in a series of
    federally sponsored studies dating back to the 1970s that have examined
    the ability of armor-piercing weapons to penetrate spent fuel containers.
    A draft version of a Sandia study from 1978, for example, concluded that
    a successful sabotage attack on a spent fuel container would not cause
    prompt fatalities but could cause several hundred latent cancer fatalities in
    a densely populated urban area.3 The final version of this study reduced
    the total latent cancer fatalities to fewer than 100, based on a re-evaluation
    of the quantity of radioactive material released.4 Based largely on the
    initial draft of this study, NRC established its regulations for security of
    spent fuel in transit. Because this study was based on a conservative set of
    analytical assumptions instead of on experimental data, there was a high
    degree of uncertainty regarding the quantities of radioactive material
    released, and the human health consequences. Consequently, in 1983, DOE
    commissioned Sandia National Laboratory to conduct physical tests, in
    which armor-penetrating missiles were fired at shipping containers




    2
        According to NRC, information on the types of weapons used in this analysis is classified.
    3
     Sandia National Laboratory, Transport of Radionuclides in Urban Environs: Working
    Draft Assessment, SAND 77-1927, Albuquerque, N.Mex., 1977.
    4
     Sandia National Laboratory, Transport of Radionuclides in Urban Environs: Draft
    Environmental Assessment NUREG/CR-0743, Albuquerque, N.Mex., July 1980.




    Page 38                                                      GAO-03-426 Spent Nuclear Fuel
                   Appendix II: Additional Information on
                   Studies on the Safety and Security of Spent
                   Fuel in Transit




                   containing mock spent fuel assemblies.5 The study found that, under the
                   worst-case scenario, about 24 ten-thousandths (0.0024) of 1 percent of the
                   total solid fuel inventory in the container could be released as respirable
                   particles.6 To estimate the human health impact, the study included
                   conservative assumptions, including that the attacks occurred in
                   Manhattan, in New York City, on a business day, that the fuel had been
                   removed from the reactor for only 150 days (and thus was comparatively
                   more radiologically dangerous), and that no evacuation took place to limit
                   human exposure. Based on these results and assumptions, the study
                   predicted no early deaths and between two and seven long-term latent
                   cancer fatalities.


                   Methodology of Most Recent Studies. According to NRC, the 2000
Accident Studies   Sandia National Laboratory study was conducted to address three
                   developments—the likelihood that spent fuel shipments would be
                   increasing as a result of the progress on the Yucca Mountain repository,
                   the use of containers and transportation routes that differed from those
                   considered in previous studies, and the increased effectiveness in risk
                   assessment and computer modeling of spent fuel containers.7 The overall
                   objective of the study was to determine the degree of risk involved in
                   shipping spent fuel by truck and rail.

                   The study examined the effects of severe collisions and fires on four
                   types of shipping containers—a lead-lined steel truck container, a
                   depleted uranium-lined steel truck container, a lead-lined steel rail
                   container, and a monolithic steel container. The study relied on computer
                   analysis to estimate the probability of such events and the quantity of
                   radioactive material that might be released. The analysis developed
                   19 representative truck accidents and 21 representative rail accidents.




                   5
                     According to Sandia National Laboratory officials, in addition to the high cost,
                   environmental and health regulations generally prevent the use of actual spent fuel that
                   leads to the use of mock fuel—a nonradioactive material—that generally displays enough
                   of the same properties as spent fuel for purposes of these analyses.
                   6
                    Sandia National Laboratory, An Assessment of the Safety of Spent Fuel Transportation
                   in Urban Environs, Albuquerque, N.Mex., June 1983.
                   7
                    U.S. Nuclear Regulatory Commission, Reexamination of Spent Fuel Shipment Risk
                   Estimates, NUREG/CR-6672, Washington, D.C., March 2000.




                   Page 39                                                  GAO-03-426 Spent Nuclear Fuel
Appendix II: Additional Information on
Studies on the Safety and Security of Spent
Fuel in Transit




The study simulated the effect on each of the truck and rail containers
after slamming them into a rigid surface from a variety of angles at 30, 60,
90, and 120 miles per hour. None of the cases modeled showed that the
body of the container would fail. Moreover, the modeling showed that the
seals around the lid at each end of the truck container would not allow a
release at 30, 60, and 90 miles per hour, although they may leak at
120 miles per hour. The results from modeling the two different rail
containers, however, showed that the seals may leak, for some collisions
at a speed of 60 miles per hour, depending on the angle of impact.

