ML20004B099
| ML20004B099 | |
| Person / Time | |
|---|---|
| Issue date: | 05/22/1981 |
| From: | Jordan E, Villalva I NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-81-001, PNO-81-1, NUDOCS 8105270239 | |
| Download: ML20004B099 (2) | |
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c PRELIMINARY NOTIFICATION E
M rQ) c Date: May 22,'1981 PRELIMINA.iY NOTIFICATION OF EVENT.OR UNUSUAL OCCURRENCE--PNO-81-01~
This preliminary notification constitutes EARLY notice of events 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:
Certain Westinghouse Designed Plants Subject 1 POTENTIAL ADVERSE CONTROL / PROTECTION INTERACTION On May 21, 1981 IE:HQ was notified of a potential for adverse control and protection system interaction in certain Westinghouse plants.
In the absence of proper operator action, a single random failure in the volume control tank (VCT) level control system could adversely affect the high head safety injection system for certain Westinghouse designed plants.
A failure of the VCT level control system could; (a) cause the letdown flow to be diverted to the liquid holdup tank, (b) cause the VCT liquid inventory to decrease due to normal charging flow without any makeup to the VCT via letdown. Without operator inurvention, tSe VCT could empty causing the operating centrifugal charging pump (high head safety injection system pump) to be damaged due to loss of suction fluid.
Upon a certain set of postulated conditions, the advarse interaction could lead to a system not meeting the single failure criterion. Under a more stringent set of postulated conditions, the adverse interaction could ultimately lead to core urcovery (e.g., in approximately two days in the absence of letdown isolation and operator intervention).
Westinghouse has notified all affected facilities.
No immediate NRC actions are planned based on the Westinghouse actions.
No press release is planned.
Contact:
VILLALVA JORDAN 492-4865 492-4838 DISTRIBUTION:
(Facsimile Transmission Times Noted)
H ST BLDG J/36 MARYLAND NATIONAL IE:TAS Chairman Hendrie BANK BUILDING J,M NRC/TMI Pro Office 3.% gram Commissioner Gilinsky W. J. Dircks, EDO Commissioner Bradford C. Michelson, AEOD
'Regpn I Jc h Commissioner Ahearne J. J. Fouchard, PA Region II d7 (U ACRS N. M. Haller, MPA Region IIIJ. 4 5 S. J. Chilk, SECY G. W. Kerr, OSP Region IV.2:-f C. C. Kammerer, CA H. K. Shapar, ELD Region V J. 6 I
Joo Us PRELIMINARY NOTIFICATION j
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- esi nNtitas J. G. Davis, NMSS N
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R. B. Minogue, RES
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XN XN H. R. Denton, NRR R. H. Vollmer, NRR LANDOW BLDG (Fax by HQ)
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T. E. Murley, NRR (6 MIN /PAGE)
R. G. Smith, SD D. R. Ross, NRR J. J. Cummings, CIA IE:TAS D. Eisenhut, NRrt Document Mgt. Br.
S. H. Hanauer, NRR NSAC(powerreactorsonly)1NO S. Ebbin, NSOC INPO (power reactors only) 3 45 DOT (fransporta-tion only) d PRELIMINARY NOTIFICATION
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