30 avril 2012
Au cours d’une manœuvre de test d’arrêt d’urgence, l’unité 1 s’est arrêtée automatiquement. Des alarmes incendie se sont déclenchées alors qu’il n’y avait pas de feu. Cause probable : ce serait un problème de tension électrique d’un sous-système de l’équipement de mise à l’arrêt d’urgence du réacteur qui aurait engagé son arrêt.
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Facility : SALEM - Region : 1 State : NJ - Unit : [1]
Emergency Class : UNUSUAL EVENT
50.72(a) (1) (i) - EMERGENCY DECLARED 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(2)(iv)(A) - ECCS INJECTION
"Performing an I&C functional [test] caused an inadvertent Safety Injection signal resulting in a reactor trip/safety injection. All safety systems responded as designed for a safety injection. Electrical systems are aligned to normal offsite power sources. All fire alarms have been validated by the Fire Protection Department as invalid alarms and confirmed that no fire event in the protected area.
"The reactor trip was successful and all rods [fully] inserted. Decay heat removal is via auxiliary feedwater through the atmospheric [steam] dumps. Unknown at this time is the cause of the inadvertent safety injection signal. No injuries occurred as a result of this event."
The licensee believes that the trip/safety injection may have caused piping to shake resulting in dust near the fire detection equipment resulting in the invalid fire indication.
The instrument being tested was the high steam flow channel-1 bistable for PT505. The maximum pressurizer level during this event was 95%.
The licensee notified the NRC Resident Inspector.
* * * UPDATE AT 1400 EDT ON 4/30/2012 FROM JOHN KOKOVALCHICK TO MARK ABRAMOVITZ * * *
"At 1003 hours on April 30, 2012, Salem Unit 1 experienced a reactor trip and safety injection (SI) signal due to a high steam flow coincident with a low steam pressure signal. At the time of the safety injection signal, function testing of the 1PT505 turbine inlet pressure channel was in progress. This testing required the tripping of the high steam flow bistables.
"As a result of the reactor trip and safety injection signal, the Emergency Diesel Generators started but did not load, the ECCS system (high head safety injection pumps actuated and injected into the reactor vessel, intermediate head safety injection pumps and low head (RHR) safety injection pumps) actuated. All 4 main steam isolation valves closed along with feedwater isolation and start of the auxiliary feedwater pumps. All control rods fully inserted following the reactor trip. Following the main steam line isolation, the atmospheric relief valves opened along with the lifting of several main steam safety valves.
"The unit is currently in Mode 3 and will be cooling down to Mode 4. Train A SSPS [Solid State Protection System] is currently out of service and suspected of causing the safety injection signal. Train B SSPS has not been reset due to the standing safety injection signal. With Train A SSPS inoperable and Train B SSPS not reset, TS 3.0.3 was entered and a shutdown required by TS 3.0.3 was commenced at 1345 hours.
"This report is being made in accordance with 10CFR50.72(b )(2)(iv)(B), 50.72(b)(3)(iv)(A), 50.72(b)(2)(i) and 50.72(b)(2)(iv)(A)."
The licensee exited the Unusual Event at 1249 EDT.
The licensee notified the NRC Resident Inspector. Notified the R1DO (Conte).
The NRC Operations Center notified other Federal Agencies (DHS SWO, FEMA Ops, DHS NICC, and NuclearSSA via e-mail).
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2012/20120501en.html
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