Method for eliminating control rod tine effect in reactor core calculation

Abstract

The invention provides a method for eliminating a control rod tine effect in reactor core calculation. Specific steps are: step 1: dividing a whole solving region into several node regions, and writing a to-be-solved neutron diffusion equation; step 2: by using a variable principal, writing each node functional style; step 3: expanding neutron flux density and a neutron source space basis function and substituting the neutron flux density and the neutron source space basis function into the node functional style; and step 4: by using the node functional style, obtaining a relation between an emission neutron flux and an incident neutron flux of a node surface and a relation between a node inner flux and an emission flux and an incident flux of the node surface. The method provided by the present invention is based on a variational node method; a cross section of a node functional is written into a space function; a hypothesis that a macro cross section in the node is a constant is not made during a deduction process; and finally non-uniformity in the node is displayed in a response matrix of the node, so as to realize computation of a non-uniform node and further eliminate the control rod tine effect.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor core design and safety, in particular to a method for eliminating the tine effect of control rods in reactor core calculation. Background technique [0002] As the energy strategic position of nuclear energy becomes increasingly prominent, people pay more and more attention to the safety and economy of nuclear reactors, and higher and higher requirements are put forward for the accuracy of reactor physical calculations. The control rod tine effect is an inevitable problem in reactor core calculation, and it is also an important reason that affects the accuracy of core calculation. [0003] In the calculation of the reactor core, the axial size of the calculation blocks used is generally about 20 cm, while the moving step of the control rods is only 1 to 2 cm, so it is inevitable that there will be non-uniform blocks where the control rods are partially inserted. When calculating with the ...

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Problems solved by technology

The first two methods can only weaken the tine effect of the control rods, but cannot completely eliminate it; the adaptive grid method dynamically divides the core segments according to the different insertion positions of the control rods to ensure that the bottom ends of the control rods are aligned with the segment interfaces, This method can theoretically eliminate the tine effect of the control rod, but it may cause extremely thin nodules at some positions in the core axis, which increases the calculation amount of the core and even affects the calculation accuracy

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