INES-event
INES 2

Successive events in operation during reactor restart

Four successive events (error in piping alignment, error in valve position, error in pump operation and ECCS unavailability) occurred on unit 3 at Tricastin NPP between 21 and 24 November 2000 during restart stages. These incidents are mainly relying on human and organisational factors and enlighten:
- inadequate relationship between the team in charge of action coordination during outage and operation team,
- low efficiency of human and organisational defence lines aiming at warranting a correct assessment of reactor safety and its conformance to requirements specified in general operating rules and in normal or temporary operating procedures.
- insufficient understanding and partial knowledge of these requirements from operating teams.

Each of these events would be rated, at the most, at level 1 on the INES scale. However, their accumulation within a very short period, significant of a collective lack of rigor, led the Nuclear Safety Authority to rate the last of them at level 2 on the INES Scale.

Location: TRICASTIN-3
Event date: Fri, 24-11-2000
Nuclear event report
Legenda & explanation