),
Case 1:98-cv-00474-JFM
Introduction
Document 309-7
Filed 04/16/2004
Page 1 of 15
Results in brief
Based on the viability a~sessment , DOE believes that Yucca Mountain remains a
promising site for a geologic repository and
that work should proceed to support a decision in 2001 on whether to recommend the
site to the President for development as a
repository- For the site to be rE.'Commended DOE needs to demonstrate that a reposi-
tory can be designed and built at Yucca Mountain that would protect public health and safety and the environment "for thousands of years. Uncertainties remain about
the preliminary design , and how the site and design would
key natura) processes ,
interact. To address these uncertainties
DOE plans to advance the design , complete
critical tests and analyses, and prepare
draft and final environmental impact state-
ments. When this work is completed in
2001, a decision will be made by the Secre-
tary of Energy on whether to recommend the site to the President.
The advantages of Yucca Mountain as a po-
table.
semiarid climate ,
. Yucca
tential repository site include its loCation
and deep groundwater
basin feature is unique to the western
region of the country.
Mountain is about 100 miles northwest of Las Vegas , Nevada , on unpopu-
The preliminary repository design includes
a long-
lated land owned by the Federal Govern-
lived waste package and takes ad-
Site. More than 900 nuclear weapons
Test Site.
. Water is
men t and adjacent to the Nevada Test
tests have been conducted at the Nevada
the primary means by which ra-
vantage of the desert environment and geologic features of Yucca Mountain. Together
the natural and engineered
barriers can
keep water away from the waste for thou-
sands of years. Analyses of the preliminary
design using mathematical models, though subject to uncertainties, indicate that pub-
dioactive elements (radionuclides) could be transported from a repository. Yucca
Mountain is located in a desert environment , with an average rainfall of about 7 inches per )' ear.
. The nearest groundwater ,
lic health and the environment can be protected.
. For 10
which is about
000 years after the repository is closed , people living near Yucca Mountain are expected to re(~eive little or
000 feet below the planned location of the repository, is isolated in a closed regional basin and does not flow into any rivers that reach the ocean. This closed
increase in radiation exposure.
. The
maximum radiation exposure from the repository is expected to occur after
0050
P A- 196b38
Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 2 of 15
Introduction
years. People living approximately 20 kilometers (12 miles) from Yucca Mountain at that time might reeeh' e additional radiation exposures equivalent to present- day background
about 300, 000
. Prepare an environmental impact
statement, publish it for public comment in
1999, and finalize it in 2000
radiation.
Although current assessments of repository
performance are encouraging, more work is
These tasks will cost approximately $1.1 billion to complete. If the site is suitable and
DOE submits a license application in 2002 the estimated cost to successfully complete
the licensing process, build a licensed re-
needed before the site can be recommended and a license application for construction
pository, emplace the waste, and monitQr
of a repository can be submitted to the
Nuclear Regulatory Commission (NRC).
and close the repository is approximately $18. 7 billion, in constant 1998 dollars. Giveri adequate funding and successful
completion of the licensing process , the first waste could be emplaced in a repository in .
Current schedules anticipate that the Secretary of Energy- will decide whether to recommend the site to the President in 2001 after consideririg . the views of States, affec~d Indian tribes , and NRC, as required
by the Nuclear Waste Policy Act. In turn,
the President will decide whether to
2010 , and the last waste , in 2033. With NRC approval , a repository could be closed
recom-
and sealed as early as J 0 years after the last waste is emplaced; or it could be kept open and actively monitored for hundreds
of years, ifit
mend the site to Congress.
agrees with the President's
If Congress
recommenda-
appears desirable to do so~ The $18. 7 billion cost estimate assumes a moni-
tion and the site is designated , DOE would submit to NRC in 2002 a license application for construction authorization. To support these plans , DOE wi1l:
. Obtain more information on key natural
toring period ~f 100 years , beginning with initial waste emplacement. The repository is being designed to allow future genera-
tions to decide how long the repository should be monitored, and whether and
when to close and seal it.
