19 octobre 2014
Il a été découvert que les circuits à courant continu de la pompe à huile de lubrification d’urgence de la turbine de l’alternateur principal, ainsi que l’alimentation en courant continu de la pompe de lubrification du joint n’étaient pas correctement protégés par fusibles afin d’éviter des surcharges et il y avait donc de possibles départs de feu secondaires.
Type : PWR - Puissance : 3 565 MWth - Première divergence : 10/1984
Available in english only.
Des mesures compensatoires ont été mises en place dans les bâtiments turbine et contrôle. Ces mesures ajoutées aux systèmes de détection automatique d’incendie permettent d’assurer la protection des équipements potentiellement menacés.
Event Number : 50474
Facility : CALLAWAY - State : MO
Unit : [1] - RX Type : [1] W-4-LP
Event Date : 09/19/2014 - Event Time : 11:34
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
Initial PWR : 100 % Current PWR : 100 %
Event Text
UNANALYZED CONDITION DUE TO A POSTULATED HOT-SHORT FIRE EVENT THAT COULD ADVERSELY IMPACT SAFE SHUTDOWN EQUIPMENT
"From review of Event Notification 50468 made by Wolf Creek Nuclear Operating Company on 9/18/2014, which in turn was based on review of INPO Event Report 14-33, ’Direct Current Circuits Challenge Appendix R Fire Analysis,’ it was determined that portions of the control circuits for the main turbine-generator direct-current (DC) Emergency Lube Oil Pump and the Emergency DC Seal Oil Pump at Callaway Plant are not properly fused to prevent overload and possible secondary fires. The review found that a fire at the motor starter cabinet in the turbine building could cause specific ’smart’ hot shorts that could cause overheating of the control cable and result in secondary fires outside the turbine building, including the Control Building, thereby potentially affecting safe shutdown capability for the plant. Based on this information, it has been determined that this condition is unanalyzed, and on a conservative basis, is reportable per 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety.
"As compensatory measures, hourly fire watches are in place in the affected areas of the Turbine Building and Control Building. These compensatory measures, in addition to automatic fire detection and suppression capability in these fire areas, ensure protection of the potentially affected equipment.
"The NRC Resident Inspector has been notified."
The licensee continues to evaluate other control circuits to identify if this condition exists elsewhere.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140922en.html
La boutique
Informez vous