Centrus Energy Corporation and X-energy are working on the preliminary design of a facility dedicated to the fabrication of advanced nuclear fuels. The new fuels will be based on the uranium oxycarbide tristructural isotropic (TRISO) fuel form developed by X-energy.
In 2017, a memorandum of understanding (MoU) was signed for the development of a fuel fabrication facility intended to create TRISO fuels to be used in the X-energy Xe-100 high temperature gas-cooled modular reactors and other advanced reactors. A contract was signed last March to build on the 2017 MoU and develop a conceptual design for the fuel fabrication facility. A new services contract has just been signed.
According to the new services contract between Centrus and X-energy, Centrus will contribute technical expertise and resources for the preliminary facility design. This will include detailed nuclear criticality safety analysis, infrastructure design, balance of plant support systems, and initial work on a license for the new fuel fabrication facility. Centrus will also make space available to X-energy at the Centrus Technology and Manufacturing Center in Oak Ridge, Tennessee.
Daniel Poneman is the president and chief executive officer of Centrus. He said, “We see great promise in this market and believe the advanced TRISO fuel to be produced in this facility will offer an attractive and competitive solution to power advanced reactors around the world.”
Pete Pappano is the principal investigator and vice president of fuels production at X-energy. He said that the working agreement between Centrus and X-energy had already produced a conceptual layout of the of the TRISO-X Fuel Fabrication Facility. He added, “With this new agreement, X-energy and Centrus will complete the preliminary and final designs of the TRISO-X Facility, positioning the companies to be first to market in the sector of high assay low enriched uranium (HALEU) TRISO-based fuel for advanced reactors and, potentially, accident tolerant fuel for the existing light water reactor fleet.”
The X-energy Xe-100 is a seventy-five megawatt reactor. X-energy intends to bundle four of them together in a commercial “four-pack” arrangement to produce three hundred megawatts. The TRISO fuel “pebbles” each have a center of enriched uranium carbide. This core is embedded in carbon and ceramic layers which prevent the release of radiation. The layers surrounded the core of each pebble function as a containment system. The graphite around the pebbles moderates the nuclear reaction. It is impossible for these pebbles to melt down.
Last year, at the Oak Ridge National Laboratory, X-energy created its first fuel pebbles using un-enriched natural uranium. Earlier this year, X-energy was awarded four and a half million dollars for the U.S. Department of Energy to match their own investment of four and half million dollars to design a commercial scale fuel fabrication facility. A license application is to be submitted to the Nuclear Regulatory Commission by the middle of 2021.
Harlan Bowers is the president of X-energy. He said last March that he hopes that the new fuel will be in production by 2025. The fuel would then be available to load into new advanced reactors such as the Xe-100 which are expected to be ready in the late 2020s.