05000206/LER-1981-022, Forwards LER 81-022/03L-0.Detailed Event Analysis Also Submitted

Forwards LER 81-022/03L-0.Detailed Event Analysis Also Submitted

ML20032C315
Person / Time
Site:	San Onofre
Issue date:	10/20/1981
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20032C316	List: 05000206/LER-1981-022, Forwards LER 81-022/03L-0.Detailed Event Analysis Also Submitted 05000206/LER-1981-022-03, /03L-0:on 811003,during Performance of Visual Surveillance Insp of Hydraulic Snubbers Installed on safety- Related Sys,Hydraulic Fluid Reservoir in One Snubber Found Empty.Caused by Failed Reservoir Seal Gasket
References
NUDOCS 8111090663
Download: ML20032C315 (2)

LER-1981-022, Forwards LER 81-022/03L-0.Detailed Event Analysis Also Submitted

Event date:
Report date:
2061981022R00 - NRC Website

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S AN ONOPRE NUCLE AR GENER A TING S T A TION P.O. B O K 128 S AN C LEME NT E. C A LIF OR NI A 92472 H.B R6i T E t t moNE s v avion u ne <.ar n

\\ C ' t I > L, October 20, 1981 s.

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1 U. S. Muclear Regulatory Commission y NOVO 61981-R qion V 4 us. m wisoumou J

1450 Maria Lane, Suite 210 C

Walnut Creek, California %596

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Docket No. 50-P.06 San Onofre - Unit 1 Attention:

M. R. H. Engelken, Director

Dear Sir:

This letter describes a reportable occurrence regarding a safety related hydraulic snubber on the Main Steam System piping.

Submittal is in accordance with the reporting requirements sHoulated in section 6.9.2(b) of Appendix A to the Provisional Operating License DPR-13.

While the plant was shutdown, al inspection of safety related snubbers was conducted on the 21st and 23rd of September,1981. This inspection revealed five snubbers low in hydraulic fluid, but not below the hydraulic port leJal.

and one snubber (2-SW-2-10) with no visible oil in the reservoir. All six snubbers were removed and tested in accordance with Maintenance Procedure S 01 -I-2. 31.

Snubber 2-SW-2.10 failed to pass the stroke test. The remaining snubbers were tested and subsequently determined ta he satisfactory.

Snubber 2-SW-2-10 was designated inoperable and a teardown inspection was performed. This inspection revealed that the internal bore of the cylinder was excessively scored, indicating operation with little or no hydraulic fluid. Further examination indicated that the loss of hydraulic fluid from the reservoir was due to a failed reservoir seal gasket. The internal bore was honed smooth and the snubber was reassembled with new seals. Hydraulic fluid was replaced and the snubber was functionally tested with satisfactory results.

As a precaution the reservoir seal gaskets were reolaced in the remaining five M

snubbers.

The hydraulic fluid was replaced and the snubbers were returned to f

service.

II g1 663 81topo S

CK 05000206 PDR

_2_

As a result of this snubber failure, the accessible hydraulic snubber surveillance inspection interval _will be shortened in accordance wf th Tschnical Specification 4.14.

In addition, tne preventive maintenance program will be revised to include 'he periodic replacement of the reservoir seal gasket.

Should you have any questions on the abcve, please contact me.

Si ncerely,

SRG:01080/ryh cc:

U. S. Muclear Regulatory Conmission Division of Reactor Operations Inspection L. F. Miller _ USNRC Resident Inspector i

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