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Voices of the Nation
Problems of Nuclear Waste
and Yucca Mountain
As we wrestle with the problems of the everlasting legacy of
radioactive waste from nuclear powers, weapons and medical waste, we have a bad taste
in our mouths .The campaign contributions of the nuclear industry are shaping the
national debate in Congress while serious scientist are being ignored.We are being
asked to pretend that our transportation system is perfect and accident proof . Meanwhile,
the federal push to open Yucca Mountain continues. The following page includes a
letter from John LaForge and two articles.
Yucky Yucca!
compiled and edited by M.G. Hudson
A tank "farm" at Hanford, Washington on the Columbia River from Half
Life, The Legacy of America's Nuclear Waste, by Michael E. Long, Photos by Peter
Essick. National Geographic, July,
2002. Great overview --
Text in hard copy only.
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See Public Citizen's press release regarding
the Alliance for Sound Nuclear Policy, an industry group.
The Following is a letter from Nukewatch and an attached Science
Magazine article forwarded:
Dear Friends,
We rarely send appeals to call Congress, but this is a serious emergency. The U.S.
Senate needs to be swayed to stop the Yucca Mountain nuclear waste dump bill.
Please tell your U.S. Senators to vote against the Yucca Mt. proposal. (The Senate
will vote in July on whether or not to over-ride Nevada Governor Quinn's veto of
the plan.) Use the toll free number below.
The Senate is leaning toward pushing ahead with this reckless, unnecessary bail-out
of the nuclear industry. The plan calls in part for moving some radioactive waste
on barges along Lake Michigan and other major waterways. (In our lighter moments
we're calling these daredevil plans The Nuclear Edmund Fitzgerald, Titanic Mile Island,
or Chernobyl Valdez Roulette.)
For background on the issue, I have attached a good critique of the plan from the
April 26 edition of SCIENCE magazine.
You can get patched-through to your Senator's offices toll-free with this number
(which connects you with the Stop Yucca campaign in Washington): 1-888-554-9256.
Thanks for making these calls.
Sincerely, John LaForge
Nukewatch
P.O. Box 649
Luck, WI 54853
Phone (715) 472-4185
Fax (715) 472-4184
Web http://www.nukewatch.com
Background from Science Magazine
Nuclear Waste: Yucca Mountain
by Rodney C. Ewing and Allison Macfarlane
Science Magazine 296 (5568):
659 April 26, 2002, pp. 659-660
President George W. Bush has recommended Yucca Mountain in Nevada as the U.S. site
for the disposal of 70,000 metric tons of high-level nuclear waste, mainly the used
fuel from commercial nuclear power plants. This will be the world's first geologic
repository for high-level nuclear waste.
The President's recommendation to Congress initiates an automatic series of events.
Nevada has already submitted a Notice of Disapproval to Congress. On receipt of this
notice, the Congress, within the first 90 days of continuous session, can overrule
Nevada's disapproval by a simple majority. With congressional approval, the Department
of Energy (DOE) has 90 days to submit a construction license to the Nuclear Regulatory
Commission (NRC). The NRC then has up to 4 years to decide on the license application.
With NRC approval, DOE can begin construction of the repository and apply for a license
to receive waste. In the event that Congress does not overrule Nevada's Notice of
Disapproval, there is no alternative site or strategy.
The Secretary of Energy, in his recommendation to the President, maintained that
"sound science" supports the decision (1). However, during the past 8 months
three government agencies have reviewed the suitability of a Yucca Mountain repository
and have issued a series of revealing reports. In September of last year, the Advisory
Committee on Nuclear Waste of the NRC issued a letter report (2) that, among other
points, concluded that the total system performance assessment in support of the
site recommendation (TSPA-SR) "relies on modeling assumptions that mask a realistic
assessment of risk" and that "computations and analyses are assumption-based,
not evidence-supported." Last December, the General Accounting Office (3) concluded
that, "DOE will not be able to submit an acceptable application to NRC within
the express statutory time frames for several years because it will take that long
to resolve many technical issues." This past January, the Nuclear Waste Technical
Review Board issued its report (4). The NWTRB expressed "limited confidence
in current performance estimates" and found the technical bases for the repository
performance estimates to be "weak to moderate."
