ML20049A904

Final Deficiency Rept Re Failures of Pacific Check Valves, Initially Reported on 800331.Valves W/Disc Assembly/Body Internal Interface Reworked,Incorrectly Assembled Valve Reassembled & Remaining Check Valves Inspected

ML20049A904
Person / Time
Site:	Susquehanna
Issue date:	09/23/1981
From:	Curtis N PENNSYLVANIA POWER & LIGHT CO.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, PLA-931, NUDOCS 8110020364
Download: ML20049A904 (4)

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@ Pennsylvania Power & Light Company Two North Ninth Street

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Norman W. Curtis Vice Presidcnt-Engineering & Construction-Nuclear 215/ 770-5351 September 23, 1981 Mr. R. C. Haynes N A

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Director, Region I ,,

U. S. Nuclear Regulatory Commission k

)T 631 Park Avenue King (; Prussia, PA 19406 '

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SUSQUEHANNA STEAM T:LECTRIC ST1. TION M

-FINAL REPORT ")F A DEFICIENCY INVOLVING b PACIFIC CHECK VALVES s ERs 100450/100508 FILES 840-4/900-10 N PLA-931

References:

PLA-466 (3/31/80)

PLA-502 (7/03/80)

PLA-554 (10/06/80)

Dear Mr. Haynes:

This letter serves to provide the Commission with a final report of a deficiency relating to the failures of Pacific check valves as described in previous correspondence that is referenced above. This report is submitted pursuant to the requirements of 10 CFR 50.55(e).

The attachment to this letter contains a description of the deficiency, its cause, safety implications and the corrective action taken.

We trust the Commission will find this information satisfactory.

Very truly yours, N. W. Curtis Vice President-Engineering & Construction-Nuclear A FLW:sab S'(

Attachment 8110020364 810923 PDR ADOCK 05000387- PDR S

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l Mr. R. C. Haynes September 23, 1981 cc: Mr. Victor Stello (15)

Director-Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. G. Mcdonald, Director (1)

Office of Management Information & Program Control U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. Gary Phoads U. S. Nuclear Regulatory Commission P.O. Box 52 Shickshinny, PA 18655

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l 7.'"TACHMEU* TO PLA-931 I

SUBJECT Pacific Valve Inc. swing check valves DESCRIPTION J

Six 12", 300 lbs. ANSI rating, cast carbon steel, swing check valves werr Tited as deficient because of disc / body interference which prevented closure of the valves. I Cne edditional valve installed in a *=rtical orientation was cited because it would -l l

not close by gravity. NCR 3466 (nc conformance report) was written to document the ebove conditions.

In addition to the six 12 inch check valves cited in NCR 3466, two 12 inch and four 20 inch check valves were also found to have disc interferences.

All these valves were manufactured by Pacific Valves, Inc. They art installed in the vertical pump discharge piping of the Residual Heat Removal (RHR) and Core Spray Systems.

CAUSE The valve supplier, Pacific Valves Inc., started in a ?WX dated 2/21/80 that "The cause is attributable to cacting and/or machining abberations which combine to create an unfavorable tolerance stackup. This condition results in contacts between disc and internal body contours."

The basis for this conclusion was job site and factory investigations which were conducted by Pacific valve Inc. on 12 inch and 20 inch swing check valves. The valves studied were installed in vertical pipe runs, similar to the configuration at Susquehanna, to determine the possible causes of the malfunction. The results of Pacific's investigation were as follows:

a) Disc assembly / body internal interference were detected in several of the sixteen valves at job site, b) One 12 inch valve was found to be incorrectly assembled.

c) All check valves were checked to determine the effects of packing friction during the opening and closing cycles. In all instances; it was found that excessive lever loads were required to cycle the valves. 'The standard John Crane 187-I packing had been used to prevent valve leakage. Packing tests, conducted at re.cific valve's Plant using John Crane 187-I versus Teflon, revealed that the use of John Crane 187-I packing increases the lever torque as much as 300 percent.

ANALYSIS OF SAFETY IMPLICATIONS Thest check valves are required to assure proper function of the RHR and Core Sprry Systems. They are installed in the vertical discharge pipe of each system prap. Failure of any one of these valves to close properly could cause the loss of safety function for the associated safety system. Therefore, if the deficiency were to have remained uncorrected, it could have adversely affected the safe operation of the plant. Thus, this problem has been determined to be a significant construction deficiency reportable under 10 CFR 50.55(e) .

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ATTACHME93T TO PZ.A-931 l CORRECTIVE ACTION Pacific Valves'Inc. has been involved in taking corrective action to correct this problem with 'ir valves over the past two years. They have examined j vtlwt discs in their factory for jamming tendencies. They performed design ,

, changes as necessary to precit3e recurrence. These design changes called for 4

repairs on valves to prevent discs from jamming. The acceptable repairs included extending the existing bonnet stops, grinding excess material from b>dy contours and gr<ndino or machining excess material from discs. However, titis corrective action 4n manufacturing' took place after shipment of the Susquehanna SES vdives had occurred; The corrective action for the Susquehanna SES Pacific check valves included:

a) Reworking valves with disc assembly / body internal interface.

b) Reassembling the valve found to le incorrectly assembled and inspecting all the , maining Pacific testable check valves to insure currect assembly. No other valves were found to be incorrectly assembled.

c) Renoving John Crane 187-I packing from all valves and replacing it with Tef*on packing. The change made the valves functional for start-up i , testing. However, since Teflon cannot withstand radiation, it had to be replaced with packing material suitable for the radiation service before actual unit power operation.

As a result of testing, Pacific. Valves determined that Parker Polypak Seals of Ethylen6 Propylene C.bber was the most suitable packing for this service. The replacement of the temporary Teflon packing,was covered by NCR 6688 and has been satisfactorily completed.

The corrective actions taken as described above have satisfactorily corrected the valve deficiencies and should prevent recurrence.

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