ML20236U333

PN-75-021:on 750510,required Main Generator Trip Test from 100% Power Was Conducted.Two of Four Steam Bypass Valves Stuck Open.State of MD Informed

ML20236U333
Person / Time
Site:	Calvert Cliffs
Issue date:	05/12/1975
From:	Jennifer Davis, Dreher F, Thornburg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PN-75-021, PN-75-21, NUDOCS 9807300052
Download: ML20236U333 (1)

Text

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f, ' [Snj PRELIMINARY E0TIFICATION - NOT FOR PUBLIC DISCLOSURE i h

1 May 12, 1975 l

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O PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PN-75-21 This preliminary notification constitutes EARLY notice of events of

> POSSIBLE safety or public interest significance. The information i

presented is as initially received without verification or evalustion and is basically all that is known by OIE staff as of 11:30 a.m. on date of this notification. IT SHOULD BE SPECIFICALLY NOTED THAT THIS NOTIFICATION MAY CONTAIN INFORMATION THAT LATER MAY BE DETERMINED TO BE INACCURATE OR INCONSISTENT. AN OFFICE OF INSPECTION AND ENFORCEMENT

~

NOTIFICATION OF AN INCIDENT OR OCCURRENCE (BLUE SHEET) SUBSEQUENTLY

~TILL BE ISSUED IF WARRANTED.

~ ' ~

Facility: ' Calvert Cliffs 1 Baltimore Gas and Electric Company

Subject:

INITIATION OF SAFETY INJECTION FOLLOWING A MAIN GENERATOR TRIP FROM 100% POWER At 11:55 a.m. on May 10, 1975, the required Main Generator Trip Test from 100% power was conducted. The secondary steam dump and bypass system oper-ated to reduce primary coolant temperature; however, two of the four steam bypass valves stuck open. This is equivalent to 20% of f.ull. steam flow. This

, caused a partial primary system cooldown and a reduction of primary coolant si pressure sufficient to operate the safety injection system. All safety a systems worked properly and the plant performed in accordance with design.

[ The lowest temperature and pressure reached were 470 degrees F and 1200 psig.

IE Inspectors were on site to witness the test and to observe operation and plant performance. No deficiencies were observer except for the malfunction of several secondary system steam valves. The licensee concluded that the transient was less severe than analyzed. The plant was returned to power on Sunday, May 11, 1975.

The State of Maryland has been and is being kept informed. A press release is not planned.

Contact:

FADreher, IE x7261, HDThornburg, IE x7353, JGDavis, IE x7541 Distribution:

Chairman Anders Commissioner Mason S. J. Chilk, SECY Commissioner Gilinsky Commissioner R60 den G. F. Murphy, JCAE Commissioner Kennedy - C. C. Kammerer, CA T. J. McTiernan, AIA, B. Huberman, PE L. V. Gossick, EDO D. F. Knuth, IE J. A. Harris, PA 1 l H. H. Brown, ISP q-B. C. Rusche, NRR K. R. Chapman, NMSS H. K. Shapar, ELD D y

c.c Transmitted: P Bldg /J/.7 A, ; H St /4 : go,,,; MD Bldg ut # l- o m .

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PRELIMINARY NOTIFICATION - NOT FOR PUBLIC DISCLOSURE l

l 9807300052 750512 PDR I&E l PN-75-021 PDR ,