ML20085A147

Final Deficiency Rept U-55 Re Robertshaw Thermostatic Flow Control Valves.Castellated Nut & Cutter Pin Installed & Valve Body O-ring Eliminated,Preventing Valve Stem from Disengaging.Also Reported Per Part 21

ML20085A147
Person / Time
Site:	Callaway
Issue date:	06/24/1983
From:	Schnell D UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
REF-PT21-83 10CFR-050.55E, 10CFR-50.55E, IEIN-82-56, U-55, ULNRC-640, NUDOCS 8307050096
Download: ML20085A147 (1)

Text

_ _ . _ _ _ - - _ _ _ _ _

.  ; O

/ ,s UNION ELECTRIC COM PANY 1901 GRATIOT STREET ST. Louis, MISSOU RI June 24, 1983 ... u M o o o ~ . . ..

- OON ALO P. .CMNELL P. O. SOM 9 4.

..c........., .1. lou .. m..Ou n. .s . ..

Mr. James G. Keppler, Director U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 g p _ yg3 ULNRC- 64 0

Dear Mr. Keppler:

FINAL 10 CFR 50.55(e) REPORT NO. U-55 ROBERTSHAW THERMOSTATIC FLOW CONTROL VALVES CA1LAWAY PLANT UNIT 1 Union Electric Company advised the NRC on May 27, 1983 of a deficiency reportable under the criteria of 10 CFR Part 50.55(e) regarding Robertshaw Thermostatic Flow Control Valves.

The valves are employed in the Callaway diesel generators supplied by Colt Industries and function to regulate the engine coolant fluid flow. This deficiency had been reported under Part 21 by Colt and is the subject of IE Information Notice No. 82-56, dated December 30, 1982. The defect involves the potential for the valve stem nut to disengage and thereby lower the coolant temperature setpoint. Operating the diesels with an excessively low coolant temperature may lead to engine damage. This deficiency was reported to both Mr. H. M. Wescott, U.S. NRC Region III and Mr. John Neisler, Callaway NRC Resident Inspector on May 27.

Union Electric has verified through the implementation of a field rework plan that the Callaway diesel generators have the potentially defective valves. Furthermore, consistent with the recommendations of IE Information Notice 82-56, the rework plan provided for installation of a castellated nut and cotter pin and the elimination of the valve body "O" ring. This corrective action is now complete.

q 1$0' 3

B307 DR  % [ oh PDR _ gg)

\ 9 s

i 1 . n Mr. James G. Keppler June 24, 1933 Page 2 This potential deficiency is considered a significant deficiency as the failure of the flow control valves to maintain the desired coolant flow setpoint could compromise the diesel generator's ability to perform their intended safety function.

No other specific analysis of the safety implications of this potential defect has been performed as the potential deficiency has been corrected.

This letter serves as our final report on this subject.

Very truly yours, E

s

( ,.

Donald chnell JJS/mc cc: II . M. Wescott, Region III Richard DeYoung, Director I&E John Neisler, NRC Resident Inspector Missouri Public Service Commission