processes , including how radionuclides could be transported by groundwater beneath the repository
. Test. the
performance of candidate waste
package materials and evaluate alternative repository designs
. Continue analyzing the interaction be-
A monitored geologic repository is one component of a total waste management system. The total estimated future cost to complete the program, including transportation of waste and storage at the repository, is $36. 6 billion , in constant 1998 dollars. This
tween the repository and the natural processes
1'1'18
Viability Amssment
through closure and decommissioning, assumed to begin in 2110 and to be completed in 2116. It does not include $5. 9 billion that has been spent on the program through fiscal year 1998includes costs from 199~J
2000
ElwlronmtnIallmpact Statement
- 200t
Silt Re(:O(l1mencialion
1 2043 . . 211b
Op6onal
Assulllfd
CIo$Uft
Optiofla'
aDSU,.
Closure
I. .2002 EmpilCtmentbegins
lic4!n&e AppIiation
. 2010
t2ori ~nl
C4fRjIIettd
Stop If Iii! II umuiUble
Schedule for major repository milestones
0051
PA- Qf\()~Q
Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 3 of 15
Background
The nuclear waste problem
Countries worldwide have accumulated high- level radioactive waste by using
nuclear materials to produce
electricity, to
power naval vessels , and to make nuclear ' weapons. Some elements of this waste are
hazardous for a few years to several hun-
dred years; some elements are hazardous for many. thousarids of years. This waste must he safely contained until it no longer
poses a significant risk to human health and
-the .envirohmcnt.
Indian Point Nuclear Power Plant Buchanan, NY
DOE spent nuclear fuel
By 2035 ,
the United States will have accumulated ~pproximately 2, 500 metric tons
of spent nuclear fuel from reactors that pro-
Storage pool for commercial spent nuclear fuel
Commercial spent nuclear fuel
As of December 1998, the United States had accumulated 38 500 metric tons of used or
duce materials for nuclear weapons, from research reactors , and from reactors on the. Navy's nuclear- powered ships and submarines. The majority of DOE spent nuclear
fuel is currently stored at three major sites
in Idaho , South Carolina, and Washington.
spent" m\clear fuel from commercial
nuclear power plants; this amount could
Under a negotiated settlement agreement between the State of Idaho , the Navy, and
DOE , all spent fuel must be removed from
Idaho by the year 2035~
more th,an double by the year 2035 if all currently operating plants complete their
initial ,IO-
y(,ar license period. The spent fuel is now stored in 33 states at 72 power plant
sites and one commercial storage site and
is likely to remain where it is until a dis-
posal or central storage facility is constructed. When a power plant ceases operations, the spent nuclear fuel and other radioactive materials must be removed before the plant can be fully decommissioned
and the site used for other purposes.
F Atea Tank Farm at Savannah River Site ,
near Aiken , SC
0052
J\
-1
O~(\A (\
..-"'.......
Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 4 of 15
Background
High-level radioactive waste
The production of nuclear weapons has left
a legacy of high- level radioactive waste that was created when spent nuclear fuel was treated chemically to separate uranium and
plutonium. The remaining high- level
must be disposed of in a secure facility that
will not only keep the waste away from
people but will also keep people away from. the weapons-usable material for thousands of years. Ensuring national security and
waste is in liquid and solid forms; 100 million gal-
lons are stored in underground tanks in Washington, South Carolina, Idaho , and
New York.~ Under agreements between DOE and the states where the waste is stored , this high- level waste will continue to be solidified and placed in about 20 000
canisters for future disposal in a permanent gc(jlogic repository.
preventing the proliferation of nuclear
weapons depends on developing a permanent, safe, and secure disposal facility for surplus . plutonium and other weapons materials.
Total inventory
At present, spent nuclear fuel and high-level
radioactive waste are temporarily stored at
Surplus plutonium and other nuclear
weapons materials
78 locations in 35 states, as shown below.
