ML20236U391

PN-75-047:on 750701 Sacramento Municipal Utility District Notified Region V by Telephone That Exam of Turbine Disclosed That Several Blades Had Broken Off of Fifth Stage on Low Pressure Side of Turbine.Facility Shutdown on 750701

ML20236U391
Person / Time
Site:	Rancho Seco
Issue date:	07/08/1975
From:	Jennifer Davis, Galen Smith, Thornburg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PN-75-047, PN-75-47, NUDOCS 9807300105
Download: ML20236U391 (1)

Text

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'y (QW PRELIMINARY NOTIFICATION - NOT FOR PUBLIC DISCLOSURE July 8, 1975 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE --PN-75-47

(' ' '

This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information gresented is as initially received without verification or evaluation

.a and is basically all that is known by OIE staff as of 3:00 p.m. on the 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 WILL BE ISSUED IF WARRANTED.

.Eacility: Rancho Seco Sacramento Municipal Utility District m.,.- .

Subject:

Failure of Turbine Blades The Sacramento Municipal Utility District notified the NRC Region V office by telephone that an examination of their turbine disclosed that several blades had broken off of the fifth stage on the low pressure side of the turbine. The facility was shut down on July 1 to determine the cause of turbine vibrations which had reached 15 mils at the time of shutdown.

The examination revealed that several of the blades had br'oken off at s

- the root , allowing the clamp between the blades and the rotor to shift. "

Westinghouse representatives charact;erize the problem aa one which will require a minimum of two months to repair.

The licensee indicated that either a replacement rotor will be obtained from the Pacific Gas & Electric Company's Diablo Canyon project or the rotor will be sent to Sunnyvale, California for repair. In either event, it is estimated that a two-month shutdown will be required. O

/

The licensee issued a press release when the facility was shut down. '

Region V is planning to issue a press release concerning the extended outage.

OIE (Region V) received initial notification of this occurrence by

., .n z telephone from the Rancho Seco site management at approximately C zt:HD 3:00 p.m. on July 1, 1975, and supplemental information relating to

.a the axtent of damage was provided by telephone by site management -

7

[Q on the morning of July 8, 1975. '

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Contact:

GHSmith, IE x7621 HDThornburg, IE x7353 JGDavis, IE x7541 w g- *-

distribution:

o Chairman Anders Commissioner Mason S. J. Chilk, SECY l

m commissioner Gilinsky Commissioner Rowden G. F. Murphy, JCAE QGCommissioner Kennedy C. C. Kammerer, CA L. V. Gossick, EDO O D. F. Knuth, IE J. A. Harris, PA B. C. Rusche, NRR

H. H. Brown, ISP T. J. McTiernan, AIA K. R. Chapman, NMSS H. K. Shapar, ELD

( (r transmitted: P Bldg V o ; H St V Mg; MNBB y o ; Luge # C 2.

PRELIMINARY NOTIFICATION - NOT FOR PUBLIC DISCLOSURE L__ _ . _ . _ _ _ _ _ - - __ ----