ML13303B379
| ML13303B379 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/31/1992 |
| From: | Zimmerman R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Krieger R SOUTHERN CALIFORNIA EDISON CO. |
| References | |
| NUDOCS 9202110239 | |
| Download: ML13303B379 (3) | |
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UNITED STATES 0
CC NUCLEAR REGULATORY COMMISSION REGION V 1450 MARIA LANE
- q WALNUT CREEK, CALIFORNIA 94596-5368 January 31, 1992 Docket No. 50-361 Southern California Edison Company San Onofre Nuclear Generating Station P. 0. Box 128 San Clemente, California 92674-0128 Attention: Mr. R. W. Krieger, Station Manager Gentlemen:
Subject:
Temporary Waiver of Compliance from San Onofre Unit 2 Technical Specifications (TS) 3.7.1.2.1, 3.3.3.6, 3.6.3, and 3.3.2 Involving Environmental Qualification of Auxiliary Feedwater (AFW) Injection Valves and Other Components This letter documents the granting of a temporary waiver of compliance to the Southern California Edison (SCE) Company for San Onofre Nuclear Generating Station Unit 2, Operating License NPF-10. As described in your January 30, 1992 letter, your staff determined during the course of your design basis document (DBD) program that a break, inside the AFW pump house, in the steam line to the turbine-driven auxiliary feedwater pump (TDAFWP) could have conse quences not previously foreseen. These involved the flow of steam through piping tunnels to a valve room which contains four containment isolation valves for the AFW system. Your letter noted that this flow of steam could create a harsh environment for which the AFW valves and certain other compo nents are not environmentally qualified.
We wish to recognize your efforts to identify and correct problems such as this one. As you noted in your letter, your initial response upon identifying this concern on January 27 was to isolate the steam supply to the TDAFWP, thereby entering a TS Action Statement which requires shutdown of the Unit if the condition is not resolved within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. You also began fabricating and installing steam barriers in the AFW piping tunnels to prevent significant flow of steam to the valve room in the event of a TDAFWP steam line break.
You requested a waiver from the above referenced TS requirements to permit restoring the TDAFWP to service while installation of the steam barriers was being completed. You noted that the 72-hour Action Statement expired at 1:00 p.m. on January 30, and that installation of the barriers was expected to be completed between about noon and 4:00 p.m. Your waiver request was sup ported by the following:
A preliminary evaluation completed by your staff concluded that the granting of this waiver would be of no safety significance. This evaluation included reference to a fracture mechanics analysis which concluded that steam line leakage would be apparent prior to a guillotine 9202110239 920131 PDR ADOCK 05000361 P
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break. You concluded that a leak could be detected and the TDAFWP steam line could be isolated before significant steam passed to the valve room.
In addition to the actions stated in your January 30 letter, you stated that an operator, with direct communication to the control room readily available, would be posted on a continuous basis at the AFW pump house, and would tour the TDAFWP steam line every 30 minutes, until installation of the steam barriers is completed and the requested waiver is no longer required.
You noted that probabilistic risk analysis had shown the event of concern to be extremely unlikely. You also stated that the TDAFWP steam line was hydrostatically tested for four hours at 1365 psig in October 1991, with satisfactory results.
Region V, with NRR concurrence, concluded after reviewing your request that a temporary waiver of compliance from the referenced TS requirements would not adversely impact public health or safety. Accordingly, a temporary waiver was verbally granted, to remain in effect for up to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> beginning at 9:00 a.m. PST on January 30, 1992.
This approval of your requested temporary waiver of compliance was conditioned upon the implementation of the compensatory measures described above and in your letter dated January 30, 1992. We also note that you informed us sub sequently on January 30 that installation of the steam barriers was completed at about 3:00 p.m. on that date, and that you had exited the temporary waiver of compliance at that time.
Sincerely, R. P. 'mmerman, Director Division of Reactor Safety and Projects cc:
H. B. Ray, Senior Vice President, Nuclear H. E. Morgan, Vice President and Site Manager State of California
-3 bcc:
J. Martin, RV B. Faulkenberry, RV R. Zimmerman, RV K. Perkins, RV S. Richards, RV P. Johnson, RV K. Johnston, RV C. Caldwell, SONGS T. Murley, NRR J. Partlow, NRR M. Virgilio, NRR T. Quay, NRR G. Kalman, NRR A. Mendiola, NRR M. Blume, RV R. Huey, RV REGIO V PJ on SRichards MVirgilio, NRR RZimmerman 1/
92 1/20D/92 1/3/92 1/ /92
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