DOE’s study that predicted the health effects of these releases used a
computer code. The code calculated the dispersion of radioactive particles
and the resultant dose to the population. To estimate latent cancer deaths,
DOE made a number of key assumptions. DOE’s analysis assumed the
accident occurred in the most populous center of an urban area and that
the population distribution from the accident site in the urban center to
the outer fringes was similar to the average populations—projected to the
year 2035—of the 20 largest U.S. metropolitan areas, plus Las Vegas,
Nevada. Stable weather conditions—with comparatively slow wind
speeds—were assumed to prevail at the time of the accident.8 Finally, the
population was assumed to be exposed to remnants of the release for 1
year after the accident, with no evacuation or cleanup.

Previous Studies. The 2000 Sandia study reexamined the risks
associated with the transport of spent fuel by truck and rail and compared
the results to two previous studies—one conducted by NRC in 1977 and
one performed by DOE’s Lawrence Livermore National Laboratory in
1987. According to NRC, the 2000 Sandia study extended the methods
used in the 1987 report for container analysis and used improved risk
assessment methods.

The 2000 Sandia study found that previous NRC-commissioned studies
overestimated the risks of human exposure due to transportation
accidents. According to NRC and Sandia officials, they have become more
confident in their results as analytical techniques and data have improved.
In 1977, NRC examined the risks of shipping a variety of radioactive
materials, including spent fuel.9 At that time, NRC determined that the


8
    Higher wind speeds would result in faster dispersion and hence a lower population dose.
9
 U.S. Nuclear Regulatory Commission, Final Environmental Statement on the
Transportation of Radioactive Material by Air and Other Modes, NUREG-0170,
Washington, D.C., 1977.



Page 40                                                     GAO-03-426 Spent Nuclear Fuel
Appendix II: Additional Information on
Studies on the Safety and Security of Spent
Fuel in Transit




risks of accidental releases involved in shipping spent fuel and other
radioactive materials were quite small—specifically, the study estimated
latent cancer deaths to be about 3 in 200 years of shipping spent fuel at
estimated rates for 1985. The study concluded that the existing NRC
requirements were adequate to protect public health. Partly because this
study was based on conservative engineering judgments and did not
include physical tests of shipping containers in severe accidents, NRC
subsequently commissioned a study published in 1987 that found that the
risks of spent fuel releases under transportation accident conditions were
much smaller.10 Performed by Lawrence Livermore National Laboratory
for NRC, this study included a more sophisticated analysis than the 1977
study, using historical data on past transportation accidents to determine
the likelihood of specific accident scenarios. The study then used a
computer-based analysis of accident scenarios involving collisions and fire
temperatures exceeding NRC standards. The 1987 study found that in
99.4 percent of all rail and truck accidents, the container would experience
no significant damage, and no radioactive material would be released.




10
  Lawrence Livermore National Laboratory, Shipping Container Response to Severe
Highway and Railway Accident Conditions, NUREG/CR-4829, a report prepared at the
request of the Nuclear Regulatory Commission, 1987.




Page 41                                              GAO-03-426 Spent Nuclear Fuel
                   Appendix III: Comments from the Department
Appendix III: Comments from the
                   of Energy



Department of Energy




         Page 42                                            GAO-03-426 Spent Nuclear Fuel
                   Appendix IV: Comments from the Nuclear
Appendix IV: Comments from the Nuclear
                   Regulatory Commission



Regulatory Commission




         Page 43                                            GAO-03-426 Spent Nuclear Fuel
          Appendix IV: Comments from the Nuclear
          Regulatory Commission




Page 44                                            GAO-03-426 Spent Nuclear Fuel
                  Appendix V: GAO Contact and Staff
Appendix V: GAO Contact and Staff
                  Acknowledgments



Acknowledgments

                  Daniel J. Feehan (303) 572-7352
GAO Contact
                  In addition to the individual named above, Doreen Feldman, Michael
Acknowledgments   Hartnett, Gary Jones, Cynthia Norris, Robert Sanchez, Amy Stewart,
                  Barbara Timmerman, and Dwayne Weigel made key contributions to
                  this report.




(360181)

                  Page 45                                       GAO-03-426 Spent Nuclear Fuel
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