PNO-II-82-065, visual & Ultrasonic Exams Revealed Cracks in 51 of 96 Thermal Shield Bolts.Removal of Bolts & Associated Locking Clips Revealed 19 of 27 Bolt Heads Broken.Bolts Will Be Replaced W/Stud & Nut Assemblies

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PNO-II-82-065:visual & Ultrasonic Exams Revealed Cracks in 51 of 96 Thermal Shield Bolts.Removal of Bolts & Associated Locking Clips Revealed 19 of 27 Bolt Heads Broken.Bolts Will Be Replaced W/Stud & Nut Assemblies
ML20054G053
Person / Time
Site: Oconee Duke Energy icon.png
Issue date: 06/11/1982
From: Herdt A, Ignatonis A
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
References
PNO-II-82-065, PNO-II-82-65, NUDOCS 8206210029
Download: ML20054G053 (1)


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June 11, 1982 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PN0-II-82-65 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verifi-cation or evaluation, and is basically all that is known by IE staff on this date.

FACILITY: Duke Power Company Licensee Emergency Classification:

Oconee Unit 3 Notification of Unusual Event Docket No. 50-287 Alert  ;

Seneca, South Carolina Site Area Emergency i General Emergency X Not Applicable

SUBJECT:

THERMAL SHIELD BOLT CRACKS As the result of visual and ultrosonic examinations--scheduled after thermal shield bolt failures were identified in Units 1 and 2--the licensee found cracks in 51 of the 96 thermal shield bcits in Unit 3 during tests completed on June 9. Upon removing the bolts and associated locking clips,19 of the 27 bolt heads thus far removed were found broken but still retained in their clips. No other defects were observed.

All thermal shield bc'ts will be replaced with stud and nut assemblies, as was done for Units 1 and 2, where similar problems were identified (PN0 I1-81-52 and PN0 II-81-52a, issued on July 16, 1981, and August 7, 1981).

Unit 3 was shut down on April 23 for in-service inspection and refueling. Replacement of the thermal shield bolts is not expected to affect the scheduled restart date in September.

Media interest is not expected. The licensee does not plan a news release at this time. The NRC does not plan a press release.

The State of South Carolina has been notified.

Region II (Atlanta) received notification of this occurrence by telephone from the licensee at 2:45 p.m. on June 10.

This information is current as of 11 a.m. on June 11.

Contact:

A. J. Ignatonis, RII 242-5588; A. R. Herdt, 242-5535 DISTRIBUTION:

H. Streat MNBB Phillips E/W Willste MAIL:

Chairman Palladino EDO NRR /a es/ TE- NMSS ADM:DMB Comi. Gilinsky PA OIA RES D0T: Trans Only Comm. Ahearne MPA AE0D Applicable State Comm. Roberts ELD Comm. Asselstine Air Rights INP0 SECY SP NSAC ACRS CA PDR Regions:

Licensee: _ , f/ 4 B (ReactorLic~ensees)

Applicable Resident Site /;s g 8206210029 820611 PDR I&E PNO-II-82-065 PDR /g' 3t/