ML20196H961
| ML20196H961 | |
| Person / Time | |
|---|---|
| Issue date: | 10/23/1979 |
| From: | Martin J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| References | |
| FRN-44FR61372, RULE-PR-50 NUDOCS 9812090235 | |
| Download: ML20196H961 (9) | |
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REGULATION OF GE0 LOGICAL REPOSITORIES by John B. Martin, Director Division of Waste Managenent Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Comission Washington, D.C.
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Paper to be presented at the Conference at the Keystone Center for Continuing Education, Keystone, Colorado, October 23, 1979.
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In the past, the NRC effort was largely directed to developing the capability to evaluate a repository application which was expected at an early date.
Upon the establishment of the Waste Management Division at NRC we did an appraisal of our practices and made some fundamental changes.
The primary i
focus of the NRC waste management program is now on developing a regulation so that the National program can be planned, organized and directed in terms of clearly stated criteria.
This is particularly underscored in the IRG recommendations.
First, let me give you a status report on the development of our regulation.
Last week, we provided to the Commission, for its consideration, the proposed Part 60 regulation on the procedural aspects of licensing the disposal of high-level wastes in geologic repositories.
These procedures were derived after careful review of the comments received on the General Statement of Policy published for comment in November 1978, consideration of recommenda-j tions of the IRG, and further staff review of alternative approaches to i
licensing.
The staff is currently concentrating on developing draft technical requirements for licensing.
These will be forwarded to the Commission for its consideration about the first of the year. They will be published as an Advanced Notice of j
Rulemaking which will be aimed at seeking public comment on major technical l
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issues before a proposed technical rule is developed. Currently the staff I
has prepared strawman technical criteria which are being used to focus thinking on the major technical issues and to identify research needs.
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l 2-I would now like to outline the proposed licensing procedures and our technical approach to regulation of high-level waste disposal in geologic media which will form the basis for the technical rule.
I will begin with the licensing procedures.
The NRC Waste Management staff doubts whether a decision to commit to full construction of a repository can be made on the basis of information collected i
from records, surface exploration and geophysical testing with a limited i
number of borings.
Neither the NRC staff nor geoscience experts agree on just how much and what quality information is the minimu:n required to satis-factorily characterize a site. However, there does seem to be general agreement that exploration at depth, that is, sinking of an exploratory shaft with lateral borings and in-situ testing at the planned depth of waste emp'lacement, I
would be a prudent and conservative pre-construction requirement that would allow the truly meaningful comparison of alternatives required by the National Environmental Policy Act. As a result, it is the NRC Waste Management staff's current thinking that DOE should characterize several sites prior to i
submitting a formal application for construction of a repository at any single site.
Such an approach would pennit a detailed comparison of the various sites and should promote the selection by DOE of the environmentally preferred repository site.
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, It should be noted that characterization of several sites has been recommended by the IRG as being essential to the National program for the disposal of high-level waste.
Prior to initiating such a characterization program, DOE would be required to ' submit to the NRC and to make available to the public a site characterization report which, among other things, sets forth the rationale for selecting a particular site for detailed site characterization.
The site characterization report should describe the site characterization program including the extent of planned excavations, plans for in-situ tests, and other investigative activities that DOE would intend to puruse over the following year or so. We at NRC intend to direct our technical and research programs toward the detail of the at-depth exploration and testing program.
We contemplate a procedure where DOE will formulate a detailed site characteri-zation plan. NRC would then review DOE's site characterization plan to include public meetings and issue an " Office Director's Opinion" as to its adequacy. Site characterization activities conducted by DOE would be carried out under the review and guidance of the NRC with opportunities for public comment and public meetings. The intent of this type of approach to licensing is to ensure that enough information and data are developed on a sufficiently broad base so that the best licensing decisions can be made. Doing less may make it very difficult to conclude a construction authorization proceeding since basic information might be missing.
Investigating several sites will ensure that the required technical data will be gathered without making a i
premature commitment to any one particular site.
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. i The NRC staff would prefer that four or five such sites be characterized before a decision is made on whether to proceed with construction. There still seems to be considerable debate on the scope of investigations, types of tests needed to characterize a site, how they should be done, and how sites should be compared.
I am hopeful that this meeting will shed some j
. light on these issues and help develop some consensus on this t7pic.
Following site chara~cterization and receipt of the DOE applica;.an for a construction permit, the NRC Waste Management staff estimates that it will take approximately two to three years to evaluate the site-specific application, conduct the formal hearings, and reach a decision on whether to authorize const ruction.
