Preliminary design of TRISO-X fuel plant completed

X-energy was announced by the DOE in October 2020 as one of two awardees - the other being TerraPower - to receive USD80 million each of initial cost-shared funding to build an advanced reactor demonstration plant that can be operational within seven years. DOE selected X-energy to deliver a commercial TRISO fuel fabrication facility and a four-module version of its Xe-100 reactor, which the company plans to site at Energy Northwest's Columbia nuclear power plant in Washington State. DOE will invest about USD1.23 billion in X-energy's project over the seven-year period.

X-energy's proprietary pebble-type fuel, TRISO-X, seals uranium particles in alternating layers of pyrolytic carbon and silicon carbide. This creates 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 TRISO-X facility will produce such fuel on a commercial scale. In addition to supporting the deployment of the Xe-100 in Washington State, the facility will also be capable of supporting other Xe-100 sites and a variety of customers needing other fuel forms of TRISO.

In March 2018, Centrus signed a contract with X-energy to complete a conceptual design of the TRISO-X facility, which itself followed a 2017 Memorandum of Understanding on the development of a fabrication facility to provide TRISO fuel for X-energy's Xe-100 high temperature gas-cooled modular reactor and other advanced reactors.

X-energy subsequently contracted with Centrus in November 2018 to support the facility's preliminary design work. Under that agreement, Centrus has provided X-energy with technical expertise and resources to support preliminary facility design, including detailed nuclear criticality safety analysis, infrastructure design, and balance of plant support systems, as well as initial work on a licence application for the facility. Centrus also provided facility space to X-energy at Centrus' Technology and Manufacturing Center in Oak Ridge, Tennessee, where X-energy and Centrus employees are working together on the project.

Under a new contract supported by the DOE Office of Nuclear Energy Demonstration Tier of the Advanced Reactor Demonstration Program, X-energy will finalise the detailed design of a commercial-scale TRISO-X fabrication facility.

"Completion of preliminary design is a key step in our commercialisation efforts toward a first-of-a-kind Nuclear Regulatory Commission regulated Category II facility capable of handling HALEU for the coming fleet of advanced reactors," said Pete Pappano, president of X-energy subsidiary TRISO-X.

"Centrus is pleased to be part of X-energy's team in designing and developing this next generation fuel fabrication facility," said Larry Cutlip, President of Centrus subsidiary American Centrifuge Operating. "We greatly value this partnership and look forward to continuing this important work to bring TRISO-X fuel to market."

The Xe-100 is a Generation IV advanced reactor design which X-energy says is based on decades of high-temperature gas-cooled reactor operation, research and development. Designed to operate as a standard 320 MWe four-pack power plant or scaled in units of 80 MWe, it is engineered to deliver reliable and load-following grid-scale power to electricity systems and to pair seamlessly with renewables. At 200 MWt of 565°C steam, the Xe-100 is also suitable for other power applications including mining and heavy industry.

Last month, Cameco and X-energy entered a non-binding and non-exclusive Memorandum of Understanding to explore possible areas of cooperation to support the potential future deployment, fuelling and servicing of Xe-100 reactors in Canada and the USA. The Xe-100 has also been selected by Ontario Power Generation as a potential technology for an SMR which it aims to have in operation at its Darlington site as early as 2028.