Corrosion of fission products concentrating evaporators at La Hague: ASN calls AREVA to a hearing

On Thursday 11 February 2016, the ASN Commission called Philippe Knoche, Managing Director, to a hearing concerning the corrosion of the evaporators used to concentrate fission products on the La Hague site in presence of Philippe Varin, Chairman of the Areva group. This equipment, which  was designed for an operational life of thirty years, entered into service between 1989 and 1994.

Initial thickness measurements were taken on these evaporators by Areva in 2012 at the request of ASN, during the first ten-yearly periodic inspection of the UP3-A plant. Areva conducted further measurements in 2014 and 2015. The latest results from these measurement campaigns, transmitted in December 2015, reveal faster corrosion of certain evaporators than originally anticipated in their design.

These results compromise the medium-term safety of the facility. The ability of this equipment to withstand pressure in its heating systems or earthquakes could be called into question in the coming years and, for the most degraded evaporator, potentially as of 2018.

In the light of these new data, ASN decided to make the continued operation of this equipment conditional upon compliance with certain requirements. Areva shall in particular reinforce the monitoring of these evaporators and install additional means (isolation, early detection, etc.) such as to limit the consequences of any leak or breach.

ASN shall be attentive to the development of corrosion in this equipment and shall check compliance with the conditions defined for its continued operation. ASN may be required to demand the shutdown of the facility in the event of excessive deterioration.