ML13310B236
| ML13310B236 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/17/1984 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Baskin K Southern California Edison Co |
| References | |
| LSO5-84-02-036, LSO5-84-2-36, NUDOCS 8402230121 | |
| Download: ML13310B236 (5) | |
Text
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February 17, 1984 Docket No. 50-206 LS05-84-02-036 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 GENERIC ITEM B-24, CONTAINMENT PURGING/VENTING DURING NORMAL OPERATIONS 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 containments 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, as you know, an Interim Position on containment purging and venting was transmitted to you on 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.
By letter dated February 17, 1982 the staff issued a status report on the various aspects of this review for San Onofre Unit 1. Provided below is the disposition of each of the four major components of this review.
- 1. Conformance to Standard Review Plan Section 6.2.4 Revision 1 and Branch Technical Position CSB 6-4 Revision 1 The draft safety evaluation transmitted as Enclosure 4 to the February 17, 1982 status report identified four open items.
Each of these is discussed below.
A. Lock Closed, 24-inch purge line isolation valves The staff requested the licensee to propose a Technical Specification reflecting their commitment to maintain the 24-inch isolation valves of the purge system in a locked closed position during operating modes 1 through 4. By letter dated September 9, 1983, the licensee submitted the Technical Specification request. The staff issued Amendment No. 71 to the license to incorporate this change on A
l February 17, 1984.
PDPD
Mr. Kenneth February 17, 1984 B. Limit use of 6-inch vent valve The licensee was requested to limit the use of the 6-inch vent line to a specified annual time that is commensurate with identified plant safety needs. However, as discussed under 2 below, the staff has now concluded that these valves should be locked closed during Modes 1, 2, 3 and 4 until the licensee can demonstrate to the staff's satisfaction that the valve operators have the ability to close the valves against the buildup of pressure from a LOCA. Review of this issue will be continued on a plant-specific basis.
C. Debris Screen The draft safety evaluation recommended that a debris screen be provided for the 6-inch containment ventilation system. By letter dated September 8, 1983, the licensee provided a discussion of the provisions that ensure that the 6-inch isolation valve closure will not be prevented by debris entrainment. These provisions include the relative location of the valves inside containment, the venting direction of the valves and the piping design of the system. In addition, housekeeping procedures are provided during maintenance activities to minimize the potential for entry of debris. The staff concludes that for these small lines the above provisions are adequate to prevent debris blockage of the isolation valve such that debris screens are not necessary.
D. Leakage Integrity Tests of the 6-inch and 24-inch isolation valves Because of the potential for seal deterioration, the staff recommended that the licensee perform leakage integrity tests of the containment ventilation isolation valves.
The purpose of these tests is to identify excessive degradation of the resilient seats. These tests are to be performed in addition to the type C tests required by Appendix J.
The licensee's letter of January 26, 1983 described the proposed leakage rate tests for the containment ventilation isolation valves.
The program includes quantitative acceptance criteria, test frequency and reporting requirements.
The licensee's September 9, 1983 proposed Technical Specification changes to meet the provisions of Appendix J of 10 CFR 50 include the requirement to conduct seal tests on both active and passive contain ment ventilation isolation valves every six months. Therefore, the staff concludes that, except as noted below, the proposed program for monitoring valve leakage integrity is acceptable.
Mr. Kenneth February 17, 1984 For the 6-inch valves the testing frequency must be increased to every 3 months if they are to be used during normal operation. This aspect will be reviewed with the issue on the 6-inch valve operability.
- 2. Valve Operability By letter dated February 16, 1984, the staff issued a safety evaluation report which concluded that the licensee had not demonstrated that the 6-inch vent valves could close in the event of a LOCA. Therefore, the staff concluded that the licensee should maintain the 6-inch vent valves in the closed position during Modes 1, 2, 3 and 4 until such time as the licensee can submit acceptable information that demonstrates that the vent valves will operate in the event of a LOCA. The 24-inch valves were not evaluated as these valves are already locked closed during Modes 1, 2, 3 and 4.
- 3. Safety Actuation Signal Override The staff safety evaluation of this aspect was provided by letter dated December 6, 1982, as supplemented by letter dated October 27, 1983.
The licensee has committed to various plant modifications to achieve confor mance with staff guidelines. The modifications will be included in the integrated living schedule for San Onofre 1. As noted in the staff's January 20, 1984 letter the schedule dates for this plan are still under negotiation between the staff and the licensee.
- 4. Containment Leakage Due to Seal Deterioration This aspect was discussed under 1.D above.
The staff finds that all aspects of this generic item have been completed or will be completed within the scope of another licensing action. Generic item B-24 is considered complete. Resolution of'any future issues in this area will be handled on a plant-specific basis.
Sincerely, Original signed by Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing cc:
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- 2. Valve Operability By letter dated 1984, the staff issued a request, pursuant to 10 CFR 50.54f, that the licensee maintain the 6-inch vent valves in the closed position during Modes 1, 2, 3 and 4 until such time as the licensee can submit acceptable information that demonstrates that the vent valves will operate in the event of a LOCA. The 24-inch valves were not evaluated as these valves are already locked closed during Modes 1, 2, 3 and 4.
- 3. Safety Actuation Signal Override The staff safety evaluation of this aspect was provided by letter dated December 6, 1982, as supplemented by letter dated October 27, 1983.
The licensee has committed to various plant modifications to achieve confor mance with staff guidelines. The modifications will be included in the integrated living schedule for San Onofre 1. As noted in the staff's January 20, 1984 letter the schedule dates for this plan are still under negotiation between the staff and the licensee.
- 4. Containment Leakage Due to Seal Deterioration This aspect was discussed under 1.D above.
The staff finds that all aspects of this generic item have been completed or will be completed within the scope of another licensing action. Generic item B-24 is considered complete. Resolution of any future issues in this area will be handled on a plant-specific basis.
Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing cc:
See next page DISTRIBUTION Docket File OELD NRC PDR ELJordan Local PDR JMTaylor NSIC ACRS (10)
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Mr. Kenneth February 17, 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 Mayor 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