29 octobre 2012
Le réacteur n° 1 qui fonctionnait à pleine puissance s’est arrêté en urgence suite à la perte de la charge électrique sur le générateur. La cause de la perte de charge est en cours de recherche. Selon la synthèse de la NRC, le système d’injection de réfrigérant haute pression a fonctionné correctement. Contrairement aux autres réacteurs où il est utilisé en urgence, ce circuit servirait ici en situation normale. Le réacteur a été conduit en situation d’arrêt à chaud avec des niveaux d’eau et de pression se situant dans les plages prévues.
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Facility : NINE MILE POINT - State : NY - Unit : [1] - RX Type : [1] GE-2,[ Event Date : 10/29/2012 -
Emergency Class : NON EMERGENCY
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 1 A/R Y 100 Power Operation 0 Hot Shutdown
Event Text
RPS ACTUATION WHILE CRITICAL DUE TO GENERATOR LOAD REJECT
On October 29, 2012 at 2100 EDT, Nine Mile Point Unit 1 experienced an automatic reactor scram due to a generator load reject. The cause of the load reject is currently under investigation. All control rods fully inserted and all plant systems responded per design following the scram.
Following the automatic scram, the High Pressure Coolant Injection (HPCI) System automatically initiated as expected. At Nine Mile Point Unit 1, a HPCI System actuation signal on low Reactor Pressure Vessel (RPV) level is normally received following a reactor scram, due to level shrink. HPCI is a flow control mode of the normal feedwater systems, and is not an Emergency Core Cooling System. At 2101 EDT, RPV level was restored above the HPCI System low level actuation set point and the HPCI System initiation signal was reset. Pressure control was established on the Turbine Bypass Valves, the preferred system. Three Electromatic Relief Valves actuated due to this scram and re-closed automatically.
Nine Mile Point Unit 1 is currently in Hot Shutdown, with reactor water level and pressure maintained within normal bands. Decay heat is being removed via steam to the main condenser using bypass valves. Both Reserve Station Transformers are in service and being supplied by their normal power sources. Both Emergency Diesel Generators are operable and in standby.
The unit is currently implementing post scram recovery procedures.
The licensee has notified the NRC Resident Inspector. Notified R1DO (Caruso).
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2012/20121030en.html