ITER Neutron Shielding Layer Structure Of The Heat Transfer Mechanism Research And Analysis

The International Thermonuclear Experimental Reactor ITER is an international collaboration project, its purpose is to build a large superconducting Tokamak, through scientific and technological means to achieve the peaceful use of nuclear fusion energy. Neutron shielding blocks are the basic units of ITER vacuum chamber neutron shielding layer, composed of a plurality of component assembly, for neutron shielding in the fusion reaction flow. In the fusion reaction conditions, neutron shielding blocks by radiation and heat effect of high temperature will produce thermal stress. In order to obtain the temperature distribution in the fusion reaction conditions of neutron shielding blocks, the heat transfer analysis of neutron shielding blocks using the Ansys software, in the process of analysis are mainly thermal variation function, cooling water and block the convective heat transfer, the cladding layer and the cold screen radiation boundary conditions. The results of physical properties of contrast material, neutron shielding blocks of the temperature change in the material property requirements range, meet the thermal properties of materials required.This subject comes from the project of international cooperation:"ITER vacuum chamber neutron shielding design and research"(Framework contract ITER/CT/09/6000000003)Vacuum interior neutron shielding layer is composed of8600small assembly consisting of a doughnut shaped in a large device. In fusion reactions in normal circumstances, neutron shielding layer is soaked in the vacuum chamber of the cooling water, come mainly from the vacuum chamber shell internal cladding and the outside of the shell of cold screen pass to heat the baking process, in addition to the analysis of heat transfer. Then get the neutron shielding block temperature distribution, and thermal structure coupling the bolt itself as well as the influence of the structure strength.This topic research content:first introduced in the vacuum chamber for neutron shielding structure design and design basis, and neutron shielding design concept as well as the initial design; then it introduces the basic theory of heat transfer and application of neutron shielding layer, and the heat load of introduction, as well as the neutron shielding layer of the heat transfer mechanism.Then introduced the neutron shielding block model pretreatment process, including modeling, material selection, unit selection, attribute the introduction and so on.Finally, selected neutron shielding layer outside the region analysis of heat conduction, and select a common block thermal structure coupling analysis of baking and analysis.The purpose of this paper is the first part of neutron shielding layer region model of the sample, the neutron shielding structure in the vacuum chamber shell subjected to nuclear thermal steady state thermal analysis; then to neutron shielding layer in comparison with standard piece for reference, this block of steady-state thermal analysis, neutron shielding blocks obtained in thermal under the condition of temperature distribution, and then integrated these analysis results of neutron shielding blocks in the structure design of the impact, especially on the preload bolt anti-loose and structure strength analysis.To ensure that the shielding layer structure in thermal loads and the rationality of the design, eventually determine shielding layer structure in the normal condition of safety and reliability.