A Method for Computing Axial Swelling Effect of Fast Neutron Stack Components

Abstract

A method for calculating the axial swelling effect of fast neutron reactor components, comprising the following steps: 1. Separate the transport calculation grid from the burnup calculation grid, the transport calculation grid remains unchanged throughout the calculation, and the fuel consumption calculation grid The consumption calculation grid keeps growing in the same proportion with the axial swelling of the fuel assembly; 2. Based on the variational block method, the weak form of the solution of the neutron transport equation is constructed, and the section in the block is a function related to the spatial position. A variety of materials are allowed inside the transport calculation block; 3. Use spherical harmonic functions and spatial orthogonal polynomials to expand the flux, and use the response matrix method to solve the flux expansion moment, so as to obtain the flux distribution of each block; 4 , Calculate the burnup depth of the burnup block according to the average power of the burnup block, obtain the uniform cross section of the burnup block according to the fuel consumption interpolation, and adjust the uniform cross section inside the burnup block according to the axial elongation of the component , and then obtain the required non-uniform section in the calculation node.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor core design and safety, in particular to a method for calculating the axial swelling effect of fast neutron reactor components. Background technique [0002] Fast neutron reactors can convert fissile nuclides into fissile nuclides, greatly improving the utilization rate of uranium resources, which is of great significance to the sustainable development of nuclear energy. At present, fast reactors are still in the experimental and design stages, and accurate numerical simulations are essential for large-scale commercial use of fast reactors. [0003] Different from existing commercial pressurized water reactors, fast reactors usually use metal uranium-zirconium alloys as fuel in order to make the energy spectrum harder and obtain better breeding effects. Metal fuel has a large temperature expansion coefficient, and it is also prone to swelling and deformation when it is irradiated. In the...

AI Technical Summary

Problems solved by technology

[0004] Traditional methods of dealing with tine effects do not work well for axial swelling effects

First of all, the adaptive grid method will cause too fine grids in the core nodes, which not only greatly increases the calculation amount, but also makes it difficult for the node flux to converge

Calculating with the re-homogenization method requires the calculation of the homogenized cross-section for each node, which greatly increases the amount of calculation

Images