Although nuclear energy is often touted as a “pollution-free energy source,” that it is really not accurate. Not only do nuclear power plants constantly spew out minute amounts of radiation in the steam they emit, nuclear power also produces thousands of tons of spent nuclear fuel or so-called “nuclear waste.”

According to the U.S. Energy Information Administration, nuclear waste is piling up all across America, with the total amount of nuclear waste in the U.S. today topping 70,000 metric tons.

More on spent nuclear fuel storage in the U.S.

Nuclear Fuel

Nuclear waste is clearly becoming a major problem in the U.S. today. The most recent U.S. Nuclear Fuel Data Survey data indicate a total of 241,468 fuel assemblies, totaling up to around 70,000 metric tons of uranium, are being stored at 118 commercial nuclear reactors in the U.S. This spent nuclear fuel results from operations at nuclear power plants from from 1968 through June 2013.

Of note, Illinois, Pennsylvania, and South Carolina have the highest amount of stored nuclear material, with over 4,000 MTU in each state.

The EIA report highlights that nuclear reactors are fueled by fissionable material (typically uranium), that is enriched and made into fuel rods. The fuel rods are linked together to form fuel assemblies, which are then put in the reactor core and irradiated. Fuel assemblies can be used in nuclear reactors for a number of cycles, with each cycle somewhere between 18 and 24 months. Following the cycle of multiple irradiations, the spent fuel assemblies are highly radioactive and high security storage is required.

Radioactive Spent Nuclear Fuel Piling Up In US: EIA

Keep in mind that there are two common storage methods used for spent fuel: spent fuel pools and dry cask storage. Spent fuel pools means storing spent fuel assemblies in pools of cold water that cool the assemblies as well as provide some protection from radiation. Dry cask storage is when spent fuel previously cooled in a spent fuel pool (at least three years) to be placed inside a metal cask filled with an inert gas. The casks has several layers around it, typically made of concrete and steel, to prevent radiation from leaking out.

The EIA notes that standards for spent nuclear fuel storage are set by the U.S. Nuclear Regulatory Commission.

Of interest, close to two-thirds of total spent nuclear fuel comes from pressurized-water reactors, and around one-third from boiling-water reactors. Almost all spent nuclear fuel is stored on-site at the nuclear power plants in the U.S. Although it is not done anymore because of the risks involved, around 1% of the total amount of U.S. nuclear waste was transported from the nuclear plants to off off-site storage facilities.