A Three-Dimensional CFD Model for a Performance Verification of the Liquid Poison Injection System of a CANDU-6 Reactor

A three-dimensional (3-D) computational fluid dynamics (CFD) model has been developed to analyze the liquid poison injection phenomenon of shutdown system 2 (SDS-2) of a Canada deuterium uranium (CANDU) reactor. Because the SDS-2 injects highly pressurized liquid poison into the moderator in a very short time, it is a major safety priority to confirm the effectiveness of the SDS-2 as one of the shutdown systems. In general, it is difficult to directly measure the velocity and concentration of the poison jet during an injection because of the complex nature of the injection system and the process. Therefore, a series of investigations has been performed to develop a CFD model for liquid poison injection phenomenon with limited validations. In this study, the validation of the existing CFD model for the poison injection phenomenon of the CANDU SDS-2 is extended to be applicable to a CANDU-6 reactor as well as a larger CANDU reactor. The analyses showed that the poison jet growth for those experiments simulated by the 3-D CFD model agrees reasonably with the experimental results. Therefore, it is concluded that the proposed 3-D CFD model can be used to assess the effectiveness of a liquid poison injection in compliance with the intended functional design requirements of the CANDU SDS-2.