Improving nuclear safety and radiation protection


ASN suspends the test certificate for a steam generator in the Fessenheim NPP affected by one of the irregularities detected in Areva’s Creusot Forge plant

Published on 20/07/2016 • 04:30 pm

Information notice

ASN has suspended the test certificate it issued to Areva NP in 2012 for a steam generator at present installed on the Fessenheim NPP reactor 2. This suspension follows the detection of an irregularity in one of the parts of this steam generator, called the “lower shell”, manufactured by Areva’s Creusot Forge plant.

The forging process for the lower shell of this steam generator, made in 2008, was not compliant with the technical file submitted to ASN and with the state of the art. ASN was not informed of this nonconformity. Had ASN been aware of this nonconformity, for which there was no particular substantiating documentation, it would not have issued the test certificate in 2012. EDF informed ASN of the consequences of this irregularity in mid-June.

ASN is responsible for monitoring the manufacture of the nuclear pressure equipment that is most important for nuclear safety. On the basis of a review, several inspections and the results of hydrotesting during which the equipment was subjected to high pressure, ASN issued test certificates confirming the suitability of this equipment for service. These certificates are required for commissioning.

ASN asked Areva NP to send it a file presenting the approach it intends to adopt to demonstrate the compliance of this steam generator with the regulations.

On 13th June 2016, EDF shut down Fessenheim NPP reactor 2 and on 15th June 2016 sent ASN its initial analysis of the irregularity detected. Until such time as the test certificate suspension is lifted, the steam generator and therefore the reactor must be kept shut down.  

Date of last update : 08/06/2017