ML20248F192

PNO-78-123:on 780423,following Spurious Reactor Trip,Ms Generator Safety Valves Opened & Failed to Reseat Properly, Causing Safety Injection Sys Actuation.Reinstallation of Original Safety Valves W/Higher Rated Springs,Considered

ML20248F192
Person / Time
Site:	Three Mile Island
Issue date:	06/21/1978
From:	Klinger G, Nolan F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-78-123, NUDOCS 9806040146
Download: ML20248F192 (1)

Text

-

fl)h, M/Vand }

PRELIMINARY NOTIFICATION '

June 21, 1978

5 g"p" I

PRELIMINARY NOTIFICATION OF. EVENT OR UNUSUAL OCCURRENCE -- PNO-78-123 c'

{

This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance. The information i presented is as initially received without verification or evaluation and is basically all that is known by IE staff as of this date.

Facility: Metropolitan Edison Company Three Mile Island Nuclear Station, Unit 2 (DN50-320)

Middletown, Pennsylvania

Subject:

EXTENDED DELAY IN POWER ESCALATION TESTING On April 23, 1978, following a spurious reactor trip, the Main Steam f Generator Safety Valves opened and failed to reseat properly, causing a '

safety injection system actuation. (

Reference:

PNO-78-92). Subsequent testing of the safety valves indicated continued improper closing characteristics, possibly attributable to use of undersized valve springs. I

{

Two tentative courses of corrective actions are being considered by licensee management: reinstallation of the original safety valves with '

higher rated springs, or replacement of original safety valves with '

g valves from another manufacturer. The latter option would involve extensive piping modifications. Corrective action will result in a  ;

delay in power escalation testing of an additional 50-90 days. The  !

l -) plant will remain in cold shutdown until adequate safety valves are installed. {

l' This Preliminary Notification is issued for information only and no further action by IE is anticipated, except for routine inspection of the safety valve modifications and testing.

Media interest is not expected. The Commonwealth of Pennsylvania has i been informed. A press release is planned by the licensee after final determination of corrective actions.

NRC, Region I, (Philadelphia) received notification of this occurrence by telephone from the Unit Superintendent - Technical Support at 2:15 p.m., June 20, 1978.

Contact:

GKlingler, IE x28019 FNolan, IE x28019 .

Distribution: Transmitted H St f!S k ~

Chairman Hendrie Commissioner Bradford i

Commissioner Kennedy S. J. Chilk, SECY C. C. Kannerer, CA Commissioner Gilinsky (ForDistribution)

Transmitted: MNBB 8~' f3 P Bldg I.'I I E. Volgenau, IE L. V. Gossick, ED0 E. G. Case, NRR Region I~~ P: W T' S. H. Hanauer, EDO 3 6 SSBldgflf(s J. J. Fouchard, PA (MAIL) s N. M. Haller, MPA C. V. Smith, HMSS T. J. McTiernan, 01A l

R. G. Ryan, OSP R. Minogue, SD H. K. Shapar, ELD 9906040146 780621 l RELIMINARY NOTIFICATION N&-7 23 , PDR I