Exelon on Friday shut down its reactor at the Three Mile Island nuclear power plant in Pennsylvania.
Unit 1 powered down for the last time at noon, according to an Exelon press release. Workers will now spend several weeks removing used fuel from the reactor for cooling.
The reactor retirement came more than a week earlier than previously anticipated, a senior U.S. Nuclear Regulatory Commission official said Tuesday.
“We originally were told it would shut down by the end of this month, but apparently it’s going to be Sept. 20, so they’re moving that up,” Bruce Watson, chief of the Reactor Decommissioning Branch within the NRC’s Office of Nuclear Material Safety and Safeguards, said during a presentation at the agency’s Reg Con 2019 in King of Prussia, Pa.
An Exelon spokesman on Thursday said the closure date was first disclosed at an NRC public meeting in July. He did not discuss the thinking behind the expedited schedule.
The pressurized-water reactor near Harrisburg, went operational in September 1974 and was bought buy Exelon Generation in 2000. The company in 2017 announced its plans to retire the reactor, citing low natural gas prices and market challenges highlighted by other nuclear power plant operators in explaining their own closures. Management indicated government assistance could keep the plant alive, but Pennsylvania lawmakers have resisted the zero-emission credit programs that have sustained nuclear power providers in other states.
“At a time when our communities are demanding more clean energy to address climate change, it’s regrettable that state law does not support the continued operation of this safe and reliable source of carbon-free power,” Exelon Nuclear President and Chief Nuclear Officer Bryan Hanson said in the release. “It’s critical that we continue to pursue policy reform to prevent other carbon-free nuclear resources from being pushed out of the market by rules that fail to evenly value clean energy resources and at the same time allow emitting resources to pollute for free.”
After closure and defueling, the Three Mile Island reactor will be placed into “safe storage,” or SAFSTOR, mode, under which completion of decommissioning can be delayed for up to 60 years. That gives nuclear licensees time to increase funding for decommissioning as radioactivity levels drop.
Active decommissioning at Three Mile Island would begin in the 2070s, with license termination in 2079, under Exelon’s schedule. The projected cost is $1.245 billion, covering decommissioning, spent fuel management, and site restoration. Exelon expects its decommissioning trust fund for the plant will cover all costs, but has committed to making up any shortfall.
Exelon will shrink staffing at the reactor in three phases following closure, from 515 to 300 for preliminary decommissioning, then to 200 in 2021, and finally to roughly 50 in 2022 for maintenance and security in SAFSTOR. Some personnel have taken other jobs at Exelon, while others are retiring or leaving the company, the release says.
Apart from the fuel still in the reactor, Unit 1’s used fuel is in a cooling pool. A dry-storage facility is scheduled to be built and operational by 2022, though a contractor has not been named. The waste will be held in 46 canisters.
In July, Exelon completed the sale of the Oyster Creek Nuclear Generating Station in New Jersey to energy technology company Holtec International for decommissioning. But the Chicago-based power provider has said it would retain ownership of its Three Mile Island reactor.
“There are no plans to sell TMI at this time,” Exelon spokesman Paul Adams said by email. “However, Exelon Generation regularly evaluates all facilities and assets, and consider all options, including sales, to optimize our value for energy customers, communities and stakeholders.”
Including the Three Mile Island reactor, there are now 23 reactors in decommissioning in the United States, Watson said. Thirteen of those are in active decommissioning, while 10 are SAFSTOR mode.
The shutdown leaves 96 operational nuclear power reactors in the United States, according to the Nuclear Energy Institute, the Washington, D.C.-based trade group for the industry.
FirstEnergy Corp. is the owner of the other reactor at Three Mile Island, Unit 2, which never resumed operations after famously partially melting down in 1979. Unit 2 is also in SAFSTOR after being defueled and decontaminated.
On Monday, the NRC renewed the Department of Energy license for dry storage of waste from Unit 2 at the Idaho National Laboratory.
The independent spent fuel storage installation (ISFSI) is now licensed through March 19, 2039. The above-ground storage pad holds 341 canisters of spent fuel core debris left by the Unit 2 accident.
In applying for renewal of the NRC license, the Energy Department committed to not shipping any more waste to the ISFSI. Under a separate agreement with the state, it must send the spent fuel core debris and other nuclear waste out of Idaho by 2035.
The NRC has said it determined that renewing the license would not have a significant impact on the environment, woud not endanger the “common defense and security,” and is not expected to threaten public health and safety.
