ML20134D871
| ML20134D871 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 07/26/1985 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| (55(E)-85-20), (NMP2L-0455), (NMP2L-455), NUDOCS 8508190427 | |
| Download: ML20134D871 (2) | |
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- 4 NMtNie Ie444444 ISONAWet Powem COAPOAAftcel/300 Emt ticuttvAn0 WEST. SYHACUSE N Y 13202/f tLEPHONE (JtS) 4741Sil July 26, 1985 (NMP2L0455)
Mr. R. W. Starostecki, Director U.S. Nuclear Regulatory Comission Region !
Division of Reactor Projects 631 Park Avenue l
King of Prussia, PA 19406 l
Re: Nine Mlle Point - Unit 2 I
Docket No 50-410 l
Dear Mr. Starosteck1:
Enclosed is an interim report in accordance with 10CRF50.55(e) for the problem concerning the reactor core isolation cooling /high pressure core spray pump condensate storage tank suction Ifne elevation versus suppression pool level.
This problem was reported via tel-con to T. Silko of your staf f on June 25, 1985.
Very truly yours.
(QQM C. Y. MengM l
Vice President Nuclear Engineering and Licensing I
CVM/GG/cla l
(0273T) xc Of rector of Inspection and Enforcement U.S. Nuclear Regulitory Comission Washington, DC 20555 R. A. Gram NRC Senf or Resident Inspector Projectfile(2)
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4 N!AGARA H0 HAWK POWER CORPORATION l
NINE MILE POINT - UNIT 2 j
DOCKET NO. 50-410 j
Interim Report for a Problem Concerning Reactor Core Isolation Cooling /iligh Pressure Core Spray Pump Condensate Storage Tank Suction Line Elevation Versus Suppression Pool Level (55(o)-85-20)
Description of the problen A review of the suction lines to the reactor core isolation cooling system iden tified a potential path for suppression pool water to flow outside of secondary containment to the condensato storage tank located in the condensato storage tank building.
The reactor core isolation cooling system normally takes suction f rom the condensate storage tank.
In the even t of a low level in the condensate storage tank, reactor core isolation cooling main pump and pressure pump suction will be switched to the suppression pool.
For this to occur, 2tCS*tiOV136 opens to allow flow f rom the suppression pool and, upon fully open ing, si gnals 2!CSafiOV129 to close.
Valve 2!CS*tt0V129 is the only automatic isolation of the reactor core isolation cooling pump suction line fron the condensate storage tank available during changeover to suction f rom the suppression pool.
Although there are check valves downstream of the condensate storage tank and reactor core isolation cooling pressure es.mp located upstrean of the suppression pool tie-in, an alternate suction line from the suppression
)ool to the maintenance pump was added as a result of General Electric's A;0 57 During a Loss-of-Coolan t-Acciden t, if valve 2!CS*fiOV129 were to f all to fully close durine changeover to 1.uppression pool suction, there would be a potential flow pati created through the alternate suction Ifne that could allow suppression pool water to flow through the pressure pump suction line or minimum flow line towards the condensato storage tank.
A single f ailure of a power supply breaker conmon to 21CS*fiOV136 and 2tCS*tiOV129 or other failures could result in both valves failing in the open position.
The matter is still under investigation, and a f fnal report will be s ubmi tted by December 16,1985 This problem is not appifra51e to high pressure core spray.
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