Research And Program Design Of Point-core Integral Calculation Method For Three-dimensional Y Radiation Field

The calculation of 3D gamma-radiation field is of great significance in the work path optimization and radiation shielding design of nuclear facilities and nuclear power plant overhaul.It is one of the basic work to optimize the radiation protection.The principle of calculating the 3D gamma-radiation field is based on the theory of photon transport.There is no analytical solution for the photon transport equation.It is mainly dependent on the numerical calculation method.The numerical calculation of the3D gamma-radiation field is large and the calculation speed is slow.It is difficult to meet the needs of the optimization work of radiation protection.The point kernel integral method is a semi empirical analytical calculation method to calculate the 3D gamma-radiation field.Point kernel integration has many advantages,such as intuitive principle,simple calculation,complete parameter and fast computation speed.In this paper,the point kernel calculation is introduced in detail and the buildup factors in the point kernel calculation method is studied in detail.A point kernel calculation program for calculating the 3D gamma-radiation field is designed and verified.In the study of buildup factors,the standard buildup factors is used for calculated for the infinite medium isotropic point source gamma dose.The actual situation,the relative light angle calculation object is limited,or the light source itself has angular distribution.In this paper,the adaptability of point kernel calculation method is systematically evaluated.At the same time,in the actual situation,the light source to the detection point path often passes through a variety of different media,and the incidence direction of the photon is usually oblique incidence medium interface,and the interface will not be the standard infinite plane.These cases are very different from the standard point kernel calculation modeling,and the calculation error introduced may be very large.This paper also conducts a systematic assessment of these conditions.Finally,this paper calculates the set model of the point kernel calculation program for calculating the 3D gamma-radiation field with the MC program MCNP program,and compares the results.The program of point kernel calculation for 3D gamma-radiation field distribution is evaluated.