ML20087N111

Final Deficiency Rept U-68 Re Emergency Diesel Generator Keepwarm Heater Failure Due to Sticking Check Valve. Initially Reported on 840222.Valve Internals Removed

ML20087N111
Person / Time
Site:	Callaway
Issue date:	03/23/1984
From:	Schnell D UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
U-68, ULNRC-778, NUDOCS 8404030119
Download: ML20087N111 (3)

Text

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, [C> " Y $ O h18 UNION ELECTRIC COM PANY 8 901 GR ATIOT STR E ET ST. Louis, Missouri no~.co r .cm uc March 23, 1984 "^p'ga ^f, o",*,,= = -

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Mr. James G. Keppler Regional Administrator U. S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 ULNRC- 778

Dear Mr. Keppler:

FINAL 10CFR50.55 (e) REPORT U-68 EMERGENCY DIESEL GENERATOR JACKET WATER KEEPWARM HEATER FAILURE CALLAWAY PLANT On February 22, 1984 Union Electric informed the NRC Region III Office of a 10CFR50.55(e) regarding the failure of an emergency diesel generator keepwarm heater at the callaway Plant.

This heater is installed as a component of the Jacket Water Keepwarm System, which operates in conjunction with the Lube 011 Keepwarm System to maintain the diesel at operating temperature during standby conditions.

The normal standby temperature range of the jacket water is 150-160 degrees F. At the time of the incident, jacket water temperature was 90 degrees F and the keepwarm pump was running.

The Startup Engineer placed the jacket water heater control switch in the manual position and in so doing, bypassed the temperature control thermostat. Within 10 minutes, the heater overheated and failed.

Investigation by the diesel generator supplier (Colt Industries) has attributed the problem to a sticking check valve located immediately past the jacket water keepwarm heater. The check valve is a lift type, mounted in a horizontal position and manufactured by the Henry Vogt Corporation. We have experienced

, intermittent sticking of the check valve in the closed position I

with the keepwarm pump in operation. During the incident, this check valve stuck shut, preventing jacket water flow to the heater, thereby causing it to overheat.

When this valve fails to open, the Jacket Water Keepwarm Syste.a is prevented from operating. Therefore, the jacket water will not be maintained at its designed standby temperature and the 10 second diesel starting criteria could be exceeded. Union Electric has determined that the intermittent operation of this check valve is a reportable deficiency under 10CFR50.55(e) criteria.

8404030119 I PDR ADOCK 0 0 0PDR 83 S

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Mr. Jcmas G. Kappler March 23, 1984 Page 2 Colt has indicated that these valves are not required for proper operation and recommended that the valve internals be removed. Union Electric and Bechtel concur with this decision.

Subsequently, the valve internals have been removed on both diesels.

This is Union Electric's final report on this subject.

Very trulg_yours, Donald F. Schnell GSA/bjk cc: J. E. Konklin, NRC Region III RichnUd DeYoung, Director I&E NRC Resident Inspectors,.Callaway Plant (2)

Missouri Public Service Commission

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Mr. Jamsa G. K ppler March 23, 1984 Page 3 bec: D. F. Schnell J. F. McLaughlin S. J. Seiken B. L. Meyers J. H. Smith R. W. Bradford C. C. Wagoner G. P. Rathbun, KG&E F. D. Field

S. E. Miltenberger R. J. Schukai M. A. Stiller

, W. H. Weber L R. L. Powers l G. S. Augspurger J. C. Gearhart J. V.'Laux J. R. Veatch D. W. Capone W. S. Strothman A. C. Passwater D. E. Shafer W. B. Bobnar W. H..Zvanut R. P. Wendling R. W. Ferguson I

W. R. Bird (Consumers Power)

DFS/ Chrono 3456-0610-M018 AC:61E02 (As a QA Record)

N. Date QA Date

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