ML20207D819
| ML20207D819 | |
| Person / Time | |
|---|---|
| Issue date: | 07/16/1986 |
| From: | Ward D Advisory Committee on Reactor Safeguards |
| To: | Zech L NRC COMMISSION (OCM) |
| References | |
| ACRS-R-1205, NUDOCS 8607220196 | |
| Download: ML20207D819 (2) | |
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UNITED STATES P
NUCLEAR REGULATORY COMMISSION PDA
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E ADVISORY COMMITTEE ON REACTOR SAFEGUARCt
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WASHINGTON, D. C. 20555 July 16, 1986 Honorable Lando W. Zech, Jr.
Chairman U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Zech:
SUBJECT:
ACRS VIEWS ON FIRE PROTECTION RESEARCH AND FIRE-REj.ATED SYSTEMS INTERACTIONS During its 315th meeting, July 10-12, 1986, the Advisory Coninittee on Reactor Safeguards considered various activities associated with nuclear power plant fire protection provisions, including the Appendix R modi-(
fication process and fire-related portions of the safety research program. These matters were also discussed by the ACRS Subcommittee on Auxiliary Systems at a meeting held on June 26, 1986.
We identified specific items of concern in the safety research area. We would like to share these since' they may be of interest to you, and as a basis for I
reconsideration of resource allocation for fire-related research.
It is our understanding that all fire-related safety research programs will be terminated at various stages of completion by the end of FY 1986.
In FY 1987, the Office of Nuclear Regulatory Research intends to perform a scoping study to reexamine the program needs, to determine the likely level of fire risk, and to establish future priorities.
Our first concern is the loss of program momentum and information that will result from premature termination of ongoing activities while awaiting results of the proposed scoping study.
Any termination of needed i
reseacch is a loss, and will be costly to reconstitute later.
The NRC Staff indicates that, based on Probabilistic Risk Analyses (PRAs) that have been performed, there is a significant contribution to core-melt frequency from fire in a number of plants.
Although the risk l
associated with fire is subject to large uncertainties, it is clearly nontrivial and the ability of fire to exacerbate severe accident situa-tions has already been demonstrated. Therefore, one needs to understand better how fires can start and propagate, and the consequential effects of fire and fire-fighting measures (or their inadvertent actuation) on safety-related equipment throughout the plant.
Such information needs to be developed if the risk is to be properly analyzed and minimized, and the value-impact of potential backfits appropriately calculated.
The uncertainty must be narrowed if the results are to be useful for decision making.
In this regard, fires in the control room area are of special concern because of the confluence of essential plant control systerrs and the i
1 0607220196 860716 PDR ACRS R-1205 PDR
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Ttie Honorable Lando 14. Zech, Jr.
- July 16, 1986 likely sensitivity of cor, trol room components 'to the adverse environment resulting frcn fir 9 and fire suppfession.
Mthough censiderable re-saar:h has been done in this area, (mpertant work remains to be complet-ed and documented concerning fire source characterization, full-scale room erviroimier*; tetts, component failure threshold tests, and valida-tion of fir; environment computer codes against full-scale room tests.
A majority of this work for FY 1986-1987 will rencin unfinished or undene.
The fire PRAs performed to date have not had the benefit of sufficient test data and information such as would be developed by this work.
This significantly increases the uncertainty in the risk esti-na tes.
In addition, much of this work would add to a technical base that would be cpplicable to the analysis of fire situations, r'i s k aversion, and value-irrpact considerations throughout the plant.
Our second concern relates to the fire-induced control system inter-at;tions issue which we thought was going to be within the scope of the rwelutioti cf USJ A-17, " Systems Interactions in Nuclear Power Plants."
We are now aware that the pt oposed resolution of USI A-17 does not inchde fire-induced interactions or those creited by fire mitigation efforts or the effects of a ceismic event on fire mitigation features.
We are concerned that this aspect cf the issue has been overlooked.
A research effort may be required to explore adequately the issue and its ramifications, including its potential contribution to ecmon cause and severe accidents.
The results of some of the predoc, and proposed (Lut, now terminated) fire-related research may be needed in support of this effort.
We urge reconsideration of the budget and manpower allocations that have Id tc the tercination of the fire-related portions of the safety tresearch program, and would like to be kept informed of how the fire-Induced O stem interaction' issue will be handled. We are anxious to see a continuity Cf effort on fire-related research while the Staf f deter-mines it.s future priorities.
Finally, we believe that if the NRC does not perform this research there may ne a need for a set of regulations requiring industry to deal with the uncertain aspects of compchent behavior under various fire con-ditions.
Sincerely, O
s David A. Ward Chairman
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