ML20138G299
| ML20138G299 | |
| Person / Time | |
|---|---|
| Issue date: | 10/16/1985 |
| From: | Ward D Advisory Committee on Reactor Safeguards |
| To: | Palladino N NRC COMMISSION (OCM) |
| References | |
| ACRS-R-1161, NUDOCS 8510250451 | |
| Download: ML20138G299 (10) | |
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8 NUCLEAR REGULATORY COMMISSION n
3 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS Q
WASHINGTON, D. C. 20555
%*****$g October 16, 1985 Honorable Nunzio J. Palladino Chairman U. S. Nuclear Regulatory Comission Washington, D. C.
20555
Dear Dr. Palladino:
SUBJECT:
ADDITIONAL ACRS COMMENTS ON THE EPA STANDARDS FOR A HIGH-LEVEL RADI0 ACTIVE WASTE REPOSITORY During its 306th meeting, October 10-12, 1985, the Advisory Comittee on Reactor Safeguards met with you and the other Comissioners to offer comments regarding the Environmental Protection Agency (EPA) Standards for a High-level Radioactive Waste (HLW) Repository, which was the subject of our report to you dated July 17, 1985.
In response to the request made during this meeting, we are pleased to submit the following additional comments on the EPA standards which were published as a final rule on September 19, 1985.
These standards will apply to tne facili-ties being proposed by the Department of Energy and must be met in the associated licensing review conducted by the NRC.
Our purpose in writing yuu at this time is to highlight the fact that the standards being promulgated by the EPA are unreasonably restrictive and contain serious deficiencies.
This will undoubtedly introduce unnecessary obstacles into the licensing process for an HLW repository, with only minimal benefit to the public health and safety. Our justifi-cations for these comments are outlined below.
Development of these standards has been under way within the EPA since December 1976.
During this period, the ACRS and its Subcommittee on waste management were briefed periodically by EPA representatives, and at each such meeting comments and suggestions were discussed on an informal basis. In early 1983 the EPA submitted the then-current draft of the proposed standards to its Science Advisory Board (SAB) for review.
Detailed coments by the High-Level Radioactive Waste Disposal Subcomittee of the SAB included the following:
The Subcomittee recomended "that the release limits specified in the proposed standards be increased by a factor of ten, thereby causing a related tenfold relaxation of the proposed soci-etal objective (population risk of cancer)."
The Subcomittee recommended "that use of a quantitative probabi-listic condition on the... release limits be made dependent on EPA's ability to provide convincing evidence that such a condition is practical to meet and will not lead to serious impediments, legal or otherwise, to the licensing of high-level-waste geologic f
g o2 g 1 851016 R-1161 PDR
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Honorable Nunzio J. Palladino October 16, 1985 repositories.
If such evidence cannot be provided, we recommend that EPA adopt qualitative criteria, such as those suggested by the NRC."
1 Of particular concern to the SAB Subcommittee, in tenns of meeting the conditions of the standards, was the fact that containment requirements should be such that the cumulative releases of radionuclides from a repository to the accessible environment for 10,000 years after dis-posal, from all significant processes and events that may affect the disposal system, shall:
"have a likelihood of less than one chance in 10 of exceeding" the quantities (given in an accompanying Table); and "have a likelihood of less than one chance in 1,000 of exceeding ten times" these same quantities.
The SAB Subcommittee also recomended specific changes in the probabi-listic aspects of the draft standards to help make it more practical for an applicant to make a case that the quantitative probabilistic criteria had been met.
Although the wording in the standards includes the statement that
" performance assessments need not provide complete assurance" that these requirements will be met, there remains the basic fact that the stan-dards, as published, are far too restrictive.
In our opinion, the establishment of overly restrictive standards, relieved by leniency in their implementation, is not an appropriate approach.
The proper approach would have been to develop reasonable standards that could have been more definitively enforced.
The problems cited above were but a few of those observed and commented upon by the SAB Subcommittee.
