Preliminary Neutronics Design And Analysis For Accelerator Driven Subcritical Thorium Burning Reactor

Featured with rich reserve, good fuel breeding capability, less transuranic production, and anti-proliferation, thorium based nuclear energy is a great potential option for nuclear development. Mainly because of the fertile property of thorium, currently thorium based nuclear technology is non-sufficiently developed. Advantaged by hard spectrum and more additional neutrons as benefits for external source and sub-criticality, Accelerator Driven Subcritical System (ADS) is suitable for thorium fuel. For combining the advantages of thorium with ADS, the concept of Accelerator Driven Subcritical Thorium Burning Reactor (CLEAR-Th) was proposed, and neutronics design and analysis were performed in this paper.Main constraints and objectives were proposed including safety margin limit, thermal power output, proton beam current and burnup. Referring to investigations on relative ADS designs, a preliminary design was provided on spallation target, fuel, coolant, structural materials and core layout:the core is fueled with thorium-plutonium mixes oxide and cooled by LBE; T91steel is used as structure material; keff is set as0.98at the beginning of fuel cycle. Optimizations on percentage of fissile materials, ratio between height and radius of fuel region and thickness of radial reflector were carried out by using multi-functional neutronics simulation system SuperMC.Performance of CLEAR-Th was analyzed on burnup, relativity coefficients and fuel cycle management, showing that the key design objective of stable energy production was met. Based on this design, stable closed Th-U fuel cycle can be achievable. CLEAR-Th is also featured with low production of long-lived minor actinides and good inherent safety. An attractive option for thorium based nuclear energy system can be provided by CLEAR-Th.