[en] The objective of the BEATRIX-II experiment is to design, conduct, and evaluate a Collaborative, in-situ tritium-recovery experiment in the Fast Flux Test Facility (FFTF). Continuous monitoring of candidate solid breeder material's performance with respect to thermal conductivity, temperature stability, and tritium release is to be accomplished up to extended lithium burnup levels under simulated blanket environments. 6 refs., 21 figs., 10 tabs