Skip to content

Book Review: Too Hot to Touch: The Problem of High-Level Nuclear Waste

May 25, 2015

tags: Atomic Energy Commission, dry cask storage, groundwater, high-level radioactive waste, low-level radioactive waste, National Academies of Science, National Research Council, Nevada Test Site, Nuclear Regulatory Commission, Plowshare Program, radionuclide migration, spent nuclear fuel, transuranic waste, unsaturated zone, Ward Valley, waste disposal, WIPP, Yucca Mountain

 

by Howard Wilshire

Too Hot to Touch: The Problem of High-Level Nuclear Waste, Cambridge University Press

By William M. and Rosemarie Alley 2013

This review is presented in two separate sections: SECTION 1. A summary impression of the book and SECTION 2. More detailed comments on individual chapters 10, 14, 17, and 18. Note: this review was originally posted April 13, 2014 and included a long section giving brief reviews of every chapter. That section has been deleted, but can be supplied upon request to any interested party.

SECTION 1

While Too Hot to Touch contains substantial information useful in educating the public about the dire mess we have made of dealing with both military and civilian high-level nuclear waste (HLRW), it is badly organized on two levels, arrangement and subject matter of chapters in the three parts, and internal disorganization within particular chapters:

Parts I and II contain chapters not relevant to the book’s subject matter. For example, Part I inappropriately contains a chapter (10, A can of worms) about a proposed low-level radioactive waste (LLRW) facility, and Chapter 11 is about an existing repository that is forbidden to accommodate high-level radioactive waste (HLRW); Chapter 14 in Part II has such a minimal amount of material, cited in Chapter 18, relevant to HLRW disposal that it interrupts the flow of information about HLRW.

Chapters 8, Dry cask storage, and 11, WIPP repository do not belong in Part I as they are not part of the problem, but rather partial solutions to the problem. Chapter 16, How long is long? in Part II is essentially irrelevant to the issue of HLRW disposal, disrupting the flow of information that seems, from the book’s title, to be its primary subject. The title of Part II, The mountain, is presumably a reference to Yucca Mountain, but starts with a chapter (12, The search for a geologic repository) that barely mentions Yucca Mountain and is followed by a chapter (13, Nevada wins the lottery) that appears to be a lead-in to the main topic of Part II (Yucca Mountain). Separating chapter 13 from the main package of Yucca Mountain chapters with chapter 14, The Nevada Test Site, makes it difficult to focus on the authors’ message(s).

Disorganization infects some chapters internally as well, for example Chapter 17, Leaving almost no stone unturned. Others, for example Chapters 6 (The peaceful atom and its wastes), and 15 (Yucca Mountain) are so incomplete as to interfere with the book’s continuity.

Chapters not relevant to the book’s subject (10, A can of worms and 14, The Nevada Test Site) or too disorganized for an easy short summary (17, Leaving almost no stone unturned and 18, Surprise) are reviewed in SECTION 3.

On the brighter side, I found the historical information provided in such chapters as 1 (The awakening), 2 (Brainstorming), 11 (WIPP), 12 (The search for a geologic repository), and 20 (The project gets into hot water) informative and interesting.

The treatment of science in the book is a mixed bag. There are quite good explanations of scientific issues involved in earlier attempts at addressing the problems of waste disposal. But when it comes to the repository, to Yucca Mountain, the book’s explanations of scientific issues are too often fuzzy, annoyingly incomplete, and embroidered with too much marginal background material. Arcane subjects such as TSPA (Total System Performance Assessment) and conceptual groundwater models are abruptly introduced and poorly explained.

There are too many omissions of important studies relevant to the book’s subject, for example the book contains no comprehensive statement of the scope of the HLRW problem: how much of it do we have?, where is it?, how is it being stored?, how much more are we creating annually?, who controls it? There is no comprehensive statement of what was expected from the concept of multiple barriers to loss of waste containment. And, discussions of specific waste sites, both domestic and foreign, lack adequate statements of their geologic settings, including Yucca Mountain.

Edit

LEAVE A COMMENT

from Uncategorized

SECTION 2

Chapter 10, A can of worms

This account expands on my Amazon review of Too Hot to Touch. In my opinion, chapter 10 is a knowledgeable misrepresentation of events surrounding a proposed low-level radioactive waste (LLRW) disposal site in Ward Valley, California. Departing from the principal subject matter of the book (HLRW), it is the second longest of 22 chapters. I was directly involved in this matter and was criticized, along with respected colleagues. William Alley was also personally involved in this issue, but does not disclose that fact in his book.

