Insufficient seismic resistance of emergency diesel generators

Print View Posted on: 25 January 2018

Event Date: 09 November 2017 Event Type: Power Reactor
Event Location: France, PALUEL-1 INES Rating: 2 (Final)

Surge (expansion) tanks of emergency diesel generators were found corroded.Inadequate maintenance lead to not identify the corrosion and as consequence manage it. Their condition was such that their expected seismic resistance was not ensured.
Both of the two EDGs were concerned on Paluel reactors 1 and 2, which is relevant to an INES level 2 event.
The event is rated level 1 on the INES scale for the earthquake resistance deficiencies of the surge tanks of one emergency diesel generator set of the Nogent 1, Penly 1, Belleville 2, Cattenom 2 and Paluel 3, reactors, given that only one generator set out of the two is affected.
The corroded surge tanks of the reactors concerned were repaired or replaced between August and October 2017.
This event is different from the one reported on 20 June 2017 (event ID 2017/24), which was related to EDGs auxiliary systems’ ground anchors.

INES Rating: 2 - Incident (Final) as per 18 January 2018
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

Julien Husse
Autorité de Sûreté Nucléaire (ASN)
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