Multi-point wall temperature measuring device for rod bundle fuel assembly under motion condition

Abstract

The invention discloses a multi-point wall temperature measuring device for a rod bundle fuel assembly under a motion condition. The multi-point wall temperature measuring device comprises one or moreisolating ceramic pipes, and annular grooves are formed in the inner circumferential walls of the isolating ceramic pipes in the circumferential direction of the isolating ceramic pipes. Temperaturemeasuring rings are arranged in the annular grooves, and one or more sheathed thermocouples are arranged on the inner walls of the temperature measuring rings. When heat-transfer characteristic experimental study is carried out on the simulating rod bundle fuel assembly, metal round pipes are utilized to be powered on and heated to serve as heating element pipes. The annular grooves are formed inthe inner circumferential walls of the isolating ceramic pipes, the temperature measuring rings are arranged in the annular grooves, and the one or more sheathed thermocouples used for temperature measuring are arranged on the inner circumferential walls of the temperature measuring rings. During using, according to the axial length of the heating element pipes, temperature measuring point positions are determined; and then the isolating ceramic pipes are fixed to the temperature measuring point positions, and the temperature measuring rings transmit heat on the temperature measuring point positions to the sheathed thermocouples to achieve accurate measuring of the local wall surface temperature of the heating element pipes.

Description

technical field [0001] The invention relates to the technical field of thermal-hydraulic research of reactors, in particular to a device for measuring multi-point wall temperatures of rod bundle fuel assemblies under motion conditions. Background technique [0002] In order to improve the economics of nuclear reactors, under the premise of ensuring the safety of the reactor, it is necessary to increase the thermal power per unit volume of the core, the temperature of the coolant, etc., which are closely related to the heat transfer capacity of the core, that is, the heat transfer performance of the reactor fuel assembly. Heat transfer characteristics are the core technical indicators of fuel assembly performance, and are of great significance to the design and demonstration of fuel assemblies and to improve the comprehensive performance of assemblies. Floating nuclear power plants, marine nuclear power and other reactor core structures all use rod bundle structure fuel assem...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a multi-point wall temperature measuring device for bundle fuel assemblies under moving conditions, which solves the problem of measuring the wall temperature of simulated bundle fuel assemblies under high temperature and high pressure conditions, and can simultaneously measure multiple heating elements of simulated assemblies under moving conditions The local wall temperature at different positions is used to carry out thermal-hydraulic experimental research on the heat transfer characteristics of the fuel assembly with a bundle structure, and to obtain key design parameters such as the heat transfer coefficient of the fuel assembly

In view of the particularity of the structure of the existing rod bundle fuel assemblies and the complexity of the component flow field and temperature field under motion conditions, which leads to the difficulty in obtaining thermal parameters such as the wall temperature of the fuel assembly, the applicant simulated the rod bundle fuel assembly When carrying out the experimental research on heat transfer characteristics, the metal circular tube is used as the heating element tube, and at least one insulating ceramic tube whose outer diameter matches the inner diameter of the heating element tube is arranged in the heating element tube. There is an annular groove on the inner peripheral wall, and the temperature measuring ring is set in the annular groove, and at least one armored thermocouple for temperature measurement is arranged on the inner peripheral wall of the temperature measuring ring. Determine the temperature measurement point, and then fix the insulating ceramic tube at the temperature measurement point, and the temperature measurement ring transfers the heat on the temperature measurement point to the armored thermocouple to realize the partial wall surface of the heating element tube Accurate measurement of temperature; among them, since the heating element tube needs to be energized to generate heat in the heat transfer experiment of the fuel assembly, the shell of the armored thermocouple is usually made of stainless steel. The thermocouple shell is easy to contact with the inner wall of the heating element tube and become electrified. Once the armored thermocouple shell conducts electricity, the accuracy of thermocouple measurement cannot be guaranteed. For this, the applicant sets insulating ceramic tubes between the heating element tube and the armored thermocouple. , annular groove and temperature measuring ring, not only can fix the armored thermocouple on the inner wall of the heating element tube to realize the positioning of the armored thermocouple, but also avoid the flow field of the temperature measuring component on the external flowing working medium of the heating element tube , the temperature field caused interference, and finally realized the accurate measurement of the wall temperature at different positions of the heating element tube in the heat transfer experiment of the fuel assembly

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