About Us
Three Mile Island Unit 1, located in south central Pennsylvania, generates clean, safe and
reliable power for more than 800,000 homes. TMI Unit 1 began operating in 1974, and in early 2008 Exelon Nuclear asked the U.S. Nuclear Regulatory Commission (NRC) to renew its operating license through 2034. To learn more about the relicensing process
click here.
With approximately 520 employees, TMI Unit 1 is a dedicated community partner. TMI employees are also dedicated to their jobs at the plant and conduct all of their work with safety as their top priority.
TMI Unit 1 was purchased in 1999. TMI Unit 1 is part of Exelon Nuclear, a business unit of Exelon Generation; which is a part of Exelon Corporation. Exelon Corporation is the nation's largest owner and operator of nuclear power stations.
A brief look at TMI Unit 1
Generation:
- Number of units: 1
- Total site net capacity: 852 megawatts
- 2007 net generation: 6.6 billion kilowatt hours
- 2007 capacity factor: 90.6 percent * (refueling outage year)**
- Customers served: 800,000 homes
Type and manufacturer of reactor:
- Pressurized Water Reactor- Babcock & Wilcox
Site Features:
- Site size: 382 acres
- Location: Londonderry Township, Dauphin County, Pennsylvania
Ownership:
- Exelon Nuclear - a business unit of Exelon Generation, that is a part of Exelon Corporation
*The amount of electricity actually produced compared with the theoretical maximum production.
**TMI Unit 1 conducts a refueling outage every two years. During the outage, TMI Unit 1 does not produce electricity.