ML19256C660
| ML19256C660 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/17/1979 |
| From: | Klinger G, Mckee P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-79-411A, NUDOCS 7910110645 | |
| Download: ML19256C660 (2) | |
Text
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PRELIMINARY NOTIFICATION September 17, 1979 (7
L-PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-79-411A f)
This prelimintry notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance.
The information presented is as initially received without verification or evaluation and is basically all that is known by IE staf f on this date.
Facility:
Southern California Edison Company San Onofre Nuclear Generating Station Unit No. 1 San Clemente, California Docket No. 50-206
Subject:
PIPE CRACKS IN SAFETY-RELATED STAINLESS STEEL PIPING This updates PNO-79-411 issued on September 10, 1979.
The first of weekly surveillance examinations of the pipe clamps installed on two defective welds in the 8-inch, scoedule 10, piping on the discharge of the refueling water storage tank (RWST) were conducted by the licensee on September 14, 1979.
These examinations revealed an additional through-wall crack in a weld which had previous indications of two through-wall cracks, and two additional through-wall cracks in a weld which previously had only surface indication of cracks without evidence of through-wall cracking.
Based upon these findings, the licensee shut down the San Onofre unit on the evening of September 14, 1979.
As of 8:00 a.m. on September 17, 1979, repairs were in progress to remove and replace the two defective welds, with this work estimated to continue through the evening of September 17.
On September 16, 1979, a crack indication was revealed in a weld in the "B" safety injection loop piping.
In this instances the crack was revealed on the inside diameter of the 6-inch, schedule 80, piping and extends to approximately 25% wall thickness.
This defective weld has been removed and will be replaced prior to plant startup.
During the period September 14-17, 1979, examinations are being conducted of welds on piping inside containment which are of the type covered by IE Bulletin 79-17.
By the morning of September 17, approximately 50 of a total of approximately 200 such welds had been examined.
These examinations have revealed no crack indications.
The licensee's current schedule is to complete examinations of all pipe welds covered by IE Bulletin 79-17 (Stagnated, borated water systems) by October 24, 1979.
Those welds inside containment and not normally accessible during plant operation may be examined prior to resuming plant operation, although a final decision in this regard has not been made by the licensee.
Such a decision would extend the current outage by several days.
CONTINUED 1448 241 7 9101106py
September 17, 1979 PNO-79-411A Continued
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The above information was provided to the NRC's Region V (San Francisco) office by telephone by the acting Site Manager at approximately 3:30 p.m.
on September 14, and at approximately 7:50 a.m. on September 17, 1979.
Contact:
PMcKee, IE x28019 GKlingler, IE x28019 Distribution:
Transmitted H St Chairman Hendrie Commissioner Bradford S. J. Chilk, SECY Commissioner Kennedy Commissioner Ahearne C. C. Kammerer, CA Commissioner Gilinsky ACRS (For Distribution)
Transmitted:
MNBB P. Bldgjg!L}~?
V. Stello, IE L. V. Gossick, EDO H. R. Denton, NRR Region,16, H. L. Ornstein, E00 R. C. DeYoung, NRR J. J. Fouchard, PA R. J. Mattson, NRR Landow N. M. Haller, MPA D. Vassallo, NRR J. J. Cummings, OIA R. G. Ryan, OSP D. Eisenhut, NRR H. K._Shapar, ELD SS Bldg (MAIL)
W. J. Dircks, NMSS R. Minogue, SD S. Levine, RES PRcLIMINARY NOTIFICATION 1448 542
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