The core of the story told in Chapter 10 is: 1) disruption of the process of establishing a low-level radioactive waste (LLRW) disposal facility at Ward Valley, California by three U.S. Geological Survey (USGS) geologists the Alleys call the “Wilshire group” (myself and two other senior USGS geologists); 2) the National Academy of Sciences (NAS) review of 7 concerns of the “Wilshire group” raised with Secretary of the Interior Bruce Babbitt; and 3) the testimony of David Prudic, USGS hydrologist, before the NAS panel.

Chapter 10 starts by setting up David Prudic as a principal scientist in the publicly contentious issue of establishing a LLRW facility at Ward Valley, California. This is done in a folksy way, but describes him as “a stickler for detail and scientific rigor” with important information to present to the NAS panel gathered in Needles, California July 7-9, 1994 to examine the “Wilshire group’s” concerns.

Enroute to Prudic’s testimony, the “Wilshire group” is charged in the book with various sins, the most significant one, made twice, is they “raised issues [about the safety of Ward Valley] outside their field of training and expertise (p. 137).” For William Alley, a hydrogeologist, this seems to be a claim of territorial rights—a presumption that only hydrogeologists, are qualified to talk about water movement in the subsurface, and not geologists (in particular, the “Wilshire group”).

Lesser charges were made of breaching USGS protocols by directly contacting Interior Secretary Babbitt with their concerns (I plead guilty; otherwise our concerns would not have reached the Secretary); and sending a detailed report on their concerns to Babbitt “…that had not gone through the peer-review process that precedes release of any USGS scientific document (p. 137).” The Alleys are wrong on both counts: the “detailed report” was not sent to Babbit, but rather to the person who requested it, U.S. Senator Barbara Boxer, and it was peer-reviewed, just not officially by the USGS.

Here is what really happened: The “Wilshire group” sent a one-page memorandum (February 24, 1993) to Secretary Babbitt expressing our concern about the inadequacies of the very limited USGS involvement in preparation of the Ward Valley Environmental Impact Report/Statement (EIR/S), and offering our assistance as he evaluated transfer of federal land to the state of California—we were, after all, his employees since the USGS is an agency within the Department of the Interior, and we did have expert experience with the geology of the Ward Valley region. On May 26, 1993 we were invited by the Secretary’s office to submit a statement of our concerns, which we provided in a two and one-half page outline, dated June 2. We had no further contact with Secretary Babbitt or his office staff.

Secretary Babbitt’s staff (unknown to us) released our June 2 memo, a copy of which found its way to the company—US Ecology—which was licensed by the State of California to operate the Ward Valley dump. US Ecology sent Babbitt a lengthy rebuttal of our short outline. We were completely unaware of that document until September 1993 when we were contacted by Senator Boxer’s office. When they discovered we had not seen the US Ecology rebuttal, they faxed a copy and asked for our response. After reading it, we told Boxer’s staff that it was “slick and wrong.” They then asked us to respond to the US Ecology critique and elaborate our concerns. It is that report (we call it the “Boxer report”)—sent to Senator Boxer December 2, 1993 that the Alleys erroneously refer to on p. 137. We did go through USGS channels for approval to respond to Boxer.

Strangely, the Alleys miss two main points about peer-review of the report: it was the decision of USGS management, in which William Alley participated, that our response to the US Ecology rebuttal be done as private citizens, and the report therefore did not go through the USGS peer-review process. It appears also that the Alleys did not read the “Boxer report” as its title page and text acknowledge peer reviewers.1

In preparation for the NAS review, the “Wilshire group” expanded to 10 members (by agreement with the National Research Council (NRC), six of whom are USGS scientists,2 but continued to be identified by the Alleys as three geologists raising issues “outside their field of training and expertise.” All seven of our concerns were addressed by experts on the NAS panel, but I will address only the issue of contaminant migration through thick unsaturated zones to the water table. Widely considered geologic barriers to contamination of groundwater, thick unsaturated zones represent formidable barriers at Ward Valley (~650 feet thick) and at the Beatty Nevada LLRW disposal site (~280 to 370 feet thick), the latter studied by Prudic and colleagues. Considered by Ward Valley proponents to be geologic analogs, information about either of the two sites was deemed applicable to the other.

