Reactivity Management Strategies for an Integral Pressurized Water Nuclear Reactor

Abstract

In the last 15 years, there has been a growing interest in the small modular nuclear reactors (SMR) and their applications. SMRs offer numerous benefits, including inherent safety features. SMRs are under development for all main reactor lines, but an important role for its outstanding safety features will be played by the so-called integral pressurized water nuclear reactors (iPWR). To achieve high proliferation resistance, extended fuel cycles for iPWR have been proposed. Obtaining such a large cycle length, using low fuel enrichment, without shuffle, and with a relatively small core size is a challenge for the neutronic design of the reactor core. In this work, a full-core neutronic computational model based in Serpent code was developed, it permitted to simulate the performance of the proposed reactor core configurations. Different variants of use of integral burnable absorbents in 48-months fuel cycle were studied, and the reactivity worth of the control rod groups was estimated. A fuel cycle extended of more than 1400 EFPDs is reached, and a minimal reactivity penalty was obtained.