ML20028F362

From kanterella
Jump to navigation Jump to search
Forwards LER 82-168/03L-0.Detailed Event Analysis Submitted
ML20028F362
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 01/11/1983
From: Ray H
SOUTHERN CALIFORNIA EDISON CO.
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20028F363 List:
References
83-16, NUDOCS 8302010280
Download: ML20028F362 (2)


Text

.

NO Southern California Edison Company I;gy g5 S AN ONOFRE NUCLE AR GENER ATsNG ST ATION R .o. 0 u .

~26 S A N C LEMENTE. C A LIFORNI A 92672 H. B. R A Y I{?vrtspeche

,1 1,0~ "aaaa'a January 11, 1983 " " " " - " "

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 30-Day Follow-Up Report Licensee Event Report No.82-168 San Onofre Nuclear Generating Station, Unit 2 Pursuant to Section 6.9.1.13.b of Appendix A Technical Specifications to Facility Operating License NPF-10 for San Onofre Unit 2, this submittal provides the required 30-day written report and copy of Licensee Event Report (LER) resulting from an occurrence involving Limiting Condition for Operation (LCO) 3.1.3.1 associated with Control Element Assemblies (CEA's).

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.

On December 12,1982, at 0801 with the plant in Mode 1, the indicated position for shutdown CEA 12 (Group B) went from 148 inches to 120 inches resulting in a reactor trip due to a high Local Power Density (LPD)/ low Departure from Nucleate Boiling Ratio (DNBR) signal. The requirements of LC0 3.1.3.1 Action Statement 'c' were met at this point in that as a result of the reactor trip, the plant was placed in Mode 3.

8302010280 830111 PDR ADOCK 0500036 G XE -R 83-ile

R. H. Engelken January 11, 1983 As a result of the reactor trip and concurrent turbine trip, plant loads transfered from the unit auxiliary transformers to the reserve auxiliary transformers. However, during this transfer, Motor Control Center (MCC) 2BC failed to energize. Several secondary plant steam valves failed to shut, resulting in excessive steam demand, and rapid RCS cooldown.

The high LPD/ low DNBR signal, resulting in the reactor trip, was caused by failure of a reed switch. The switch was repltced. No further corrective action is planned. Enclosed LER 82-168 addresses this event.

The cooldown, caused by the failure of MCC 2BC to energize, also caused Safety Injection Actuation Signal (SIAS) and Containment Cooling Actuation Signal (CCAS) to be initiated. Due to sufficient RCS pressure, the SIAS initiation did not result in safety injection flow. LER 82-168 will be revised after further investigat;cn of the failure of MCC 2BC to energize, and will identify the cause and corrective action to be taken to prevent recurrence.

There was no impact on the health and safety of plant personnel or the public associated with this event.

If there are any questions regarding the above, please contact me.

Sincerely, b

Enclosure:

LER 82-168 cc: A. E. Chaffee (USNRC Resident Inspector, San Onofre Units 2 and 3)

R. Pate (USNRC Resident Inspector, San Onofre Units 2 and 3)

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