The Alleys present their own assessment of this issue, leading to the testimony of David Prudic regarding his long-term USGS research at the Beatty, Nevada LLRW facility. The bottom line of Prudic’s testimony was that water movement in the unsaturated zone at Beatty and Ward Valley had been restricted to the upper ~30 feet of the thick unsaturated zones during the past 16,000 to 33,000 years. Therefore, contamination of the groundwater by materials dumped at those sites was not credible, at least for thousands of years.

There was, however, the inconvenient finding during site characterization of a very small amount of tritium at a depth of 100 feet at Ward Valley. Tritium, a radioactive isotope of hydrogen, was a major component of fallout worldwide from bomb testing during the Cold War; it is also a major constituent of radioactive materials dumped at Beatty. Tritium migrates with water and fallout tritium is widely used as a tracer for water movement in the subsurface. Hence, the finding at a depth of 100 feet in Ward Valley, if correct, would mean it had traveled 100 feet in less than 50 years, and would thus contradict Prudic’s conclusions. Discussion was vigorous, with most of the NAS panel leaning toward discounting the Ward Valley data as resulting from improper sampling or analytical error.

During Prudic’s presentation, one panel member asked him if he had any tritium data on the unsaturated zone at Beatty. His answer was that samples had been submitted for tritium analysis but he had not seen the results. The Alleys’ characterization of this episode (p. 144-145) was that “Prior to the [NAS] meeting Prudic learned that the tritium results had come back and were larger than expected, but he hadn’t seen the results.” Prudic avoided answering the question and the Alleys’ book tries to make it appear that he had told the panel of the results, but he had not. Put plainly, Prudic was informed by telephone of the tritium findings by his colleague Robert Striegl two weeks before the NAS meeting, but he hadn’t received a copy of the piece of paper on which the lab report was written. The reported results for tritium contamination were indeed much larger than expected and affected the entire unsaturated zone.

Further questioning revealed that Prudic did in fact have data showing groundwater contamination by tritium in a well drilled by USGS in 1987 just outside the dump. Groundwater from that well was sampled in 1989 yielding replicated positive tritium values. Prudic speculated that the tritium came from drilling fluid from the 1987 well emplacement although the well had been purged before it was sampled. Further probing revealed major tritium contamination of groundwater in a US Ecology monitoring well very close to the USGS well in 1982-1984, for which Prudic had no explanation.

Prudic’s failure to inform the panel of what he really knew about the new tritium results, whether or not he had seen them on a piece of paper, had a significant impact on the NAS panel’s report. Four months after the May 11, 1995 release of that report, a panel member made the following statement to a meeting of the Nuclear Regulatory Commission:

Mr. Wierenga: [Excerpt] “I had the pleasure this year to serve on a national academy panel to look into Ward Valley. As you know, Ward Valley was licensed by the State of California as a disposal site for low level nuclear waste. And it became very clear to the panel that it was not possible to give this site favorable recommendation just based on the data from the contractor. There would have been no chance in the world that we would have had the majority of the committee do this. As it is, there’s all the additional information, some of it at Yucca Mountain, some of it at the Beatty site, some of it from New Mexico [WIPP site], some of it from Texas [Sierra Blanca] – the committee basically disagreed with the three hydrologists [sic][“Wilshire group”] who said that the site was not suitable and there were major problems.“3

The problem with this statement is that Beatty was the only facility among the sites listed that had actually served as a waste repository, and Prudic had left the panel uninformed about new data in hand that had the potential to directly contradict his hypothesis. Models of processes in the unsaturated zone serve useful purposes, but they can only be verified by real data on what has actually happened or is happening. Prudic’s model was in jeopardy, and he seemed reluctant to inform the panel of potential problems, old ones as well as budding ones. Absent from the Alleys’ book is any mention of these issues.

The preliminary results of the 1994 USGS sampling of the deep unsaturated zone outside of the Beatty dump were clearly unsettling to Prudic and Striegl, leading them to try on several explanations that preserved their model, which would not allow such contamination to have occurred naturally. As the Alleys state (p. 145), “it was unprecedented that tritium gas would work its way through the deep UZ to 350 feet outside the fence (emphasis in original)”. Unprecedented, that is, except for the substantial earlier data that tritium, whether gas or liquid, had indeed accomplished that trick at Beatty, more than once.

