ML20093N472

Supplemental Final Deficiency Rept Re Generic Defects in Gould/Rundel 4-position & 2-position Selector Switches Failure.Initially Reported on 840209.Failed Units to Be Replaced from Alternate Supplier

ML20093N472
Person / Time
Site:	Wolf Creek, Callaway, 05000000
Issue date:	07/20/1984
From:	Seiken S STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
SLNRC-84-103, NUDOCS 8408010386
Download: ML20093N472 (2)

Text

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SNUPPS Stendenfiaed Nuclear Unit -

Power Plant Systern

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s choke ch.rry need July 20, 1984 Rockville, Meryland 20050 mon see.coio SLNRC 84-103 FILE: 0491.10.2 SUBJ: Gould/Rundel Salector Switch Failures, 10Ci' k .55(e) Report 84-01 Mr.: John T. Collins Regio: al Administrator, Region. IV

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ii; U.S. Nuclear Regulatory Commission Suite 1000, Parkway Central Plaza ggg  !

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Docket Nos. STN 50.482 and STN 50-483 Ref: a) SLNRC 84-0028, dated 2/9/84: Subject as-Above b) SLNRC 84-0067, dated 4/13/84: " " "

Dear Mr. Collins:

The reference letters describe generic deficiencies in the Gould/Rundel 4-position selector switches installed in the SNUPPS Callaway and Wolf Creek plants. The references further address design modifications and

. improvements in manufacturing and test controls subsequently implemented by Gould/Rundel to correct these deficiencie and to eliminate the erratic behavior experienced with the 4-position devices. Notwithstanding the design and manufacturing improvements implemented by the manufacturer and corrective measures estslished by Bechtel Power Corporation, in the form of increased shop inspection, additional failures have been experienced at

! Wolf Creek with these units. Included are failures in the 2-position j switches which are of a design similar to the 4-position. units.

i. Since issuance of the reference reports, failures have been observed at Wolf ~ Creek in two(2) 4-position selector switches and three (3) 2-position selector switches, all manufactured by Gould/Rundel. Examination of Gould/

Rundel manufacturing and Bechtel shop inspection records indicate satis-factory functional performance testing of all five (5) of these units prior to release for shipment. No new failures have been experienced at Callaway since issuance of the reference reports nor have any been noted ith the 3-position units installed at Callaway cid Wolf Creek.

The' precise cause of failure of the current batch of Gould/Rundel itches located at Wolf Creek is uncertain. Evaluation of the basic design indi-cates both the 2- and 4-position units to be susceptible to damage during handling, installation and/or checkout testing. The design and manufac-turing/QC improvements addressed previously have been unsuccessful in eliminating the inherent cause(s) of these failures. It should be noted however, there has been no indication of failure once the units are satis-factorily installed and functionally tested.

8408010386 840720 PDR ADOCK 05000482

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. s SLNRC 84-103 Page Two The 3-position-devices also manufactured by Gould/Rundel, have hcd no report of failure or operating difficulty. Examination of these units indicate they are different in design from the 2- and 4-position units.

Rather than utilizing a shaft acting on contact actuators through nylon

cams, the 3-position switch utilizes twin rods, acted on by a heavy stepped cylindrical cam mechanism, to actuate the contacts. Furthermore, except for two(2) rods that protrude slightly from the rear, the 3-position switch has no contact actuators whit h protrude from the main body of the. switch assembly as in the case of both the 2 and 4-position units. Consequently.--

it a.opears the design of the 3-position is not susceptible to the type of

. failures observed with the 2- and 4-position devices.

To fully resolve this matter and eliminate the potential for further fail-ure, actions are being initiated at Wolf Creek to change out and replace all 2 and 4-position Gould/Rundel switches with qualified devices procured from an alternate switch supplier. Changeout and replacement at Wolf Creek will be accomplished on or before start of commercial operations. To permit continuation of testing at Wolf Creek, the five (5) failed units will be replaced with similar Gould/Rundel devices pending receipt of qualified switches from an alternate supplier.

Union Electric will separately assess the impact of these failures, if any, upon Callaway Plant and will address the issue of reportability under the terms of its operating license.

The supplement is intended as the final report on the subject matter. If you have any questions or desire further information, please contact the undersigned.

Very truly yours, k

S. W. Seiken, Manager Quality Assurance SJS/dck/6b18 L cc: W. L. Forney, USNRC/ Region III E. H. Johnson, USNRC/ Region.IV l H. Bundy, USNRC/WC l R. C. DeYoung, Dir ector, 0IE, Wash. D.C.

G. L. Koester, KGE D. T. McPhee, KCPL l D. F. Schnell, UE Record l

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