NRC Gives Thumbs-Up to Spent Nuclear Fuel Technology

In a report with important implications for the future of Argonne’s nuclear technology programs, a national panel of scientists gave a thumbs-up to continued use of an Argonne technology for treating spent nuclear fuel. The Argonne process could recover useful uranium from certain spent DOE fuel, while saving taxpayers millions of dollars in disposal costs. In addition to recycling the valuable uranium, the process keeps the short-lived and long-lived waste products together, which disables the plutonium for use in weapons.

After tracking the progress of Argonne’s now completed electrometallurgical treatment program for three years, the National Research Council (NRC) concluded that “no technical barrier” exists to further use of the tech-nology.

“The U.S. Department of Energy subsequently selected our technology for use in treating 26 metric tons of sodium-bonded fuel from Experimental Breeder Reactor-II,” said Bob Benedict, who manages the development of Argonne’s electrometallurgical technology. Experimental Breeder Reactor-II was a research reactor that was shut down in 1994. DOE may also select the technology for use on an additional 34 metric tons of sodium-bonded fuel from another reactor.

Argonne developed electrometallurgical treatment specifically for sodium-bonded fuel. This is a metallic fuel that is bonded to its outer casing by the element sodium. “But sodium reacts chemically with air and water,” Benedict said, “so the fuel has to be treated to remove and neutralize the sodium before it can be disposed of.” The process converts the sodium into sodium chloride, common table salt.

Argonne’s electrometallurgical process removes the useful uranium from the fuel, significantly reducing the amount of waste. The waste takes one of two forms: a ceramic or a metal alloy. The ceramic waste, which is impervious to air and water, is produced by heating and compressing a composite of borosilicate glass and zeolite, a mineral that binds the fission products within its structure. The NRC report cites the expected performance of this ceramic under repository conditions as “comparable to that of borosilicate, high-level-waste glass.”

The metal alloy is made from the remains of the stainless-steel cladding that encased the fuel while it was in the reactor and noble or “non-reactive” metals produced as a byproduct of the fission reaction.

The NRC report is significant beyond Argonne, Benedict said, because an agreement between former Idaho Governor Phil Batt and the Department of Energy requires all DOE spent fuel, including that at the Argonne-West site— home to Experimental Breeder Reactor-II—to be out of the state by 2035. Argonne’s fuel must be treated to stabilize it before it can leave the state.

The NRC panel also recommended that DOE consider the electrometallurgical treatment technology for use beyond sodium-bonded metallic fuel.

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