Core reactivity control for a soluble boron free small modular reactor

Abstract

In order to remove soluble boron in PWRs, reactivity control systems which can replace the broad reactivity control functions of soluble boron should be derived. In this study, combinations of BAs, control rods and SSS are proposed for the SBF SMR. BAs would replace most of the soluble boron function of controlling the excess reactivity in order to minimize insertion of control rods during power operation. In order to achieve subcriticality at cold condition with only control rods, all fuel assemblies are to be loaded with control rods. Two SSS options are also proposed in this study: one derived from a proven system and another an innovative design. The reactivity control using these design options is evaluated to fulfill the relevant GDCs and ATWS rules for normal and abnormal conditions.