ML041890435

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Event # 40684, Nine Mile Point Re Residual Heat Removal System Isolation Due to a Rise in Reactor Pressure
ML041890435
Person / Time
Site: Nine Mile Point Constellation icon.png
Issue date: 04/18/2004
From:
NRC Region 1
To:
References
40684, FOIA/PA-2004-0243
Download: ML041890435 (4)


Text

0512012004 U.S. Nuclear Regulatory Commission Operations Center Event Report Page I Power Reactor Event# 40684 Site: NINE MILE POINT Notification Date /Time: 04/18/2004 23:45 (EDT)

Unit: 2 Region: 1 State: NY Event Date I Time: 04/18/2004 18:30 (EDT)

Reactor Type: 11] GE-2,[2] GE-5 Last Modification: 04/18/2004 Containment Type: MARK I MARK II NRC Notified by: DAVE RICHARDSON Notifications: BRIAN MCDERMOTT R1 HQ Ops Officer: ARLON COSTA Emergency Class: NON EMERGENCY 10 CFR Section:

50.72(b)(3)(iv)(A) VALID SPECIF SYS ACTUATION Unit I Scram Code IRX Crit IInit Power Initial RX Mode Curr Power Current RX Mode 21 N No 0 Cold Shutdown 0 Cold Shutdown RESIDUAL HEAT REMOVAL SYSTEM ISOLATION DUE TO A RISE IN REACTOR PRESSURE "At 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> on 18 April 2004, Nine Mile Point Unit 2 was restoring from reactor pressure vessel leakage test.

"Reactor pressure was -82 psi, temperature -178 degrees, reactor level was solid with both reactor recirculation pumps running in slow speed per the leak test procedure.

"'B' residual heat removal system was being warmed up in preparation for going in to service. Reactor water cleanup reject from the vessel was secured to maintain RPV [Reactor Pressure Vessel] pressure stable in order to provide driving head for flow through the residual heat removal discharge line to radwaste The line is warmed up from the reactor, back through the Shutdown cooling isolation valve, to radwaste prior to placing shutdown cooling in service. When warm-up criteria are met, the operating procedure directs securing flow.

When flow was secured, this effectively isolated the solid reactor vessel, resulting in a rise in reactor pressure.

Pressure peaked at -146 psi before operators established reactor water cleanup reject flow.

'When RPV pressure reached 128 psi, the residual heat removal system isolation was automatically initiated as designed. The shutdown cooling injection valve, which was open to support piping warm-up, closed as designed.

All other shutdown cooling valves were closed prior to the event per the warm-up lineup."

RPV is currently depressurized with shutdown cooling in service. All systems are functioning as expected.

The licensee notified the NRC Resident Inspector.