Some of these storage sites are close. to popu-
The end of the Cold War has brought the problem of cleaning up and closing weapons plants that are no longer
lation centers and are located near rivers, lakes , and seacoasts. The stored materials , ifleft where they are indefinitely, could
become a hazard to nearby populations and the environment. 'I' hese nuclear materials
require safe and permanent disposal.
needed arid
disposing of surplus plutonium and other
nuclear materials associated with weapons
production. These radioactive materials
L0C8~onS of Spent Nuclear Fuel (SNF)
tlld High-l8V81 Waste (HlW)
. eo..m...:Io1 lie""""
Ie
_SNF..s.o.
-~lIeact""
T DOE.()wnH SNFend HlW
. c....m..daISNF'-F~
....~_SHf. """"'SNF (...."",_"".._...DOE........
l P""'
locations of spent nuclear fuel and high. level radioactive waste destined for geologic disposal
....,Od_30
1998
0053
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.." "
~~'=~Page 5 of 15
Case 1:98-cv-00474-JFM
Background
Document 309-7
Filed 04/16/2004
Geologic disposal
Geologic disposal of radioactive waste has been the focus of scientific research for more
than 40 years. As early as 1957, a National Academy of Sciences' report to the Atomic Energy Commission recommended burying
radioactive waste in geologic formations.
In 1962, the Atomic Energy Commission
began investigating salt formations , including bedded salt and salt domes, as poten-
tial host rock for repositories. In 1975 , the Energy Research and Development Administration , predecessor to DO E , selected a site near Carlsbad , New Mexico , for the Waste" Isolation Pilot Project , which is to dispose of tl'8nsuranic waste. In 1976, the Energy Research and Development Administration alHo began to investigate other geo.
logic formations and to consider different
Dry cask storage of commercial spent nuclear fuel
proach for nuclear waste disposal. A panel of ~he National Academy of Sciences noted
disposal concepts , including deep-seabed disposal , disposal in the polar ice sheets,
and rocketing waste into the sun. After extensive evaluation ofthe options , DOE concluded in 1981 that disposal in an underground mined geologic repository remained . the preferred option.
in 1990 that there is "a worldwide scientific consensus that deep geological disposal,
the approach being followed by the United
States , is the best option for disposing of
high- level radioactive waste.
However, there are differing views on how
Unlike the hazards of toxic materials such as lead, mercury, and arsenic, which do not
" break down, the hazard of radioactive ma-
rapidly waste should be disposed of and whether it should be disposed ofirrevers. ibly. Some argue that waste should be
stored for several generations to aUow sci. entists to learn more about. geologic disposal
terials declines over time. Early efforts to study disposal options, therefor . sought to find the most effective ways for available
technology to isolate waste long enough for
and to take advantage of new and better
technologies that may come
along. That
the hazard to decline to low levels. That search led to geologic environments that
have remained stable for millions of years
would keep aU options open for future generations. But it would also require them to bear all the costs of exercising those options.
and are likely to remain so. Scientists
widely agreed that waste packaged in robust , long. lived waste packages and placed deep in such stable geologic environments could be isolated from the biosphere for the
One way to preserve these options and still provide a permanent solution is to dispose of waste in a manner that permits , but does
not require , the retrieval of waste; the waste
would be disposed of, but not irreversibly.
The Nuclear Waste Policy Act of 19828 requires that spent nuclear fuel emplaced in
long time periods necessary.
Since the first scientific study in 1957 , virtually every expert group that has looked at the nuclear waste problem has agreed
that a geologic repository is the best ap-
a repository be retrievable for any reason
pertaining to public health and the environment , or to permit recovery of the poten-
tially valuable contents of the spent fuel
prior to permanent closure of a repository.
