Kernel formation marks progress towards TRISO restart

BWXT says it is the only US manufacturer of irradiation-tested uranium oxycarbide tristructural isotropic (TRISO) fuel using production-scale equipment. The company in October 2019 announced plans to restart and expand its existing TRISO production line to meet emergent client interests in Department of Defense microreactors, space reactors and civil advanced reactors.

TRISO particles contain a spherical kernel of enriched uranium oxycarbide surrounded by layers of carbon and silicon carbide, which contains fission products. Such fuel can withstand extreme heat and has very low proliferation concerns and environmental risks. BWXT has cooperated with the US Department of Energy on the development and qualification of TRISO-based fuel for over 15 years, the company said.

Late last year, BWXT announced it had started the production of the uranium solutions which are a starting material for kernel formation. It has now also demonstrated the capability to form and sinter the uranium oxycarbide fuel kernels that serve as a precursor to the TRISO coating process, the company said. Sintering is the process of applying heat and pressure to form the solid kernel.

With the completion of these activities, BWXT is now focusing on bringing two additional furnaces online (an additional sintering furnace and a coating furnace) to meet projected production demand before restart activities are complete.

BWXT Nuclear Operations Group, Inc (NOG) was last month awarded a contract from the US Department of Energy's Oak Ridge National Laboratory to manufacture TRISO nuclear fuel to support the continued development of the Transformational Challenge Reactor, which will use a core of uranium nitride coated fuel particles within an advanced manufactured silicon carbide structure.