ITER Neutron Shielding Block Structure Analysis Under Multiple Working Conditions

The plan of ITER (International Thermonuclear Experimental Reactor) is a blend of international research cooperation project which purpose is to build a large superconducting Tokam and displays the possibilities of peacefully use of fusion energy from the angle of science and technology.The vacuum chamber is the vacuum place where the nuclear reactions carry out, The IWS (In Wall Shielding)is located in the vacuum chamber between the inner and outer shells, its role is to shield the Neutron and reduce the waviness of toroidal magnetic field. In the process of research, it will be involve many subjects that including statics, mechanics of materials, materials science, dynamics, finite element theory and so on.This topic originates from the International cooperation project "ITER the design and research of vacuum chamber of neutron shield "(Framework contract ITER/CT/09/6000000003)The research is focused on the simulation analysis of the neutron shielding structure for multiple working conditions before manufacturing the neutron shielding structure, which is in order to ensure the safety and the reliability of the designed whole device, and ensure the neutron shielding structure working normally under the electromagnetic force, seismic load, gravity load and other loads, for providing the basis for designing structure.The contentes of the research are as follows:first, the principles of nuclear fusion, and the possibilities of peaceful use of fusion energy from the angle of science and technology have been and displayed; second, the constitute of the ITER device and shielding layer have been introduced. Through the preliminary structure design for the shield structural, further to detail design and assembly of components, acquired the shield block assembly model. This article is intended to based on a standard shield block model, to analyse the baking transient thermal and thermal stress on the shield block; thirdly, carrying out the simulation analysis of the structural strength of the shield block, evaluating the load stress of the shielding blocks in the electromagnetic force, gravity and vertical displacement with reference to the ASME standard. Put forward the QR algorithm to remove the structural stress secondary stress, and then assessed the results after the removal of secondary stress, and provided a reference for the optimization design of the neutron shielding blocks; finally, analyse the modal and seismic spectral response analysis of shield block in accordance with the requirements of the ITER project, it turned out the natural frequencies and mode shapes as well as the maximum displacement and maximum stress on the shield block shield block when imposed by the earthquake response spectrum, and then ensured the safety and reliability of the shielding structure under seismic loads.