Heat Removal Capacity of Heat Pipe Designs for In-Core Passive Decay Heat Removal System

Abstract

A passive in-core cooling system (PINCs) can be adopted in control rods for passive safety of advanced nuclear power plants. A hybrid heat pipe is a heat transfer device to take the roles of both neutron absorption and heat removal by combining the functions of a heat pipe and a control rod. The unique characteristic of the hybrid control rod is the presence of neutron absorber inside the heat pipe. Many previous researchers studied the effect of parameters on the thermal performance of heat pipe. However, the effect of inner structure on the thermal performance of heat pipe has not been investigated. As a first step of the development of hybrid heat pipe, the annular heat pipe which contains neutron absorber in the normal heat pipe was prepared and the thermal performance of the annular heat pipe was experimentally studied. The annular heat pipe showed higher thermal resistances in the evaporator region with a maximum increase of 100 %, although condenser thermal resistances and total thermal resistances were was similar with those of normal heat pipe. In the aspect of operational limit, the annular heat pipe showed lower maximum heat transfer capacity than a normal heat pipe due to a smaller cross-section of vapor path in evaporator region, which resulted in high shear at the vapor-liquid interface of the wick structure. In addition, several further works to assess the effect of inner structure on the maximum heat removal rate of the hybrid heat pipe were presented. © Copyright (2015) by American Nuclear Society All rights reserved.