ML18101A861

Interim Part 21 Rept Re Velan Valve Corp Check Valve Failure to Close.Insp of Internals Showed Moderate Wear in Gap Between Valve Disc & Hanger Arm.New Disc Installed & Valve Tested Satisfactorily

ML18101A861
Person / Time
Site:	Salem
Issue date:	08/01/1995
From:	Eric Simpson Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-95 LR-N95121, NUDOCS 9508040161
Download: ML18101A861 (3)

Text

e PS~G Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038-0236 Nuclear Business Unit AUG 011995 LR-N95121 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:

10CFR21 INTERIM REPORT, VELAN CHECK VALVE FAILURE TO CLOSE SALEM GENERATING STATION UNITS 1 AND 2 FACILITY OPERATING LICENSE NO. DPR-70 AND DPR-75 DOCKET NOS. 50-272 AND 311 Pursuant to the notification requirements of 10CFR21, Public Service Electric and Gas Company (PSE&G) hereby provides this interim report concerning a potentially reportable deficiency due to dimensional tolerances of valve components. Specifically, the 12 Auxiliary Feedwater Pump suction check valve, 12AF4, was found in a failed open position during ASME Section XI testing. The bottom portion of the disc was about an inch off the seat.

Inspection of the internals showed moderate wear in the gap between the valve disc and hanger arm. With an as-found clearance between the disc and the hanger of 0.108", the disc could become cocked and prevent full closure when it was rotated to certain positions. To correct the deficiency, a new disc was installed and the valve was tested satisfactorily. The as-left clearance was 0.095".

The valve manufacturer, Velan Valve Corporation, evaluated the 12AF4 dimensional data and determined it to be acceptable. Velan was unable to explain why the valve failed to close and concluded that the problem is an isolated incident. The root cause of the failure has not been determined. An industry NPRDS data base search found four failure to close events for this model valve.

These events were evaluated and found to be unrelated to the 12AF4 failure to close.

The ability of the Unit 1 and 2 AF4 valves to perform their safety related functions is reasonably assured based on the following:

Previous inspections of all Mark No. A-125 valves have shown no signs of degradation or catastrophic failure.

After the disc was replaced, 12AF4 could not be jammed open with an as-left clearance between the disc and hanger of 0.095 in. The last measured clearances for all other AF4 valves were less than 0.095 in.

CE-1'1

____ --- . Cl kOi fL'f:_ A The power is in your hands. , 9508040161 95oeo 1 If O PDR ADOCK 05000272 95*2168 REV. 6/94 S PDR

• I' Document Control Desk LR-N95121 AUG 01 1995 The AF4 valves are tested quarterly by partially stroking open and closed to demonstrate operability and the valves are verified closed by radiography.

There is insufficient information at present to determine if this occurrence could have created a substantial safety hazard in accordance with 10 CFR 21. PSE&G will continue its root cause analysis with the vendor and potentially with outside consultants. At least one Mark No. A-125 valve will be opened, inspected and tested during the current Unit 1 forced outage.

This inspection and a final determination of reportability in accordance with 10 CFR 21 is scheduled to be completed by January 31, 1996.

Should you have any questions, please contact us.

Sincerely, E. C. Simpson Senior Vice President -

Nuclear Engineering

Document Control Desk LR-N95121 AUG 01 1995 c Mr. T. T. Martin, Administrator - Region I

u. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. L. Olshan - Licensing Project Manager

u. s. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. c. s. Marschall (S05)

USNRC Senior Resident Inspector Mr. K. Tosch, Manager, IV NJ Department of Environmental Protection Division of Environmental Quality Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625 Mr. Bert Nilsson Velan Valve 550 McArthur St. Laurent Montreal, Quebec H4T1X8