In-Situ Tritium Recovery from Li2O Irradiated in Fast Neutron Flux - BEATRIX-II Initial Results

Abstract

The BEATRIX-II experiment in FFTF is an in-situ tritium recovery experiment to evaluate the tritium release characteristics of Li{sub 2}O and its stability under fast neutron irradiation to extended burnups. This experiment includes two specimens: a thin annular specimen capable of temperature transients and a larger temperature gradient specimen. During the first 85 days of the operating cycle of the reactor, the tritium recovery rate of a temperature transient capsule was examined as a function of temperature, gas flow rate, gas composition and burnup. Temperature changes in the range from 525 to 625{degree}C resulted in decreasing tritium inventory with increasing temperature. Lower gas flow rates resulted in slightly lower tritium release rates while gas composition changes affected the tritium release rate significantly, more than either flow rate or temperature changes. Three different sweep gases were used: He with 0.1% H{sub 2}, He with 0.01% H{sub 2}, and pure He. Decreasing the amount of hydrogen in the sweep gas decreased the steady-state release rate by as much as a factor of two. A temperature gradient capsule is more prototypic of the conditions expected in a fusion blanket and was designed to provide data that can be used in evaluating the operationalmore » parameters of a solid breeder in a blanket environment. The operation of this canister during the first 85 EFPD cycle suggests that Li{sub 2}O is a viable solid breeder material. 9 refs., 5 figs., 3 tabs.« less