Most research scientists can appreciate the feeling of dismay when a perfectly beautiful hypothesis is threatened by ugly facts. What is difficult to appreciate is Prudic’s unwillingness to tell the NAS panel what he knew. The panelists were, after all, experts with a lot of experience. He could have told them the results were preliminary and needed verification, and surrounded the information with whatever caveats he chose. He could have chosen, perhaps reasonably, not to reveal this information in a public setting, but there were months ahead in which he could have informed the panel in a non-public venue as they worked on completing their report. This opportunity was not exercised. Instead, a USGS report written by Prudic on Beatty and Ward Valley in which the same conclusions about restricted water movement in the unsaturated zone as he presented at the July 7-9 NAS meeting was special-delivered to the panel at its second meeting a month later.

Fallout from Prudic’s choice to leave the NAS panel uninformed of his preliminary tritium results was a split decision of the panel’s recommendation to verify the small tritium values reported for Ward Valley. The majority of panelists favored performing the new measurements during site development, an expression of their confidence that the original measurement was in error. Two panelists, both hydrogeologists, favored verification before the dump was permitted. What influence Prudic’s data might have had is unknown, but the panel’s report was seen as a green light for constructing the dump, mitigated by a number of recommendations including testing for tritium.

Why the NAS panel chose to discount the pre-1994 data on tritium contamination of groundwater at Beatty is not clear.4 They were given an oral account of the issues at their second public meeting in August 31-September 2, 1994, and a 21-page comprehensive report, on which the oral presentation was based, was delivered to the NAS October 12, 1994.5 It showed clearly why interpreting the reported contaminations as results of migration of the contaminants through the unsaturated zone is viable. This report is not referenced in the NAS report. Also in October 1994 another report6 giving substantial additional information on Beatty contaminant migration was published; this report is cited only in one of the two panel dissents (Appendix F). The two 1994 reports were available to the NAS panel for eight months before their report was released. Presumably the dissenting opinions were known to all panel members in ample time to perhaps have introduced a stronger element of caution into their deliberations. Appendix F is an excellent, experience-based, fully referenced account, directly relevant to Prudic’s model of water migration in arid lands unsaturated zones. And, who knows, maybe reviewing this information would have led the Alleys to a more circumspect endorsement of the (unverified) Prudic model of water movement in the unsaturated zone.

Completion of retesting the Beatty sampling, months after release of the NAS report, left no question that the dump was the source of the tritium contamination, and, as the Alleys put it (p. 146), “For the first time, scientific lingo described what the test results had revealed: a plume of unexpectedly high levels of tritium had been detected in the unsaturated zone 350 feet7 outside of the Beatty, Nevada LLRW disposal facility.” Of course, “In spite of years of study, the exact cause of the tritium gas in the unsaturated zone remains unknown” (p. 151). One thing was learned: the model of fluid behavior in the unsaturated zone on which the NAS relied is not valid. Another lesson derives from knowledge of a tritium plume moving laterally long distances through the unsaturated zone, which conflicts with the NAS report’s discussion of the potential for lateral flow (p. 130).

NOTES AND REFERENCES

1“Boxer report” disclaimer: “This report does not represent the policies or positions of any government agency. It does represent the professional judgments of its authors who are employed by the U.S. Geological Survey as research geologists. The report has been reviewed by professional scientists in geology, hydrology, isotope geochemistry, and soil physics, and has been modified by consultation with many experts in these fields within and outside of the USGS

2The enlarged “Wilshire group” was composed of five geologists, two hydrologists, one soil physicist, one isotope geochemist, and one biologist. The NRC denied us our choice of an expert on the LLRW waste stream, a very controversial issue, misunderstood by the NAS panel report.

3Aside from identifying the “Wilshire group” as three hydrologists, there are two errors in Wierenga’s statement: the panel was charged only with evaluating the seven concerns of the “Wilshire group”, not sanctioning the site. We made it clear to the panel at the outset of the NAS review that we did not have a position on the suitability of the site for the proposed use; our problems were with the adequacy of the EIR/S’ supporting data and analysis.

