PNO-II-80-116, on 800625,on Unit 3,cracks Were Identified in Three of Sixteen Studs Used to Attach Lower Manway Cover to Steam Generator.Licensee Has Examined Remaining Studs & Found Addl Cracks
| ML16161B225 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/26/1980 |
| From: | Robert Lewis, Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| References | |
| PNO-II-80-116, NUDOCS 8010170002 | |
| Download: ML16161B225 (1) | |
PRELININARY NOTIFICATIO J
6 June 26, 1980 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-II-80-116 This preliminary notification constitutes EARLY notice of an event of P.OSSIBLE safe'ty or public inte ificance. The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff as of this.date.
FACILITY:
Duke Power Company Oconee Units 1, 2, and 3 Docket Nos. 50-269, 50-270, 50-287 Seneca, South Carolina
SUBJECT:
CRACKING OF MANWAY COVER STUDS On June 25, while preparing to make repairs to the leaking "A" steam generator tubes on Unit 3 (see PNO-II-80-109),
licensee personnel identified cracks in three of the sixteen studs used to attach the lower manway cover to the steam generator. (The.upper and lower manway covers are part of the reactor coolant system boundary.)
The licensee inspected the remaining studs ultrasonically (UT),
and five of the remaining studs showed UT indications for a total of eight anomalies out of sixteen studs.
The licensee has UT inspected all studs on the upper and lower manways of Unit 3 and has found only one additional UT indication in one stud on the upper manway of the "B" steam generator. All studs except for those in the lower manway of the "B" steam generator will be replaced.
These studs are 2 inch diameter (8 threads/inch) studs fabricated from SA 320 (Grade L43) carbon steel.
Units 1 and 2 are in operation,. but Unit 1 will shut down on Friday, June 27 for a two week outage.
All Unit 1 manway studs will be UT inspected at that time.
Unit 2 manway studs were previously removed, cleaned and visually inspected during a recent outage.
Several studs were replaced, but no cracking was observed during those visual inspections.
A Region II met4llurgist was sent to the Oconee site to inspect the cracked studs and to review the licensee's UT procedures.
The other Regions have been notified because they have B&W units.
Neither the licensee nor the NRC plans to issue a news release.
The State of South Carolina has been notified.
Region II (Atlanta) received notification of this occurrence by telephone from the resident inspector at 4:45 p.m. on June 25. This information is current as of 9:00 a.m. on June 26.en
Contact:
R. Martin, RII 242-5534; R. C. Lewis, RII 242-5535 Distribution:
Transmitted H. St.
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Chairman Ahearne Commis'sioner Hendrie S. J. Chilk, SECY Commissioner Gilinsky Commissioner Bradford C. C. Kammerer, CA Commissioner Kennedy ACRS (For Distribution)
Transmitted:
MNBB /d.2 P. Bldg. to IE:XOOS /eZr(IE:HQ Dist.)
W. J. Dircks, EDO H. R. Denton, NRR C. Michelson, AEOD R. H. Vollmer, NRR Landow
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J. J. Fouchard, PA R. J. Mattson, NRR J.J Cming, A
N. M. Haller, MPA D. F. Ross,.NRR R. G. Ryan, SP D. Eisenhut, NRR MAIL H. K. Shapar, ELD S. H. Hanauer, NRR R. Minogue, SD IE:XOOS Willstea1s-S Document Mgt. Br. (For PDR/LPDR)
Applicable Resident SiteZ '
J. G. Davis, NMSS Regional Offices R. J. Budnitz, RES PRE I INARY NOTIF CATION 8 010170 ool