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NNSA reaches milestone in developing new nuclear fuel for U.S. high-performance research reactors

Qualification of the new high-density fuel will allow for the conversion of U.S. high performance research reactors, such as the Advanced Test Reactor located at Idaho National Laboratory, shown here.

NNSA is leading the charge to develop and qualify a new fuel that will enable the conversion of high-performance research reactors in the United States currently using highly enriched uranium (HEU).

This month, NNSA presented the U.S. Nuclear Regulatory Commission (NRC) with a preliminary report on uranium-molybdenum (U-Mo) monolithic fuel. The report contains data about the performance of the new fuel in a reactor and how it holds up under a variety of conditions.

“The report will help the NRC understand the science that will support converting these reactors to low-enriched uranium (LEU) fuel,” said Jessica Halse, associate assistant deputy administrator for NNSA’s Material Management and Minimization program. “Once they’ve read it, the regulators can ask NNSA questions that will help to finalize future tests of the fuel and complete the final Fuel Qualification Report.”

This report is a notable achievement in the effort to switch the six HEU-fueled high-performance research reactors in the United States to LEU, and marks a key milestone in NNSA’s program to develop a fuel that cannot be used in a nuclear weapon.

Due to their challenging operating conditions, converting these reactors from HEU to LEU fuel is not easy. The process could take many years, but developing a new LEU fuel is essential to ensuring optimal performance.

These reactors perform unique science and are a critical part of the U.S. nuclear complex. However, combined they use 200 kilograms of HEU each year – enough material for at least eight weapons.

When the final report is approved by the NRC, the individual reactors can submit documentation to the NRC demonstrating that the new fuel performs safely in their specific conditions. This is the final step before the reactors convert to LEU fuel.

Once the NRC qualifies this new fuel, it will be used to convert some of the most innovative and critical reactors in the United States.

The six U.S. high-performance research reactors pending conversion include:

  • Advanced Test Reactor at the Idaho National Laboratory, Idaho
  • Advanced Test Reactor Critical Assembly at the Idaho National Laboratory, Idaho
  • High Flux Isotope Reactor at the Oak Ridge National Laboratory, Tennessee
  • Massachusetts Institute of Technology Reactor in Cambridge, Massachusetts
  • National Bureau of Standards Reactor in Gaithersburg, Maryland
  • University of Missouri Research Reactor in Columbia, Missouri

As part of its vital nuclear nonproliferation effort, 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 about NNSA’s Material Management and Minimization mission.