(Updates with details, EDF comment)
By Susanna Twidale
LONDON, April 25 (Reuters) - EDF Energy, owned by French power company, has extended an outage at its Hunterston B8 nuclear reactor in Scotland by two weeks while the nuclear regulator assesses whether it is safe for it to restart after cracks were discovered last year.
Hunterston B nuclear plant on the west coast of Scotland is more than 40 years old. It has two reactors and both have been offline since last year after cracks were found on the graphite core during routine inspections at the facility.
Hunterston B8 has been offline since last October had been expected to return to service on April 30. That has now been extended to May 14.
Before EDF Energy is allowed to restart the reactor it must show it can operate safely. It has presented a safety case to Britain’s nuclear regulator, the Office for Nuclear Regulation (ONR) which will then decide whether the reactor can be restarted.
The safety case must demonstrate that the reactor would be able to operate and shutdown safely during normal operation and during an unlikely earthquake scenario.
“To support time for the ONR assessment, we have declared May 14, 2019 .. a slight adjustment to the previously declared date,” an EDF Energy spokeswoman said via email.
Under energy market rules the company must provide an indication of when the reactor is likely to return to service, but the spokeswoman said it is not possible for the company to confirm exactly how long the ONR process will take.
Hunterston’s other reactor, B7, has also been offline since March last year due to the same issue. EDF Energy has yet to submit a safety case to the ONR for that unit’s return to operations.
Combined, the two reactors at Hunterston can provide enough electricity to power more than 1.7 million homes.
EDF Energy’s 15 nuclear reactors in Britain provide about 20 percent of the country’s electricity. Almost half of that capacity is due to go offline by 2025, with Hunterston B scheduled to close in 2023.
Reporting by Susanna Twidale; Editing by Mark Potter and Nina Chestney