4The NAS report’s majority decided (p. 23) “…that the Beatty site may be useful in understanding some natural processes, but it is limited in evaluating the behavior of the Ward Valley site because of the historical uncertainties.”That is, because of “unexplained anomalies in the 30-year monitoring records of well data,” which did not accord with the panel majority’s views of unsaturated zone processes.

5Committee to Bridge the Gap and Southern California Federation of Scientists, The Proposed Ward Valley Radioactive Waste Facility: Papers Submitted to the National Academy of Sciences, October 12, 1994

6Conference of Radiation Control Program Directors, Inc. Environmental Monitoring Report for Commercial Low-Level Radioactive Waste Disposal Sites, Chapter 4, Environmental Summary of the Beatty, Nevada Low-Level Radioactive Waste Disposal Site, October 1994

7Contamination extended far beyond the UZB-2 drill hole located 350 feet from the dump fenceline. An 820 X 820 feet grid of 58 sample points outside of the dump fence were sampled in 5.5 foot deep hand-driven cores. All cores were positive for tritium, ranging from <50 tritium units to 35,000 tritium units (TU). Contours of equal TU show a declining gradient to the southwest from the dump. The full depth to which tritium contamination penetrated at these sample points is not known. R. G. Striegl and others, Tritium in Unsaturated Zone Gases and Air at the Amargosa Desert Research Site and in Spring and River Water, Near Beatty, Nevada, May 1997, U.S. Geological Survey Open-File Report 97-778

Chapter 14, The Nevada Test Site

Designation of the Nevada Test Site (NTS) to replace the Pacific island testing areas is a remarkable story of fuzzy rationalizations and deliberately falsified public assurances by politicians, federal agencies, and too many scientists. The story told here is too cute for my tastes, but is interesting. Following the story is an account of early testing that presaged very serious problems to come. However, the chapter has nothing to do with disposal of HLRW and does not belong in Part Two, The mountain. It is more appropriately an element of the Cold War legacy.

Taking a big leap in the bomb-testing story, pages 212-214 relate some aspects of the Plowshare Program for peaceful uses of nuclear explosions (PNE), a section that belongs in Chapter 6. The 1963 Limited Test Ban Treaty banned atmospheric testing and struck fear in the heart of physicist Edward Teller that he might have to stop detonating bombs, and sent AEC Chairman Glenn Seaborg into raptures: “Plowshare can help mankind reshape the earth into a Garden of Eden by overcoming the forces of nature”.

The Plowshare Program was intended to make sure weapons testing continued in the guise of peaceful applications, but the descriptions in Too Hot to Touch leave too much out. It is stated (p. 213) that “…the only experiment actually tried in practice was using bombs to ‘stimulate’ natural gas production in Colorado and New Mexico.” In all 27 nuclear detonations were performed with peaceful uses in mind, 10 to test PNE explosives design; six to determine excavation characteristics (including Sedan Crater, Fig. 14-2); four for heavy element (transuranic) production; three for natural gas production stimulation; two to examine emplacement techniques; and one each for steam power generation and determining blast effects in limestone rocks. 23 of these tests were conducted on the NTS.1 Ten other projects made it to the drawing boards, but, happily, were never executed. Three of these were mentioned by the Alleys, including the proposal to excavate the right-of-way for Interstate Highway 40 and railroad through the Bristol Mountains in California by simultaneous detonation of 23 nuclear bombs (totaling 1,830 kilotons). This project was actually endorsed by the National Research Council, Army Corps of Engineers, and the U.S. Geological Survey.2   Other harebrained proposals, among an elite list, that made it to the drawing boards were a series of water projects that I thought might have attracted William Alley’s attention; these included a project that aimed to “conserve” surface waters along Arizona’s Gila, Salt, and Little Colorado rivers by directing them into bomb craters that would serve either as reservoirs or groundwater recharge basins.