0054
P A- 196042
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Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 6 of 15
Background
regulations require that a geologic
Nuclear Regulatory Commission (NRC) repository be dcsiln1ed for waste retrieval at any time up to 50 years after waste emplacement begins.
repository at Yucca Mountain that could
give future generations the choice of
allowable under NRC regulations, or of keeping it open and monitoring it for hundreds of years.
The DOE is designing a monitored geologic
A geologic repository will not require perpetual human care and will not rely on the stability of society for thousands of years into the future. Jt will rely instead on geologic formations that have remained rela-
clos-
ing and sealing the repository as early as
tively stable for millions of years and on long- lived engineered barriers.
437
Nuclear Pow Operatlnf! Worldw.
25
Nuclear Power Reactors
Being Buift
\:!I
r~~
79
Nuclear Power Reactors
or
Ordered
Planned
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. J. -10 Bufding Road~
~10 Ordering ()( Planning Readen
Worldwide status of nuclear power reactors. In the United States. 104 operating reactors produce 20 percent orthe nation s electricity. Worldwide data is from the fiies oUhe Australian Nuclear Science and Technology Organisation, based on information as of June 5 , 1998.
0055
P A- 196043
~-=_.--. .
Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 7 of 15
Background
The law and the regulations
The Nuclear Waste Policy Act of 1982
(NWPA) directed DOE to develop a system
for the safe and final disposal of spent
program-to pay forthat effort. The NWP
requires utilities with nuclear power plants
to pay a fee to fund the disposal program.
nuclear fuel and high- level radioactive waste.
The Federal Government bears the costs of disposing of defense waste.
The NWP A also assigns distinct roles to the Environmental Protection Agency (EPA)
The NWPA set an ambitious schedule for
DOE to site two geologic repositories and
required DOE to contractwi th utilities to begin disposalin the first one by January , 1998. The DO E formally identified nine potentially acceptable sites across the nation and later narrowed the list to three sites: Dear Smith County, Texas; Hanford
Washington; and Yucca Mountain , Nevada.
In 1987, Congress directed DOE to study only one of the sites-the one at Yucca
and the Nuclear Regulatory COmmission
(NRC). The EPA is required to establish
standards for protection of the general en-
vironment from releases of radioactive ma-
terial from a repository. The NRC. is responsible for establishing technical
requirements and criteria , consistent with
EP A standards,
for approving or disapprov-
Mountain- to decide whether it is suitabl~
for a repository. This legislation, known as
the Nuclear Waste Policy Amendments Act
of 1987
10 also
ing applications to construct , operate, and eventually close a repository. In 1981 and
1983 , NRC issued regulations for a geologic
repository in anticipation of
EPA stan-
estabJished the Nuclear
dards.u
Subsequently, the Energy Policy Act of
199212 modified the process for setting en-
Waste 1' echnical Review Board , composed of experts appointed by the President to re-
view the DOE program.
The NWP A . reaffirms the Federal Government's responsibility for developing
repositories for the permanent disposal of spent nuclear fuel and high- level radioac-
vironmental standards for a repository at Yucca Mountain. The Act directed the National Academy of Sciences (NAS) to pro-
vide findings and recommendations
on
tive waste. It also affirms the responsibility of the generators of
the waste-the nuclear utilities and the federal defense nuclear
standards for the Yucca Mountain site based on and consistent with the NAS findings and recommendations. The Act directed NRC to revise its regulations as necessary to be consistent with the EPA standards , once issued. The NAS published 13 The EPA is currently its report in 1995.
developing its standards.
these standards and directed EPA to issue
0056
P A-
96044
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Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 8 of 15
Background
How geologic disposal would work
. The baf;ic concept of geologic disposal is
place carefully prepared and packaged
waste in excavated tunnels in geologic for-
mationf; such as salt, hard rock, or clay. The concept relies on a series of barriers, natu. ral and engineered, to contain the waste for
thousands of years and to minimize the amount of radioactive material that may
eventually be transported from a repository and reach the human environment.
they differ in the barriers they emphasize. The German disposal concept, for example, relies heavily on the geologic barrier, the rock salt formation at the prospective disposal site. The Swedish method, on the other hand, relies heavily on thick copper waste packages to contain waste.
