Burn performance of fast ignited, tritium-poor ICF fuels

The potentials of fuels that are predominantly deuterium, with a small tritium content (tritium-poor deuterium), are examined in the context of the inertial confinement fusion (ICF) scheme known as 'fast ignitor', which is based on external heating of a portion of a precompressed target. For this purpose, the burn performance of compressed spheres of pure or nearly pure deuterium with an off-centre deuterium-tritium (DT) seed, ignited by an ultrapowerful external beam, has been studied using two dimensional (2-D) numerical simulations. The dependences of the fuel energy gain on the fuel mass and energy, and on the tritium fractional content F-T, have been studied; Limiting gain curves have been obtained for fixed values of F-T and of the isentrope parameter a. It is found that assemblies with F-T = 0.5-1%, fuel mass m approximate to 20 mg, compressed at density rho approximate to 1000 g/cm(3), can achieve tritium self-sufficiency (i.e. net tritium production). At alpha approximate to 1.5, the corresponding fuel energy at ignition is of the order of 1 MJ and the fuel energy gain can be about 1000. The potentials of tritium-poor configurations are also compared with those of equimolar DT fuels with different ignition configurations.