Peach Bottom Atomic Power Station Units 2 and 3 are located in Delta, Pennsylvania approximately 18 miles south of Lancaster, Pennsylvania. The General Electric BWRs are operated by Exelon Generation Co., LLC. The plants are owned (50%) by Exelon Corp. and owned (50%) by PSE&G Power, a wholly owned subsidiary of Public Service Enterprise Group, Inc. Unit 2 is licensed to operate until August 8, 2033. Unit 3 is licensed to operate until July 2, 2034. Also located on the same site is Unit 1 (show at the top of the photo), a General Electric high-temperature gas-cooled reactor that was shutdown in October 1974. Some decommissioning activities for Unit 1 have been performed but will not be completed until the end of 2034.
The ISFSI for Peach Bottom began accepting SNF from Unit 2 in 2000 and from Unit 3 in 2001 pursuant to a general license. All SNF assemblies from Unit 1 were removed from the fuel pool as part of the decommissioning process and shipped to Idaho National Laboratory for storage. The ISFSI is located approximately 2000 feet south of the main plant site and enclosed with its own security fences. The ISFSI is capable of holding 72 containers. As of the end of June 2011, there were 3,672 SNF assemblies stored in 54 dry casks (the photo only shows 44). The casks are manufactured by Transnuclear — the TN metal cask system and the TN-68 canister type. As of the end of 2010, there were 5,850 metric tons of SNF stored at the 5 nuclear power plant sites located in the State of Pennsylvania – Beaver Valley, Limerick, Peach Bottom, Three Mile Island, and Susquehanna.
In October 2010, Exelon discovered that two of its dry casks on the ISFSI, each containing 68 SNF assemblies, were leaking helium. The leak occurred in one of the casks as a result of a defective weld created during the manufacturing process. The other leak occurred as a result of oxidation on the main lid seal created when water leaked past the protective cask cover. Exelon reported both events to the US Nuclear Regulatory Commission. After further evaluation, Exelon concluded that there was no actual safety consequences and that the casks did not lose their ability to maintain proper storage of the SNF assemblies. The defects were repaired and the casks (and their contents) have since been returned to the ISFSI.