The President's decision should be based on a compelling and transparent analysis
of the safety of the site. This analysis requires a strong scientific basis. Although
the Secretary of Energy has detailed the activities over the past 15 years [e.g.,
the collection of over 75,000 feet of core and 18,000 geologic and water samples
(1)], such figures alone do not establish the scientific basis for the recommendation.
The necessary science to support this decision requires an analysis that couples
atomic-scale processes, such as spent fuel and waste package corrosion, to crustal-scale
processes, such as volcanic activity and climate change, that extend over temporal
scales of thousands, if not tens of thousands, of years.
This is an unprecedented, first-time effort. Geologic disposal of high-level nuclear
waste is not a short-term science and engineering effort like the Manhattan Project,
for which near-term success was evident. The construction of a repository does not
demonstrate its safety. The safety case can only be based on a scientific understanding
of the processes that control the release of radionuclides and a design strategy
that uses a series of independent barriers to reduce the uncertainty in the safety
analysis. The current understanding of the performance of the engineered barriers
(e.g., the waste form and waste package) and the geologic processes of the mountain
(e.g., transport though the unsaturated and saturated zones) falls far short of that
required to make a substantive evaluation of the safety of the repository. We can
never know whether the repository "worked" as designed. Even with an operating
period lasting for hundreds of years and the possibility of an engineered "fix"
for problems, we cannot know whether the predicted behavior of the repository matches
its actual performance. This would be an unreasonable expectation; however, the law
requires that there be a "reasonable assurance" that the repository meets
regulatory requirements. How do we develop a reasonable assurance? For most technologies,
operating experience is the basis for predicted reliability. Nuclear reactors are
safer today than when originally designed and built. This is because we have the
benefit of actual operating experience with over 400 nuclear reactors around the
world. In the absence of relevant operating experience, we are left in an unusually
demanding position in which we must rely on our understanding of natural processes
that operate on geologic time scales in order to predict the future behavior of a
nuclear waste repository. This task requires extensive knowledge and a strategy that
minimizes the uncertainty in the safety analysis.
The DOE has based its positive recommendation to the President on a comprehensive
performance assessment of the repository in its Preliminary Site Suitability Evaluation,
with thousands of pages of supporting documents. The DOE's conclusion is that the
Yucca Mountain repository will meet the Environmental Protection Agency's (EPA's)
final radiation protection standard in the Code of Federal Regulations, 40 CFR 197,
and the NRC's repository licensing criteria, 10 CFR 63.
Both the EPA standard and the NRC regulations have taken nearly 20 years to develop
and have only recently been available for public comment. The site-specific standard
and the implementing regulation are based on the calculation of a dose to individuals
at a distance of approximately 20-km from the repository over a 10,000-year period.
The determination of compliance depends almost exclusively on the results of the
total system performance assessment. At the same time, the disposal strategy has
moved away from the use of geologic barriers and now relies heavily on the role of
engineered barriers, mainly a highly durable, metal waste package protected from
water by umbrella-like "drip" shields. By lessening the importance of the
geologic barriers, the properties of the site become less important. Indeed, the
original concept of geologic disposal has been turned on its ear.
