05000344/LER-1981-031, Forwards LER 81-031/03L-0.Detailed Event Analysis Encl

Forwards LER 81-031/03L-0.Detailed Event Analysis Encl

ML20040B820
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	01/14/1982
From:	Yundt C PORTLAND GENERAL ELECTRIC CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20040B821	List: 05000344/LER-1981-031, Forwards LER 81-031/03L-0.Detailed Event Analysis Encl 05000344/LER-1981-031-03, /03L-0:on 811215,containment Recirculation Sump Suction Valve Failed to Reopen During Inservice Testing of Train B ECCS Valves at Full Power.Caused by Failure of Torque Limit Switch Due to Mechanical Shock
References
CPY-042-82, CPY-42-82, NUDOCS 8201260443
Download: ML20040B820 (2)

LER-1981-031, Forwards LER 81-031/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3441981031R00 - NRC Website

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Port!and General Liectric Company January 14,19f52 i

Trojan tiudear Plant CPY-042-82 P.O. I!ox 439 luinier, Oregon 97048 (503) 556-3713 I

Mr. R.11. Engelken, Director

.US Nuclear Regulatory Commission

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Creekside Oaks Of fice Park 1450 Maria Lane - Suite 260 l

Walnut Creek, California 94596-5368

Dear Sir:

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In accordance with the Trojan Plant Operating License Appendix A, USNRC Technical Specification 6.9.1.9.b, attached is Licensee Event Report No.

81-31 concerning containment recirculation sump suction valve, M0-2069B, I

which failed closed rendering "B" ECCS train inoperable in accordance with STS 3.5.2.e.

MO-2069B is also required to be operable as specified in STS 3.6.3.1 for containment isolation. There was no effect on public l

health or safety. This is a 30-day reportable occurrence.

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Sincerely, i

C. P. Yundt

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General Manager CPY/MLD/ LAW:ga j

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REPORTABLE OCCURRENCE 1.

Report No:

81-31 2.

Report Date:

January 14, 1982 3.

Occurrence Date:

December 15, 1981 4.

Facility:

Trojan Nuclear Plant, PO Box 439, Rainier, Oregon 97048 5.

Identification of Occurrence:

Recirculation sump suc tion valve, MO-2069B, would not open as indicated by its position lights on the main control panel after successfully closing the valve as specifled in the inservice valve testing instructions.

6.

Conditions Prior to Occurrence:

The plant was at 100% power, steady state operationa, and inservice valve testing to record "B" train ECCS valve cycle times was in progress.

7.

Description of Occurrence:

After successfully closing MO-2069B the operator could not reopen the valve from the control room.

Several attempts were made to open the valve.

8.

Designation of Apparent Cause of Occurrence:

The torque 1imit switch on the valve operator failed due to mechanical shock and disengaged the motor operator as soon as the valve started to open.

9.

Significance of Occurrence:

MO-2069B is required to be operable in accordance with STS 3.6.3.1 for containment isolation.

Both valves outside of containment and down-stream of MO-2069B were already closed and deenergized ensuring containment isola ti on.

MO-2069B is required to be open in accordance with STS 3.5.2.e for RllR recirculation flow.

Since recirculation flow is required approximately 1 - 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> af ter a LOCA and "A" train valve was open, there would have been no impact on the plant in the event of a 1.0CA.

There was no effect on plant or public safety.

10. Corrective Action

"h" train of ECCS was immedie' ty declared inoperable.

A containment entry was made on December 16, 1981 and the torque limit switeb on the valve motor operator was replaced.

The valve was then cycled satis-factorily and left in the open position.

Tlu "B" train of ECCS was declared operable 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> af ter the initiating event. A maintenance evaluation is being conducted into this over-torque problem and possible redesign of these valve motor operators. Additionally, testing will be perf ormed during the next refueling oittage to determine if the torque requirements f or these valves can be reduced and still ensure required leakage rates are not exceeded.