ML13310B226
| ML13310B226 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/16/1984 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Baskin K Southern California Edison Co |
| Shared Package | |
| ML13310B228 | List: |
| References | |
| LSO5-84-02-029, LSO5-84-2-29, NUDOCS 8402170228 | |
| Download: ML13310B226 (3) | |
Text
February 16, 1984 Docket No. 50-206 LS05-84-02-029 Mr. Kenneth P. Baskin Vice President, Nuclear Engineering Licensing and Safety Department Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Baskin:
SUBJECT:
COMPLETION OF VALVE OPERABILITY REVIEWS FOR 6" BUTTERFLY VALVES USED FOR VENT OF CONTAINMENTS Re:
San Onofre Nuclear Generating Station, Unit No. 1 In our letter of November 29, 1978, we identified the generic concerns of purging and venting of containment to all operating reactor licensees and requested your response to these concerns. Our review of your response was interrupted by the TMI accident and its demands on staff resources.
Consequently, an Interim Position on containment purging and venting was transmitted to you by letter dated October 23, 1979. You were requested to implement short-term corrective actions to remain in effect pending completion of our longer term review of your response to our November 29, 1978 letter.
One of the remaining interim corrective actions (and the subject of this letter) still in place while our longer term review is being completed is to:
"Maintain the containment purge and vent isolation valves closed whenever the reactor is not in the cold shutdown or refueling mode until such time as you can show that:
- a. All isolation valves greater than 3" nominal diameter used for containment purge and venting operations are operable under the most severe design-basis accident flow-condition loading and can close within the time limit stated in your Technical Specifications, design criteria or operating procedures. The operability of butter fly valves may, on an interim bas-is, be demonstrated by limiting the valve to be no more than 300 to 500 open (900 being full open).
The maximum opening shall be determined in consultation with the valve supplier. The valve opening must be such that the critical valve parts will not be damaged by DBA-LOCA loads and that the valves will tend to close when the fluid dynamic forces are introduced."
d 40217022 840216 PDR ADOCK 05000206
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Mr. Kenneth February 16, 1984 Your letters of December 14, 1979 and February 29, 1980, provided your commitment to operate in conformance with this Interim Position pending completion of our long-term review of valve operability. Your letter of September 9, 1983 submitted proposed Technical Specification changes for locking closed valves on the 24" purge line during Modes 1, 2, 3 and 4.
We have completed our review of the analysis you submitted in your letters concerning operability of the valves used in the containment vent systems at San Onofre Unit 1. Our Safety Evaluation containing the documentation of this review is enclosed. We find that the information submitted failed to demonstrate the ability of the 6-inch valves to close against the buildup of containment pressure in the event of a LOCA.
Therefore, you are requested to inform us in within 30 days of receipt of this letter of:
- 1. Your assessment of the operability of your 6-inch vent valves in light of the concerns outlined in our enclosed Safety Evaluation.
- 2. Whether or not you intend to maintain the vent valves sealed closed in accordance with Standard Review Plan Section 6.2.4, II.6.f and to verify them to be closed every 31 days whenever the reactor is not in the cold shutdown or refueling mode until such time as you submit acceptable information that demonstrates that your vent valves will operate in the event of a DBA-LOCA.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely,.
Original signed by Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing
Enclosure:
DISTRIBUTION Safety Evaluation Docket File OELD NRC PDR ELdordan cc w/enclosure:
Local PDR JMTaylor See next page NSIC ACRS (10)
ORB #5 Reading EMcKenna DCrutchfield HSmith EReeves VNoonan DL:YRB 5 DL
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DE: EQBA DL~4 EMcKenna:cc EReeves VNoonan clv DArthfield D/ISTRII/84 /84 DocetFie8EL
Mr. Kenneth P. Baskin 3 -
February 16, 1984 cc Charles R. Kocher, Assistant General Counsel James Beoletto, Esquire Southern California Edison Company Post Office Box 800 Rosemead, California 91770 David R. Pigott Orrick, Herrington & Sutcliffe 600 Montogmery Street San Francisco, California 94111 Harry B. Stoehr San Diego Gas & Electric Company P. 0. Box 1831 San Diego, California 92112 Resident Inspector/San Onofre NPS c/o U.S. NRC P. 0. Box 4329 San Clemente, California 92672 M-ayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego San Diego, California 92101 California Department of Health ATTN:
Joseph 0. Ward, Chief Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814 U.S. Environmental Protection Agency Region IX Office ATTN:
Regional Radiation Representative 215 Freemont Street San Francisco, California 94111 John B. Martin, Regional Administrator Nuclear Regulatory Commission, Region V 1450 Maria Lane Walnut Creek, California 94596