The U. S.
1979 Report to the President by the
approach, as recommended in the Inter-
Water is the primary means by which radionuclidcs could reach the human environ-
agency Review Group on Nuclear Waste Management, 14 is to design a repository in
which the natural and engineered barriers
ment. rrherefore, the primary functions of the barriers are to keep water away from
the waste as long as possible , to limit the amount of water that finally does contact
work as a system, so that some barriers will continue to work even if others fail, and so that none of the barriers is likely to fail for
the waste, to slow the release of radionuelides from the waste , and to reduce the con-
the same reason or at the same time. This design strategy is called defense in depth. The barriers include the chemical and
physical forms of the waste , the waste pack-
centrations of radionuclides in groundwater.
All countries pursuing geologic disposal are
ages and other engineered barriers, and the
natural characteristics of Yucca Mountain.
taking the multibarrier approach, though
",eo
' ;gz:t'..
~;i,j7~t:~~?~~. ~~i-." "~i ~L_ :"Jit'.. m~~'~"1'ji,!li.~~;'
1'.
;'-i
J.il.
CUtaway
. 'i'i
1",.
10:"""-
showing artist' s concept of the complex of underground wnnels into YA1ich waste would be emplaced. A repository at Yucca Mountain would rely on the semiarid climate. natural baniers, and engineered barriers to contain and isolate waste for thousands of years.
1\1\
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Case 1:98-cv-00474-JFM
Background
Document 309-7
Filed 04/16/2004
Page 9 of 15
Why Yucca Mountain? .
. Yucca Mountain is remote
from pQpulation
years. Based upon what
is known about
centers. L()(:ated about 100 miles northwest
of Las Vegas, Nevada, Yucca Mountain is
. ons test
the site, disruption of a repository at Yucca Mountain by volcanoes , earthquakes, ero-
on the edge of the nation' s nuclear weapsite, where more than 900 nuClear
tests have been conducted. TJtis
sion , or other geologic processes and events appears ' to be highly unlikely.
Yucca Mountain has a desert climate. This
unpopulated land is owned by the Federal Government.
Yucca Mountain provides a stable geologic
is important because water movement is the primary means by which radioactive waste
could be transported from a repository.
environment. . A flat- topped ridge running
six. miles from north to south, Yucca Moun-
average, Yucca Mountain currently
receives
about seven inches of rain and snow per
year. Nearly aU the precipitation, about 95
tain has changed little over thE'
last
million
percent, either runs off or cwaporates. Geological information indicates that the reo
gional climate ~as changed over the past
Location of the proposed monitored geologic repository at Yucca Mountain. Nevada
0058
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Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 10 of 15
Background
million years and the long- term average
precipitation has been about 12 inches per year~omparable to that of present- day
Santa Fe, New Mexico. Even if this were to
groundwater in the region is trapped within a closed desert basin and does not flow into
any rivers that reach the ocean.
be the case in the future, most of the water would run off or evaporate rather than soak into the ground and possibly reach the repository.
A repository would be built about 1, 000 feet
below the surface and 1, 000 feet above the
The concept of disposing of waste in the unsaturated zone in the desert regions of the
Southwest was first advanced by the U.
Geological Survey in the 1970s. In 1976,
the director of the Geological
Survey sug-
gested that the region in and around the
Nevada nuclear weapons test site offered a variety of geologic formations and other attractive features , including remoteness and an arid climate. 15 In 1981 , a Geological Sur-
water table in what is called the unsaturated zone. The water table is about 2 000 feet beneath the crest of Yucca Mountain.
