INES-event
INES 2

Inadequate setting of the auxiliary feedwater turbopump

After the replacement of an auxiliary feedwater turbopump during the 2009-outage, the rotational speed of the pump was adjusted to a lower level because of vibration problems with the pump. The pump was tested and requalified according to the technical specifications but the curve (flow-rate <-> pressure) was not verified – as required by ASME-XI. The actual flow rate delivered in case of specific accidents could no longer match the flow rate postulated in the safety report. Nevertheless, an independent emergency feedwater system could offer additional capacity in such circumstances. This anomaly was discovered on 18 marth 2011 during a test which was suggested by the authorities.

Location: DOEL-4
Event date: Fri, 18-03-2011
Nuclear event report
Legenda & explanation