Comparative assessment of methods for the reactivity measurement in subcritical systems by pulsed experiments

Abstract

The determination of the subcriticality level for source-driven systems is an important problem that can be handled by several deterministic methods developed for the interpretation of flux signals in pulsed experiments. The paper compares the performance of several methods for different physical characteristics of the system considered and for different durations of the source pulse. The effects of the subcriticality level and of the experimental uncertainty are also investigated. Furthermore, an analysis of the influence of spatial effects is carried out. The study gives some indications on the most suitable method in a specific experimental configuration pointing out at the situations where non-conservative evaluations of the reactivity can be expected, i.e. when the system effective multiplication constant is underestimated.