Resonance calculation method for research heap based on equivalent geometric theory

Abstract

The invention discloses a resonance calculation method for a research reactor based on an equivalent geometric theory. The resonance calculation method comprises the following steps: establishing an independent isolated lattice cell model for each fuel lattice cell in a target research reactor; solving the fixed source equation to obtain a neutron escape probability and a collision probability; and then the non-rod-shaped geometric fuel is equivalent to one-dimensional rod-shaped equivalent fuel based on escape probability conservation. Then, based on collision probability conservation, the surrounding structural material is converted into a ring shape from a non-ring shape; obtaining a Dankov correction factor of a fuel zone through a neutron current method; and finally, the outer radius of the equivalent moderator area is obtained based on the Dankov correction factor conservation of the fuel area. An equivalent one-dimensional lattice cell model is established through the one-dimensional rod fuel, the annular structure material and the moderator area, and then resonance calculation is conducted to obtain the effective self-shielding section of the problem. Compared with the prior art, the method can greatly improve the resonance calculation efficiency of non-rod and non-plate geometric fuel in numerical reactor simulation calculation on the premise of ensuring the precision.

Description

technical field [0001] The invention relates to the field of nuclear reactor core design and safety, in particular to a resonance calculation method for research reactors based on equivalent geometric theory. Background technique [0002] Nuclear reactors can be used not only for power generation and heating, but also for irradiation of new materials, production of isotopes, and neutron photography. Such reactors are called research reactors. Due to the different tasks of research reactors, their characteristics are also different, such as the neutron fluence rate at a specific location reaches a certain level, etc. These characteristics lead to a large difference in the core design of research reactors and commercial pressurized water reactors, fuel geometry and fuel The arrangement of components is more complex. In order to meet the various tasks of research reactors, it is necessary to accurately and efficiently simulate the standard neutron flux level in the reactor. Th...

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Problems solved by technology

Although a lot of research on resonance calculation methods has been carried out at home and abroad, the traditional resonance calculation method is still difficult to apply to complex geometry research reactors. First, there are various geometric forms of fuel in complex geometry research reactors. The theory has a geometric adaptability problem. Although the escape probability of complex geometry can be approximated by three rational approximations, the calculation accuracy is not enough; the resonance integral table is needed in the calculation of the subgroup method, and the calculation accuracy of the uniform integral table is not enough. A uniform resonance integral table needs to be calculated in advance for several fixed geometric fuels, so there is also a problem of geometric adaptability; geometric adaptability, calculation efficiency and calculation accuracy cannot be considered

The ultrafine group method needs to calculate the collision probability, and the characteristic line method will greatly reduce the calculation efficiency for large-scale complex geometric problems

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