ML20086G497

RO 83-146:on 831223,safety Injection Tanks (Sits) 007 & 010 Exceeded Nitrogen Pressure Limit of 625 Psig While SIT 009 in Process of Being Filled.Caused by Inleakage of Borated Water Through Fill Valves

ML20086G497
Person / Time
Site:	San Onofre
Issue date:	12/27/1983
From:	Haynes J SOUTHERN CALIFORNIA EDISON CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
RO-83-146, NUDOCS 8401120205
Download: ML20086G497 (2)

Text

..

s CD db b* 33 i h$ g h Southern California Edison Company ,5CE q

SAN ONOFRE NUC LE AR GENER A TING ST ATION O p.o.soxtaa S AN C LEMENTE, C A LIFOR NI A 92672 J.G HAYNll 1ELEPHONE STATION M ANAGER EFI4) 492 7700

-[Mcember 27, 1983 U. S. Nuclear Regulatory. Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, suite 210 Walnut Creek, California 94596-5368 Attention: Mr. J. B. Martin, Regional Administrator

Subject:

Docket No. 50-361 Prompt Report Licensee Event Report No.83-146 San Onofre Nuclear Generating Station, Unit 2 Pursuant to Section 6.9.1.12.b of Appendix A, Technical Specifications to Facility Operating License NPF-10 for San Onofre

. Unit 2, this submittal provides the written confirmation of our December 23, 1983, prompt notification to the NRC of a reportable occurrence involving the Safety Injection Tanks.

On December 23, 1983, at 0832 with Unit 2 in Mode 1 at 100% power, contrary to Limiting Condition for Operation (LCO) 3.5.1.d, safety Injection Tanks (SIT's) 007 and 010 exceeded their nitrogen pressure limit of 625 psig while SIT 005 was in the. process of being filled. Since Limiting Conditicn for Operation (LCO) 3.5.1 provides for only one inoperable SIT, LCO 3.0.3 was entered. At 0834, SIT *008 wat returned to operable status upon completion of the filling process. At 0837, SIT 010 was returned to operable l status after nitrogen presssure was returned within the limits of

( LCO 3.5.1.d and LCO 3.0.3 was exited. At 0842, SIT 007 nitrogen l pressure was returned within limits and LCO 3.5.1 Action Statement

'a' was exited.  !

[- 4 l

i The increase in nitrogen pressure of SIT's 007 and 010 was due to an increase in their water level. This was caused by the inleakage of borated water through their fill valves during the j filling of SIT 008 with the common fill header pressurized. We are continuing our investigation of this event. A 14-Day l Follow-up Report and copy of Licensee Event Report (LER) No. 1 l

83-146, delineating the cause and corrective actions taken, will 1 l be submitted by January 6, 1984. l k.

l 840112O205 831227 7 -cm y

Mr. J. B. Martin December 27, 1982 If there are any questions regarding the above, please so advise.

Sincerely, Yh &

cc: A. E. Chaffee (USNRC Resident Inspector, Units 1, 2 and 3)

J. P. Stewart (USNRC Resident Inspector, Units 2 and 3) 4 l

- . _ . - . - . - . _ - . . - _ - - _ -