ML20138K273

Final Part 21 & Const Deficiency Rept Re Missing Lock Welds on Anchor/Darling Swing Check Valves.Initially Reported on 850911.Set Screws Staked During Insp & Disc Nut Pins Peened as Alternative to Lock Welding

ML20138K273
Person / Time
Site:	Hope Creek
Issue date:	10/11/1985
From:	Martin T Public Service Enterprise Group
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
REF-PT21-85-461-000 PT21-85-461, PT21-85-461-000, NUDOCS 8510300126
Download: ML20138K273 (3)

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I- Public Service Electric and Gas Cornpany Thomas J. Martin 80 Park Plaza, Newark, NJ 07101 201-430 8316 Mailing Address: P.O. Box 570, Newark, NJ 07101 Vice President I

Engineering and Construction October 11, 1985 I

I I Dr. Thomas E. Murley, Administrator l U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue J King of Prussia, Pennsylvania 19406 1

Dear Dr. Murley:

SIGNIFICANT CONSTRUCTION DEFICIENCY ANCHOR / DARLING SWING CHECK VALVES HOPE CREEK GENERATING STATION On September 11, 1985, a verbal report was made to Region I, Office of Inspection and Enforcement representative, Mr. J. I Strosnider, advising of a potentially significant construction l deficiency concerning Anchor / Darling swing check valves. The following final report is provided in accordance with 10CFR50.55(e).

Description of the Deficiency Bechtel Project Engineering was advised by Anchor / Darling Valve Company that 150 lb. and 300 lb. swing check valves supplied to Hope Creek may have missing lock welds. The missing lock welds had been discovered during installation of similar valves at the Palo Verde Nuclear Generating Station. Anchor / Darling advised that lock welds were required in two places; to secure a set screw which prevents rotation of the hinge pin and; to retain the disc nut pin which prevents the disc nut from backing off the disc, rendering the valve inoperable.

To determine if similar problems existed in valves installed at Hope Creek, Bechtel Construction was directed to disassemble and inspect all sixteen such valves. To date, fourteen valves have been inspected and none had their hinge pin set screws lock welded or otherwise secured. In addition, the disc nut pins on four of the valves inspected were not lock welded or otherwise secured. Two valves still remain to be inspected, pending release by PSE&G Startup Group.

8510300126 851011 PDR S

ADOCK 05000354 8[0 PDR

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Dr. T. E. Murley 2 10/11/85 Corrective Action Anchor / Darling has advised that staking of the hinge pin set screws is an acceptable alternative to lock welding and that disc nuts may be secured by either rolled pins or solid pins with their ends peened in lieu of lock welding. The set screws are being staked at the time of inspection. The disc nut pins are all being peened with the exception of one which did not extend beyond the disc nut. Anchor / Darling has advised that an acceptable alternative would be to center the pin in the nut and then peen the nut to secure the pin.

Analysis of Safety Implication Bechtel has evaluated the deficiencies and identified two potential failure modes:

1) The disc could loosen and lodge in downstream piping or in the valve-to-pipe area or other restriction,

2) The disc could fail to seat properly.

Failure mode 1 could result in partial or complete flow blockage with resultant reduction in flow. Failure mode 2 could allow back flow through an idle loop or pump, thus reducing the flow delivered to the system.

For the Core Spray and RHR pump discharge check valves, failure mode 1 could reduce ECCS capability below that required for core cooling, thus affecting safe operation of the plant. Failure of Safety Auxiliary Cooling System valves, by either failure mode 1 or 2, could reduce the flow of cooling water below the qualification requirements of equipment considered necessary for safe operation of the plant.

Based upon the above analysis, it was determined that safe opera-tion of the plant may have been adversely affected had the problem gone undetected and uncorrected. We, therefore, consider the deficiency reportable in accordance with 10CFR50.55(e).

Very truly yours,

l Dr. T. E. Murley 3 10/11/85 C Office of Inspection and Enforcement Division of Reactor Construction Inspection Washington, D. C. 20555 NRC Resident Inspector - Hope Creek P. O. Box 241 Hancocks Bridge, NJ 08038 Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parktay, Suite 1500 Atlanta, GA 30339

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