 INES 2 |
FAILING TO COMPLY WITH THE OPERATING PROCEDURES |
On Saturday 29 January 1994, during preparations to restart Unit 5, which had been shut down since 21 August 1993, the operator failed to comply with procedures during one of the scheduled operations: dropping the water level in the reactor coolant system to midloop operation level.
During the incident, the level of water was allowed to fall below the authorized limit. The throughput of the pumps and the intensity of the pump motors therefore fluctuated for eight hours, before the operations team took adequate steps to rectify the situation.
This incident had no direct consequence on the safety of the installation or on the environment: the temperature of the reactor coolant water did not alter, and pump performance returned to a satisfactory level once the level of coolant was increased.
This incident was initially graded level 1. But after an on-site inspection made by the safety authority, this incident was re-graded level 2 on the severity scale in the light of the failure to comply with procedures, the poor quality of the operating documents, the lack of information of the operations team and the conclusions to be learnt from it for both Bugey and the entire population of French nuclear power plants.
Event date: Sat, 29-01-1994
