An Additive Manufacturing Technology for the Fabrication and Characterization of Nuclear Reactor Fuel

Phase I of this Small Business Innovation Research (SBIR) project was conducted under Department of Energy's (DOE) Advanced Technologies for Nuclear Energy (NE) topic 19(b), entitled “Advanced Technologies for the Fabrication, Characterization of Nuclear Reactor Fuel”. Phase II and IIA preserve the two-pronged vision and goals outlined in Phase I. First, this project seeks to provide a technological answer to DOE-NE's needs, specifically in advancing the performance of accident tolerant fuel/cladding concepts in light water reactors (LWR) and TRISO fuel fabrication techniques. Second, this project will contribute to the advancement of the DOE-NE's long-term con-gressional mandate to enhance current reactor safety, reliability, and life, reduce nuclear proliferation risks, improve the affordability of new nuclear reactors in part through more sustainable nuclear fuel cycles. The present proposal builds upon cross-cutting advances in the following fields:(i) additive manufacturing (AM),(ii) micro-electromechanical-systems (MEMS) design, (iii) micro- and nano-scale fabrication and (iv) ceramic matrix composites (CMCs). These advances are employed in the development of novel Silicon Carbide fiber (SiCf) rein- forced Silicon Carbide matrix (SiCm) CMC fuel structure. They allow the integration of the full functionality of TRISO fuel at a microscopic level encapsulated into SiC filaments, which are in turn embedded into a SiCm to form a fully integrated nuclear fuel and cladding structure. This innovation merges the functionality of TRISO fuels and cur- rent fuel rods into a single element. This novel fuel structure offers a passively safe, integral and energy efficient Silicon Carbide alternative to Zircalloy fuel rods assemblies in LWR with little change to reactor control architecture. The proposed fuel structure's elevated temperature capability and chemical inertness implies lower amounts of and easier to store generated nuclear waste. Finally, micro-encapsulation of fissile material into a CMC would make fissile material retrieval extremely difficult, thereby lowering the risk of nuclear proliferation. The Phase II of this project was focused on the scalability of nuclear-technology bound SiC fibers. For a commer- cially viable “fuel-in-fiber” concept, the core SiC fibers must be manufacturable in large quantity at competitive prices. With this objective most behind us, we now propose to focus on the value added processes that gives the advanced fuel concepts made using additive manufacturing its full force.