Reactor-Fuel-Independent Reactivity Determinations

Curves for the reciprocal asymptotic period versus positive reactivity for ENDF/B-IV delayed neutron data are presented for ²³²Th, ²³³U, ²³⁵U, ²³⁸U, ²³⁹Pu, ²⁴⁰Pu, and ²⁴¹Pu nuclides. A procedure is described for reducing the dependence of reactivity interpretations, through period measurements, on the nuclidic composition of the fuel. The sensitivity of the results to incremental changes in the delayed neutron parameters is also presented. Reactivity, in dollar units, is sensitive to the relative yields of the delayed neutron groups.