ML20071K871
| ML20071K871 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 07/21/1982 |
| From: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| RO-82-036, RO-82-36, NUDOCS 8208020253 | |
| Download: ML20071K871 (2) | |
Text
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.An Southem Califomia Edison Company ht S AN ONOPRE NUCLE AR GENER ATING STA TION 85.0. BO E 128 S AN C LEMENTE. C ALIFORNI A 92672 s
H. 8. R AY July 21, 1982 Teu.
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STATION M AN AGE.
(784)492 7700 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94596-5368 Attention:
Mr. R. H. Engelken, Regional Administrator
Dear Sir:
Subject:
Docket No. 50-361 Prompt Report Licensee Event Report No.82-036 San Onofre Nuclear Generating Station, Unit 2 Pursuant to Technical Specification 6.9.1.12.1 to Operating License NPF-10 for San Onof re Unit 2, this letter confirms our July 20, 1982 prompt notification to the resident inspector of a reportable occurrence involving Limiting Condition for Operation (LCO) 3.4.3 on the Pressurizer
+
Heater Controls.
On July 16, 1982, while in Mode 3 during troubleshooting in cabinets to locate a Ground Lead, Pressurizer Level and Pressure Control was lost for 2 - 3 minutes.
Investigations revealed that a recent facility change re-configured the relay contact logic of the pressurizer heater -
i controls, rendering it inoperable had there been a loss of of f--site
}
power. This conclusion was reached at 1130 a.m. on July 20, 1982 and immediate constraint was placed on the operation of the plant per Technical Specification 3.4.3 Action b.
l The Pressurizer Heaters (Primary and Back-up) can be tripped by three sets of relays on high-hlgh, or high pressurizer pressure, or low level i
in the pressurizer. The relay contacts in question involve the high-high pressure, set at 2340 psia. This relay was wired such that the relay will trip the heaters when it is de-energized. A temporary corrective measure was initiated promptly to disable the high-high setting for the saf ety related heaters (Back-up Heaters). A permanent l
design change is being evaluated and will be implemented at a future r
i B208020233 820721 PDR ADOCK 05000361
Mr. R. H. Engelken date. The 14-day follow-up report will address this permanent design change.
It should be noted that protection for tripping the heaters by the high pressure set point (2275 psia) is still available, and that the heaters were available during this period since there was no loss of off-sito power.
s If there are any questions, please contact me.
Sincerely, p
6 cc:
A. E. Chaf fee (USNRC Resident inspector, San Onof re Unit 2)
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