Fine power reconstruction method for fuel assembly

Abstract

The invention provides a fine power reconstruction method for a fuel assembly. The method includes the steps that 13 boundary conditions of fast group and thermal group node volume flux, neutron flux of the four faces of a node, neutron current and neutron flux of four angular points and a node x-direction and y-direction transverse one-dimensional integral neutron flux expansion function are acquired through calculation of a nodal method; a fast group neutron flux distribution expansion function and a thermal group neutron flux distribution expansion function based on an orthogonal function family primary function are acquired; four boundary conditions are added, bothway integration is conducted on the fast group neutron flux distribution expansion function and the thermal group neutron flux distribution expansion function, and neutron flux distribution restrained by a weighting function is acquired; 17-order expansion coefficients of fast group and thermal group neutron even flux distribution are calculated according to the acquired 13 boundary conditions and the neutron flux distribution restrained by the weighting function; fine power distribution of the fuel assembly is obtained accordingly. The calculation precision and calculation efficiency can be remarkably improved, calculation is easy and convenient, and code reconstruction is easy.

Description

technical field [0001] The invention relates to the technical field of nuclear design, in particular to a fuel assembly fine power reconfiguration method. Background technique [0002] Reactor fuel management calculations frequently require solving multidimensional neutron diffusion equations. In the early design software, the finite difference method was used to solve the problem. Due to the limited performance of the computer at that time, 105 to 106 grids needed to be established by using the finite difference method at the same time, and the calculation efficiency was low. Therefore, the mainstream core commonly used in international light water reactor projects Design software, such as the SMART software of AREVA in France, the ANC software of Westinghouse in the United States, including the COCO software independently developed by the China Kehua Institute of Nuclear Power Technology, are all based on the block method to achieve a higher efficiency core neutron flux a...

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Problems solved by technology

For example, the currently used commercial boiling water reactor not only includes wide and narrow water gaps in the radial direction, but also the axial coolant density changes dozens of times that of the pressurized water reactor, and the three-dimensional non-uniformity is very strong; and in order to further improve fuel utilization efficiency, pressurized water The stack may use different types of components for mixed loading. The huge difference in energy spectrum between components leads to very strong non-uniformity even in the radial direction of the core. Therefore, in this case, the traditional fine power reconstruction based on The method cannot meet the requirements in terms of calculation accuracy

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