ML19282B585

Provides Requested Info Re Buna-N Components in Asco Solenoids.Gives Schedule of Parts Replacement & Insp. Describes Preventive Maint Program Requiring Rebuilding of Various Valves.These Valves to Be Overhauled at Next Outage

ML19282B585
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	02/05/1979
From:	Moody D VERMONT YANKEE NUCLEAR POWER CORP.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
WVY-79-10, NUDOCS 7903150423
Download: ML19282B585 (2)

Text

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p VERMONT Y AN KEE NUCLEAR POWER CORPOR ATION SEVENTY SEVEN GROVE STREET RUTLAND, YERMONT 05701 REPLY TO:

ENGINEERING OFFICE TURNPIKE RC AO WESTBoRO, M ASS ACHUSETTS 01581 TELEPHONE 897 366-909I WVY 79-10 February 5, 1979 United States Nuclear Regulatory Cocmission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Attention: Boyce H. Grier, Director

References:

(a) License No. DPR-28 (Docket No. 50-271)

(b) USNRC Inspection and Enforcement letter dated December 19, 1978, Bulletin No. 78-14

Subject:

Buna-N Components in ASCO Solencids Referencs (b) requested Vermont Yankee to review Euna-N application in the control rod scram system and provide information pertaining to the time since installation and for installed material, the time since packaging, schedule for replacement (if necessary), and the schedule for future periodic maintenance.

The Scram Pilot Valves are inspected each refueling outage. In September,1976, all body gaskets (0-rings) were replaced and 44 of 89 sets of exhaust and pressure diaphragms were replaced. The remaining 45 sets were replaced in October, 1977. In October, 1978, six of these valves had their solenoid core assemblies removed and the subject Buna-N discs showed no evidence of degradation. Three of these valves were reassembled with new core assemblies. The remaining 86 solenoid core assembly discs were installed approximately in 1970 during original plant construction.

The above replacement parts were supplied through General Electric Company and no curing or packaging information (dates) is available.

Spares presently in stock exhibit no dates of packaging. The replaced parts were, however, purchased not more than one year prior to installation.

The Backup Scram Valves and the Scram Discharge Volume Vent and Drain Pilot valves are included in a preventative maintenance program which requires inspection and rebuilding of these valves as necessary.

Due to the nature of the checklists, the specific replaced parts infor-mation for each valve. is not retrievable. The preventative maintenance procedure will be modified to include space for the repair date and the packaging date of repair kit parts if available.

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United States Nuclear Regulatory Commission February 5, 1979 Office of Inspection and Enforcement Page 2 All valves discussed in this letter will be overhauled during the next refueling outage as required to satisfy the recocmended criteria for the Buna-N components. The lifetime before replacement of these parts will be seven years based upon correspondence and recoemendations from the supplier, and on-site inspections of the valves and observed conditions of the Buna-N components.

We trust that you will find this information satisfactory; however, should you desire additional information, please contact us.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION n'\ ,

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D. E. Moody Manager of Operations DD1/e=