Researching parameters correlation is important to analysis of reliability uncertainty for passive system. The only criterion for traditional method to determine the parameters correlation is the correlation coefficie...Researching parameters correlation is important to analysis of reliability uncertainty for passive system. The only criterion for traditional method to determine the parameters correlation is the correlation coefficient threshold. This method is subjective and needs improvement. Taking loss of normal feedwater accident of AP1000 passive residual heat removal system( PRHRS)as example,a comprehensive method was proposed to resolve the subjectivity problem of traditional method. Comprehensive method took account of scatter diagram of parameters and thermal transmission rule and significance testing of correlation coefficient comprehensively when judging parameters correlation. By comparing the effect of parameters judged by traditional and comprehensive methods respectively, we found the distance of traditional method was larger than that of comprehensive method,showing some parameters impacting thermal transmission rule removed by traditional method and comprehensive method could judge more precise and scientific parameters. So comprehensive method should be used to judge linear relation between parameters and thermal transmission rule.展开更多
The components from spent fuel are discharged from the core and then stored in the framework of the spent fuel pool for cooling. However, it is of great significance to save the storage space of the spent fuel pool by...The components from spent fuel are discharged from the core and then stored in the framework of the spent fuel pool for cooling. However, it is of great significance to save the storage space of the spent fuel pool by shrinkage and shearing work to increase the spare fuel lattice number. In order to solve the problem of shrinkage and shearing work of spent fuel involving the problem of radioactive safety, the radioactive source item is calculated by ORIGEN2 program base on Unit 1 Ⅱ of Lingao Nuclear Power Plant(NPP), and the radiation dose rate of the related component shrinkage operation scene is simulated by the MCNP5 program. In addition, the effectiveness of shielding measures is discussed, and the maximum dose rate is within 0.35 μSv/h at the distance of 2.5 m from component center, and the maximum dose rate is almost 0 at the distance of 3.2 m from the component center. The intensity of the radiation dose produced by the related components is very low and can be neglected, which belong to the green area of NPP. The program calculation system from source term calculation to shielding calculation is established, and an engineering example is referenced, and its application and analysis are carried out. It provides a basis for radioactive safety analysis and evaluation for the shrinkage operation of spent fuel and makes the shrinkage technology of fuel-related components safer and more reliable.展开更多
The continuous indication of the neutron density and its rate of change are important for the safe startup and operation of reactors. The best way to achieve this is to obtain analytical solutions of the neutron kinet...The continuous indication of the neutron density and its rate of change are important for the safe startup and operation of reactors. The best way to achieve this is to obtain analytical solutions of the neutron kinetics equations because none of the developed numerical methods can well satisfy the need for real-time or even super-time computation for the safe startup and operation of reactors in practice. In this paper, an accurate analytical solution of point kinetics equations with one-group delayed neutrons and an extraneous neutron source is proposed to calculate the change in neutron density, where the whole process from the subcritical stage to critical and supercritical stages is considered for step reactivity insertions. The accurate analytical solution can also be used as a benchmark of all numerical methods employed to solve stiff neutron kinetics equations.展开更多
基金Nuclear Reactor System Design Technology Foundation of National Key Laboratory,China(No.HT-JXYY-02-2014002)
文摘Researching parameters correlation is important to analysis of reliability uncertainty for passive system. The only criterion for traditional method to determine the parameters correlation is the correlation coefficient threshold. This method is subjective and needs improvement. Taking loss of normal feedwater accident of AP1000 passive residual heat removal system( PRHRS)as example,a comprehensive method was proposed to resolve the subjectivity problem of traditional method. Comprehensive method took account of scatter diagram of parameters and thermal transmission rule and significance testing of correlation coefficient comprehensively when judging parameters correlation. By comparing the effect of parameters judged by traditional and comprehensive methods respectively, we found the distance of traditional method was larger than that of comprehensive method,showing some parameters impacting thermal transmission rule removed by traditional method and comprehensive method could judge more precise and scientific parameters. So comprehensive method should be used to judge linear relation between parameters and thermal transmission rule.
基金Supported by the Project of Radiation Shielding Calculation Based on Unit 1 Ⅱ of Lingao Nuclear Power Plant of China
文摘The components from spent fuel are discharged from the core and then stored in the framework of the spent fuel pool for cooling. However, it is of great significance to save the storage space of the spent fuel pool by shrinkage and shearing work to increase the spare fuel lattice number. In order to solve the problem of shrinkage and shearing work of spent fuel involving the problem of radioactive safety, the radioactive source item is calculated by ORIGEN2 program base on Unit 1 Ⅱ of Lingao Nuclear Power Plant(NPP), and the radiation dose rate of the related component shrinkage operation scene is simulated by the MCNP5 program. In addition, the effectiveness of shielding measures is discussed, and the maximum dose rate is within 0.35 μSv/h at the distance of 2.5 m from component center, and the maximum dose rate is almost 0 at the distance of 3.2 m from the component center. The intensity of the radiation dose produced by the related components is very low and can be neglected, which belong to the green area of NPP. The program calculation system from source term calculation to shielding calculation is established, and an engineering example is referenced, and its application and analysis are carried out. It provides a basis for radioactive safety analysis and evaluation for the shrinkage operation of spent fuel and makes the shrinkage technology of fuel-related components safer and more reliable.
基金supported by the National Natural Science Foundation of China (10575131)
文摘The continuous indication of the neutron density and its rate of change are important for the safe startup and operation of reactors. The best way to achieve this is to obtain analytical solutions of the neutron kinetics equations because none of the developed numerical methods can well satisfy the need for real-time or even super-time computation for the safe startup and operation of reactors in practice. In this paper, an accurate analytical solution of point kinetics equations with one-group delayed neutrons and an extraneous neutron source is proposed to calculate the change in neutron density, where the whole process from the subcritical stage to critical and supercritical stages is considered for step reactivity insertions. The accurate analytical solution can also be used as a benchmark of all numerical methods employed to solve stiff neutron kinetics equations.
