ML19261C420
| ML19261C420 | |
| Person / Time | |
|---|---|
| Issue date: | 03/06/1979 |
| From: | Vollmer R Office of Nuclear Reactor Regulation |
| To: | Morrison W NRC OFFICE OF STANDARDS DEVELOPMENT |
| References | |
| RTR-REGGD-01.131, RTR-REGGD-1.131 NUDOCS 7903220404 | |
| Download: ML19261C420 (2) | |
Text
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'*p UNITED STATES
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- 4 NUCLEAR REGULATORY COMMisslON f
7 1 j WASHINGTON, 0. C. 20555 k, S.
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MAR 6 1379 MEMORANDUM FOR:
W. M. Morrison, Assistant Director for Genaral Engineering Standards, DES FROM:
R. Vollmer Assistant Director for Systems and Project- 00R
SUBJECT:
REGUL ATORY GUIDE 1.131 - REVIEW / COMMENT By your memorandum dated February 6,1979, you requested that we review a proposed revision to the subject regulatory guide. Our review is complete and we have the following comment and recommendation.
Regulatory position C.18 endorses the provisions of IEEE Std. 383-1974, Section 2.3.3, as acceptable for simulating thermal and radiation aging.
The standard calls for electrical cable to be exposed to elevated temperature and radiation environments sequentially without regard to the possibility of synergistic effects from aging in a combined environment. This is incompatible with the preliminary results of recent studies sponsored by the NRC Office of Reactor Safety Research which have shown that some electrical cable insulation materials exhibit synergistic effects when exposed to elevated temperatures and radiation simultaneously.
The Office of Nuclear Reactor Regulation is continuing to study the available data concerring synergistic effects. We understand that in the interim, the Division of Systems Safety is proposing to take the position for new Construction Permit SERs that the possible synergistic effects of elevated temperature and radiation must be considered when aging electrical cables. We recommend that Regulatory Guide 1.131 be revised to be compatible with the current Division of Systems Safety position.
7903220t/CY
2-We havt discussed these comments and our recommendation via telephone with the SD Task Leader for Regulatory Guidt.1.131, A. S. Hintze.
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R. V'llmer, Assistant Director o
for Systems and Projects Division of Operating Reactors Centact:
E. Butcher X-28077 cc:
S. Hanauer A. S. Hintze R. Satterfield G. Lainas A. Szuktewicz R. Feit D. Mcdonald E. Butcher C. Heft S. Pawlicki
.