LONDON (Reuters) - EDF Energy has extended an outage at the Hunterston B-7 reactor on the west coast of Scotland to Jan. 15, 2020 from a previously scheduled Oct. 1, the British arm of French utility EDF said on its website.

It has been offline since March 2018 after routine inspections found cracks in its graphite core. Its restart has been delayed several times since.

Before the reactor can restart Britain’s Office for Nuclear Regulation (ONR) must be satisfied with the company’s safety case, showing the reactor would be safe to operate even in the unlikely event of an earthquake.

“After discussions with ONR we have agreed that some additional technical analysis will be completed to support the ... safety case assessment,” Hunterson B station director Colin Weir said.

The other reactor at the plant, which is more than 40 years old, was given approval to restart power production last month.

The two reactors at full capacity can provide enough electricity to power more than 1.7 million homes.