“Some of the plants that were permanently shut down have been totally dismantled, as in the case of Maine Yankee and Connecticut Yankee,” Sheehan said. “If you go to those sites today, all you will find from the nuclear operations are the dry cask storage facilities. Other decommissioned plants, like Millstone, are mothballed, awaiting the shutdown of the other units still operating at the site.” The reactor core holds 368 fuel assemblies, each of which remains in the reactor for 4-anda- half years before being moved to the spent fuel pool. The capacity of the spent fuel pool is 3,355 assemblies and room must be maintained to keep space for the full-core offload of the reactor’s 368 assemblies.Each dry cask weighs about 100 tons and contains 68 fuel assemblies.
NRC considers long-term on-site storage of waste – Brattleboro Reformer