ML20038C889

Forwards LER 81-022/01T-0.Detailed Event Analysis Encl

ML20038C889
Person / Time
Site:	Oconee
Issue date:	12/04/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20038C890	List: ML20038C889 ML20038C897
References
NUDOCS 8112140231
Download: ML20038C889 (3)

Text

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Wcr Pots.otst TELEPHONE:AntA 704 Straea PaeouctioN 373-4083 Mr. James P, O'Reilly, Director U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 Re: Oconee Nuclear Station Docket No. 50-269

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-269/81-22. This report is submitted pursuant to Oconee Nuclear Station Technical Specification 6.6.2.1.a(9), which concerns performance of components that requires remedial action to prevent operation in a manner less conservative than assumed in the accident analyses in the safety analysis report, and describes an incident which is considered to be of no significance with respect to its effect on. _ '

the health and safety of the public.

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Attachment # / + LnJ cc: Director Records Center Office of Management & Program Analysis Institute of Nuclear Power Operations U. S. Nuclear Regulatory Commission 1820 Water Place Washington, D. C. 20555 Atlanta, Georgia 30339 Mr. W. T. Orders NRC Resident Inspector Oconee Nuclear Station l

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DUKE POWER COMPANY OCONEE UNIT 1 REPORT NUMBER: R0-269/81-22 REPORT DATE: December 4, 1981 OCCURRENCE DATE: November 13, 1981 FACILITY: Oconee Unit 1, Seneca, South Carolina IDENTIFICATION OF OCCURRENCE: Six installed ITT Grinnellvariable spring hangers were not carrying specified design loads.

CONDITIONS PRIOR TO OCCURRENCE: Cold Shutdown DESCRIPTION OF OCCURRENCE: It has been determined that six installed variable spring hangers were not carrying specified design loads. These spring hangers are located on the emergency feedwater discharge, upper ring headers surrounding each steam generator. The piping and hangers are located in the space between the steam generator and the steam generator insulation.

APPARENT CAUSE OF OCCURRENCE: The apparent cause of this occurrence is that the subject spring coils have set under load due to high temperature conditions.

ANALYSIS OF OCCURRENCE: Piping analysis has been completed for the same piping system on Oconee 2, which utilizes the same hangers in the same environment.

The analysis of Oconee 2 piping, using load versus deflection test results obtained from the hangers removed from Oconee 1, has confirmed the adequacy of the pipfng system stresses. The analysis has shown some load increases on support / restraints adjacent to the deficient springs, but the review has in-dicated that the support / restraint system is adequate. The results of the Oconee 2 piping analysis are applicable to Oconee 1 piping. Oconee 3 does not have the same piping configuration. Since the analysis has indicated that the piping stresses are adequate, it is considered that the health and safety of the public were not affected by this incident.

CORRECTIVE ACTION: Based on the initial conclusion that exposure to high temperatures resulted in spring deficiencies, the following actions are planned:

1) For Oconee 1, new springs are to be installed in place of the six existing springs found to be deficient. The insulation around each steam generator is to be modified to exclude the spring hangers from an environment exceed-ing 350F which is the acceptable temperature at which ITT Grinnell currently rates their spring products. The remaining portions of the piping system were undergoing modifications at the time the springs were identified as deficient. All piping and support / restraint analyses and modifications for the current piping configuration will be complete before the start up of Oconee 1.

2) Similar piping and support / restraint modifications are olanned for the up-coming Oconee 2 refueling outage. The six Figure 98 springs will be replaced and insulation modifications will be made as described for Oconee 1. All piping and support / restraint modifications will be completed before Oconee 2 startup.

R0-269/81-22 Page 2

3) Duke Power is conducting a survey to determine the existance of any nuclear safety related variabic springs in a temperature environment exceeding 350F. If problems are identified, appropriate corrective actions will be taken.