EDF Energy extends outages at UK's Hunterston B nuclear plant

LONDON (Reuters) - EDF Energy, owned by France’s EDF, has extended outages at two nuclear reactors at its Hunterston B plant in Scotland while it waits for Britain’s nuclear regulator to assess their safety cases.

Hunterston B-8 reactor is now expected to restart on April 30, a month later than previously forecast. Hunterston B-7 is scheduled to restart on June 29, compared with a previous date of April 30, according to EDF Energy’s website.

In March last year, the two reactors were taken offline to carry out inspections of the graphite core. These confirmed the presence of cracks and showed these were happening at a higher rate than modelled.

Since then, EDF Energy has been conducting more inspections and has improved its modelling on how the reactors would operate in normal conditions and in a highly unlikely earthquake, EDF Energy said.

“We can show conclusively that it will operate and shut down as designed, with absolutely no erosion of safety. In all circumstances all control rods will enter the core and there is no challenge to safe operation,” the firm said in a letter to the site’s stakeholders.

A safety case for the plant’s return to service has been submitted to Britain’s nuclear regulator. However, it is not known how long this process will take and so the restart dates have been revised, it added.

Reporting by Nina Chestney; Editing by Mark Potter