ML20094A470

Interim Significant Deficiency Rept SDR 84-04 Re Limitorque Operator Motor Pinion/Worm Shaft Clutch Gear Failure. Limitorque Will Conduct Cycle Testing & Westinghouse Will Conduct Metallurgical Tests.Next Rept Expected by 840930

ML20094A470
Person / Time
Site:	Wolf Creek, Callaway, 05000000
Issue date:	07/20/1984
From:	Seiken S STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM
To:	Jay Collins, James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
SDR-84-04, SDR-84-4, SLNRC-84-106, NUDOCS 8408030255
Download: ML20094A470 (3)

Text

a' s f SNUPPS Standardized Nuclear Unit Power Plant System 5 Choke Cherry Road '

Rockville, Maryland 20850 taan eswoio SLNRC 84- 106 FILE: 0491.10.2 SUBJ: interim Significant Deficiency heport (SDR 84-04): Limitorque SB-2-80 Actuators Mr. James G. Keppler Regional Administrator, Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Mr. John T. Collins Regional Administrator, Region IV U. S. Nuclear Regulatory Commission Suite 1000, Parkway Central Plaza Arlington, Texas 76012 Docket Nos. STN 50-482 and STN 50-483

References:

1) ULNRC-828, dated 5/17/84; Final 10CFR 50.55(e) Part 21 Report: Limitorque Operator Motor Pinion / Worm Shaft Clutch Gear Failure, U-64

2) SLNRC 84-90, dated 6/1/84; Interim Significant Deficiency Report (SDR 84-04)

Gentlemen:

In Ref.1) Union Electric reported on the actions taken at Callaway Plant to resolve deficiencies with Limitorque Model SB-2-80 high torque actuators used with valves BN-HV-8812 A & B and EJ-HV-8811 A & B installed in the Berated Refueling Water Storage and Residual Heat Removal Systems, respec-tively. Ref. 1) also advised that testing of the failed SB-2-80 operators at the Limitorque factory failed to reproduce the failures that had occurred at Callaway and that a review of Westinghouse and Limitorque records revealed no problems similar to those found at Callaway. In view of the fact that testing of the SB-2-80 units was not conclusive in establishing the cause(s) of failure, Union Electric elected to replace the model SB-2-80 actuators with qualified model SB-1-60 actuators. Installation checkout and testing of the replacement units confirmed satisfactory performance; no indication of failure or difficulties such as that experienced with the 58-2-80 units was indicated. On the basis of this testing, the Ref.1) report was furnished to NRC as a final report although it was indicated that the failures raised generic questions and concerns requiring follow-up attention. It was ferther noted that such generic concerns would be followed up by SNUPPS.

Ref. 2) confirmed that the failure of the model SB-2-80 units at Callaway has potential for occurance at Wolf Creek and that SNUPPS would pursue this matter in conjunction with Kansas Gas and Electric and Westinghouse.

pA7 8408030255 840720 PDR ADOCK 05000482 S PDR JUL p g N04 )D l

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~ SLEC 84- 106 Page 2.

The purpose of this letter is to provide an update to the Ref.1) and 2)

. reports and to outline a course of action being taken to address the generic implications associated with the reported failures. These actions consist of a comprehensive test and evaluation program prepared in con-junction with Westinghouse and Limitorque reflecting the following mile-

~ stone events:

1. Limitorque will conduct cycle testing of the SB-2-80 valve oper-ators at their research laboratory. This testing will include the capability to apply simulated valve stem load conditions for the full length of travel. Previous tests, due to test fixture limitations in the production test facility at Limitorque, had not included this type. loading. This testing is scheduled to begin in late July and should be completed in August.

2. Westinghouse will assemble an SB-2-80 operator and valve at its Electro-Mechanical Division (EMD) facility with sufficient instrumentation to evaluate valve and operator loads. Cycle testing and visual inspections will be accomplished at EMD to provide insight-into potential failure mechanisms. This phase of the testing is to begin the week of July 23, 1984 and should be completed in August.

3. Westinghouse is to conduct metallurgical tests on the failed parts from the Callaway units at EMD and also will determine the feasi-bility of using a Scanning Electron Microscope at their Research and Development Center in Churchill, Pa. to assist in failure eval-uation. The scope of this effort is presently being established.

4. The $8-2-80 operators presently at Wolf Creek at HV-8811 A & B and HV-8812 A & B valve locations will be inspected either during or upon completion of Hot Functional Testing currently in process at that site. One valve will be cycled several times (20-25 cycles) and reinspected. It is noted that Wolf Creek has had no reported problems or failures during the conduct of previous start-up testing.

It is expected that the testing effort described above, with the possible exception of the Scanning Electron Microscope tests, will be completed by mid-September. The inspection of units installed at Wolf Creek will be accomplished at the earliest reasonable opportunity dependent upon overall plant activity. The results of these tests and the need for additional testing and analysis will be determined at that time. A follow-up report highlighting the results of this activity will be made by September 30, l')84.

Should there be any questions concerning this report, please do not hesi-tate to call the undersigned or Bob Kosky of the SNUPPS Staff.

Very truly yours, f

bY.

REK/dck/la3&4 cc: See Page 3.

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HSLNRC'84 106

- Page:3.

cc:-' D..F. Schnell' UE G. L. Koester KGE D. T. McPhee KCPL

.H. Bundy USNRC/WC J. H. Neisler USNRC/ CAL' B.'H.'Little USNRC/ CAL R. C. DeYoung NRC/IE:HQ

8. L.'Forney NRC/IE:III

.E. H. Johnson NRC/IE:IV Record F

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