ML20236U880

PN-75-103:on 751007,crack Discovered in 18 Inch Containment Purge Line Where 8 Inch Nitrogen Supply Line Joins.Unit Was at 85% Power at Time Crack Found.State of Illinois Notified

ML20236U880
Person / Time
Site:	Dresden
Issue date:	10/08/1975
From:	Jennifer Davis, Thornburg H, Warnick R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PN-75-103, NUDOCS 9807310132
Download: ML20236U880 (2)

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g PRELIMINARY NOTIFICATION - NOT FOR PUBLIC DISCLOSURE October 8, 1975 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE --PN-75-103 This preliminary notification constitutes EARLY notice of events of ,

POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation 1 and is basically all that is known by OIE staff as of 1:45 p.m. on the

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date of this notification. IT SHOULD BE SPECIFICALLY NOTED THAT THIS l

NOTIFICATION MAY CONTAIN INFORMATION THAT LATER MAY BE DETERMINED TO (

BE INACCURATE OR INCONSISTENT. AN OFFICE OF INSPECTION AND ENFORCEMENT j NOTIFICATION OF AN INCIDENT OR OCCURRENCE (BLUE SHEET) SUBSEQUENTLY WILL BE IS5UED IF WARRANTED. -

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Facility: Dresden Unit 2 (Commonwealth ' Edison Company)

Subject:

CRACK IN CONTAINMENT INERTING LINE

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At approximately 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> on October 7, 1975, a crack was discovered l in the 18 inch containment purge line where the 8 inch nitrogen supply '

line joins it. The rubber seat on the 18 inch butterfly containment

, isolation valve, which is located between containn?.nt and the junction EE with the 8 inch nitrogen supply line, was also found to be cracked. .

The pipe crack is in the base met'al of the 18 inch line extending {

( about 2/3 of the way around the weld which joins the 8 inch nitrogen  ;

supply to the 18 inch purge line. The crack is 3 to 4 inches from the weld. The unit was at 85% power at the time the crack was found.

Power was reduced immediately in preparation of placing unit in cold shutdown.

The crack in the seat of one of two redundant containme3t isolation /

valves (although not open to atmosphere) represents a degradation of the primary containment function since it is questionable whether d' or not this one valve is capable of performing its intended function. A-If the valve is not capable of performing its intended function, the O thruvall pipe crack represents a violation of primary containment Q integrity.

The auxiliary boiler used to vaporize the liquid nitrogen supply was out of service for 2 to 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> during the inerting of contain-ment. The pipe crack and valve damage were found as a result of an investigation conducted to determine the effects of inerting ..

with cold nitrogen.

1 Continued

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l 9807310132 751008  !

PDR I&E PN-75-103 PDR I

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(=/ Continued October 8, 1975 Page 2 PN-75-103 The licensee.is evaluating repair technique and estimates that I the unit will be down until October 13, 1975. An inspector is l at the site. Region III and the licensee are making press releases.

l The State of Illinois has been notified.

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l Region III received notification of this occurrence by comuni-

~ - .. cation with inspector at site from Co monwealth Edison at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on October 7, 1975.

Contact:

RFWarnick, IE x7261 HDThornburg, IE x7353 JGDavis, IE x7541 Distribution:

Chairman Anders Commissioner Mason S. J. Chilk, SECY Commissioner Gilinsky Commissioner Rowden G. F. Murphy, JCAE 3 Commissioner Kennedy C. C. Kamerer, CA l f L. V. Gossick, EDO D. F. Knuth, IE J. A. Harris, PA l

i .- B. C. Rusche,.NRR J. La Fleur, ISP T. J. McTiernan, AIA @

l K. R. Chapman, NMSS H. K. Shapar, ELD .

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H St / h ; MNBB V l h ; Luge,,s j, Transmitted: P Bldg N,.

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_. PRELIMINARY NOTIFICATION - NOT FOR PUBLIC DISCLOSUPI L____._____.__