Development of a two-dimensional static neutronics model of the pebble bed modular reactor core for FLOWNEX

Abstract

High temperature gas cooled reactors have a special importance in the future of nuclear technology. Due to their high thermal capacity, high burn-up and thermodynamic efficiency, a decrease in the electricity generation cost is expected. New generation high temperature reactors are designed to be inherently safe. The most efficient way of hydrogen production, IS process, requires very high temperatures. Very High Temperature Gas Cooled Reactors (VHTR) of the future are considered as the heat source for hydrogen production. Two fuel types are used in high temperature reactors, namely pebble and prismatic block fuels. The South African Pebble Bed Modular Reactor (PBMR) is a promising design to be built in the near future. A very important aspect of the design of a High Temperature Gas Cooled Reactor (HTR) is to predict the neutronics of the reactor, as this determines the fission heat release. This thesis deals with the development of a model for the prediction of neutronics behaviour of the PBMR core which will be used in conjunction with a thermal hydraulic code for the design of the PBMR.