ML19242C465

LER 79-018/03L-0 on 790703:while Switching Vital Bus 3 to Alternate Source Containment Isolation,Phase B Actuation Occurred.Caused by Hi-Hi Containment Pressure.Revised Procedure for Transferring Vital Bus

ML19242C465
Person / Time
Site:	Beaver Valley
Issue date:	08/03/1979
From:	Werling J DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19242C464	List: ML19242C463 ML19242C465
References
LER-79-018-03L, LER-79-18-3L, NUDOCS 7908100451
Download: ML19242C465 (1)

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NRC FORM 366 U. S. NUCLEAR REGJLATORY COMMISSION (7 77)

LICENSEE EVENT REPORT CONTROL 8 LOCK: l 1

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[TITl %cR' nc l L @lGI 0 l 5 lOOCLET 0 l 0NUMBER l0 l 3 l 3 6dl 4 @l 0 EVENT l 7 lOATE 0 l 3l 7l 9 @l 0]REPORT 74 FS 8l 0lOATE 3l 7l 9]@ 80 7 8 6J 69 EVENT OESCRIPTION AND PROSABLE CONSECUENCES h O 2 l At 1015 h N rs while switching Vital Bus No. 3 to the alternate source, conta:nment I o 3 l isolation Phase B actuation occurred. This tripped both' emergency 4KV stub bus I fiiT 1 I breakers resulting in loss of the ogsrating residual heat removal pump. RHR flow g I was returned at 1036 hours0.012 days <br />0.288 hours <br />0.00171 weeks <br />3.94198e-4 months <br /> by resetting the high-high containment pressure l

[5Tsl I comparators. The RHR heat exchancer inlet temperature had increased by seven i O 7 l degrees to 114 deerers. The health and safety of the eeneral public was not l F5Ti 1 t jeopardized. I 7 8 e so

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i o l The stub bus breakers tripped because of an apparent high-hich containment pressure I g l caused by a voltage spike when the No. 3 Vital Bus was switched to its alternate I m l source. The procedure for transferring the vital bus to its alternate source was I i 3 l revised to add a precaution to deenercize the containment hich-hich pressure l g l bistables when enterinc Operational Mode 5. ]

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NAME OF PREPARER a PHONE:- '12-643-1258  ?