ML20087L611

Ao:On 740404,following Completion of Operations Refueling Tests,Isolation Valves 1AOV-2084 & 1AOV-2083 Closed Automatically on Signal from R-19 Process Monitor,Indicating Liquid W/Radioactivity Above Normal Levels

ML20087L611
Person / Time
Site:	Point Beach
Issue date:	04/11/1974
From:	Burstein S WISCONSIN ELECTRIC POWER CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8403270299
Download: ML20087L611 (2)

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April 11, 1974 Mr. John F. O' Leary, Director Directorate of Licensing U. S. Atomic Energy Commission Washington, D. C. 20545

Dear Mr. O' Leary:

DOCKET no. 50-266 FAILURE OF SAMPLE LINE VALVE TO CLOSE POINT BEACH NUCLEAR PLANT This letter is to report the details of an abnormal occurrence at Point Beach Nuclear Plant, Facility Operating Li-conse No. DPR-24, as defined by Section 15.1.a.D of the Techni-cal Specifications. This written report, filed in accordance with Section 15.6.6.A.2 of the Technical Specifications, follows a telephone report made on the ir.cident to Mr. K. R. Baker of Region III, Directorate of Regulatory Operations, on April 4, 1974, as v::quited by 5cu Liv 24 13.6.6.A.1 vf the Techasimel Gyeci-fications.

On April 4, 1974, the Operations Refueling Tests, ORT #51 and ORT #52, to leak test the 3/8 inch diameter steam generator sample line isolation valves lAOV-2084 and 1AOV-2083, were completed satisfactorily. At 2:30 P.M., following comple-tion of the tests, the sample line isolation valves of both the "A" and "B" steam generators were placed in their normally open position.

At 2:47 P.M., both the isolation valves closed auto-matically on a signal from the R-19 process monitor, indicating that liquid with radioactivity levels above normal background-levels had passed down the sample lines.

The source of the radioactivity was quickly traced to-the test arrangement used to pressurize the lines with air for conduct of the valve leak tests; the contamination in question having been carried over from a valve test of the pressurizer steam space isolation valvo.

The' decision was mada to flush the sample lines to clear the contcmination; the valves being manually opened at 2:55 P.M. At the completion of the flush, the manual open sig-

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Mr. John F. O' Leary, Director April 11, 1974 nal was removed but the flushing operation was found not to have cleaned the probes. The radiation signal again called for the sample line isolation valves to close. LAOV-2084 closed; 1AOV-2083 did not. A visual inspection of the valve verified its open position.

At 3:05 P.M., air was manually failed to 1AOV-2083 and the valve closed immediately, indicating that the operating problem Jay in the solenoid valve co.+. rolling the air supply to the valve. The solenoid valve was replaced and the radiation monitor probes ucre cleaned. The valve then tested satisfac-torily.

The faulty solenoid valve has since been disassembled and inspected but no immediately obvious reason for its failure to function correctly has been discerned to date. If the cal-function was caused by some particle of foreign matter lodging under a valvo scat, this particic was lost during the removal and disassembly of the solenoid.

In examining the safety aspects of this malfunction, it should be noted that while the steam generator sample line isolation valve 1AOV-2083 is a normally open valvo, the manual valvc at th; sampic cink ic ncrmally closed and is Only Opencd .

by qualified personnel for the purpose of drawing a sample, fol-lowing which it is immediately closed again. In addition, a second manual valvo, upstream of 1AOV-2083 but outside of the containment, can be utilized in emergencies to isolate the sample line should 1AOV-1083 fail to function. Therefore, it is not considered that this event created any hazard to the health and safety of the public.

Considering the possibility that the lodging of a foreign particle was not the cause of the valve's malfunction, it is our intention to continue our investigation of this and similar solenoid valves in the plant. Should this investigation t

disclose a specific prcblem, generic or otherwise, we will submit l

a further report on the matter.

l Very truly yours, l

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Sol Burstein .

Exect) ive Vice. President cc: Mr. K. R. Baker Directorate of Regulatory Operations, Region III

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