ML20072N784

ROs83-072 & 83-041:on 830706,w/Unit 2 in Mode 5 & Unit 3 in Mode 4,marine Fouling of Inservice Component Cooling Water HXs Resulted in High Differential Pressure & Reduced Saltwater Cooling Flow.Hxs Realigned

ML20072N784
Person / Time
Site:	San Onofre
Issue date:	07/08/1983
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
RO-83-041, RO-83-072, RO-83-41, RO-83-72, NUDOCS 8307180093
Download: ML20072N784 (2)

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1, Southern California Edison Company y S AN ONOFRE NUCLE AR GENER ATING ST A TION f,

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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 Nos, 50-361 and 50-362 Prompt Reports Licensee Event Reports83-072 (Docket No. 50-361) and 83-041 (Docket No. 50-362)

San Onofre Nuclear Generating Station, Units 2 and 3 Pursuant to Sections 6.9.1.12.b of Appendix A, Technical

- Specifications to Facility Operating Licenses NPF-10 and NPF-15 for San Onofre Units 2 and 3 respectively, this submittal provides the written confirmation of our prompt notification to the NRC on July 6, 1983, of a reportable occurrence involving the Component Cooling Water (CCW) System. This written confirmation has been delayed one day in order to permit a more complete review of this occurrence.

On July 6, 1983, while Unit 2 was in Mode 5 and Unit 3 was in Mode 4, marine fouling of the inservice CCW heat exchangers resulted in high dif ferential pr essure and reduced Saltwater Cooling (SWC) flow. The Unit 2 Train A CCW heat exchanger and both Train A and B CCW heat exchangers at Unit 3 were inservice and at 0227, SWC flow was reduced to the point that the heat exchangers were declared inoperable. This resulted in exceeding Limiting Condition for Operation (LCO) 3.7.4 for Unit 3, only, since the LCO is applicable to Modes 1 through 4 and Unit 2 was in Mode 5. Exceeding LCO 3.7.4, for Unit 3, resulted in invocation of LCO 3.0.3. Operability was restored at 0300 following a momentary cessation of SWC flow while

{ the Unic 3 CCW heat exchangers were realigned to a different SWC

) pump, which apparently allowed marine debris in the heat exchangers to become dislodged and increased SWC flow.

l 8307180093 830708 PDR ADOCK 05000361 / 0 R-21 u _ Y _. . __ . . _ 83- 9 /

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Mr. J.B. Martin During the period that both Unit 3 CCW heat exchangers were inoperable, both trains of the Control Room Emergency Air Cleanup System (CREACUS) were cooled by the Unit 3 CCW system.

Consequently, LCO 3.7.5, which requires that both trains of CREACUS be operable with either Unit in Modes 1 through 4, was exceeded. Exceeding LCO 3.7.5 would have required invocation of LCO 3.0.3 for both Units 2 and 3, however LCO 3.0.3 had already been invoked for Unit 3 based on having exceeded LCO 3.7.4, as discussed above, and the action requirements of LCO 3.0.3 were already satisfied at Unit 2 by virtue of that Unit being in Mode 5.

The 14-day follow-up reports and copies of Licensee Event Reports (LER's)83-072 (Docket No. 50-361) and 83-061 (Docket No. 50-362) will be submitted by July 21, 1983, to address this event.

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

Sincerely, b

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

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

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