ML19210D699

LER 79-029/03L-0:on 791012,during Routine Plant Tour,Pinhole Leak Detected in Upstream Weld of Supply Isolation Valve. Cause Unknown.Weld Will Be Repaired During Next Shutdown

ML19210D699
Person / Time
Site:	Cooper
Issue date:	11/09/1979
From:	Doan P NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19210D695	List: ML19210D694 ML19210D699
References
LER-79-029-03L, LER-79-29-3L, NUDOCS 7911270464
Download: ML19210D699 (1)

Text

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NRC FOAM 366 U. S. NUCLE AR REGUL AToRY CoMMISSloN (7 77)

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DATE I 8 61 ET NUMBER EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h O 2 puring normal operation, a routine tour of the plant indicated a through-wall crack l o 3 pf a weld in the REC supply to the south critical loop, upstream of the supply o 4 lLsolation valve. This portion is isolatable from the critical loop. The redundant ;

o s fEC loop and Service Water supply were available to supply this critical loop. If  ;

O s phe weld failed completely, it would be detectable. Reference LER Report No. 78-27 g O 7 ffor an event of similar nature. This event presented no adverse consequences from l 0 s [the standpoint of public health and safety. 80 I

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42 lg lAlg 43 J l0 3 5lg 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS i O IThe component involved is a weld. The failure is a through-wall crack which has sur-l l1 Iil Ifaced as a oinhole leak of undeterminable cause. A soft patch has been applied and I

, , Ithe weld evaluated acceptable for continued service. During the next shutdown of m l sufficient duration, the weld will be replaced. An evaluation of a similar failure l i i 4 Iwhich was not reportable, will dedermine the cause. Update report will be submitted.]

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P COOPER NUCLEAR STATION P.O. Box 98, BRoWNvlLLE, NEBR A5KA 68321 Nebraska Public Power Distr =ct i TEtEPeoNe <402> .2s.3.i >

CNSS790554 November 5, 1979 Mr. K. V. Seyfrit U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region IV 611 Ryan Plaza Suite 1000 Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.2 of the Technical Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on October 8, 1979. A li-censee event report form is also enclosed.

Report No.: 50-298-79-28 Report Date: November 5, 1979 Occurrence Date: October 8, 1979 Facility: Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

A condition which lead to operation in a degraded mode permitted by a limiting condition for operation established in Section 3.19.B of the Technical Specifications.

Conditions Prior to Occurrence:

The reactor was at a steady state power level of approximately 9}%

of rated thermal power.

Description 'f Occurrence:

Unile laspecting the cable spreading room it was noted that a four inch diameter pipe sleeve in the fire wall between the cable spreading room and the cable expansion room was not properly sealed.

Designation of Apparent Cause of Occurrence:

Inadequate control of installe. tion of fire seals during a microwave communications system installation in December 1978.

1398 185

Mr. K. V. Seyfrit November 5, 1979 Page 2.

Analysis of Occurrence:

The four inch sleeve, located in the wall between the cable spread-ing room and the cable expansion room, carries two 1 inch conduits through it. One conduit contains control cable for reactor re-circulation motor generator set ventilation flow indication. The other conduit contains cable for microwave communication. The space inside the four inch sleeve and outside of the two one inch conduits was not adequately sealed. The possibility of a fire starting in this area is minimal because no combustible material was present. The cable spreading room is equipped with an auto-matic sprinkler system which could extinguish a fire if one started.

The possibility of a fire spreading through the unsealed sleeve was remote because the sleeve contained no combustible material. This occurrence presented no adverse effect to public health and safety.

Corrective Action:

The four inch sleeve was immediately sealed and an adequate fire barrier established. All remaining sleeves in this area were inspected and verified to be properly sealed. The Technical Spec-ifications also require that the penetrations in the cable spread-ing room be inspected every 18 months. This event was discussed with the appropriate personnel.

Sincerely, L. C. Lessor Station Superintendent Cooper Nuclear Station LCL:cg irtach.

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REPORT OATE EVENT DESCRIPTICN AND PROB ABLE CONSEQUENCES h O 2 During inspection of cable spreading room it was noted that one 4 inch pipn sleevo I o 3 fin the wall between cable spreadine room and cable evnnnaion room una noe ann 1pa i o 4 T.S. 3.19.B. The possibility of a fire in this aren is minimal because no combus- 1 IOI5I Itible material was present. Cable spreadine room is eauipped with an automatic l O 6 l cnrink1 pr evneon. Nn si gni fi e nn e ncenvranco e n nte nlano Thic ovone hnd nn offoce l 0 7 lunon nublic health nnd unfaty_ This avane is nne renprieive. I O a l 7 8 3 00 SYSTEM CAUSE CAUSE COMP. VALVE CODE CUDE SU8 CODE COMPONENT CODE SU8 CODE SUSCODE 7

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33 34 3b 36 37 40 41 42 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i o l Four inch sleeve in the wall has apparently been unsealed since December 1978.

Ii li l l The sleeve was immediately sealed. All other sleeves in this area were also in-

, , spected and verified to be properly sealed. The incident was discussed with ap-i 3 l propriate personnel, i A i . I

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