ML20010J015

Forwards LER 81-016/01T-0.Detailed Event Analysis Encl

ML20010J015
Person / Time
Site:	Oconee
Issue date:	09/17/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20010J016	List: ML20010J015 ML20010J023
References
NUDOCS 8109290505
Download: ML20010J015 (3)

Text

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D UK E PO~.v E R COMPANY T; g Ir~ '

POWEN UUU. DING 422 Sourn Circucu Srnzer, Crunnotrz, N. C. 2824a

1 Sco 23 AB: 3' WILLIAM O. PA R K E R. .J R.

VICF Potss org t TELEPwoNE:Anta704 Straw Paoovctiom 373-4083 September 17, 1981 Mr. James P. O'Reilly, Director U. S. Nuclear Regulatory Commission Region II 101 Marietta St aet, Suite 3100 Atlanta, Georgia 30303 Re: Gconee Nuclear Station Docket No. 50-269

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-269/81-16. This report is submitted pursuant to Oconee Nuclear Station Technical Specifi- '

catien 6.6.2.1.a($). which concarns potential degradation of the reactor coolant pressure boundary, and describes an incident which g g dered to be of no significance with respect to its effect on t 4tehltll hndi's safety of the public. ,'

V y truly yours,

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William O. Parker, Jr.

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JFK/php Attachment cc: Director Mr. Bill Lavallee Office of Management & Program faalysis Nuclear Safety Analysis Center U. S. Nuclear Regulatory Commission P. O. Box 10412 Washington, D. C. 20555 Palo Alto, California 94303 Mr. F. Jape Resident Inspector-NRC Oconee Nuclear Station 3h5

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0109290505 810917 PDR ADOCK 05000269 S PDR.

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DUKE POWER COMPANY OCONEE UNIT 1 REPORT NUMBER: 269/81-16 REPORT DATE: September 17, 1981 -

OCCURRENCE DATE: September 3, 1981 FACILITY: Oconee Unit 1, Seneca, South Carolina i i  !

IDENTIFICATION OF OCCURRENCE: Linear crack indications on lA2 RCP #1 seal i housing bolts.

CONDITIONS PRIOR TO OCCURRENCE: Cold Shutdown.

DESCRIPTION OF OCCURRENCE: During Magnetic Particle Testing (MT) of'the

1. 1 seal housing bolts on the 1A2 RCP, linear indications were observed on 11 of the 12 bolts tested. The linear indications are circumferential in the shank to head transition area of the bolt. Subsequent testing of the lAl and 1Bl RCP bolts were completed with 4 of 12 bolts on the 1A1 RCP having linear indications. No indications were found on the 1B1 RCP bolts.

Testing of the 1B2 bolts has not been completed.

It is felt that this occurrence involves potential degradation of reactor coolant system pressure boundary and is thus reportable pursuant to Technical Specification 6.6.2.1.a(3).

APPARENT CAUSE OF OCCURRENCE: The cause of the linear indication on the bolts has not been determined.

ANALYSIS OF OCCURRENCE: The number 1 seal housing is attached to-the RCP main flange utilizing 12 2" x 8" socket head cap screws. The bolts involved are AISI 4140 alloy steel and are plated. The bolts on the lAl and 1A2 seal housings are chromium plated, and the bolts on the 151 and 1B2 pumps are magnesium phosphate plated.

The linear indications were discussed using a " wet" magnetic particle inspec-tion technique (MT). The indications vary in length from 1/16" to 2" circumferential1y where the bolt- head joins the shank portion of the bolt.

No indications were found using ultrasonic testing methods (UT).

The Oconee Units 2 and 3 RCP's are Bingham-Williamette and have a different seal configuration; therefore this event is of no concern with respect to Units.2 and 3.

Since the linear indications are small and appear to be confined to the surface of the bolts it is considered that any failure of the bolts would be indicated by increased reactor coolant leakage which would be detected by routine leakage calculations. Ample time would be available'for a controlled unit shutdown. Thus, it is considered that this event is of no.

consequence with respect to safe operation of the unit and that the_ health and safety of the public were not affected.

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A Report Number 269/81-16 Page 2 CORRECTIVE ACTION: Since Oconee Unit 1 was at cold shutdown at the time of the discovery"of this event, no immediate corrective action was required.

The 1B2 seal housing bolts will be inspected prior to. unit startup. Bolts with rt.,ectable indications will be replaced for i l Unit"1 RCP's. Additional -

testing will'bc conducted to determine the nature and extent of the defects to determine the cause of the bolt crack indications.

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