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

15 May 2020

X-energy's TRISO-X fuel is to be irradiated at the Massachusetts Institute of Technology (MIT) Nuclear Reactor Laboratory's research reactor, the company has announced. Data from the irradiation testing will be used to support licensing of X-energy's Xe-100 and other TRISO-based reactors.

Cerenkov radiation creates a blue glow in the core of MIT's reactor (Image: MIT Nuclear Reactor Laboratory)

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.

Researched and written by World Nuclear News