05000361/LER-1982-139, Forwards LER 82-139/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-139/03L-0.Detailed Event Analysis Submitted

ML20070L201
Person / Time
Site:	San Onofre
Issue date:	12/10/1982
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20070L204	List: 05000361/LER-1982-139, Forwards LER 82-139/03L-0.Detailed Event Analysis Submitted
References
NUDOCS 8301030036
Download: ML20070L201 (2)

LER-2082-139, Forwards LER 82-139/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
3612082139R00 - NRC Website

text

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Southern California Edison Company SCE S AN ONOFRE NUCLE AR GENER A TING S T A TION P .O. B O R 128 S AN CLEMENTE, C A LIFORNI A ,267g H. B. R A Y reorpsoNg

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December 10, 1982 i% a2 "a U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement S ,

Region V -c GI 1450 Maria Lane, Suite 210 @

Walnut Creek, California 94596-5368

]Q Attention: Mr. R. H. Engelken, Regional Administrator 5

~

Dear Sir:

Docket No. 50-361 'd 30-Day Report Licensee Event Report No.82-139 San Onofre Nuclear Generating Station, Unit 2

References:

1) Letter, H.B. Ray (SCE) to R.H. Engelken (NRC),

dated August 31, 1982, "30-Day Report-Licensee Event Report Nos82-084, -085, -086, -088, -091, and -092"

2) Letter, H.B. Ray (SCE) to R.H. Engelken (NRC),

dated October 15, 1982, "30-Day Report-Licensee Event Report No.82-115"

3) Letter, H.B. Ray (SCE) to R.H. Engelken (NRC),

dated November 18, 1982, "30-Day Report-Licensee Event Report No.82-128" This submittal is in accordance with the reporting requirements of Section 6.9.1.13b of Appendix A to Facility Operating License NPF-10.

It describes a reportable occurrence involving Limiting Condition for Operation (LCO) 3.1.3.1 associated with Control Element Assemblies (CEA's). A completed copy of LER 82-139 is enclosed.

LC0 3.1.3.1 requires that while in Modes 1 and 2 all 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.

8301030036 821210 PDR ADOCK 05000361 0 PDR EN 62M3

R. H. Engelken December 10, 1982 On November 13, 1982, at 1632 with the plant in Mode 1, while attempting to raise Tayg after synchronizing the generator to the grid, regulating CEA 23 (Group 6) slipped from 87 inches to 75 inches resulting in entry into Action Statement 3.1.3.1.d.l.

Action Statement 3.1.3.1.d.1. allows operation to continue in Modes 1 and 2 provided that within one hour the misaligned CEA is restored to operable status within its specified alignment requirements. At 1636 while attempting to manually lower the remaining rods in Group 6 to 75 inches, in accordance with Procedure S023-3-5.8, CEA 22 was also observed to have slipped resulting in a reactor trip due to high Local Power Density (LPD)/ low Departure from Nucleate Boiling Ratio (DNBR). Since the sequence of events prior to the reactor trip occurred rapidly and the Core Protection Calculator (CPC) trip buffer had not been reset after a reactor trip at 0540 on November 13, 1982, post-trip information to quantify CEA 22 slippage was unavailable.

Subsequent investigation revealed that the slippages were attributable to slow operation of the grippers which prevented one of the grippers (upper or lower) from making up to the CEAs prior to the other gripper releasing. The corrective action taken was similar to that described in the referenced letters (i.e., all six regulating group gripper actuation voltages were increased to the maximum and the duration of voltage application for CEA 23 was increased by 100 msec; no increase in the duration of voltage application for CEA 22 was determined to be necessary).

Additionally, Startup Procedure S023-3-1.1 has been revised to assure verification of resetting of the CPC trip buffer prior to attempting a reactor startup. CEA 23 was tested successfully and reactor startup commenced at 1930 on November 13, 1982. No other problems have been experienced and no further corrective action is planned.

This event had no effect on public health and safety since it did not affect the ability of the CEA to be inserted into the core, when required.

If there are any questions, please contact me.

Sincerely, l v

Enclosure:

LER 82-139 cc: A. E. Chaffee (USNRC Resident Inspector, San Onofre Unit 2)

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

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