The narrative then returns to brief accounts of the bomb detonation history on the NTS, followed by a very nonspecific account of health impacts of atmospheric tests.3

Missing in this chapter, are the dozens of so-called “safety” or “equation of state” surface experiments that blew up packages of plutonium and uranium with high explosives to examine the size distributions of resulting radioactive particles. In rationalizing the lack of cleanup of most such sites, the U.S. Energy Research and Development Administration (now the DoE) stated “The above ground areas where safety experiments have been conducted in the past offer unique sites for studies of the behavior of plutonium in the natural environment. Recognizing this, the Nevada Operations Office intentionally has preserved these areas.4

One of these “safety” experiments, Area 13, just offsite from the NTS, is especially important because of several years of careful monitoring of soil, soil organisms, vegetation, and cattle impacts. Processes of biotic transport, from soil organisms to transient wildlife and health impacts on cattle impounded in the contaminated area were studied in detail.5

NOTES AND REFERENCES

1A.G. West and R.C. Kelly, A Selected Annotated Bibliography of the Civil, Industrial, and Scientific Uses for Nuclear Explosions, TID-4500, Oak Ridge, Tenn., U.S. Atomic Energy Commission, Division of Technical Information Extension, 1971

2National Research Council, Application of the Plowshare Program of Nuclear Excavation Experimentation to Highway Construction, Circular No. 20, 1966; B.C. Hughes, The Corps of Engineers’ Nuclear Construction Research Program (in L.E. Weaver, Ed. Education for Peaceful Uses of Nuclear Explosives, University of Arizona Press, 1970); F.N. Houser and E.B. Eckel, Possible Engineering Uses of Subsidence Induced by Contained Underground Nuclear Explosions, U.S. Geological Survey Professional Paper 450-C, 1962

3To help fill in the large gap regarding health impacts of atmospheric testing in Too Hot to Touch, see S.I. Schwartz (ed.), Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940, Brookings Institution Press, 1998; see also Chip Ward Canaries on the Rim: Living Downwind in the West (New York: Verso Press, 1999)

4U.S. Energy Research and Development Administration, Final Environmental Impact Statement, Nevada Test Site, Nye County, Nevada, by Energy Research & Development Administration, 1997

5Much of the information on Area 13 is in gray literature, summarized by Wilshire and others, The American West at Risk, Appendix 6

Edit

LEAVE A COMMENT

from Uncategorized

Chapter 17, Leaving almost no stone unturned

On the whole, this chapter is a poorly organized agglomeration of topics, contains far too much “backround material” that is irrelevant to the subject of the book and the immediate topic, fails to clearly explain the TSPA in its various iterations, and gives no idea of the negative expert opinions of the adequacy of the TSPA for site recommendation or licensing. Description of “major experiments” without saying at least briefly what they revealed, is at best annoying.

With the cart leading the horse, this chapter starts with the delivery of a truck load of copies of license applications, each weighing 110 pounds we are told, to construct a nuclear waste repository at Yucca Mountain. Having still not provided the reader with a simple, straight forward-account of what a geological repository was supposed to accomplish1, the reader is launched into DoE’s Total System Performance Assessment (TSPA) based on about 3 billion dollars worth of studies of Yucca Mountain accumulated through 1998—these studies comprised the main part of the 110 pound applications for licensing construction of the Yucca Mountain repository.

The TSPA, the reader is informed, “was built by stringing together computer models of widely differing levels of detail…[which] are highly simplified descriptions of the real world.” By implication, this approach is deemed necessary because “In spite of [the] limitations, using computer models for prediction is irresistible given society’s demands of certainty. It is simply not good enough to say that a site looks good….Regulators require quantitative predictions to compare to standards for site performance, with the assumption that predictions based on our knowledge of physics and chemistry are better than no predictions at all.” I suspect that society can come to grips with uncertainties if they are clearly explained, and, especially, if it has to. As for regulators “requiring quantitative predictions”, simplified models won’t get them there no matter how many iterations they are put through.2

Evaluating how good the several versions of the TSPA may be in assessing the degree of confidence that the repository will behave in an acceptable manner over a long period of time, is not easy. Too Hot to Touch broaches the subject in terms of assessing the TSPA’s “credibility” by giving a lengthy description of the Nuclear Waste Technical Review Board’s (NWTRB) creation (established as part of the 1987 Nuclear Waste Act amendments), staffing (“selected in a similar fashion to the Supreme Court justices, but with term limits”), and given authority and autonomy.

