05000361/LER-1982-137, Forwards LER 82-137/03L-0.Detailed Event Analysis Submitted

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Forwards LER 82-137/03L-0.Detailed Event Analysis Submitted
ML20069N965
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 11/19/1982
From: Ray H
SOUTHERN CALIFORNIA EDISON CO.
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20069N969 List:
References
NUDOCS 8212070281
Download: ML20069N965 (2)


LER-2082-137, Forwards LER 82-137/03L-0.Detailed Event Analysis Submitted
Event date:
Report date:
3612082137R00 - NRC Website

text

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No Southern California Edison Companfitj 9 1=

S AN ONOFRE NUC LE A R GENER A TING ST A TlON ,f P .O. B O X 126

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S AN C LEMENTE, C ALIFORNI A 92672 f ST AYlON M AN AGE R ( F 14) 49 7 7 700 November 19, 1982 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94596-5368 Attuntion: Mr. R. H. Engelken, Regional Administrator

Dear Sir:

Subject:

Docket No. 50-3f 30-Day Interim Report Licensee Event Report No.82-137 San Onofre Nuclear Generating Station, Unit 2 This submittal is in accordance with the reporting requirements of Section 6.9.1.13b of Appendix A to Facility Operating License NPF-10.

It describes a reportable occurrence involving Limiting Condition for Operation (LC0) 3.4.5.2.d associated with identified leakage from the Reactor Coolant System (RCS).

While in Mode 3, at 1100 on October 20, 1982, routine operator inspection revealed the absence of Chemical and Volume Control System (CVCS) letdown flow through flow orifice 2FE-0202 and a decreasing Volume Control Tank (VCT) level. The leakage exceeded LCO 3.4.5.2.d and, therefore, Action Statement b was invoked. The decreasing VCT level was terminated by isolating CVCS charging and letdown flows at 1110.

Subsequent investigation revealed that a CVCS system relief valve 2PSV-9206 had lifted and remained open, discharging liquid to the Miscellaneous Waste Tank (T063). 2PSV-9206 is believed to have initially lifted due to pressure fluctuations associated with re-routing letdown flow from back-pressure regulator 2PV-0201A to back-pressure regulator 2PV-02018.

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R. H. Engelken November 19, 1982 After an unsuccessful attempt to reseat 2PSV-9206, a gag device was placed on the valve at 1400. The redundant back-pressure regulator 2PV-0201A was put back in service and caution tags were placed on 2PV-0201B to prevent its use until the problem could be investigated. The CVCS charging and letdown flows were subsequently re-established, the gag removed and the valve remained closed.

The cause of the sticking relief valve is currently unknown and will be investigated when plant conditions pennit the letdown flow to be isolated for sufficient time to allow valve and regulator inspection and repair or adjustment. No problems have been experienced with either back-pressure regulator 2PV-0201A or relief valve 2PSV-9206 since this event.

A revised LER will be provided when the results of our investigation are finalized.

Since relief valve flow was directed so as to be collected by a system designed for this purpose, there was no impact on health and safety of plant personnel or the public.

If there are any questions regarding the above, please contact me.

Sincerely, MFylnu%

Enclosure LER 82-137 cc: A. E. Chaffee (USNRC Resident Inspector, San Onofre Unit 2)

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Office of Management Information and Program Control Institute of Nuclear Power Operations