The Effect of Half-life and Branching Fraction Uncertainties on the Effective Neutron Multiplication Factor

This calculation demonstrates how uncertainties in half-life and branching fraction affect postclosure isotopic concentrations and the quantification of those effects in terms of reactivity.
The uncertainty in production (preclosure) is included in the uncertainty in reactivity quantified by benchmarking codes to the critical experiments. This calculation is limited to quantifying the effects of decay uncertainties only in the postclosure period. This calculation is intended as an illustration of the methodology to arrive at the effect on keff from the uncertainties in the half-life and branching fraction of radioisotopes.
This calculation will address the Nuclear Regulatory Commission (NRC) concern regarding the effects of canceling errors in decay calculations.