Additional problems in Working Draft No.
6 of the EPA standards were discussed with an EPA representative during a meeting of the ACRS Subcommittee on waste management on June 18 and 19, 1985.
These included the following:
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The standards, as published, do not appear to be internally consis-l tent.
Although the latest data were used for estimating the i
biological effects of various radionuclides, the associated dose limits for individual body organs were not based on appropriate risk criteria.
The health risks associated with the release limits specified in l
the standards are much lower (by factors of a thousand or more) than the risks considered acceptable by the EPA for other environ-mental stresses, such as hazardous toxic chemicals.
The overly restrictive standards may result in the rejection of some sites proposed for an HLW repository that otherwise might be acceptable.
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Honorable Nunzio J. Pa?ladino October 16, 1985 As indicated above, the standards will definitely complicate the processes, both technical and legal, of demonstrating that a given site * > acceptable.
We realize that both the NRC Staff and the DOE Staff have accepted the EPA standards.
Although we can understand, to some degree, the desires of both staffs to complete this step, we are troubled by the serious deficiencies that exist in the standards.
The compromises that have been made at this stage will lead to extended delays and an uncertain outcome in the licensing process for an HLW repository, with only slight benefit to the public health and safety.
Although the ACRS could undertake a more detailed review and critique of the EPA standards, we believe that the SAB Subcommittee has already done this in a professional manner. A copy of the Executive Sumary of their report is attached for your information.
We hope this letter is helpful.
Although we realize that the EPA standards have been published, we believe that they contain such serious deficiencies that the NRC should take prompt action to voice these con-cerns.
Sincerely, David A. Ward Chairman
Attachment:
Section II, " Executive Summary" of Report on the review of Proposed Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes (40 CFR 191) by the SAB, EPA, dated January 1984
References:
1.
Letter from Herman E. Collier, Jr., Chairman, EPA High-Level Radio-active Waste Disposal Subcomittee, to Mr. William D. Ruckelshaus, Administrator, EPA, dated February 17, 1984 transmitting Report on the review of Proposed Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes by the High-Level Radioactive Waste Disposal Subcommittee, Science Advisory Board EPA, dated Janaury 1984 2.
SECY-84-320, "NRC Staff Comments to EPA on the SAB Report on Pro-posed EPA Standard for Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Waste (40 CFR Part 191)," dated August 9,1984, including Working Draft No. 8. Final 40 CFR 191, Subchapter F - Radiation Protection Programs, dated July 19, 1985
Honorable Nunzio J. Palladino October 16, 1985 3.
SECY-85-272, " Report on the EPA's Environmental Standards for High-level Radioactive Waste Disposal," dated August 13, 1985 4.
Memorandum from R. E. Browning, Director, Division of Waste Management, to R. F. Fraley, ACRS,
Subject:
NRC Staff Views on Implementation of the EPA HLW Standards, dated September 11, 1985 i
er 9
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From Report on the review of Proposed Environmental Standards for the 1
e Management and Disposal of Spent Nuclear Fuel, High-Level and Trans-uranic Radioactive Wastes by the SAB, EPA, dated Jar.uary 1984 SECTION II EXECljTIVE SIN ARY The High-Level Radioactive Waste Disposal Subcommittee (HLRW) of the Executive Committee of the Science Advisory Board (SAB) has com-pleted an extensive review of the scientific and technical basis for EDA's proposed rule for the disposal of high level radioactive wastes, the highlights of which are presented in this summary.
Technologies now exist for tha disposal of such wastes, and stan-dards adopted for them should strike an appropriate balance between conservatism and practicality.
Overall, the Subcommittee is confident that, consistent with the intent of this standard-setting program, the job of disposing of high-level radioactive waste can be achieved with reasonable assurance for the well-being of present and future genera-tions.
