The influence of uncertainties in material properties, and the effects of dimensional scaling on the prediction of fusion structure lifetimes

The sensitivity of lifetime predictions for fusion reactor blanket structures is investigated by applying the Monte Carlo numerical technique. A structural computer code, Stress Analysis Including Radiation Effects (STAIRE), developed for the analysis of mirror fusion blankets, is used as a deterministic model for the prediction of the lifetime of semicircular coolant tubes. Uncertainties in material variables are treated as probabilistic inputs to the STAIRE code and output distributions are obtained.

Irradiation creep rates are shown to be sufficient for relaxation of swelling-induced stresses under most conditions. In absence of high stresses, the creep limit seems to be life-limiting, although this depends on the design-dependent swelling limit. In the case of the Mirror Advanced Reactor Study (MARS) blanket design, a lifetime of several hundred dpa is shown to be highly probable.