The Nuclear Regulatory Commission is asking for comment on a plan by GPU Nuclear to essentially maintain the long-shut Three Mile Island Unit 2 in its current state for up to 20 years, until the operating Unit 1 is shut, so the two units can be decommissioned together.
On June 28, the GPU Nuclear (GPUN) submitted its Post Shutdown Decommissioning Activity Report (PSDAR) for Three Mile Island Unit 2 (TMI-2). The PSDAR provides an overview of GPUN’s proposed decommissioning activities, schedule, and costs for TMI-2. The NRC said in a notice to be published in the Aug. 14 Federal Register that it is requesting public comments by Sept. 27 on the PSDAR.
The NRC issued GPUN operating license DPR-73 for TMI-2 in February 1978. Commercial operation of TMI-2 began in December 1978. In March 1979, TMI-2 experienced severe damage to the reactor core and has been in a non-operating status since the accident. GPUN defueled the reactor vessel and decontaminated the facility to the extent that the plant is in a safe, inherently stable condition known as post-defueling monitored storage (PDMS). Approximately 99% of the fuel was removed from TMI-2 and shipped to Idaho National Engineering and Environmental Laboratory under the responsibility of the U.S. Department of Energy.
The accident made the shutdown of TMI-2 unique from all other reactors in that GPUN did not follow the standard, statutory process for cessation of operations. The formal transition of TMI-2 from post-accident cleanup to PDMS required NRC approval. GPUN obtained NRC approval to maintain TMI-2 in the PDMS state until decommissioning with the issuance of License Amendment No. 45 dated September 1993.
The infamous partial meltdown was the worst accident in U.S. commercial nuclear power plant history and ushered in a new era of tougher regulation through NRC.
License Amendment No. 45 also converted GPUN’s operating license to the current possession-only license. As a result, the NRC considers GPUN to have submitted a certification of permanent cessation of operations and a certification of permanent fuel removal as of September 1993.
In 1996, the NRC amended its regulations to require, among other things, that power reactor licensees submit a PSDAR instead of a decommissioning plan. On June 28, GPUN submitted its PSDAR. “The GPUN stated that its PSDAR will maintain TMI-2 in the PDMS state up to an additional 20 years to coincide with the end of the TMI, Unit 1 (TMI-1) Operating License to synchronize decommissioning of TMI-1 and TMI-2,” the NRC noted.