05000206/LER-1982-006, Forwards LER 82-006/99X-0.Detailed Event Analysis Submitted

Forwards LER 82-006/99X-0.Detailed Event Analysis Submitted

ML13333B635
Person / Time
Site:	San Onofre
Issue date:	03/02/1982
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML13333B636	List: 05000206/LER-1982-006, Forwards LER 82-006/99X-0.Detailed Event Analysis Submitted 05000206/LER-1982-006-99, /99X-0:on 811120,refueling Water Tank Level Decreased & Sphere Sump Actuation Increased.Caused by Water Leaking Through Containment Spray Block Valves CV-82 & CV-114 Due to Open Isolation Valve
References
NUDOCS 8203100264
Download: ML13333B635 (2)

LER-1982-006, Forwards LER 82-006/99X-0.Detailed Event Analysis Submitted

Event date:
Report date:
2061982006R00 - NRC Website

text

Southern California Edison Company C

SA** CL tSett CAL*..POuadA 84898 March 2, 1982 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, Director DOCKET No. 50-206 SAN Of0FRE-UNIT I

Dear Sir:

This letter describes an occurrence involving the Containment Spray System. This occurrence is not reportable in accordance with the requirements of the Provisional Operating License DPR-13 but is considered significant and is, therefore, being provided for your information.

On November 20, 1981. preventive maintenance was conducted on the Refueling Water Pumps.

As a part of the procedure, the pumps were started. This resulted in a decrease in Refueling Water Tank level and actuation of a Sphere Sump Pump.

It was suspected that the water had gone into contairnment through one or both of the Containment Spray block valves CV-82 & CV-114. Containment entries were made which verified that the water had come out through the containment spray header, collected outside the secondary shield, and drained to the containment sump.

Upon external inspection and cycling, no indications of valve failure were observed.

Due to the apparent external pressure source to the spray system, valve positions on connected systems were checked and the hot leg recirculation system isolation valve was found slightly open.

This line is pressurized to 3W0 psi by the letdown line and via the open isolation valve, could have raised the contzirnrent spray header pressure to an abnormally high (but within design) value.

I 2/

Awcv 6

111_lra

Ar. R.

Engelken, Director Karch 2, 1982 based or the above data, the most probable event scenario was that due to h

combirned effects of the refueling water pump operation and the slightly open hot leg recirculation valve-CV-82 & CY-114 leaked by and allowed water into the cortr.ainment spray header.

This occurrence does not indicate a loss of containment spray capability and so does not have safety implications.

To avoid recurrence, the procedure for equipment control implementation has been revised to ensure that the refuelinrj woter pumps are not tested for operability without having their dis charge valves closed.

In addition, a detailed containment inspection will be conducted during the March 1982 outage.

This inspection will be accomplished to determine the presence and evaluate the potential adverse impact of any ermaiin boic acid deposits on plant equipment.

Sincerely.

Encl:

Licensee Event Report 82-006 cc:

U. S. Nuclear Regulatory Comssion rff(ice of iaspection and Enforcemt U. S. Melear Aeivlatory Commission Office of Ma&geamnt Informatio A rgram Control (MIPC) lAStitte of balear Power Operations bkler Safety Aaelysis Cester L f Oiller (U

) See Ofre Unit I Resident IMspctor)