Spent Nuclear Fuel: Options Exist to Further Enhance Security	 
(15-JUL-03, GAO-03-426).					 
                                                                 
Spent nuclear fuel, the used fuel periodically removed from	 
nuclear power reactors, is one of the most hazardous materials	 
made by man. Nuclear power companies currently store 50,000 tons 
of spent fuel at 72 sites in 33 states. That amount will increase
through 2010, when the Department of Energy (DOE) expects to open
a permanent repository for this fuel at Yucca Mountain, Nevada.  
Concerns have been raised since September 11, 2001, that	 
terrorists might target spent fuel. GAO was asked to (1) review  
federally sponsored studies that assessed the potential health	 
effects of a terrorist attack or a severe accident on spent fuel,
either in transit or in storage, and (2) identify options for DOE
to further enhance the security of spent fuel during shipping to 
Yucca Mountain. 						 
-------------------------Indexing Terms------------------------- 
REPORTNUM:   GAO-03-426 					        
    ACCNO:   A07267						        
  TITLE:     Spent Nuclear Fuel: Options Exist to Further Enhance     
Security							 
     DATE:   07/15/2003 
  SUBJECT:   Accident prevention				 
	     Counterterrorism					 
	     National preparedness				 
	     Internal controls					 
	     Nuclear facility security				 
	     Nuclear fuel reprocessing				 
	     Nuclear waste disposal				 
	     Nuclear waste management				 
	     Risk management					 
	     Sabotage						 
	     Strategic planning 				 
	     Yucca Mountain (NV)				 

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GAO-03-426

Report to the Chairman, Subcommittee on Energy and Air Quality, Committee
on Energy and Commerce, U. S. House of Representatives

United States General Accounting Office

GAO

July 2003 SPENT NUCLEAR FUEL

Options Exist to Further Enhance Security

GAO- 03- 426

The likelihood of widespread harm from a terrorist attack or a severe
accident involving commercial spent nuclear fuel is low, according to
studies conducted by DOE and NRC. Largely because spent fuel is hard to
disperse

and is stored in protective containers, these studies found that most
terrorist or accident scenarios would cause little or no release of spent
fuel, with little harm to human health. Some assessments found widespread
harm is possible under certain severe but extremely unlikely conditions
involving spent fuel stored in storage pools. As part of its ongoing
research program and to respond to increased security concerns, NRC has
ongoing and planned studies of the safety and security of spent fuel,
including the potential effects of more extreme attack scenarios,
including deliberate aircraft crashes.

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 number of shipments and picking up fuel in
an order that would reduce risk, such as moving older less dangerous fuel
first. These options could reduce the risk during transport and at some
locations where the fuel is currently stored. However, contractual
agreements between DOE and owners of spent fuel may limit DOE's ability to
choose among these options. In addition, it is not clear that the benefits
of these measures would justify the potential costs, including a possible
renegotiation of the contracts between DOE and the spent fuel owners.
Spent nuclear fuel, the used fuel periodically removed from nuclear

power reactors, is one of the most hazardous materials made by man.
Nuclear power companies currently store 50, 000 tons of spent fuel at 72
sites in 33 states. That amount will increase through 2010,

when the Department of Energy (DOE) expects to open a permanent repository
for this fuel at Yucca Mountain, Nevada. Concerns have been raised since
September 11, 2001, that terrorists might target spent fuel. GAO was asked
to (1) review federally sponsored studies that assessed the potential
health effects of a terrorist attack or a severe accident on spent fuel,
either in transit or

in storage, and (2) identify options for DOE to further enhance the
security of spent fuel during shipping to Yucca Mountain.

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. Highlights of GAO- 03- 426, a 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

Page i GAO- 03- 426 Spent Nuclear Fuel 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 Contents

Page ii 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

This is a work of the U. S. Government and is not subject to copyright
protection in the United States. It may be reproduced and distributed in
its entirety without further permission from GAO. It may contain
copyrighted graphics, images or other materials. Permission from the
copyright holder may be necessary should you wish to reproduce copyrighted
materials separately from GAO*s product.

Page 1 GAO- 03- 426 Spent Nuclear Fuel 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.

United States General Accounting Office Washington, DC 20548

Page 2 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 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 Results in Brief

Page 3 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
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
Background

Page 4 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 5 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 6 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 7 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 8 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 widespread harm
to human health from a terrorist attack or 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 identified a scenario resulting
in widespread harm* largely because of the protective containers required
by NRC. For example, these studies repeatedly found that transportation
containers would be very difficult to penetrate, and in the worst- case
scenarios where they may be penetrated,

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. Likelihood of

Widespread Harm from Terrorist Attacks or Severe Accidents Involving Spent
Fuel Is Low

Page 9 GAO- 03- 426 Spent Nuclear Fuel Since the late 1970s, federal
studies have examined the effects of both terrorist acts of sabotage and
severe accidents involving shipping

containers for spent fuel. Sabotage studies have sought to determine
whether radioactive material could be released from shipping containers 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. 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. Shipping Containers
Protect against

Widespread Release of Fuel in Transit

Sabotage Studies

Page 10 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.

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. Accident
Studies

Page 11 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 12 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.

Although NRC believes that the results of the federally sponsored studies
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. Ongoing and Planned

Assessments

Page 13 GAO- 03- 426 Spent Nuclear Fuel According to NRC officials, the
studies are expected to be completed by 2006.

