Model for the prediction of Nb3Sn critical current as a function of field, temperature, strain, and radiation damage.

摘要

Conductors designed for fusion machines must operate at high fields, under large mechanical loads, and in a high neutron flux. Present designs favor the use of Nb(sub 3)Sn with force-cooling by supercritical helium to extract large nuclear and ac loss heat loads. Consequently, the magnet designer must have a good knowledge of the critical current of the superconductor as a function of field, strain, temperature, and radiation damage. Expanding on work by Hampshire, et al. and Ekin, combined with radiation damage studies of Nb(sub 3)Sn, we express the critical field (B(sub c20)) as function of temperature, strain and damage energy (E(sub d)). Similarly, the zero-field critical temperature (T(sub c0)) is expressed as a function of strain and damage energy. The expressions of B(sub c20) and T(sub c0) are combined into a functional form that allows an accurate and consistent estimate of the critical current density at the operating conditions of fusion magnet conductors. 9 refs., 4 figs.