In the face of the scientific uncertainties about the site, there is a surprising
sense of urgency to move forward with a positive decision on Yucca Mountain as a
nuclear waste repository. In the coming months, utilities that own nuclear power
plants and states that have spent nuclear fuel stored at the reactors will press
hard for action to approve the Yucca Mountain site, their concern heightened by fears
of terrorist attacks on the storage facilities. Some have argued that the future
of nuclear power is at risk in the absence of a positive decision. The Secretary
of Energy has said that a permanent geologic repository "will promote our energy
security by removing a roadblock to expanding nuclear power" (5). Thus, the
present sense of urgency is driven not by an understanding of the properties of the
Yucca Mountain site, but rather by larger-scale policy decisions concerning nuclear
power and national security. Decades of effort costing billions of dollars, and,
in fact, our entire site-specific regulatory framework are now at risk if we do not
accept Yucca Mountain as a repository. As a public, we are presented with a major
policy decision for which there is no alternative strategy or site. In fact, the
Nuclear Waste Policy Act Amendments of 1987 eliminated alternative sites. The present
decision to make Yucca Mountain a repository for high-level nuclear waste is a political
decision that was presaged by the 1987 NWPAA. The scientific basis for the selection
of the Yucca Mountain site continues to be only a marginal consideration.
What of the science? Are there essential scientific and technical issues that can
potentially affect the performance of the repository? Does the method of analysis
provide a substantive basis for evaluating the safety of the repository? Are there
deficiencies in the disposal and containment strategy, either as proposed by DOE
or as allowed by the standards and regulations?
In our view, the disposal of high-level nuclear waste at Yucca Mountain is based
on an unsound engineering strategy and poor use of present understanding of the properties
of spent nuclear fuel.
The repository has been placed at a depth of 300 meters below the surface in the
unsaturated zone, some 300 meters above the water table. The United States is the
only country in the world that has pursued the concept of placing a repository in
the unsaturated zone. The original rationale for selecting the unsaturated zone at
Yucca Mountain was based on having a "dry" repository, as water would be
the main agent for release and transport of radionuclides. A dry repository has been
elusive, as the percolation flux of water through the repository has been difficult
to estimate (6). Initial predictions of 4 mm/year were reduced to less than 0.5 mm/year
during the early years of the project, and the low value seemed to validate the original
concept. However, in 1996, scientists at Los Alamos National Laboratory discovered
elevated levels of 36Cl at the repository horizon (7). If this 36Cl is the result
of atmospheric testing of nuclear weapons, which ended in 1963, the "bomb pulse"
36Cl provides evidence for rapid transport of some water through the unsaturated
zone. Although this issue, the role of fast path transport in the unsaturated zone,
remains unresolved, these results have changed the basic picture of how the repository
works. As described by Daniel Metlay, a staff member for the Nuclear Waste Technical
Review Board, instead of being a "tin roof," Yucca Mountain is "more
akin to a torn wet blanket" (5). The efforts to keep the repository dry have
resulted in a variety of engineered "fixes." For example, the "hot"
repository design would drive water away from the repository horizon. Only after
cooling would water seep back through the formations. Another fix has been the drip
shield that would protect the waste packages from water that finds its way to the
repository horizon. Regardless of the results of future scientific studies or the
efficacy of the engineering fixes, the uncertainty in the estimated percolation flux
will ultimately be tied to climate change. It is a poor design strategy that relies
on assumed boundary conditions, rather than the properties of the repository itself.
The Yucca Mountain repository is essentially a repository for the disposal of used
nuclear fuel that consists mainly of reduced uranium in the form of UO2. More than
95% of the total radioactivity will originate from this spent nuclear fuel. After
the engineered barriers have failed, the release of radionuclides will depend on
the chemical durability of the fuel. In the presence of even minor amounts of moisture
and under oxidizing conditions, UO2 is not stable. The process of degradation, initiated
by oxidation of U4+ to U6+, is rapid and pervasive (8). Orders of magnitude of durability
for the spent fuel would be gained by maintaining reducing conditions at the repository
horizon (9). This is well established by many experimental studies using UO2 or actual
spent nuclear fuel and is confirmed by numerous studies of uranium deposits (10).
At Yucca Mountain, the passive properties of the repository site do not provide a
long-term barrier to radionuclide release.
