8 mai 2014
Suite à des réexamens de dossiers, il a été découvert la possibilité d’un départ d’incendie sur le câblage d’un moteur continu. La possibilité de survenue de ce problème est liée à une protection électrique insuffisante du circuit. Ce départ d’incendie pourrait affecter les équipements de mise à l’arrêt sûr du réacteur.
Type Fukushima 1 (BWR Mark1) - Puissance 1 850 MWth - Première divergence : 09/1969
Available in english only.
Event Number : 50098 - Facility : NINE MILE POINT - State : NY -
Unit : [1] - RX Type : [1] GE-2
Event Date : 05/08/2014 - Event Time : 16:45
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
Initial PWR Initial RX Mode Current PWR Current RX Mode 1 N Y 100 Power Operation 100 Power Operation
Event Text
POSTULATED HOT SHORT FIRE EVENT THAT COULD ADVERSELY IMPACT SAFE SHUTDOWN EQUIPMENT
"A review of industry operating experience regarding the potential for secondary fires being caused by DC Motor control circuit wiring has determined the described condition to be applicable to Nine Mile Point Unit 1 resulting in a potentially unanalyzed condition with respect to 10 CFR 50 Appendix R analysis requirements. The original plant wiring design and configuration for the containment isolation valve IV-33-04 does not include separate over current protection for the power and control wiring. The only protection for the control circuit wiring is provided by the power circuit fuses.
"In the postulated event, a fire in the reactor building at the DC MOV could cause one of the control circuit wires to short and potentially over heat creating a secondary fire in the raceway system in a different fire zone. The secondary fire could adversely affect safe shutdown equipment and potentially cause the loss of the ability to conduct a safe shutdown as required by 10 CFR 50 Appendix R. This event entered into the Nine Mile Point corrective action program as Condition Report (CR) 2014-004630.
"This condition is being reported in accordance with 10 CFR 50.72(b)(3)(ii)(B). Interim compensatory measures (i.e., fire zone inspections) have been implemented for affected areas of the plant."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140509en.html#en50098