EDF Energy, owned by France's EDF, has again extended outages at the two reactors at its Hunterston NPP in Scotland, regulatory data on the company's website showed. Both reactors have been offline since last year after routine inspections found cracks in its graphite core. The Hunterston B7 reactor is now scheduled to return to service on 31 July from the previous date of 30 June, and Hunterston B8 is scheduled to return on 24 June (previously 30 May). The outages have been extended several times before, most recently in April while the Office for Nuclear Regulation (ONR) assessed whether it was safe for them to restart. The Hunterston B plant is more than 40 years old. The safety case for ONR must demonstrate that the reactor would be able to operate and shut down safely during normal operation and an unlikely earthquake scenario. Under energy market rules the company must indicate when the reactor is likely to return to service. However, EDF Energy said in a letter to stakeholders in April: "It is not possible for us to confirm with certainty how long this process will take; our top priority is that it’s completed with appropriate rigour."