Method for obtaining gamma dose rate distribution based on finite element-Monte Carlo-point kernel integral coupling

Abstract

A method for obtaining gamma dose rate distribution based on finite element-Monte Carlo-point kernel integral coupling comprises the following steps: automatically generating a subdivision surface by analyzing source intensity and spatial distribution of a source in a radiation shielding problem of a nuclear device, and dividing an unstructured grid by taking the subdivision surface as a boundary based on a three-dimensional CAD model of the nuclear device, carrying out conjugate transport calculation on the internal area of the subdivision surface by adopting a finite element method to obtain source bias and weight window parameters, providing the source bias and weight window parameters to a Monte Carlo method to carry out forward transport calculation on the internal area of the subdivision surface to obtain a neutron surface source and a photon surface source of the subdivision surface, and taking the neutron surface source and the photon surface source of the subdivision surface as source items; calculating an area outside the subdivision surface by adopting a point kernel integration method to obtain gamma dose rate distribution; the method has high complex geometric adaptability, the efficiency is higher than that of a traditional Monte Carlo method, the calculation efficiency is greatly improved under the condition that the calculation precision is guaranteed, and a reliable scheme is provided for rapid and accurate calculation of the radiation shielding problem of the nuclear device.

Description

technical field [0001] The invention relates to the field of radiation shielding calculation of nuclear devices, in particular to a method for obtaining gamma dose rate distribution based on finite element-Monte Carlo-point nuclear integral coupling. Background technique [0002] Determining the radiation field level is one of the important bases for radiation protection work. The theoretical calculation method is not limited by time and space, and is an important method for determining the radiation field level. At present, there are three basic methods of radiation field level calculation: (1) Monte Carlo method: non-deterministic method, which can solve complex geometry, but the calculation time is long and the performance is not good enough when dealing with deep penetration problems; (2) deterministic method: Such as the finite element method, the calculation speed is relatively fast, but it is not as accurate as the Monte Carlo method when solving complex geometry; (3)...

AI Technical Summary

Problems solved by technology

At present, there are three basic methods for calculating the radiation field level: (1) Monte Carlo method: non-deterministic method, which can solve complex geometry, but the calculation time is long and the performance is not good enough when dealing with deep penetration problems; (2) Deterministic method: Such as the finite element method, the calculation speed is relatively fast, but it is not as accurate as the Monte Carlo method when solving complex geometries; (3) point kernel integration method: semi-empirical method, the calculation speed is fast, but the calculation results are significantly higher when solving complex geometries

[0003] The three methods have their own advantages and disadvantages, and it is difficult to meet the needs of rapid and accurate calculation of the radiation field level of nuclear installations in actual engineering.

If the Monte Carlo method alone is used to calculate the radiation field level theory, it will take too long, which will limit the decommissioning work to be carried out on time, and in some important areas (such as the plant around the primary circuit) will appear due to breaking through the thick shielding structure (such as the reflective layer). Due to the problem of low count rate, the reliability of the calculation results cannot be guaranteed; if the theoretical calculation of the radiation field level is carried out by the finite element method alone, it is difficult to guarantee the correctness of the calculation results of the complex geometric components including the source item, such as the area where the core is located; The theoretical calculation of the radiation field level by the point kernel integration method will significantly overestimate the gamma dose rate and increase the cost of decommissioning work

[0004] Aiming at the shortcomings of the current radiation field calculation method that cannot take into account both calculation accuracy and calculation efficiency, a method based on finite element-Monte Carlo-point kernel integral coupling to obtain gamma dose rate distribution is invented

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