X-energy TRISO-X fuel to be irradiated at MIT

Irradiation of fuel is scheduled to take place later this year, the Maryland-based company said yesterday. "This research with MIT will provide confirmation of the performance and quality of our TRISO-X fuel," X-energy CEO Clay Sell said.

Tri-structural isotropic - TRISO - nuclear fuel particles, used as fuel for high-temperature reactors, were first developed over 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.

X-energy's proprietary pebble-type fuel, TRISO-X, seals uranium particles in a protective coating, which the company says eliminates the meltdown risk associated with traditional nuclear plants. It has been manufacturing TRISO-X for over three years, and is, to date, the only US company actively producing TRISO fuel.

The company's Vice President of Fuel Production, Pete Pappano, described the first-time irradiation testing as an "incredible milestone" for the team. Data from the project would enable licensing for the company's Xe-100 small modular reactor, he said. The 200 MWt (75 MWe) SMR will use TRISO-X fuel.

X-energy was one of three companies - the others being BWX Technologies Inc and Westinghouse Government Services - selected earlier this year by the US Department of Defense to begin design work on a mobile nuclear reactor prototype.

MIT Nuclear Reactor Laboratory's 6 MW MITR reactor, built in 1956 and upgraded in 1974, is the second largest university research reactor in the USA. The light-water cooled and moderated, heavy-water reflected, nuclear reactor produces an average core power density of about 70 kW per litre.