EDF ordered to extend work on canal at Tricastin

In September 2017, ASN ordered temporary shutdown of the Tricastin plant owing to the risk of failure of a 400 metre long portion of the Donzère-Mondragon embankment in the event of an earthquake. Assessments carried out showed that the flooding that would result from failure of the embankment would have caused a nuclear fuel melt accident in the four reactors and would have made deployment of the on-site and off-site emergency management resources particularly difficult. EDF later that year completed reinforcement work and ASN approved the restart of the reactors in December the same year.

In a decision notice of 25 June that it made public yesterday, ASN said it had not ordered the closure of the plant's four pressurised water reactors as it had for initial work on the canal in September 2017, but that EDF "must increase surveillance of the canal, monitor pressure on the dykes and maintain sufficient staff and equipment to respond to any damage resulting from an earthquake".

It added: "EDF has planned additional works on this dyke so that it can withstand an extreme earthquake defined after the Fukushima accident. The decision adopted by the ASN on 25 June, 2019, requires this reinforcement to be completed no later than the end of 2022."

ASN's decision was the subject of a public consultation held via its website between 4 and 18 April 2018.