The concept of placing spent nuclear fuel in the unsaturated zone where it will experience
oxidizing conditions is simply a poor strategy. This is a strategy that finally relies
on an optimistic assessment of the long-term durability of metallic waste packages,
such as the presently proposed Ni-Cr-Mo alloy, C-22, an alloy for which there are
only limited data. The Secretary of Energy has pointed to studies of "over 13,000
engineered material samples to determine their corrosion resistance in a variety
of environments" (1), but there are few data on the C-22 alloy, and the uncertainty
in its extrapolated behavior is high (11).
In addition to these fundamental issues of strategy, there are other unresolved technical
issues (4): the continuing controversy over the frequency and impact of volcanic
activity (12), the role of sorption in the unsaturated zone in reducing radionuclide
mobility (13), and the role of colloids in enhancing transport (14).
With further study, Yucca Mountain may be judged to be an adequate site for the disposal
of nuclear waste, but a project of this importance, which has gone on for 20 years,
should not go forward until the relevant scientific issues have been thoughtfully
addressed. Some have suggested a "staged" approach that would allow an
opportunity for such studies, but of course, "staged" can have two meanings.
To move ahead without first addressing the outstanding scientific issues will only
continue to marginalize the role of science and detract from the credibility of the
DOE effort. As Thomas Jefferson cautioned George Washington, "Delay is preferable
to error."
References and Notes
1.Letter to President G. W. Bush from Secretary of Energy S. Abraham, Recommendation
for the approval of the Yucca Mountain site, 14 February 2002.
2.Advisory Committee on Nuclear Waste, letter report to R. A. Meserve, Chairman,
U.S. Nuclear Regulatory Commission, 18 September 2001.
3.Government Accounting Office, "Nuclear waste: Technical, schedule and cost
uncertainties of the Yucca Mountain repository project" (GAO-02-191, Government
Accounting Office, Washington, DC, December 2001); available at http://www.gao.gov/new.items/d02191.pdf
4.Nuclear Waste Technical Review Board, letter report to Congress and the Department
of Energy, 24 January 2002.
5.Remarks delivered by Secretary of Energy S. Abraham to Global Nuclear Energy Summit,
Washington, DC, 14 February 2002.
6.D. Metlay, in Prediction Science, Decision Making and the Future of Nature, D.
Sarewitz, R. A. Pielke Jr., R. Byerly Jr., Eds. (Island Press, Washington, DC, 2000),
pp. 199-228.
7.K. Campbell, A. Solfsberg, J. Fabryka-Markin, D. Sweetkind, J. Contam. Hydrol.,
in press.
8.D. J. Wronkiewicz et al., J. Nucl. Mater. 190, 107 (1992).
9.L. H. Johnson, L. O. Werme, Mater. Res. Bull. 19, 24 (1994).
10.K. A. Jensen, R. C. Ewing, Geol. Soc. Am. Bull. 113, 32 (2001).
11.A. A. Sagüés, Mater. Res. Soc. Proc. 845, 845 (1999).
12.C. B. Connor et al., J. Geophys. Res. 105, 417 (2000).
13.D. Vaniman et al., Geochim. Cosmochim. Acta 65, 3409 (2001).
14.A. B. Kersting et al., Nature 396, 56 (1999).
R. C. Ewing is in the Departments of Nuclear Engineering and Radiological Sciences,
Geological Sciences and Materials Science, and Engineering, University of Michigan,
Ann Arbor, MI 48109-2104, USA.
A. Macfarlane is in the Security Studies Program, Massachusetts Institute of Technology,
Cambridge, MA 02139, USA.
*To whom correspondence should be addressed. E-mail: rodewing@umich.edu
Volume 296, Number 5568, Issue of 26 Apr 2002, pp. 659-660.
Copyright © 2002 by The American Association for the Advancement of Science.
All rights reserved.
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Also see Alliance for Sound Nuclear
Policy a "Front Group" for Nuclear Energy Institute (NEI).
Material from Science Magazine used under Fair Use copyright law for educational
purposes.
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