Session: 08-08: Computational Fluid Dynamics (CFD) and Applications - VIII

Paper Number: 135738

135738 - Investigation of the Heat Transfer Properties of Natural Circulation Flow in the Irradiation Channel of the Hfetr 

Abstract: 

The High Flux Engineering Test Reactor (HFETR) is a pressure hull reactor designed to operate at 125 MW, utilizing light water as both coolant and moderator, and beryllium as a reflector. It is noteworthy that this reactor holds the distinction of being the most powerful research reactor currently in operation in China. Furthermore, it is capable of conducting studies on the irradiation performance of a wide range of reactor fuels and materials within the reactor. The distinctive multi-lobe grid design of HFETR provides increased flexibility in the design of core loading, allowing for adjustments to be made in response to changes in irradiation tasks. HFETR has developed several stagnant water channels to isolate the cooling water within the channels from the cold removal water of the reactor using a separator tube. The transport of neutrons within a reactor results in the deposition of energy in the material. As a result, the irradiator in the active zone of the reactor generates heat, leading to an increase in temperature of the surrounding cooling water. In contrast, the cooling water in the non-active zone maintains a lower temperature. The density difference between cold and hot fluid initiates natural convection in the stagnant water irradiation channel, facilitating the transfer of heat generated by the device in the channel to the cooling water of the reactor through natural convection heat transfer. The investigation of heat transfer characteristics in the natural circulation flow of cooling water, based on a still water channel, holds significant importance for controlling temperature parameters of irradiation devices within the channel and ensuring the safety of reactor tests. This paper presents the establishment of a flow heat transfer calculation model for the irradiation test of instrumentation materials in the HFETR still water channel using COMSOL Multiphysics software. The reliability of the calculation model was verified based on the measured results of cooling water temperature in the channel under different reactor power steps. The study investigated the distribution of temperature and velocity fields of the cooling water in the tunnel under varying heat flux densities. It also determined the heat transfer coefficient of the outer surface of the irradiation device and evaluated the natural circulation heat transfer capacity in the irradiation tunnel. The findings indicate that the static water channel of HFETR exhibits favorable natural circulation capability, which enhances the safety of the irradiation test. Additionally, this lays the groundwork for the thermal analysis and calculation of relevant irradiation tests in the static water channel.

Presenting Author: Shuai Jin Nuclear Power Institute of China

Presenting Author Biography: Jin Shuai is an assistant researcher, graduated from Harbin Institute of Technology, mainly engaged in radiation test related thermal hydraulic work

Authors:

Shuai Jin Nuclear Power Institute of China
Sheng Sun Nuclear Power Institute of China
Wenhua Yang Nuclear Power Institute of China
Junping Si Nuclear Power Institute of China
Yixing Xu Nuclear Power Institute of China
Jin Lei Nuclear Power Institute of China