Analysis of Tritium Production in a Sphere of ⁶LiD with Oralloy Core Irradiated by 14-MeV Neutrons

Tritium production in a sphere of ⁶LiD with an Oralloy core irradiated by a central source of 14-MeV neutrons has been calculated and compared with experimental measurements. The experimental assembly consisted of an Oralloy sphere surrounded by three solid ⁶LiD concentric shells with ampoules of ⁶LiH and ⁷LiH located in several positions throughout the assembly. The Los Alamos Monte Carlo Neutron Photon Transport Code (MCNP) was used to calculate neutron transport throughout the system and tritium production in the ampoules. The MCNP calculations were three-dimensional and employed ENDF/B- V cross sections. The overall experimentally observed-to-calculated ratios of tritium production were 0.996 (±2.5%) in ⁶LiH ampoules and 0.903 (±5.2%) in ⁷LiH ampoules. Tritium production in a sphere of ⁶LiD without an Oralloy core has been reanalyzed using ENDF/B-V cross sections, and the results are reported. The reanalyzed observed-to-calculated values of tritium production were 1.053 (±2.1%) in ⁶LiH and 0.999 (±2.1%) in ⁷LiH. The foregoing several uncertainties do not include an estimated <6% systematic error in the observed values.