ML20009C230
| ML20009C230 | |
| Person / Time | |
|---|---|
| Issue date: | 07/14/1981 |
| From: | Mark J Advisory Committee on Reactor Safeguards |
| To: | Palladino N NRC COMMISSION (OCM) |
| References | |
| PROJECT-669A ACRS-R-0936, ACRS-R-936, NUDOCS 8107200393 | |
| Download: ML20009C230 (3) | |
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WASHINGTON, D. C. 20555 July 14,1981
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n rable Nunzio J. Palladiro S
U. S. Nuclear Regulatory Commission Washington, D.C.
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SUBJECT:
NEW SAFETY CONCEPTS FOR FUTURE CONSTRUCTION
Dear Dr. Palladino:
In a letter dated September 11, 1980 NRC Chairman John F. Ahearne asked the ACRS for suggestions concerning potential safety improvements which could be incorporated into any new design for nuclear power plants. We respo'nded with a letter dated December 9,1980 to Chairman Ahearne in which we listed some specific issues warranting consideration for potential impviements, outlined a few possible approaches that might be useful in pursuing the subject, and stated that we would try to develop additional comments by the summer of 1981.
An ACRS Subcommittee held meetings on this subject on January 28, 1981, April 8,1981, and May 6,1981. During these meetings the Subcommittee heard presentations and discussions from representatives of Westinghouse Electric Corporation, Combustion Engineering, Inc., KMC, Inc., General Electric Company, Bechtel Power Corporation, Stone & Webster Engineering Corporation, Electric Power Research Institute, the Department of Energy, and the NRC Staff; the Subcommittee also held a closed session on sabotage desigl considerations which was attended by an NRC contractor assisting the Staff in this area.
None of the industry representatives proposed a systematic or comprehensive approach to attacking and resolving the matter of appropriate safety-related design improvements for future LWRs, although some of the reactor vendors indicated they were considering specific improvements in their future prod-uct line. The NRC Staff does not appear to have a significant ongoing ef-fort ov'iented specifically at defini.ig the requirements for future LWRs; however, they indicated that the IREP program and other probabilistic risk analyses, together with a series of studies recently contracted with Sandia Laboratory in support of the proposed rulemaking on degraded cores, should be of potential future use in this regard.
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Honorable Nunzio J. Palladino July 14, 1981 If the NRC Staff is to do more than review each new application on an ad hoc basis, except as new requirements may arise from the currently proposed rule-makings, a rang. of possible approaches should be considered, including the following:
1.
Require that probabilistic risk analysis be used to evaluate the suitability of the proposed design at the construction permit stage.
2.
Rely on the lessons learn 2d from probabilistic risk analyses on current plants to provide insight over some extended period of time as to new requirements which would be implemented when suitable in-formation has been developed and a need has been demonstrated.
3.
Establishment of a list of possible design improvements intended to prevent accidents leading to core melt, similar to that initiated for the degraded core rulemaking, and the development of enough con-ceptual design information and evaluation of the costs and benefits to enable NRC decision making.
4.
Establishment of a set of studies, including alternate design op-tions, intended to provide a basis for resolving as many of the unresolved safety issues and other generic issues as practical.
5.
Selection of specific topics of potentially special significance, such as design features to minimize the likelihood of sabotage by an insider, and the accomplishment of sufficient conceptual design studies and other analyses to enable the development of NRC re-quirements in these matters, as appropriate.
6.
Undertake an LWR nuclear power plant design study which attempts to include tne best features of all plants in order to at least provide a standard for comparison.
7.
Undertake studies intended to identify plant features, systems, and components which are better designed to facilitace proper and.-Me-quate maintenance.
8.
Undertake a set of studies intended to provide a better basis for judging what one might do at various stages in the progression of serious accidents in order to identify possible improvements in design of equipment or instrumentation.
9.
Review the general design criteria and similar significant safety requirements used in other countries, compare them with U.S. cri-teria, and decide whether the U.S. criteria should be modified.
- 10. Undertake a revision of the general design criteria to accomplish any desired changes in requirements.
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Honorable Nunzio J. Palladino July 14,1981 We believe that, while none of the alternatives listed are likely to be adequate individually, a combination of such alternatives, suitably molded and coordinated into a systematic and comprehensive program, could provide an appropriate overall approach. We recognize that the NRC licensing staff faces a severe licensing load daring the coming months and that manpower resources are currently at a premium. However, we believe that it is im-portant that the NRC be able to define its changed requirements for the de-sign of future LWRs on a timely basis, say thirty months. Otherwise, new plants are likely not to have a more nearly optimal safety-related design, and the licensing process is likely to be more ad hoc. The increased on-going consideration of the merits of LWR standardization provides a still greater emphasis 09 the need for a timely definition by the MRC of the safety requirements for future LWRs.
We believe that much useful information could be generated by the reorien -
tation of a significant portion o? the current safety research progam without reducing the support level for those research programs,which have the greatest potential for risk reduction, or which deal with issues not generally believed to be well controlled by current regulatory ' positions.
We suggest that the nuclear industry be encouraged to participate actively in the development of safety improvements for future reactors.
An NRC policy which makes it clear that proposed improvements will not autwati-cally become candidates for backfitting could be helpful in this regard.
With regard to the matter of design improvements to reduce the potential for serious sabotage by an insider, it appears that only a detailed, NRC-sponsored and guided effort is likely to develop a systematic new approach.
For some of the other matters, however, the development of tentative per-formance requirements may be all that is needed for the purpose. Consider-ations such as these would, of course, enter into the development of a cohesive, coordinated NRC program on this subiect.
Although an improved management and operation capability by the licensee for a nuclear power plant does not fall under the ca'.egory of design im-provement, we believe this also warrants considerable attention by the NRC and the industry and sNuii become a generic feature of our approach to new LWRs.
In a very general way, and quite apart from the specific items mentioned above, the encouragement of interest and concern on such matters may also be an important contribution the NRC can make.
We recommend that the NRC give the appropriate priority and resources to the task of developing safety requirements for future LWRs.
Sincerely, J. Carson Mark Chai rman
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