Evaluation of the Moderator Temperature Coefficient of Reactivity in a PWR

V. Memoli, and A. Cammi
Department of Nuclear Engineering, Politecnico di Milano, Milan, Italy

The moderator temperature coefficient (MTC) plays an important role within power thermal reactor dynamics. In order to run a reactor safely, a negative moderator coefficient temperature is necessary to reach stability during changes in temperature that can be caused by a step insertion of reactivity. Thus, MTC calculation is a key point in the reactor design process.

The aim of the present work is to implement a simple model for the MTC estimation in a Pressurized Water Reactor (PWR). The model is based on the well-known two-group diffusion theory, which allows critical calculations to be performed with good approximation.