Transient analysis on the thermal-mechanical characteristics of a heat pipe cooled reactor core

Abstract

BackgroundAs a nuclear power system with high energy density and strong adaptability, heat pipe cooled reactor can play an important role in space and deep sea exploration, and is attracting more and more attention from all over the world. Due to the solid-state core and high-temperature operation of the heat pipe cooled reactor, the thermal expansion and thermal stress are non-negligible. The nuclear-thermal-mechanical coupling effect should be considered for the heat pipe cooled reactor core.PurposeThis study aims to investigate the thermal-mechanical characteristics of the reactor core, and evaluate the safety performance of the reactor under typical conditions and transient accidents for a typical heat pipe cooled nuclear reactor, Nuclear Silence ThermoElectric Reactor (NUSTER).MethodsBased on FLUENT and MECHANICAL modules in finite element analysis software ANSYS, calculation of the nuclear-thermal-mechanical coupling was conducted for the reactor core of NUSTER under the steady-state and the reactor reactivity insertion accident respectively, hence the temperature and stress distribution were obtained. The core design safety was evaluated by comparing the temperature and stress peak values of each component with the melting point and yield strength of material.Results & ConclusionThe comparison results show that NUSTER core can operate safely within the safety limit in both steady state and accident conditions. Each component has a safety margin of 200 K for temperature and 150 MPa for stress under accident condition, so the core design safety has been verified.

Keywords

• heat pipe cooled reactor
• nuclear-thermal coupling
• thermal-mechanical coupling
• core safety assessment