ML20095J798
| ML20095J798 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 04/29/1992 |
| From: | Pelletier J VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-PT21-92 BVY-92-49, NUDOCS 9205040141 | |
| Download: ML20095J798 (2) | |
Text
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. VERMONT YANKEE N,UCLEAR POWER CORPORATION Ferry Road, Brattleboro, vT 05301-7002 ENGINE ING OFFIC3
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90 MMN STREET BOi, TON M A 01740
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16081773 6711 April 29,1992 BVY 92-49 BY FACSIMILE United States Nuclear Regulatory Conimission ATTN: Document Control Desk Washington, DC 20555
Reference:
a.
1.icense No. DRP-28 (Docket No. 50 271)
Subject:
10 CFR 21.21 Notification Regarding Anchor Darling Swing Check Valves
Dear Sir:
in accordance with 10 CFR 21.21, Vermont Yankee is hereby providing notifica' ion of a reportable condition.
The reportable condition involves a defect in a safety-related swing check valve -
as received by Vermont Yankee from the manufacturer. The component is described as a 12"x10"x12" - 150# weld end carbon steel swing check valve. This component was manufactured by the Anchor Darling Valve Company.
This valve was purchased by Vermont Yankee for installation as part of a safety-related system modification. The specification stated that the valve shall be capable of fully opening to allow flow of air at the following conditions: differential pressure 3.5" to 7" water, temperature 160'F; flow rate 1500 scfm. The soecification also stated that under zero differential precsure conoitions, the valve shall be seated.
During disassembly of the valve by Vermont Yankee maintenance personnel prior to installation, it was discovered that the swing arm would not move freely.
through its entire range of motion. The cause of the binding was ?ubsequently identified as insufficient clearance between the swing arm-and shaft bushings, Contrary to the techn: cal requirements of the procurement document, the valve did no function as required by the specification; therefore. a deviation was determined to exist as defined in 13 CFR 21.
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VERMONT YANKEE NLCLEAR POWER CORPOR ATION
^ ' United States Nuclear Regulatory Commission April 29,1992 Page 2 A non-functional check valve (stuck in either the open or closed position) could present a number of systems related problems, depending on the application utilized.
For example, flow from a particular system could be restricted resulting in reduced system performance, or flow could be diverted from its intended path.
When combined with a single active compnnent failure, existence of this defective component could result in a loss of a safety system function.
The binding condition was repaired on site by Anchor Darling personnel by machining of the shaft bushings to provide the proper clearance.
Vermont Yankee has concluded that, since the observed defect was detected and repaired prior to installation, and since the only other similar valve at Vermont Yankee (a mirror-image valve being installed on the redundant train) was inspected and found not to be defective prior to installation, there is no concern regarding the operability of this component at Vermont Yankee.
Vermont Yankee management was notified of a 10 CFR 21 applicability determination on April 27,1992. In accordance with 10 CFR 21.21(c)(3)(1), a copy of this letter is being transmitted today via facsimile to the NRC Operations Center. This letter also fulfills the reporting requirements of 10 CFR 21.21(c)(3)(ii).
Should you have any questions regarding this notification or require further information, please contact this office.
Very truly yours, Vermont Yankee Nuclear Power Corporation 7
' ames P. Pe!!etier Vice President, Engineering cc:
USNRC Region i Administrator USNRC Resident inspector - VYNPS USNRC Project Man.ger - VYNPS
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