United States successfully decommissioning commercial nuclear reactors

As of 2017, the United States has successfully decommissioned 10 commercial nuclear reactors, and another 20 are currently in various stages of the decommissioning process, the U.S. Energy Information Administration (EIA) recently reported.

Six U.S. commercial reactors have shut down since 2013, and eight more have announced plans to retire by 2025.

The retirement process for nuclear plants involves disposing of nuclear waste and decontaminating equipment. To fully decommission a plant, the facility must be deconstructed and the site returned to greenfield status, meaning it is deemed safe for reuse for purposes besides nuclear generation.

The United States uses two strategies for decommissioning nuclear plants.

The Decontamination (DECON) strategy is the faster of the two methods and takes at least seven years. It involves removing all fuel and equipment from the power plant for separate storage and decontamination.

Safe Storage (SAFSTOR), also called deferred dismantling, includes up to 50 years of containment followed by up to 10 years for decontamination.

It involves containing and monitoring the reactor and equipment until radiation drops to safe levels. This reduces the amount of radioactive material that must be disposed of, which can decrease the total decommissioning cost. It also allows more time to secure funds to pay for the decommissioning process.

Operators may also use a combination of the two methods.

A third method, known as ENTOMB, has been used outside of the United States. It involves permanently entombing the entire site in a structure designed to prevent radiation leaks.

Operators create a fund to pay for decommissioning during construction. According to the World Nuclear Association, approximately two-thirds of the total estimated cost of decommissioning all U.S. nuclear reactors have already been collected. However, when reactors retire earlier than planned, shortfalls in funding may occur, which can lead to additional expenses for electric ratepayers.

The U.S. decommissioning process is complete when the U.S. Nuclear Regulatory Commission (NRC) determines that the dismantlement has been implemented according to the plan submitted at the start of the decommissioning process. The site must also pass a final radiation survey.