The Subcommittee supports the general form of the proposed stan-dards, including (a) the use of a societal objective as an upper bound of acceptable health (cancer and genetic) effects, (b) the focus on j
performance standards in terms of release limits rather than individual exposures,(c) the reference level of the initial 10,000 year time frame applicable to both the societal objective and the release limits, (d) the use of a probahilistic approach, and (e) the use of qualitative assurance requirements, as modified by the Subcommittee, but issued as Federal Radiation Drotection Guidance to other Federal agencies in lieu of inclusion in the proposed rule.
The Subcommittee, *ile accepting the general fom of the proposed standards, recommends several changes in the standards and improvements in the supporting methodology. The principal recompendations are high-lighted in the following summation.
A more comprehensive and detailed presentation of these and other major recommendations can be found in Section IV, Major Findings and Recommendations.
A.
The Standard i
1.
The Subcommittee recommends that the release limits specified in Table 2 of the proposed standards he increased by a factor of ten, thereny causing a related ten fold relaxation of the proposed societal objective (population risk of cancer).*
1 Two memoers of the Subcommittee, Dr. Lash and Dr. Giletti, dissent from this view. They helieve that the Dffice of Radiation Programs' more stringent standard is justified and can be met by sufficient numbers of proposed disposal i
sites.
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e 2
4 The Subcommittee notes that the proposed release limits are direct-ly related to the societal objective of not exceeding 1,000 deaths in 10,000 years, and thus, compliance with this recommendation carries with it a related ten fold increase in the societal objective.
The relaxatie-of the release limits is, in the Subcommittee's opinion, justified for the following reasons. First, the proposed release limits in Table 2, and therefore the proposed sncietal objective, are consider-
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akly more stringent than those standards generally required or adopted in today's society (see for instance Tahle A on page 12 of this report).
Second, in addition to the fact that some of the cancer deaths **ich might result from these releases are calculated using conservative assumptions that probably overestimate the number, sone of these deaths would have resulted at least in part from the unmined ore from which the wastes were subsequently' generated, and thus are substitutional rather than adcitional in nature.
Third, the Subcommittee believes that the compounding of conservatism by EPA in the choice of pro 5abili-ties and specific model parameters used throughout the analysis is not warranted.
a EPA should also clarify the analytical framework that forms the basis for the limits in Table 2 of the proposed standards.
The Sub-comittee believes that such clarification will help to establish clearly the relationship betweer the release limits and the societal objective,and will facilitate future amendments to the standard as knowledge increases regarding radiation health effects or radionuclide migratinn in the biosphere.
Note:
In Section IV, a7("odels) and #13(Geochemical nata), the Subcormttee has recommended that EPA make certain specific changes and corrections to their predictive models.
Some of these changes will result in changes to the release limits for individual radionu-clides given in Table 2 of the proposed standards, and will he separate from the ten-fold change in the release limits recommended above. The Subcommittee helieves that the changes in the release limits, resulting from the changes to the predictive models, are independent of and wnuld not lead to additional m1dification to the proposed societal objective beyond the ten fold increase discussed above.
B.
Uncertainty and the Standard 1.
We reconnend that the probabilistic release criteria in the draft standard be modified to read " analysis of repository nerfor-mance shall demonstrate that there is less than a 501 char.ce of exceeding the Table 2 limits, modified as is apprnpriate. Events whose median frecuency is less than one in one-thousand in 10,000 years need not be considered."
2.
We recorrnand that use of a quantitative probabilistic condi-tion on the modified Table 2 release limits be made dependant on EDA's ability to provide convincing evidence that such a condition 3
s is practical to meet and will not lead to serious impediments, le-Gal or otherwise to the licensing of high-level-waste geologic re-oositories.
If such evidence cannot be provided, we reco u nd that EPA adopt qualitative criteria, such as those suggested by the NRC.
The Subcommittee believes that tha modified probabilistic criteria will make the propnsed standards more practical to apply without undue, time-consuming disagreenents. Further risk studies need to be performed and subjected to systematic, critical evaluation in order to establish a more acceptable probabilistic basis for the standard.
