The Clinton Power Station nuclear reactor, about 34 miles from Champaign, generates enough energy to provide heating and electricity for over 800,000 of Illinois’ almost 13 million homes.

At the moment, its license is set to expire in 2027, which could force a reactor shutdown if not renewed, but efforts are already being made to prevent that as the plant has already applied for a 20-year extension to avoid this fate.

The plant is one of seven constructed in Illinois and one of six that are still operating. Together, Illinois has eleven operating reactors, which is the most of any state in the nation.

Its license renewal application was written by the staff of Constellation, the power company that owns the physical plant; this same staff operates it, maintains it and reports whenever something breaks down. 

The application’s primary purpose is to analyze what parts of the plant, known as active components, such as water pumps, and passive components, like water tanks, need to be addressed to keep the whole facility functioning and how. These can range from one-time inspections to replacement to various “aging management programs” prescribed by the operator’s manual.

“It’s effectively a review of the plant’s structure, what’s changed over time, and what will need to be done to keep it safely running for the foreseeable future,” former U.S. Nuclear Regulatory Commission (NRC) inspector Lawrence Criscione said in an interview. “It’s supposed to cover everything that could affect the plant as a result of aging, but only aging. The Commission can’t demand that a plant report the effects of climate change on operation, for instance, nor anything else that isn’t just affected by time.”

The nearly 1,400-page document contains analyses of every instrument, device, tool, light, and pipe installed in the facility. These include physical descriptions, such as the reactor vessel being cylindrical, and a breakdown of form and function. For example, it can describe materials like reinforced concrete lined with steel and what they do, such as containing the effects of a radiation leak.

To ensure that everything written within the report matches the actual state of the power plant, the commission employs on-site inspectors, two for every power plant, to act as outside observers. 

They oversee the plant’s operations, walking through the facility daily to ensure that the equipment and employees operate capably. They report any issues or violations on a scale of one to four, with one being the most severe and four being the least, and assign them according to regulations. 

“The daily inspections are specifically meant to act as spot checks on any given plant, to make sure that it is regularly fulfilling its safety obligations,” Criscione said.

Additionally, there are regularly scheduled inspections, conducted by regional inspectors, designed to test specific, critical elements of the plants. These are less frequently done. Clinton power plant, for instance, only had eight in all of 2023. 

The application is given to the NRC, which reviews the technical aspects of the report. While it reviews management programs for every part of the plant, the commission is most interested in the passive components. 

When active components like water pumps start to break down, they can be caught easily when someone tries to use them. However, when passive components like a water tank begin to erode from the inside out, the damage can go unnoticed until the day the tank explodes. 

Therefore, the commission gives special attention to the unseen and unnoticed parts of the reactor during this review process.

Constellation did not respond to requests for comment on the application’s content, the current condition of the Clinton power plant, or the current condition of all nuclear power plants in the state.

Even as Illinois power plants try to complete this process, the state government’s eyes are already turning away from large-scale power plants. Despite lifting the moratorium on building new nuclear reactors in 2023, the state remains uninterested in covering the large startup costs of the plants, and doubly so regarding potentially subsidizing them. 

Instead, state officials have been looking at a new field for nuclear power: small modular reactors.

Representing one of the nuclear industry’s next steps, these reactors are scaled-down versions of the nuclear fission generators found in conventional power plants and more cost-efficient versions of the variety found in nuclear submarines. 

They require less funding to construct, less manpower to maintain and less space to operate. However, these benefits come at the cost of the reactors’ overall generation capacity, generally operating at less than half the power of a conventional reactor. 

So far, only three small modular reactors have been built, two in China and another aboard a Russian icebreaker ship, but efforts to create more are ongoing. At least 56 designs are being developed worldwide, 18 of which are the property of reactor design corporations in the United States.

The University of Illinois is also interested in constructing a nuclear microreactor on its campus — an even smaller model that, depending on the model specifications, only produces between 5% to 10% of the a full-scale plant does. The difference is significant, but the benefit is they are generally small enough to fit onto a semi-truck and can be shipped from an off-site manufacturer to its destination.

Illinois is very interested in developing nuclear energy in the state, both as a step to achieve its environmental goal of eliminating coal and gas generator emissions by 2045 and as a result of the power-soaking artificial intelligence (AI) industry. 

“The new interest in building new reactors and re-opening old ones is absolutely the result of AI,” Criscione said. “They’re looking at reopening the Palisades power plant in Michigan, they’re looking at Three Mile Island. All of that is because of demand for AI.”