National Nuclear Security Administration

NNSA and MIT reach pivotal step in process to convert research reactor to LEU

December 20, 2017

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NNSA is working to qualify a new LEU fuel that will be customized to the unique design of the MIT reactor core. (MIT photo)

NNSA and the Massachusetts Institute of Technology (MIT) submitted a preliminary safety analysis report to the Nuclear Regulatory Commission (NRC) on Dec. 6, reaching a critical step in the process to convert the university’s research reactor from highly enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel.

NNSA works with civilian research reactors that use weapons-usable material such as HEU to convert their fuel to LEU, a material that poses no proliferation risk. In some cases, a new LEU fuel needs to be developed – a process that can take many years.

 “MIT’s outstanding commitment towards this challenging, yet very important, LEU conversion project is exemplified by the completion of this important milestone,” said Jeff Chamberlin, director for NNSA’s Office of Conversion. “We look forward to continuing our strong cooperation with MIT, as well as with other civilian research reactors around the globe, to carry out the work required to allow conversion to LEU fuel.”

NNSA and experts from the national laboratories are working to design a new fuel that will enable the MIT reactor, as well as others, to convert to LEU. MIT’s reactor is one of five high-performance research reactors in the United States that require high-density LEU fuel for optimal performance.

The preliminary safety analysis report shows the NRC that the reactor can safely operate using the new LEU fuel. 

Over the next few years, based on feedback from the NRC’s review of the report and from the ongoing tests of the LEU fuel, MIT will submit a final safety analysis report. Once approved by the NRC, MIT would convert the reactor to the qualified LEU fuel.

Conversion of the MIT reactor will eliminate the transit of approximately 3 kilograms of HEU fuel per year.

NNSA works with civilian research reactors and medical isotope production facilities domestically and internationally to minimize, and, when possible, eliminate weapons-usable nuclear material around the world.

Learn more about NNSA’s Material Management and Minimization program.