C.
The Time Frame - 10,000 years and Beyond 1.
We recorr9and that EPA retain the 10,000-year time period as the basis for determining the adequacy of repository performance.
We believe that use of formal numerical criteria limited to this aporoximate time period is a scientifically acceptable regulatory apDreach.
2.
We recomend that the process of selection of sites for dis-posal systems also take into account potential releases of radio-activity somewhat beyond 10,000 years. Particular attention should he focused on potential relaases of long-lived alpha-emitting radionuclides and their decay products.
Although the selection of a time frame is in large part ar5f trary, we endorse EPA's choice of 10,000 years. Modeling and risk assessments for the time periods involved in radioactive waste disposal require ex-tension of such developing techniques well beyond usual extrapolations; however, the extension for 10,000 years can be made with reasonable confidence. Also, the period of 10,000 years is likely to be free of major geologic changes, such as volcanism or renewed glaciation, and with proper site selection the risk from such changes can be made neg-ligible.
Potential radionuclide releases will not stop with 10,000 years, however, but may continue in amounts equal to or exceeding those estimated for the initial period.
The degree of confidence with which impacts can be modeled much i
further in the future is much less certain.
We do not recommend de-tailed modeling calculations regarding post-10,000 year releases, but estimates should be made, and should be considered as factors in dis-posal site selection.
O.
Population vs. Individual Risk 1.
We recomend that EPA retain the use of a population risk cri-terion as the measure of performance for the proposed standards.
We find that an approach employing individual dose limits, i.e.,
considering sorm maximally exposed individual" or alternatively some
" average exposed indi vidual " would, in practice, make the standa rd 4
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difficult to meet with high assurance for very long times, and that use of a population risk approach is more practical.
In our view, however, i
it is important that for the first several hundred years residents of i
the region surrounding a repository have very great assurance that.1 hey will suffer no, or negligible, ill effects from the repository.
For l
longer periods, we believe that EPA should rely on the existence of con-tinuing requirements similar to its current drinking water standards to protect groups of individuals.
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E.
Coordination of Policies and Standards 1.
We recommend that EPA initiate action within the Federal Gov-ernment for the establishment of an interagency council to coor-dinate the development of high-level radioactive warte disposal policy, standards, and regulatory practices and to serve as a forum for exchange of scientific and technological information.
J Several Federal agencies are involved in the process of establish-ing radiation protection policies, standards and operational require-ments governing the disposal of high-level radioactive wastes, including EPA, NRC, DOE and D00, together with states, appropriate entities of Congress and the judiciary.
Overlapping and independent authorities and responsibilities exist under present laws. Conflicting terminology and standards exist, e.g., the definitions of high-level and other ra-dioactive wastes.
Coordination of Federal policies and practices is essential to the U.S. high-level radioactive waste disprial program.
Success of the program will depend on extensive interaction and agree-ment among the appropriate Federal agencies.
While the lead in coor-dination could be appropriate for the NRC or DOE, the Subcommittee feels that the obligation for achieving mutual interaction more appro-i priately belongs to the EPA under its authority to issue environmental standards and Federal Radiation Protection Guidance.
F.
Research Needs - A Matter of Priority 1.
We reconnend that EPA support, or encourage other agencies to support, continuing research in technical areas where me.ior uncer-l tainties still exist, particularly in the biological effects of radiation, the geochemical transport of radionuclides, and the characterization of rock-mass deformation.
The Subcommittee strongly endorses support of' reNarch aimed at i
diminishing or clarifying as many of these uncertainties as can be attacked with some hope of resolution.
The research, although expen-sive, could bring about a substantial reduction in the everall cost of the disposal system.
G.
Responses to Original Subcomittee Charge At the time of the Subcommittee's formation, it was directed, by the Executive Committee of the Science Advisory Board, to address six 5
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(6) principal iss ue s.
