A useful observable for estimating k_eff in fast subcritical systems

Abstract

Abstract. The neutron multiplication factor k e f f is a key quantity to characterize subcritical neutron multiplying devices and for understanting their physical behaviour, being related to the fundamental eigenvalue of Boltzmann transport equation. Both the maximum available power -and all quantities related to it, like, e.g. the effectiveness in burning nuclear wastes -as well as reactor kinetics and dynamics depend on k e f f . Nevertheless, k e f f is not directly measurable and its determination results from the solution of an inverse problem: minimizing model dependence of the solution for k e f f then becomes a critical issue, relevant both for practical and theoretical reasons.