NRC Generic Letter 79-42, Potential Unreviewed Question on Interaction Between Non-Safety Grade Systems and Safety Grade Systems
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GL79042
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON. D. C, 20555
September 17, 1979
ALL OPERATING LIGHT WATER REACTORS
SUBJECT: POTENTIAL UNREVIEWED SAFETY QUESTION ON INTERACTION BETWEEN NON-SAFETY GRADE SYSTEMS AND SAFETY GRADE SYSTEMS
You were informed by IE Information Notice 79-22, issued September 14, 1979, that certain non-safety grade equipment, if subjected to an adverse environment, could impact the safety analyses and the adequacy of the protective functions performed by safety grade equipment. Enclosed is a copy of IE Information Notice 79-22, and reprinted copies of an August 30, 1979 Westinghouse letter and a September 10, 1979 Public Service Electric and Gas Company letter which address this matter.
The NRC is concerned that a similar potential may exist at other operating light water reactor facilities, including yours, for an unreviewed safety matter related to the effects of the environment on control systems resulting from high energy line breaks inside or outside containment and the results of these effects on the required safety systems.
In accordance with 10 CFR 50.54(f) you are requested to provide within twenty
- (20) days of the date of this letter, written statements, signed under oath or affirmation, which will enable the staff to determine, in light of the concerns discussed above, whether or not your NRC license(s) to operate your nuclear power generating facility(ies) should be modified, suspended, or revoked.
Sincerely,
Harold R. Denton, Director Office of Nuclear Reactor Regulatory
Enclosures:
- 2. Westingthouse's August 30, 1979 Letter (Reprint)
- 3. Public Service Electric and Gas Company's September 10, 1979 Letter (Reprint)