| Radiation shielding calculation is a crucial safeguard for nuclear safety.Accurate and efficient radiation shielding calculation can provide reliable data reference and technical support for personnel radiation protection,dose assessment,and optimization and design of shielding structures in nuclear facilities.Common radiation shielding calculation methods include Monte Carlo method,discrete ordinates method,point kernel integration method,etc.However,due to their theoretical limitations,these methods often struggle to achieve quick assessment and accurate acquisition of radiation shielding parameters in complex radiation scenarios.Therefore,to meet the demands of radiation field shielding calculation in large spaces with complex source terms,this study proposes coupling the Monte Carlo method with the point kernel integration method.By dividing the radiation field based on spatial and source characteristics,the advantages of both methods are fully utilized to improve computational efficiency and accuracy in complex radiation scenarios for radiation shielding data.In order to achieve efficient coupling calculation,this research first developed a parallelizable point kernel integration calculation program RSEA(Radiation Shielding Effectiveness Assessment)based on the gamma point kernel integration method and neutron cross section method.RSEA can quickly calculate the gamma and neutron radiation doses by establishing a geometric model in the form of three-dimensional equations.Based on this,in order to solve the data exchange problem between the point kernel integration program and the Monte Carlo program,this paper improved RSEA and developed a dedicated point kernel integration program for coupling calculation based on RSEA,called RSEA＿C.RSEA＿C completes the coupling calculation of point kernel integral by reading the particle flow information calculated by GEANT4 at the selected interface.According to the preset radiation field calculation results,the application of RSEA＿C can improve the calculation efficiency,shorten the coupling calculation time by 90% compared with GEANT4,and reduce the average relative deviation between gamma and neutron doses and GEANT4 to 27% and 43%,thus verifying the feasibility and accuracy of the coupling calculation program RSEA＿C.This paper aims to sufficiently verify the computational effectiveness of the coupled calculation method in complex and large-scale radiation fields,with the comparison calculation of the radiation field of the nuclear-powered icebreaker reactor.As an important development direction of icebreakers,the nuclear-powered icebreaker has a typical large and complex radiation field in its reactor.Based on existing information,a simplified model of the Russian icebreaker OK-900 A nuclear power plant was constructed,and the radiation field of the reactor was calculated.The results showed that under the same calculation conditions,the coupled calculation time only requires one-tenth of the Monte Carlo program calculation time,and the application of the coupled calculation program RSEA＿C can significantly shorten the calculation time of the radiation field.However,compared with the Monte Carlo program GEANT4,there is still a certain deviation in the calculation results of the coupled calculation RSEA＿C.In the cabin near the reactor compartment,the average relative deviation of the gamma dose calculated by RSEA＿C and GEANT4 is 35%,and the average relative deviation of the neutron dose is 45%.Considering reasons such as model size and model simplification,this deviation is acceptable.This study developed a parallelizable point kernel integration program and coupled it with a Monte Carlo program to calculate and verify radiation fields.The results showed that the Monte Carlo-point kernel coupling calculation has good adaptability to radiation fields with large spatial dimensions and complex source terms.Compared with single radiation shielding calculation methods,the efficiency and accuracy of the coupled calculation method have been improved. |
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