Numerical Research of CAP1700 IHP Cooling by Natural Convection

The feasibility of using natural convection, in substitution of the cooling fans inside the integrated head package (IHP), to cool the control rod drive mechanism (CRDM) assemblies of the proposed CAP1700 design is studied in this paper. The flow and the temperature fields of the CRDMs and their surrounding areas, including the IHP, all cooled by natural air convection, were simulated using CFD. The results showed that the average temperature of the CRDM wall surface will stay equal to or below 300°C, which is the pre-requisite of using the newly developed high temperature coils. Therefore, cooling by the natural convection is judged to be feasible for the CAP1700 no-fan design.