Although a brief response to each charge is presented here, the charges are broad in scope and the Subcommittee's review of them generated a number of more explicit and specific issues which are addressed in detail in the body of this report.
l 1.
The scientific and technical rationale behind the choice of a i
10,000 year time period as the basis for assessment of disposal facility performance.
This issue has been addressed in C above.
2.
The technical basis for the selection of the proposed perform-ante requirements, including risk-assessment methodology, uncer-tainties in the data and in the analytical methods, and the esti-mation of premature deaths.
These aspects of the analysis form the basis for the proposed stan-dards and were areas mnst carefully and critically evaluated by the Subcommittee. Although the Subcommittee makes a number of recommenda-tions regarding risk assessment, pathway and health modeling and the i
need for improved documentation, we believe that Office of Radiation Programs, EPA, has handled these subjects well and, furthermore, has been positively responsive to the recommendations of the Subcommittee.
We think, however, that EPA has made overly conservative enoices and decisions throughout the development of the technical bases supporting i
the standards, leading to overestimation of the long-term effect of disposal, and hence that the proposed standards are too restrictive and compliance may be difficult to verify.
3.
The scientific appropriateness of concentrating on disposal in geologic media.
(
This part of the charge needed no consideration by the Subcommit-tee, since disposal in geologic media is mandated for at least the first two sites by the Nuclear Waste Policy Act of 1982 (PL 97-425),
enactec after the charge was prepared.
No member of the Subcommittee, however, disagrees with this initial approach.
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The validity of the conclusion that, under the proposed rule, the risks to future generations will be no greater than the risks from equivalent amounts of naturally occurring uranium ore bodies.
In reviewing this conclusion, we found, and EPA acknowledged, that the comparison is uncertain because of the extreme variability of j
uranium ore bodies.
The Subcommittee thinks that the conclusion is valid in a very general way, if suitably qualified, but feels that it is unwise and not scientifically defensible to use the unmined ore as the only reference for comparison. We recommend that the comparison be extended to include the radioactivity of natural waters and the ambient radiation in the natural environment.
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s The adequacy of the economic analysis.
5.
The Subcommittee considers there are significant shortcomings in the economic analyses supporting the proposed standards. Since the man-gement, storage, and disposal of high-level waste is a multi-billion dollar venture, we believe that the shortcomings are important and should be remedied.
It is noteworthy that, even though the savings associated with individual choices may seem relatively insignificant, the absolute costs are so large that even small percentage savings are worthwhil e.
The high absolute costs appear to be relatively independ-I ent of the proposed standard, and simply reflect the decision to use deep mined geologic disposal sites with multiple barriers. Thus, ap-preciable savings are not likely to be reali:ed in terms of basic cost the standa rds.
However, the cost of demonstrating by relaxation of compliance may be very high, and cost reductions that may be achieved by sophisticated compliance demonstrations could be substantial.
We recognize the need for cost / benefit analyses, using the best available data, but we note that a precise economic analysis will not be possible or meaningful until it is performed upon an actual repository at a specific site.
6.
The ability of the analytical methods /models used in the anal-ysis to predict potential releases from the disposal facility and their resultant effects on human health.
Included would be an evaluation of the model's ability to deal with uncertainty and the i
confidence, in a statistical sense, that the model predictions are adequate to support selection of projected performance requirements.
In general, epa's analytical methodology and modeling used through-out the development of the generic repository's performance, including releases and subsequent cancer deaths, are deemed to be conservative.
1 The Subcommittee makes several suggestions for specific improvements We emphasize that modeling, including the evaluation of and updating.
uncertainty and confidence therein, is an emerging and developing tech-Adding to the uncertainties implicit in a techique that is still nique.
under development are the multitude of poorly known factors associated with the extrapolation in time to 10,000 years and beyond, and the prob-lem of securing public acceptance of the standard.
We believe, never-theless, that the EPA's ef fort, modified as recommended by this report, will fulfill the intent of the Nuclear Waste Policy Act of 1982.
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