US energy company Exelon Corp on 20 September said it would shut down unit 1 at its Three Mile Island nuclear plant, which had been operating since 1974, by 30 September.
Exelon had announced in May that it planned to shut the 45-year old unit this month after the Pennsylvania legislature failed to pass a bill that would have subsidised nuclear power plant operation in the state. The legislature considered legislation, but too late for Three Mile Island as Exelon had said it needed to decide whether to spend the money to refuel the plant by 1 June.
Exelon said on its website it had bought the 837MWe unit Three Mile Island 1 about 20 years after the 1979 meltdown accident closed TMI 2, which is owned by FirstEnergy Corp. The accident was rated Level 5 on the seven-level International Nuclear and Radiological Events Scale. Nuclear services company EnergySolutions said in July it was in negotiations with a unit of FirstEnergy to acquire and complete the decommissioning of TMI 2.
The closure of TMI 1 will leave eight reactors in Pennsylvania. Exelon operates Peach Bottom 1&2 and Limerick 1&2, FirstEnergy operates two reactors at Beaver Valley, and Talen Energy owns two units at Susquehanna. FirstEnergy has said it would shut Beaver Valley in 2021 unless the reactors receive some financial support from federal or state programmes.
Three Mile Island employed 675 people and somre300 will remain at the site during the first phase of decommissioning, but would fall to 50 from 2022, Exelon said. The dismantling of the main components, including the cooling towers, will not begin until 2074. Decommissioning will cost around $1.2bn. Exelon estimated that all radioactive material would be removed by 2078.