In-situ tritium release behavior and post-irradiation experiments of Li2TiO3 pebbles developed by freeze-drying method

Abstract

To assess the overall performance of potential solid tritium breeders for China Fusion Engineering Test Reactor (CFETR), we conducted a series of In-situ irradiation experiments on the in-pile tritium production and extraction experimental platform at China Mianyang Research Reactor (CMRR). In 2019, we performed an in-pile tritium release experiment (IPTRE-2) on Li2TiO3 (∼90 T.D%, 6Li 7.5%, ∼30.17 g) ceramic pebbles, which are the latest developed breeders. The Li2TiO3 pebbles were produced at the Institute of Nuclear Physics and Chemistry (INPC), China Academy of Engineering Physics (CAEP), using a freeze-drying method. This paper reports on the In-situ tritium release behavior and the post-irradiation experiments of Li2TiO3 pebbles. We established the relationship between tritium residence time and temperature, which can be expressed as lgτ=-0.74+1622.4/T. Our findings indicate that the Li2TiO3 pebbles remained structurally stable without fragmentation, but their color darkened and the degradation of mechanical properties due to the reduction of Ti in Li2TiO3.