ML20087L620

Ao:On 730329,when Drain Cap Removed from Penetration 32,air Blew Lightly for Several Seconds & Showed No Signs of Diminishing.Caused by Leak of Sensing Line within Penetration Boundary.Line Will Be Repaired

ML20087L620
Person / Time
Site:	Point Beach
Issue date:	04/04/1974
From:	Burstein S WISCONSIN ELECTRIC POWER CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8403270303
Download: ML20087L620 (2)

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Wisconsin Electnc eaaracouvar 231 WEST MICHIGAf4. MILWAUKEE,WISC0f4Sifi 53201 0

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4 M April 4, 1974 4

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Mr. John F. O' Leary, Director 2 .

Q29 n,[ g Directorate of Licensing p4 M'Qp '

U. S. Atomic Energy Commission 4 q,

Washington, D. C. 20545 g L* l V

Dear Mr. O' Leary:

DOCKET NO. 50-266 MOMENTARY LOSS OF CONTAINMENT INTEGRITY POINT BEACH NUCLEAR PLANT This ?.etter is to report the details of an abnormal occurrence at the Point Beach Nuclear Plant, Unit 1, Facility Operating License No. DPR-24, as defined by Section 15.1.a.B of the Technical Specifications and, more specifically, by Section 15.3.6.A.a of the Limiting Conditions for Operation.

Ole :ritten r:r~', M1M in accordance with Section 15.6.6.A.2 n - --

of the Technic'l a Specitications, Io nows a wl @ 0A:. : ptr:

to Mr. T. Tamplin of Region III, Directorate of Regulatory Op-erations, on March 29, 1974, as required by Section 15.6.A.1 of the Technical Specifications.

At approximately 3:00 P.M. on March 29, 1973, prepara-tions were made to conduct a pressure test of a number of pene-trations in Pipeway #1 at Point Beach per Operations Refueling Test Procedure, ORT #81. As a preliminary to this test, any residual pressure in the penetration envelopes was relicved by momentarily removing a 1/4 inch threaded drain cap from the end of each of the penetrations where they protrude out of the con-tainment wall. When the drain cap was removed from penetration

1. 32, air blew lightly for several seconds and showed no signs of diminishing. Suspecting a leak into the penetration from the containment or piping within the penetration, the operator re-placed the cap.

To determine the source of the in-leakage to penetra-tion #32, a test arrangement was attached With to the air drain hole pressure to applied pressurize the pene'. ration envelope.

to the envelope, an inspection inside the containment disclosed 8403270303 740404 n PDR ADOCK 05000266 S PDR 6088

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< O O Mr. John F. O' Leary April 4, 1974 4

air issuing from the containment pressure sensing line (pene-tration #32A). This appears to confirm that the 3/4 inch dia-meter sensing line has a leak within the boundary of penetra-tion #32, in which case it must be deduced that on the three occasions that the drain cap was briefly removed, containment integrity was violated. We believe the path was from the con-tainment through the normally open sensing line via the defec-tive pipe into penetration #32, and thence to the auxiliary building via the momentarily uncapped 1/4 inch drain.

The containment pressure at the time of this occur- .

rence was 1.2 psig. Radioactive gas and particulate levels

within containment were below alarm setpoints. The total accumulated time that the 1/4 inch drain cap was removed to depressurize the penetration, to attach the test assembly and to remove the test arrangement is estimated at approximately 50 seconds. Neither the local auxiliary building monitors nor the auxiliary building exhaust stack monitors indicated any change in activity during or shortly following the cap removal.

The operator conducted his own personal monitoring at the com-pletion of the penetration tests and no contamination of his person or clothing was apparent. Therefore, while a discharge m ent to tbn an::iliary builclinn micht ha cnicu-from the- contain' lated, it is conslaereu tne rigure would be insigniricant ano not meaningful.

It is planned that the sensing line in penetration

1. 32A will be repaired during tha refueling shutdown of Unit 1 which commences on April 6, 1974. . Operating personnel have been advised to remove the penetration drain caps slowly and carefully during future tests of the penetrations and to determine that pressure differences have equalized across the cap before its complete removal. While this procedure will not prevent this type of event, it will permit a more rapid reestablishment of containment integrity, should a penetration leak be suspected.

Very truly.yours, A #

3 i Sol Burstein Execut[ve Vice President a

cc: Mr. James G. Keppler, Regional Director Directorate of Regulatory Operations, Region III l

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