ML20065B122

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Forwards LERs 82-084/03L-0,82-085/03L-0,82-086/03L-0, 82-088/03L-0,82-091/03L-0 & 82-092/03L-0.Detailed Event Analysis Submitted
ML20065B122
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 08/31/1982
From: Ray H
SOUTHERN CALIFORNIA EDISON CO.
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20065B125 List:
References
NUDOCS 8209140260
Download: ML20065B122 (2)


Text

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Southern California Edison Company ~ .

S A f 4 O ? 4 C F R F. N Le C L F A f f G E NE R A TING S T A 7 TON SQ 83.0. to o a i g g SANCLEM* N f 8. . C A LIF ORNI A 182672 H.8 RAY "'"""

s A no~ AN Aa, a August 31, 1982 17348497 1700 U. S. fluclear Regulatory Commission Office of Inspection and Lnforcement Region V 1450 Maria Lane, Suite 210 Wdinui Creek, California 94596-5368 Attention: Mr. R. H. Engelken, Regional Administrator

Dear Sir:

Subject:

Docket No. 50-361 30-Day Report Licensee Event Report No.82-084, 82-085,82-086, 82-088,82-091, and 82-092 San Onof re Nuclear Generating Station, Unit 2 Pursuant to Section 6.9.1.13b of Appendix A, Technical Specifications to Operating License NPF-10, for San Cnofre Unit 2, this submittal provides the required 30-day written repar ts and copies of Licensee Event Reporis (LER's) for six similar occurrences, involving the Control Element Assembly (CEA).

Technical Specification Limiting Condition for Operation (LCO), 3.1.3.1 states that, "All full length (shutdown and regulating) CEA's, and all part length CEA's which are inserted in the core, shall be operable with each CEA of a given group positioned within 7 inches (indicated position) of all other CEA's in its group", while the plant is operating in Mode 1 or 2.

A CEA is normally held in place by the upper gripper coil. During normal motion the lower gripper supports the CEA while the upper gripper moves to a now position. The lower gripper then releases, allowing the upper gripper to move the CEA. Between August 1, 1982 and August 7, 1982 while (1 Mode 2, several CEA's slipped or dropped violating LCO 3.1.3.1.

The cause of these slippag3s cr drops is slow operation of the grippers

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which prevented one of ihe griripers (upper or lower) from making up to ihe CEA prior lo the other gripper releasing.

8209140260 820831 PDR;ADOCK 05000361 PDR S

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R. H. Engelken August 31, 1982 This type of problem is not uncommon in new plants and its frequency of occurrence has been observed to diminish with operation. The corrective measures adopted on the NSSS Vendor recommendation included, exercising the CEA's and reducing rod speed, increasing gripper voltage and duration of voltage application, and application of hydrazine to some drives in an of fort to remove oxide deposits which might possibly be present. In addition, electronic circuit changes are being considered such that, if one gripper does not properly engage, this will be detected and the other gripper will not disengage. Engineering studies will be completed within 30 days and permanent circuit changes are expected to be implemented, If the studies prove out, by year end.

No other corrective measures are planned at this time. However, should this condition persist, replacement of the faulty Control Element Drive hbchanisms (CEDM's) will be considered.

These events have no effect on public health and safety since they do not af fect the ability of the CEA to insert into the core when required.

LER's82-084, 82-085,82-086, 82-088,82-091, and 82-092 respectively address events associated with CEA 57, 68, 38, 86, 68 and 77, on the dates indicated on the LER forms.

If you have any questions, please contact me.

Sincerely, hh0 l h ALWi cc: A. E. Chaf fee (USNRC Resident inspector, San Onof re Unit 2)

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Consnission Office of Management information and Program Control Institute of Nuclear Power Operations