1er avril 2014
Le 345 000 volts qui a été perdu sur le transformateur des auxiliaires a entrainé l’arrêt de deux pompes primaires. Cet arrêt a interrompu deux boucles de refroidissement du cœur. Le cœur étant critique, les systèmes de protection du réacteur se seraient malgré tout correctement enclenchés.
Type : PWR - Puissance 3 648 MWth - Première divergence : 06/1989
Available in english only.
Event Number : 49979 - Facility : SEABROOK - State : NH - Unit : [1] - RX Type : [1] W-4-LP -
Event Date : 04/01/2014 - Event Time : 00:26
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 A/R Y 15 Power Operation 0 Hot Standby
Event Text AUTOMATIC REACTOR TRIP DUE TO ELECTRICAL ISSUE
"At 0026 on 04/01/2014, following the turbine shutdown and removal of the main generator from service in preparation for refueling outage 16, Seabrook had a reactor trip and all control rods were fully inserted. The trip was caused by an electrical issue that caused 345 KV bus 6 to deenergize and power was lost to the Unit Auxiliary Transformers (UATs). The in-house busses transferred to the Reserve Auxiliary Transformer (RAT) supplies and the momentary loss of power to in-house Bus 1 caused 2 reactor coolant pumps to trip, generating a 2 loop loss of flow reactor trip signal. The exact cause of the initialing electrical issue is being investigated.
"The resident NRC Inspector has been notified.
"Emergency feedwater actuated at 0035 due to a low low water level in steam generator ’C’. Plant equipment response is being evaluated and the plant is stabilized in Mode 3 with decay heat removal through the steam dump system to the condensers. There was no release and the emergency feedwater system is being restored to standby.
"The event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140401en.html#en49977