Space–time kinetics modeling of Advanced Heavy Water Reactor for control studies

The paper presents the mathematical modeling of the space–time kinetics phenomena in Advanced Heavy Water Reactor (AHWR), a 920 MW (thermal), vertical pressure tube type thorium based nuclear reactor. The physical dimensions and the internal feedback effects of the AHWR are such that it is susceptible to xenon induced spatial oscillations. For the study of spatial effects and design of suitable control strategy, the need for a suitable mathematical model which is not of a very large order arises.In this paper, a mathematical model of the reactor within the framework of nodal modeling is derived with the two group neutron diffusion equation as the basis. A linear model in standard state space form is formulated from the set of equations so obtained. It has been shown that comparison of linear system properties could be helpful in deciding upon an appropriate nodalization scheme and thus obtaining a reasonably accurate model. For validation, the transient response of the simplified model has been compared with those from a rigorous finite-difference model.