Zion Nuclear Power Station
| Company type | Nuclear power plant |
|---|---|
| Industry | Energy |
| Founded | 1973 |
| Fate | Permanently closed and decommissioned |
| Headquarters | Zion, Illinois , United States |
| Products | Electricity |
| Owner | Commonwealth Edison (ComEd) |
Zion Nuclear Power Station was the third facility within the Commonwealth Edison (ComEd) portfolio to feature two reactors, providing electricity to Chicago and the northern Illinois region. Constructed in 1973, Unit 1 commenced electricity generation in December of that year, with Unit 2 following in September 1974. The plant was situated on a site adjacent to the Lake Michigan shore in Zion, Lake County, Illinois, approximately 40 miles north of Chicago and 42 miles south of Milwaukee.
The reactors, supplied by Westinghouse, were brought online in 1973 and 1974 respectively and were decommissioned over a period extending from 1998 to 2020. During its operational years, Zion stood as the tallest structure within Lake County.
Closure
Operations at Zion Nuclear Power Station ceased on February 21, 1997, with the plant officially retired on February 13, 1998. The shutdown was prompted by an incident involving a control-room operator error related to control rods in Reactor 1; at that time, Reactor 2 was offline for refueling. ComEd concluded that the $435 million expense required to replace steam generators would not be recovered before the plant’s license expiration in 2013, making continued operation economically unfeasible.
Decommissioning
By March 9, 1998, all nuclear fuel had been extracted from the reactors and transferred into the on-site spent fuel pool. The facility then entered a long-term safe storage phase (SAFSTOR) until EnergySolutions recommenced decommissioning activities in 2010 after obtaining temporary license transfer approval from the Nuclear Regulatory Commission (NRC).
Contaminated materials dismantled during decommissioning were transported to EnergySolutions’ disposal facilities located in Utah and Texas for processing. Spent nuclear fuel was relocated into dry cask storage within a newly constructed Independent Spent Fuel Storage Installation (ISFSI) at Zion, completed by January 2015. Upon completion of the project, Exelon will assume responsibility for the site including the ISFSI.
The estimated cost for decommissioning after SAFSTOR was about $1 billion as of 2010, not accounting for possible additional city demolition fees. EnergySolutions initially forecasted profit margins between 15–20%, amounting to roughly $200 million; however, these projections were later adjusted downward to 5–10% following depletion of an $800 million trust fund. The company’s CEO later emphasized that strategic positioning was the primary benefit of undertaking the project rather than financial gain.
A small fire broke out on February 14, 2013, during decommissioning operations but was promptly extinguished without any radiation hazard.
The shutdown of the plant had a notably adverse economic effect on the City of Zion.
On November 8, 2023, the NRC declared the site released for unrestricted public use. Subsequently, on November 16, Constellation Energy Generation was designated as the licensee.
Reactors
| Unit 1 | Unit 2 | |
|---|---|---|
| Operating status | Permanently closed | |
| Reactor type | Pressurized water | |
| Reactor manufacturer | Westinghouse | |
| Generation capacity | 1,040 MWe | |
| Operational date | June 1973 | December 1973 |
| Closure date | January 1998 | |