ML19276H214
| ML19276H214 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/05/1979 |
| From: | Bryan S, Klingler G, Nolan F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-79-220, NUDOCS 7910150773 | |
| Download: ML19276H214 (2) | |
Text
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PRELIMINARY NOTIFICATION July 5, 1979 q-PRELIMINARY N071FICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-79-220 This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance.
The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff on this date.
Facility:
Metropolitan Edison Compaay Three Mile Island Nuclear Station, Unit 1 Middletown, Pennsylvania Docket No. 50-289
Subject:
Failure of Decay Heat Removal Pump At 3:17 p.m. on July 3, 1979, while using the decay heat system to maintain the reactor in the cold shutdown condition, the "B" Decay Heat (DH) pump tripped.
An attempt to restart the pump was unsuccessful, and the "A" Decay Heat pump was placed in service at 3:35 p.m.
The "B" DH pump failure has been tentatively attributed to excessive motor bearing wear which may have allowed contact between the motor stator and rotor.
The motor has been sent to the vendor (Westinghouse-Philadelphia), and repair may take one to two weeks.
The Reactor Coolant System is currently being maintained at approximately 90 degrees F by the "A" DH system.
The "A" DH River Water Pump motor has higher than normal vibration (5 mils) at one location.
The licensee has taken several precautionary measures in the event of future failure of the "A" DH River Water Pump or another component of the "A" decay heat system train.
Provisions were made to allow temporary cross connecting between the "A" and "B" DH River Water Pumps.
In addition, a steam bubble (reactor coolant system pressure of 30-40 psig) was formed in the pressurizer at 7:30 a.m. on July 5,1979 to allow decay heat removal through use of the makeup / letdown system or by i. eat transfer to steam generators through the use of reactor coolant punps.
If either of these decay heat removal modes were to be initiated, the reactor coolant system pressure would have to be increased to approximately 300 psig.
As stated, these measures are precautionary only, with adequate cooling currently being maintained by the "A" DH system.
The onsite TMI-2 shift reactor operations inspector was notified (for information only) of the "B" DH pump failure by the Unit 1 Shift Supervisor at 8:30 p.m. on July 3, 1979.
This event is not considered reportable to the NRC under the terms of the facility's Technical Specifications and the plant will remain in a shutdown condition.
This PN is issued for information only.
No further action by NRC Region I is anticipated.
CONTINUED 1414 0
q 79101s0773
PNO-79-220 Continued 7/5/79 Media interest is possible because of continued public interest in Three Mile Island Nuclear Station.
The Commonwealth of Pennsylvania has been informed.
A press release is not planned by the licensee nor NRC.
NRC, Region I, (Philadelphia) received notification of this occurrence by telephone from the TMI-2 Resident NRC office at 10:00 a.m. on July 5, 1979.
Contact:
G. Klingler IE, x28019 F. Nolan IE, x28019 S. Bryan IE, x28019 Distribution:
Transmitted H St Chairman Hendrie Commissioner Bradford S. J. Chilk, SECY Commissioner Kennedy Commissioner Ahearne C. C. Kammerer, CA Commissioner Gilinsky (For Distribution)
ACRS Transmitted:
MNBB P. Bldg 5.'o o p V. Stello, IE L. V. Gossick, EDO H. R. Denton,' NAR Region 1 H. L. Ornstein, EDO R. C. DeYoung, NRR J. J. Fouchard, PA R. J. Mattson, NRR N. M. Haller, MPA D. Vassallo, NRR (MAIL)
R. G. Ryan, OSP D. Eisenhut, NRR J. J. Cummings, DIA H. K. Shapar, ELD SS Bldg R. Minogue, SD W. J. Dircks, NMSS S. Levine, RES
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PRELIMINARY NOTIFICATION 1414
$51
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