Nevertheless, the progress of the TSPA is assessed (p. 262) thusly “While the uncertainties remained great, the results of each generation of TSPA increasingly suggested that the Yucca Mountain repository would meet regulatory standards…and might even ace the license application test.” Remarkably the Alleys fail to record that in January 2002, the NWTRB expressed “limited confidence in the current performance estimates”, and found the technical bases for the repository performance estimates to be “weak to moderate 3 More damning assessments, also not cited by the Alleys, were recorded earlier: in February 1999, a very comprehensive review4 was highly critical of vital segments of the TSPA; in September 2001, the NRC’s Advisory Committee on Nuclear Waste, in response to the TSPA in support of the site recommendation was that it “relies on modeling assumptions that mask a realistic assessment of risk” and that “computations and analyses are assumption-based, not evidence-supported.”5 There appears to be no substantive evaluations of the TSPA since 2002 that might indicate improvements before submission of the license application in 2008.

In a belated effort to say something about the scientific underpinning of the license application, the subject then switches abruptly to development of the Exploratory Studies Facility (ESF), a 5-mile long U-shaped tunnel big enough for a railroad to carry scientists to various experiments performed close to, but not in the part of the mountain scheduled to be the repository. Combined with extensive surface geologic mapping, inspection of hundreds of shallow pits and trenches, and drilling of about 500 boreholes, scientific studies made in the tunnel formed the basis of the license application. The NWTRB did a useful service here by pressuring the DoE to dig a smaller tunnel above the ESF to provide direct access to rock units present in the proposed repository horizon.

Carried by the ESF railroad to location, scientists conducted more than 20 major studies. In one of these, water containing chemical tracers was released in that smaller tunnel in the geologic horizons to be used in the repository. This was to examine the relationship between water percolating through the mountain and seepage into the drifts (where the waste was to be deposited). In another study, moisture was monitored to evaluate possible preferential pathways provided by faults. It would have been more useful to explain what these two major experiments actually revealed, rather than describing the huge expensive machine that dug the tunnel, that it was painted white, and that it could not be sold even for scrap when its job was done.

Another series of studies (p. 266) examined how heat flow affects hydrologic, mechanical, and chemical processes in the proposed repository. The importance of these studies is explained in the following section How Hot is Hot? which discusses the “thermal pulse” that arises once the repository is sealed. Upon sealing, the heat generated by radioactive decay of the waste is no longer dissipated to the atmosphere, so temperatures rise rapidly above the boiling point of water and persist at those levels for about 1000 years. The repository design choices for dealing with this issue and problems attendant on each are well described in this section. But again, the reader is left uninformed about what the experiments actually revealed, while being entertained with information about the importance and immensity of the experiment.

NOTES AND REFERENCES

1The principal elements of the geological disposal strategy are: 1) it was to be deep, permanent, and long term, using to advantage the decrease in radioactivity, thermal output, and radiotoxicity over time; 2) the geologic history of stable regions was taken as indicative of continued future stability; and 3) the passive hydrologic and geochemical properties of the geologic formations were to be key to the isolation strategy. The large uncertainties in predicted future behavior were to be reduced by a system of independent, multiple barriers, geologic and engineered. (R.C. Ewing, Less Geology in the Geological Disposal of Nuclear Waste, Science, v. 286: 415-417, 1999); see also J.D. Bredehoeft et al., Geologic Disposal of High-Level Radioactive Wastes—Earth-Science Perspectives, U.S. Geological Survey, Circular 779, 1978

2A performance is quantitative only in the sense that it provides a numerical result, but the substance of the result is qualitative.” R.C. Ewing, Performance Assessments: Are They Necessary or Sufficient, in A.M. Macfarlane and R.C. Ewing (eds.), Uncertainty Underground: Yucca Mountain and the Nation’s High-Level Nuclear Waste, The MIT Press, 2006, p. 81

3U.S. Nuclear Waste Technical Review Board, Evaluation of the Department of Energy’s Technical and Scientific Work, Cover letter and report to Congress, January 24, 2002, http://www.nwtrb.gov/reports/2002ltr.pdf

4U.S. Department of Energy, Peer Review Panel, Final Report, Total System Performance Assessment, February 11, 1999, http://energy.gov/sites/prod/files/edg/media/FinalRept-TotalSystemPerformanceAssessment-PRP.pdf