Construction of the facility by DOE is estimated to require an ddditional five to eight years.
Approximately two years prior to the completion of construction, DOE would then submit an application for a license to receive waste and operate the repository. During the time the repository is being constructed, DOE would continue in-situ testing which would add to the knowledge base concerning the suitability of the site to contain the waste safely.
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. I would now like to discuss our technical rule which is under development.
The draft technical regulations will be cast in the form of performance objectives rather than detailed design requirements in order that we do not foreclose options. The performance objectives are based on a two-stage approech in which a minimum standard of performance is required and DOE is required to investigate alternatives for improving performance beyond the minimum standard.
The overriding performance objective is to meet the EPA standard.
In addition to this overall performance objective, we will specify objectives for major components or barriers of the system to assure that we have high confidence the EPA standard will be satisfied. The systems to which the performance objectives apply are the waste form and packaging, repository design, and the si te.
First I will discuss the performance objectives for waste fonas and packaging.
To date, the designs of deep geologic repositories have placed major (if not total) reliance for containment of radionuclides on the surrounding geology.
Reliance on the waste form itself and its packaging to prevent radionuclide release over the long-term has not received major snphasis.
The waste form work that has been done in the past has been devoted primarily to glass.
I The NRC Waste Management staff considers that a more prudent approach would be one in which much more emphasis is put on the waste form. Several waste form and packaging alternatives should be evaluated and characterized before final selection. The potential gains in assurance which could be made are, l
in our judgement, sufficiently large to warrant this approach. The long-tem perfomance cf the waste form, packaging, and its reactions with the host rock can be examined in the laboratory and can be extrapolated with some l
confidence through testing at aggravated conditions.
This approach has been used successfully in modern materials development work. A high degree of assurance in the performance of the waste form--packaging--host rock interface L
would also tend to offset the inevitable uncertainties in geologic performance.
As a result, the NRC Waste Management staff considers that a much more aggressive waste form and packaging development and demonstration effort should be undertaken in order to provide a multi-carrier repository system.
We are considering a requirement that the waste packaging contain the radioactive materials for the first 1,000 years after emplacement and as long as reasonably achievable thereafter. At that point, the hazard of the geologic repository's contents would not be much different than that of the l
l original ore body. This would leave the geologic medium as an independent barrier. After the first 1,000 years, we are considering a requirement that the waste package limit the annual release rate of radioactive material to on 6
the order of one part in 10 of the package inventory of radionuclides.
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, 'It.is not our intention to de-emphasize the role of geology in the isolation of high-level radioactive wastes in any way. We want the repository and the ic >
geologic system to be a fully satisfactory system to contain the wastes l
i during their hazardous lifetime. However, there are a number of uncertainties that have been raised concerning the ability to predict the behavior of the geologic system, and we may never be able to prove that we have considered l
all reasonably likely release scenarios. Therefore, duHng the period when the waste is most hazardous (approximately the first thousand years), we believe it is prudent to consider the engineered systems, principally the waste form and packaging, to be a fully satisfactory independent barrier.
i The site characteristics and repository design should be such that in the event of the maximum credible package failure, there is reasonable assurance that the trancit time of the radionuclides to the biosphere is sufficiently l'
long to allow the radionuclides to decay to levels such that releases are l
within the EPA standard. The site screening and characterization procedures that we are developing as part of our criteria are designed to build this 1
assurance through the infonnation that will be obtained throughout the licensing process.
In addition to the above perfonnance requirements, we are requiring that the repository be designed to be a stable structure that would maintain its mechanical integrity throughout the operation of the repository and for fifty years thereafter.
In that way, the option would be preserved to monitor the performance of the waste disposal system, to take corrective Actions, if required, or as a last resort, to remove the wastes.
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In addition to overall performance objectives, our strawman regulation specifies criteria for siting repositories. These criteria are in the form j
of preferred site characteristics and exclusion criteria for identifying candidate areas and sites within those areas.
These criteria are aimed at assuring that site characteristics are such that in the event of the maximum credible package failure, there is reasonable assurance that the transit time of the radionuclides to the biosphere is sufficiently long to allow them to decay to levels such that any release is within the EPA standards.
I consider it important to reiterate my earlier statement that the requirements in our present draft technical rule are strawman criteria, derived for the l
purpose of focusing attention on major issues. We hope, by developing this strawman, to promote discussion that will enable us to improve the draft rule l
before publishing it in the Federal Register.
I am optimistic that the i
l discussions we are having during these meetings will be helpful to me in t
these improvements.
Thank you.
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