ML13308B466
| ML13308B466 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/13/1977 |
| From: | Head J SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| NUDOCS 8103060022 | |
| Download: ML13308B466 (2) | |
Text
Southern California Edison Company C E P. 0. BOX 800 2244 WALNUT GROVE AVENUE J. T, HEAD, JR.
ROSEMEAD, CALIFORNIA 91770 TELEPHONE VICE PRESIDENT May 13, 1977 213-572-1472 U. S. Nuclear Regulatory Commission Region V
- Y Office of Inspection and Enforcement Suite 202, Walnut Creek Plaza 1990 North California Boulevard Walnut Creek, California 94596 Docket No. 50-206 San Onofre Unit 1 Attention
- R. H. Engelken, Director
Dear Sir:
This letter describes an incident that occurred at San Onofre Nuclear Generating Station Unit 1. Submittal is in accordance with the reporting requirements stipulated in Section 6.9.2.b of the Technical Specifications.
On April 17, 1977, the reactor coolant system (RCS) and chemical and volume control system (CVCS) combined leak rate was measured at 0.87 gpm.
Although this leak rate was not above the allowable for unidentified leakage, it was greater than that normally encountered. An investigation to determine the source accounting for the higher than normal leakage rate was commenced.
This investigation consisted of selectively isolating redundant components of the combined RCS and CVCS, and monitoring sump pump and drain pump operating frequencies.
On April 18, the leakage increased to 3.2 gpm. It was determined that the leakage water was entering the reactor auxiliary building sump from the common packing leak off line originating at the packing glands on valves FCV-1115 A, B, C, D, E, F and FCV-1112. These valves are part of the safety injection recirculation system and the leakage exceeded the allowable limit as specified in Secion 3.3.1.A (4) of the Technical Specifications. Through selective valve isolation, it was determined that the source of leak as the leak off connection at the lantern ring on FCV-1115 D packi leak off line was crimped closed and plugged.
The RCS and CVCS combined leakage was subsequently measured at 0.13 gpm. Once the leak off line had been plugged, there were no indications of leakage from the safety injection recirculation system referenced in Technical Specification 3.3.1.A (4). The reactor coolant pump seal water injection valve will be repacked and the packing leak off line returned to normal service during the next cold shutdown. Effective leakage from the recirculation loop outside containment will be calculated by placing valve FCV-1115D in the L2 category until repairs are effected.
Sincerely,
Attachment:
Licensee Event Report No. 77-10 cc: Director, Office of Inspection & Enforcement Director, Office of Management Information & Program Control