Inhomogeneous geometric variational nodal method for reactor neutron diffusion equation

Abstract

The invention discloses a non-uniform geometrical variational nodal method aiming at a reactor neutron diffusion equation. The method comprises the following steps: 1, establishing a functional containing a neutron conservation relationship inside the nodal block and flow continuity conditions on the nodal surface; 2, performing nodal discrete disposal by utilizing a finite element shape function in the x-y direction and a chip constant polynomial, and realizing non-uniform nodal geometrical and material description functions; 3, deducing to obtain a response matrix equation; and 4, solving the response matrix equation by utilizing a red-black scanning manner, and finally obtaining the neutron-flux density distribution in the whole non-uniform solving area. According to the method disclosed by the invention, the non-uniform lattice-cell structure of a nuclear reactor can be finely described; and according to the method, the nodal internal fine geometrical structure is processed based on the variational nodal method by adopting an isoparametric finite element, and then the non-uniform geometrical neutron diffusion equation is solved.

Description

technical field [0001] Aiming at the field of nuclear reactor core neutronics calculation, the invention proposes a non-uniform geometric variation segmental method for reactor neutron diffusion equation. Background technique [0002] Computational studies of nuclear reactor neutronics are applied to nuclear reactor cores, which consist of many different types of components. Depending on the stack type, the geometry and material arrangement inside the module is complex and variable. Therefore, the actual reactor neutronics problem is a three-dimensional non-uniform geometry neutronics problem. Fast and accurate neutronics calculations for nuclear reactors are the basic guarantee for reactor design and calibration. At present, in the process of core physical design, the method of solving the diffusion equation of uniform geometry is mainly used. [0003] The variational block method was first proposed by Professor E.E. Lewis of Northwestern University in the United States....

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Problems solved by technology

However, the traditional variational block method program only has the processing ability of uniform blocks, which is not enough to finely describe the non-uniform geometry inside the block, and cannot avoid the error caused by the homogenization of blocks.

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