US-based X-energy has reached an agreement with the Massachusetts Institute of Technology (MIT) for the Institute's Nuclear Reactor Laboratory to use its research reactor to irradiate X-energy's TRISO-X fuel.

The irradiation process will provide data to support licensing X-energy's Xe-100 and other TRISO-based reactors.

X-energy's reactors use tri-structural isotropic (TRISO) particle fuel that seals uranium particles in a protective coating, which makes meltdown impossible and retains the waste inside.

TRISO nuclear fuel particles, used as fuel for high-temperature reactors, were first developed more than 60 years ago. Each particle of fuel contains a kernel of uranium oxide/carbide, encased in carbon and ceramic layers which prevent the release of radioactivity. These are then fabricated into either graphite 'pebbles' or hexagonal graphite blocks.
For more than three years, X-energy has manufactured a proprietary version, TRISO-X.

"This is an incredible milestone for the X-energy team as we will now have irradiation tested fuel for the first time," said Dr Pete Pappano, vice president of Fuel Production at X-energy. The project's data will enable licensing for the Xe-100 reactor, an advanced small modular nuclear reactor design.

X-energy is the only US company producing TRISO fuel and is currently engaging with the Department of Energy (DOE) to further develop and design TRISO-X.

 X-energy has won DOE, Department of Defense (DOD), and NASA contracts totalling more than $100 million to develop nuclear fuels and build innovative nuclear reactor concepts.

Earlier this year, X-energy was one of three companies selected by DOD to begin design work on a mobile nuclear reactor prototype. The others were BWX Technologies and Westinghouse Government Services.

MIT operates the 6MW MITR reactor at its Nuclear Reactor Laboratory. The light-water cooled and moderated, heavy-water reflected reactor was built in 1956 and upgraded in 1974. It produces an average core power density of about 70kW per litre.