Declaration of Unusual Event (NUP-4.1)

Print View Posted on: 12 January 2024

Event Date: 04 January 2024 Event Type: Power Reactor
Event Location: Mexico, LAGUNA VERDE-1 INES Rating: 0 (Final)

On January 4, 2024, the Unit 1 was operating at 100% power. At 09:00 (local time) the steam tunnel cooling unit “1-RRA-FC-009A” was started due to equipment rotation resulting in the loss of energy in the Motor Control Center (MCC) “1-R31-MCC-1BA-AA” with the failure of the electrical protection of the cubicle 5D of the MCC “1-R31-MCC-1BA-A”.
At 09:05, the Auxiliary Reactor Operator reported the presence of smoke in the MCC “1-R31-MCC-1BA-A” preventing the manual opening of the cubicle 5D.
At 09:10, the Auxiliary Turbine Operator reported that the switch 7A that energize the MCC “1-R31-MCC-1BA-A” could not be manually open.
At 09:17, the Auxiliary Reactor Operator reported the presence of fire in the MCC “1-R31-MCC-1BA-A” located in the elevation 18.70 of the Reactor Building. The bus 14BA was de-energized by manually opening the switches 14BAM and 14BA resulting in entry to the procedure 1-OA-0556 "Loss of 4160/480VAC non-critical". The fire brigade was activated according to the procedure PAS-32 "Fire Protection Program".
At 09:32, an Unusual Event was declared due to fire in the protected area not extinguished in 15 minutes (NUP-4.1).
At 09:45, the Chief of the fire brigade reported that the event had been controlled and that maneuvers to recover the area would begin.
At 13:30, the Unusual Event was declared finalized.

INES Rating: 0 - Below scale (Final) as per 09 January 2024
Release beyond authorized limits? No
Overexposure of a member of the public? No
Overexposure of a worker? No

Contamination spread within the facility? No
Damage to radiological barriers (incl. fuel damage) within the facility? No

Degradation of Defence In-Depth No

Person injured physically or casualty? No
Is there a continuing problem? No
Related Information

Victor Gonzalez
Comision Nacional de Seguridad Nuclear y Salvaguardias
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