ORNL Achieves Milestone in Nuclear Fuel Recycling

Researchers at Oak Ridge National Laboratory (ORNL) in Tennessee have succeeded in making mixed-oxide pellets from recycled spent nuclear fuel in a process that does not produce a separate plutonium stream. According to an ORNL statement released in July, conventional reprocessing methods pull plutonium separately from the spent-fuel mix, creating a proliferation concern since the fissionable plutonium could be diverted for use in a nuclear weapon.

In the ORNL project, a co-extraction process is first used to separate a mixture of plutonium, neptunium, and uranium from the rest of the spent nuclear fuel. Then, a new technique called modified direct denitration converts the nuclear material from a solution in nitric acid to a solid oxide powder. Traditionally, the nuclear material, or actitudes, taken out of a nitric acid solution are in a glassy structure that has to be processed with steps such as milling and grinding. The solid oxide powder from the modified direct denitration process can be converted directly to fuel pellet form.

A June 12 article from the Scripps Howard News Service reported that Jeff Binder from ORNL's Nuclear Science and Technology Division characterized the successful process as "a significant milestone." Binder further explained that the first recycled fuel pellets produced at ORNL would be suitable for a lightwater nuclear reactor, such as those used for commercial power generation in the United States, noting, "In upcoming tests, lab researchers plan to increase the amount of fissionable material to a level that would be of use in other types of reactors."