NRC studies have reported that a risk of widespread harm to human health
from spent fuel arises from the remote possibility of a sustained 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. Widespread Release from

Wet Storage Theoretically Possible but Unlikely

Page 14 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 Lower level
of radioactivity a Higher level of radioactivity a Time after shutdown of
reactor Number of early

fatalities Number of latent cancer fatalities Number of early

fatalities Number of latent cancer fatalities

30 days 2 3, 500 200 15,000 1 year 1 b 80 b 5 years 0 b 1 b 10 years 0 b 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 15 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. To begin addressing some of the
uncertainties regarding the risks of

storing spent fuel in wet storage pools, NRC has some ongoing work, and
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. NRC Continues to Study
the

Risks of Storing Spent Fuel in Pools

Page 16 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, like shipping containers, pose a considerable
barrier to releasing spent fuel. Used to store spent fuel when it is
removed 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. Dry Storage Containers

Safeguard against Widespread Release

Page 17 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 is continuing to study potential risks to dry storage. NRC has
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
repository, the agency has several potential options for enhancing the
security of spent fuel during the Yucca Mountain shipping campaign.

Specifically, DOE could potentially minimize its total number of spent
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.

DOE could enhance the overall security of spent fuel by minimizing the
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 NRC Continues to Study Risks

to Dry Storage Containers Options May Exist to Further Enhance Security
and Safety

Minimizing Number of Shipments

Page 18 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 19 GAO- 03- 426 Spent Nuclear Fuel possible option, total shipments
could be reduced to 287* a nearly 50 percent reduction.

DOE could also enhance security by shipping spent fuel in an order that
minimizes risk. There are at least three shipping orders that would
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.

DOE could potentially enhance the overall security of spent fuel by 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. Order in Which Spent

Fuel Is Shipped Could Enhance Security

Shipping Fuel from Shutdown Reactor Sites First

Page 20 GAO- 03- 426 Spent Nuclear Fuel 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 example, one of the more radioactive elements in spent fuel* cobalt 60
* 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 25
years, cobalt 60 emits about 3 percent of the gamma radiation it did when
first removed from the reactor. Similarly, the radioactivity of cesium 137
, 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 example, uranium 235 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. Shipping Oldest Fuel
First

Page 21 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.

As discussed in the first section of this report, a fire in a wet storage
pool, 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. Shipping Fuel from Densely

Packed Pools First

Page 22 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.

According to some analysts, DOE could enhance the security of spent 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 Shipping Fuel on Trains

That Haul Only Spent Fuel

Page 23 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 24 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 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
safety of spent fuel in storage at nuclear power plants and in transit are
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 comment.
DOE generally concurred with the facts of the report, noting 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
Conclusions

Recommendations for Executive Action

Agency Comments and Our Evaluation

Page 25 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 26 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, D. C.,
at NRC*s Region III office near Chicago, Illinois, and at DOE*s Yucca
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/. Scope and

Methodology

Page 27 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

Appendix I: Nuclear Regulatory Commission Requirements for Safety and
Security of Spent Fuel Page 28 GAO- 03- 426 Spent Nuclear 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 NRC-
certified shipping containers that must meet stringent durability
performance requirements and (2) comply with requirements designed to
impede an act of sabotage on the fuel.

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
Appendix I: Nuclear Regulatory Commission

Requirements for Safety and Security of Spent Fuel

Requirements for Preventing Release of Spent Fuel in Transit

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

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

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

Spent fuel pool designs must meet specific performance criteria before NRC
can issue a license for construction or operation. The requirements 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 Requirements for

Preventing Release of Spent Fuel in Wet Storage

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

Appendix I: Nuclear Regulatory Commission Requirements for Safety and
Security of Spent Fuel Page 33 GAO- 03- 426 Spent Nuclear Fuel an event.
Since the terrorist attacks of September 11, 2001, NRC has

added additional requirements, including additional armed guards and
vehicle barriers.

NRC requires that spent fuel in dry storage be stored in containers that
protect workers and other nearby persons from significant amounts of
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. Requirements for

Preventing Release of Spent Fuel in Dry Storage

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

Appendix I: Nuclear Regulatory Commission Requirements for Safety and
Security of Spent Fuel Page 35 GAO- 03- 426 Spent Nuclear Fuel Figure 6: A
Spent Fuel Dry Storage Container

Appendix I: Nuclear Regulatory Commission Requirements for Safety and
Security of Spent Fuel Page 36 GAO- 03- 426 Spent Nuclear 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.

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

Studies on the Safety and Security of Spent Fuel in Transit

Sabotage Studies

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

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

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

Appendix II: Additional Information on Studies on the Safety and Security
of Spent Fuel in Transit Page 41 GAO- 03- 426 Spent Nuclear Fuel 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.

Appendix III: Comments from the Department of Energy

Page 42 GAO- 03- 426 Spent Nuclear Fuel Appendix III: Comments from the
Department of Energy

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

Regulatory Commission

Appendix IV: Comments from the Nuclear Regulatory Commission Page 44 GAO-
03- 426 Spent Nuclear Fuel

Appendix V: GAO Contact and Staff Acknowledgments

Page 45 GAO- 03- 426 Spent Nuclear Fuel Daniel J. Feehan (303) 572- 7352
In addition to the individual named above, Doreen Feldman, Michael

Hartnett, Gary Jones, Cynthia Norris, Robert Sanchez, Amy Stewart, Barbara
Timmerman, and Dwayne Weigel made key contributions to this report.
Appendix V: GAO Contact and Staff

Acknowledgments GAO Contact Acknowledgments

(360181)

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