The US Nuclear Regulatory Commission (NRC) has accepted an application from X-Energy Reactor Company subsidiary, TRISO-X, for a fuel fabrication facility which will use high-assay low-enriched uranium (HALEU). Anticipating the decision, TRISO-X, in October, broke ground and began construction of the facility in Oak Ridge, Tennessee. The TRISO-X Fuel Fabrication Facility (TF3) is expected to create more than 400 jobs and attract investment of approximately $300 million. TF3 is set to be commissioned and operational by 2025.
In a letter to TRISO-X, NRC said that the agency had "determined that the application provides sufficient information to proceed with a detailed technical review" and further "established a 30-month review schedule to be completed by June 2025."
TRIstructural ISOtropic (TRISO) fuel comprises three layers of carbon and ceramic materials that surround kernels or balls of high-assay low-enriched uranium (HALEU) fuel. The coatings have uniform characteristics in all directions. Fuel particles, each the size of a poppy seed, are enriched to a level four times higher than fuel used in most of today’s commercial nuclear reactors. The coatings retain fission products, making each particle its own containment system. DOE says TRISO is “the most robust nuclear fuel on earth”.
In 2020, the DOE selected X-energy for their Advanced Reactor Demonstration Program (ARDP) to receive up to $1.2 billion of federal cost-shared funding to develop, license, build, and demonstrate operational advanced reactors by the end of the decade. The TRISO-X nuclear fuel produced in the Oak Ridge TF3 will be used in X-energy’s Xe-100 high-temperature gas reactors, which are expected to be operational by 2028. Since 2016, TRISO-X has operated a pilot-scale nuclear fuel fabrication facility at the Oak Ridge National Laboratory (ORNL) to further develop its TRISO-X fuel and support the Xe-100 reactor design.
“TRISO-X will be the nation’s first commercial scale facility dedicated to fuelling reactors that require high-assay low-enriched uranium TRISO particles,” said Dr Kathryn Huff, Assistant Secretary for Nuclear Energy earlier this year. “It’s a job creator and an advanced reactor enabler that will help fuel a transition to a net-zero economy.”
However, TRISO fuel development is also continuing at several of the US national laboratories. Earlier in December, BWX Technologies (BWXT) began production of TRISO nuclear fuel intended for the first US microreactor (Project Pele). Under a $37 million award from Idaho National Laboratory (INL), BWXT will manufacture a core for Project Pele, TRISO fuel for additional reactors and coated particle fuel for NASA. The fuel will be down-blended from US government stockpiles of HALEU and fabricated into TRISO fuel at BWXT’s facility in Lynchburg, Virginia. BWXT facilities are the only private US facilities licensed to possess and process highly enriched uranium.
BWXT has expanded its specialty coated fuels production manufacturing capacity through previously announced awards funded by the Department of Defense (DOD) Operational Energy Capabilities Improvement Fund Office and NASA and programme management provided by DOD’s Strategic Capabilities Office.
Also in December, US-based Kairos Power signed an agreement to produce TRISO fuel pebbles for the Hermes demonstration reactor at Los Alamos National Laboratory’s (LANL’s) Low Enriched Fuel Fabrication Facility (LEFFF) in New Mexico. The partnership with Los Alamos is facilitated by the Laboratory’s proximity to Kairos Power’s testing and manufacturing facility in Albuquerque.
In August, Ultra Safe Nuclear Corporation (USNC) announced the opening of its Pilot Fuel Manufacturing (PFM) facility in Oak Ridge, located in the East Tennessee Technology Park (ETTP), to produce the first fuel for testing and qualification for use in its Micro Modular Reactor (MMR). The PFM contains full scale production equipment for TRISO particles, and UNSC’s FCM Fuel. The privately owned facility is located on the Manhattan Project site previously occupied by the K-25 gaseous diffusion plant. USNC produced its first uranium bearing TRISO particles earlier this year.
Nine of the ten advanced reactor designs selected for funding under ARDP, including two planned demonstration reactors – Terrapower’s Natrium and X-energy’s XE-100 High Temperature Gas-Cooled Reactor – will rely on HALEU, which is enriched to nearly 20% with uranium-235 compared with the 5% used in power reactors. However, the US is facing problems as domestic production is limited and previous supplies from Russia are no longer available.
Congress authorised the HALEU Availability Program in 2020 and eventually appropriated $45 million to “expedite” HALEU fuel-processing capacity. The Inflation Reduction Act added another $700 million and DOE has also established a HALEU consortium to support activities to secure a domestic supply of the fuel. In December, DOE also signed a contract with Centrus Energy’s subsidiary, American Centrifuge Operating (ACO), to pioneer production of HALEU at its facility leased from DOE in Piketon, Ohio. However, Centrus Energy Corp is expected to be producing less than 1 metric ton by 2023. Terrapower has postponed its Natrium plans by two years because of the HALEU shortage. It remains to be seen whether the TRISO projects will be affected by this.
Image: Artist's rendering of the TRISO-X Fuel Fabrication Facility in Oak Ridge, TN, USA (courtesy of US Department of Energy)
