Comparisons of Calculated and Measured Spectral Distributions of Neutrons from a 14-MeV Neutron Source Inside the Tokamak Fusion Test Reactor

A recent paper presented neutron spectral distributions (energy ≥0.91 MeV) measured at various locations around the Tokamak Fusion Test Reactor (TFTR) at the Princeton Plasma Physics Laboratory. The neutron source for the series of measurements was a small deuterium-tritium generator placed at various positions in the TFTR vacuum chamber. The results of neutron transport calculations are presented and compared with these experimental data. The calculations were carried out using Monte Carlo methods and a very detailed model of the TFTR and the TFTR test cell. The calculated and experimental fluences per unit energy are compared in absolute units. Significant areas of agreement and disagreement are found for different combinations of source and detector positions.