5Advisory Committee on Nuclear Waste, Letter Report to R. A. Meserve, Chairman, U.S. Nuclear Regulatory Commission, 18 September 2001. Quoted by: R.C. Ewing and Allison Macfarlane, Yucca Mountain, Policy Forum, Science, v. 296:659-660, 2002

Edit

LEAVE A COMMENT

from Uncategorized

Chapter 18, Surprise

This chapter deals with an issue of primary importance to the concept of multiple natural and engineered barriers as protections against loss of waste containment in the proposed Yucca Mountain repository. If any loss of containment were to spread radionuclides potentially affecting the biosphere, it would have to be through the agency of water transportation. Selection of the Yucca Mountain site was predicated on the assumption that little, if any, water could penetrate the thick unsaturated zone, firstly because the arid climate provides very low precipitation, secondly because most of that would run off the surface, and thirdly because the diminishingly small amount that might reach the repository level would take another several hundred thousand years to percolate through to the water table. The first geologic line of defense, then, had to do with the movement of water in the unsaturated zone.

Too Hot to Touch immediately plunges the reader into conceptual models of water movement in the mountain, which were pieced together from limited data based on drill holes and the ESF tunnels. This left a lot of room for uncertainty as is reasonably explained. Early efforts to create a detailed conceptual model suggested that about 6 millimeters of water would get below the root zone of plants per year, and would migrate downward mainly through the abundant fractures, including major faults, in the rock. Another conceptual model suggested about 4 millimeters of water per year moved through the unsaturated zone by fracture flow.

The surprise from which the Chapter takes its name came in 1996 with discovery of the radioactive isotope chlorine-36 in samples from the ESF tunnel. Cl-36 occurs naturally, but the amounts present were deemed too large to represent natural occurrence. Cl-36 was also dispersed abundantly by atmospheric bomb testing at the Nevada Test Site next door to Yucca Mountain. If the Yucca Mountain Cl-36 does represent a bomb-pulse, it was carried to a depth of 600 to 1000 feet in the unsaturated zone in less than 50 years.

While this finding has obvious implications for the efficacy of Yucca Mountain’s thick unsaturated zone as a barrier to water penetration, the Alleys run through the “ifs” and “buts” in much the same manner as they did with tritium in Chapter 10: analytical error is possible due to the difficulties of measuring such small quantities; the samples could be contaminated, especially considering proximity of Yucca Mountain to the NTS (how contaminants made there way into the area of the ESF is not mentioned); confirmatory tests of samples from 50 drill holes “near” to the location of initial Cl-36 discovery showed no Cl-36 (the samples collected in the ESF tunnel were obtained adjacent to through-going faults; no description of the drill hole cores is given); and anyway even if the results represent fast-track transport from the surface, “they represent only a small portion (about 1 percent) of total water movement through the UZ at Yucca Mountain.”

The DoE wasn’t so sanguine about these findings, losing faith in their concept of a dry mountain barrier to protect the repository. This resulted in a shift in emphasis to engineered barriers. The major problems with these manufactured barriers are reasonably well-described on pages 278-280. The issues are not, however, put in the context of the basic strategic mistake of selecting a repository site in an oxidizing environment, nor in the behavior of the dominant waste component (reduced U02), which is unstable in the presence of even minor amounts of moisture under oxidizing conditions. “Orders of magnitude of durability for the spent fuel would be gained by maintaining reducing conditions at the repository horizon, [thus] At Yucca Mountain, the passive properties of the repository site do not provide a long-term barrier to radionuclide release.1 I strongly recommend that interested readers consult reference one.

The chapter continues with a useful discussion of plutonium transport in the unsaturated zone at the NTS. The findings of long-distance transport of this highly toxic long-lived isotope in unsaturated rock materials and the mechanisms of transport also represent surprises that challenge the efficacy of arid unsaturated zones as barriers to radionuclide dispersion in the environment. However, a more thorough discussion of the mineralogy of Yucca Mountain rocks as barriers as well as facilitators of contaminant migration in the total system is needed.2

NOTES AND REFERENCES

1R.C. Ewing and Allison Macfarland, Nuclear Waste Forum, Yucca Mountain, Science, v. 296:659-660, 2002

2D.L. Bish et al., The Importance of Mineralogy at Yucca Mountain, in A.M. Macfarlane and R.C. Ewing (eds.), Uncertainty Underground, Chapter 13

Advertisements
No comments yet

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: