An explosion occurred at unit 1 of EDF’s Flamanville nuclear power plant in northern France, on 9 February causing minor injuries but no risk of contamination, authorities said. EDF said a fire had led to an explosion in the machine room of one of the two nuclear reactors. The blaze had been immediately brought under control and the unit 1 reactor was disconnected from the grid, it said. The accident was declared “over” by the regional authorities after one hour.

Jacques Witkowski, a local official, told Reuters that the five workers present when the blast happened were evacuated and treated for slight smoke inhalation.

He ruled out any deliberate act of sabotage, saying a mechanical part of a ventilator in the machine room  had probably overheated. However, the cause had not been established. Another senior local official Olivier Marmion said: “It is a significant technical event but it is not a nuclear accident.” The accident did not affect construction site of the third-generation European Pressurised Water nuclear reactor (EPR) under construction at unit 3 of the plant.

Units 1 and 2 at  Flamanville, both 1300MWe pressurised water reactors, began operation in 1986 and 1987. Unit 3, which has suffered a number of delays for technical reasons, is scheduled to begin operation in 2018. The accident is likely to have wider repercussions on the French nuclear industry, which has recently faced criticism following the discovery of flaws in the steel of some reactor components, which was manufactured at Areva’s Le Creusot Forge.  Last year 18 reactors were taken offline while checks were made by  L'Autorité de Sûreté Nucléaire (ASN – Nuclear Safety Authority). Currently the industry is undergoing major restructuring with state funds being used to help resolve major financial difficulties at Areva, which is in the process of being separated into different companies, with EDF taking over Areva’s reactor business.