French multinational power generation firm EDF has received Scottish regulatory approval to temporarily start generating power at the Hunterston B nuclear station in Ayrshire.

The restart of the reactor follows a two-year inspection and investment program. The testing focused on proving that the Hunterston station could withstand a range of earthquake scenarios, even seismic events far greater than any the United Kingdom has ever experienced, according to the EDF release.

Reactor 3 was taken offline in 2018 for graphite inspections. It has received go-ahead for restart.

Hunterston’s Reactor 4 also went offline in 2018, restarted a year later and was then was shut down for further inspection. Pending regulatory approval Reactor 4 could be restarted next year for two runs of six months each.

Whatever happens with temporary restarts, EDF plans to retire the 44-year-old Hunterston B by 2022.

“Hunterston B has quietly delivered a major contribution to the U.K. for more than 40 years,” Matt Skykes, managing director for EDF’s generation business, said in a statement. “It has far exceeded its original remit and, over its lifetime, gone on to safely produce enough low-carbon energy to power the whole of Scotland for eight years.”

EDF is building European pressurized water reactors (EPRs) at Hinkley Point C and developing plans for a replica plant at Sizewell C. It also has a minority stake in the Bradwell B project.

“I am extremely proud of all those who have run Hunterston B for more than 40 years,” Simone Rossi, EDF’s UK CEO, said. The decommissioning “underlines the urgent need for investment in new, low carbon nuclear power to help Britain achieve net zero and secure the future for its nuclear industry, supply chain and workers.”

Hunterston B is one of a fleet of 7 Advanced Gas-cooled Reactors (AGR) around the coast of Britain.