Any precipitation that does not run off or
evaporate at the surface would have to seep down nearly 1 000 feet before reaching the
vey scientist noted that the desert Southwest has water tables that are among the
deepest in the world and that the region contains multiple natural barriers that
repository. Between the repository and the water table, it would have to move through
another 1
could isolate wastes for " tens of thousands
000 feet of the unsaturated zone
. befo.' E! reaching
the water table. The
years."16
to perhaps hundreds of thousands of
View of Yucca Mountain from the south
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... --Page 11 of 15
Case 1:98-cv-00474-JFM
Reference Design
Document 309-7
Filed 04/16/2004
The design process
Designing a repository is an iterative process. The process begins with defining the
materials that are chosen to be
compatible
with the underground thermal and
primary design objectives:
protecti
ng the
. health and safety of both the workers and
the public during the period of repository
geochemical environment, and the layout of tunnels takes into consideration the geology of the mountain.
operations; minimizing the amount of ra-
dioactive material that may eventually
reach the accessible environment; and keeping costs down to an acceptable level.
To achieve the design objectives, engineers
Through successive evaluations and im-
provements, the repository design has
evolved to the current reference design. The
reference design represents a snapshot of
the ongoing design process, thus providing
pository at
work with scientists to design the mana repository to work effectively with the natural system. The
made components pf
a frame of reference to d~scribe how a reYucca Mount. ain could work.
The repository design also offers insights
about how to reduce uncertainty and modify the design to improve its performance. Im-
engineered barriers are intended to work
.
geology and climate of Yucca Mountain-to contain and . isolate waste for thousands of years. The waste package design , for example, includes
with the natural barriers-the
provements are expected to continue as
more work is completed and more information about the site is obtained.
~i'~;
1f"
, ~;t.
A conceptual model of the design process. Design objectives for repository
components are identified, and then the designs are developed, evaluated.
and improved.
"l)1'b
0060
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Document 309-7
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Page 12 of 15
Reference Design
The
reference design
spent
. At the north
In the current reference design ,
entrance to the underground
nuclear fuel and high- level radioactive waste would be transported to Yucta Mountain by truck or rail in specially designed, shielded shipping containers licensed by the Nuclear Regulatory Commission; removed from the shipping containers and placed in long- lived waste packages for disposal; carried into the underground repository by rail cars; placed on supports in the tunnels; and
repository would be the faciliti es and
equipment to transfer waste from shipping containers to waste packages. Each
waste package would be welded closed
and thoroughly checked before being
loaded onto a shielded transporter to be
taken underground.
. At the south entrance would be the
fa-
monitored until the repository is finally
closed and sealed,
cilities to support the excavation and construction of the tunnels.
. Near the
SUl1ace facilities and operations
Surface facilities woul~ be designed to receive the waste and prepare it for final disposal , and to support the excavation, con-
struction, loading, and ventilation of the
repository tunnels. 'I' he entire surface lay-
out would cover about 100 acres and have three main areas:
Workers would be shielded from direct ex. posure to radiation and contamination be~ cause waste would be handled remotely.
tory.
top of the mountain would be
the facilities that house the air intake and
exhaust fans for ventilating the reposi-
. Artist' s ooncept of repository surface facilities
0061
DJ\
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Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 13 of 15
Reference Design
Underground facilities and operations
The underground repository would consist
of about 100 hliles of tunnels. The main
. tunnels would be
would lift the waste package, carry it along the drift , and lower it onto its supports.
designed for moving work-
ers , equipment, and waste packages. Ventilation tunnels would provide air for workers. The emplacement tunnels (or drifts)
Current schedules anticipate that waste
emplacement would begin in 2010 if a .license is received from the Nuclear Regulatory Commission, after construction of surface facilities , the main tunnels , ventilation system, and initial emplacement drifts. Ad-
would accommodate the waste packages. Two gently sloping access ramps and two
vertical ventiJation sha,fts would connect the undergt' ound and surface areas.
