Feasibility study on tritium recoil barrier for neutron reflectors of research and test reactors

•Al, Ti, V, Ni and Zr are selected as the candidate tritium recoil barrier materials.•20∼40 μm thickness is required depending on the material to reduce by 3 orders.•Impact on the effective multiplication factor is about 0.2 % at most.•Activities, fabrication and usage experiences, suggests the selection of Al as the first candidate. Tritium release into the primary coolant of the JMTR and the JRR-3 M had been studied, and it is found that tritium recoil release from the chain reaction of beryllium neutron reflectors is dominant. To prevent the tritium recoil release, Al, Ti, V, Ni and Zr are selected as the candidate tritium recoil barrier materials in this feasibility study. It is clear that 20∼40 μm thickness is required depending on the material to reduce by 3 orders, and that an impact on the effective multiplication factor is about 0.2 % at most. Total evaluation including the activities, fabrication and usage experiences, suggests the selection of Al as the first candidate may have the least development risk as the tritium recoil barrier.