Derivation of Nuclear Parameters for Delayed Neutron Detector Measurements for D-D and D-T Plasma Operation at the Joint European Torus

The first attempt to calculate the parameters for ²³⁸U and ²³²Th used in the analysis of delayed neutron counter measurements of the total neutron yield from deuterium-tritium (D-T) plasmas is described. The nuclear theory of systematics is employed, together with nuclear data from the literature. As a check on the methods used, the delayed neutron parameters were also calculated f or deuterium-deuterium plasma conditions; the resulting neutron yields agreed within ± 7% with the results obtained using the experimentally calibrated delayed neutron counter assemblies. After the calculations were completed, the first D-T plasma experiment was performed at the Joint European Torus (JET). Delayed neutron measurements were made using ²³²Th samples. The calculated delayed neutron parameters gave neutron yields that agreed within ±8% with those obtained with conventional activation methods, using iron and silicon samples.