'I'
ditional drifts would be constructed over a period of about 20 years while waste. is be-
ransportation underground would be by
rail. A locomotive would haul the shielded
transporter wit.h its waste package underg1' ound from the waste- handling building . to the entrance of an emplacement drift.
ing emplaced. The current design would
accommodate 70 000 metric tons of waste, a limit imposed by the Nuclear Waste Policy
Act of 1982. However , the site is large
enough to accommodate additional waste, if that were authorized.
Then a remotely operated crane (or gantry)
Artist' s concept or repository underground fadlities and operations
0062
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Case 1:98-cv-00474-JFM
Document 309-7
Filed 04/16/2004
Page 14 of 15
Reference Design
The engineered barrier system
The engineered barrier syst,em is designed to work with the natural geologic barriers.
The reference repository design features a long- lived
and includes the waste FUtIAuemblyform. thc' concrete tunnel. floor (or in. Corrosion Allowance Outer Barrier
waste package
vert), and the steel
and concrete sup-
. port for the waste
pa~kage.
Inner
Backfill would consist of
crushed rock or other granu-
The current waste
package design would have two layers: a structurally strong outer layer of carbon steel nearly four inches thick
and a corrosion-resistant inner layer of a high-nickel alloy about three- fourths of an inch thick. Thesc' two layers would work
.. Barrier lid
lar material that would
placed around the waste packages in the emplacement drifts just before the repository is closed.
The DOE also is evaluating alternative designs, some of which might reduce unccrtainties regarding repository performance. (Design alternatives arc! discussed further under Long-Term Safety, page 30.
wastR. package.
together to preserve the integrity of the
Thc! wast(! forms inside the waste package would Pl'(lvide additional barriers against
transport of radionuclides away from the
repository. Most spent nuclear fuel is encased in Zircaloy, a metal cladding that is
Waste E;mplacement
highly resistant to corrosion. Defense highlevel radioactive waste would be solidified
Tunnel
as glass inside stainless steel canisters.
As the design process continues, DOE is
evaluating several design options that
might increase the ability of the engineered barrier system to contain waste. These include the following:
1 '"
. Drip shields that could keep
water from 'ipping on the waste packages
. C~rami(: coating on the waste packages that could further prevent corrosion
. Backfill that could protect the
waste
packages from falling rock or tunnel col. lapse, raise the waste packages' tempera-
. ture and lower the relative humidity
0063
PA- 196051
~~~
Case 1:98-cv-00474-JFM
Reference Design
Document 309-7
Filed 04/16/2004
Page 15 of 15
Confirmation and retrieval
Activities to confirm that a repository would
rounding rock. The effects of a repository
would be monitored ,
work as expected begin long before the first
" waste is emj)laced. In the current site characterization phase, information about Yucca
and the observed efactivities
fects would be compared to the model predictions. These confirmation
Mountain and the surrounding environment is being collected and compiled to pro-
would help determine whether a repository
is operating as expected.
If a problem is detected prior to closing the
vide a baseline against which to compare what would happen if a repository were . built and waste were emplaced.
Using mathematical models based on the
repository, remediai action or retrieval of
the waste would be possible using remotely
operated equipment. The Nuclear Regulatory COmmission currently requires that a
repository be designed to aJIow the retrieval
collected data and analyses of the engineered components, "Scientists forecast the probable behavior of the engineered system and the effects of a " repository on the Yucca Mountain environment. If repository operations begin, remote sensors would moni-
of waste at any time up to 50 years after waste operations begin. Retrieval of waste,
if needed, would follow, in reverse order, the same steps taken in emplacing the
tor the waste packages , tunnels, and sur- .
waste.
r ""
16
PeI1O!1NRCe confirmation
()P(~1o11 Cm.... ~
Assumed CIo8IHt
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2m.
Optional Closu'e
Sit ClliikriuUon
~... .f
1'1A3 . 2001
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The performance confirmation program begins with site characterization to establish a basefine and continues until repository dosure begins.
0064
PA- 196052