Inadequate setting of the auxiliary feedwater turbopump


Print View Posted on: 31 March 2011

Event Date: 18 March 2011 Event Type: Power Reactor
Event Location: Belgium, DOEL-4 INES Rating: 2 (Final)

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.

INES Rating: 2 - Incident (Final) as per 18 March 2011
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 Yes

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

Van Wonterghem
FANC

Frederik.Vanwonterghem@fanc.fgov.be
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