Research Of Metamorphic Testing Technology For Core Neutron Diffusion Calculation Program

Nuclear power going abroad is China's major strategic demand.Nuclear design software is an important part of supporting self-development nuclear power technology to go global.Software quality is its lifeline.Verification & Validation(V&V)is an important means of ensuring software quality.Validation makes sense only after a large amount of sufficient verification and a high degree of confidence in the software correctness.Therefore,the verification of software correctness verification is a key factor in determining the quality of nuclear design.Benchmark calculation is the main means of verification in nuclear power software.Verification is to use the benchmark as the test case to run the program,compare the calculation results with the reference outputs to check the program correctness.In order to meet the test sufficiency criteria,the verification requires a large number of benchmark problems.However,there are problems such as high experimental cost and long cycle time by constructing experimental benches for independent experiments,collecting actual nuclear power plant operation data,joining international experimental research plans,and purchasing international benchmark problems.Due to the different neutron energy spectra,geometric configurations and materials of different reactors,there are not many benchmark problems for software verification in the specific type of nuclear design.Furthermore,for the verification of a new generation of core design programs,the number of benchmark problems is less due to the lack of comparable programs.The above shortcomings will lead to two problems.The first is the Oracle test problem,that is,it is difficult for the tester to construct or get the expected output of the program to verify whether the program calculation result is correct.The second is the problem of insufficient test case sets.Therefore,it is impossible to find defects that are hidden in the deep level of the program and affect the correctness.In order to solve the above two problems,it is worthwhile to learn from the metamorphic test technology.This new testing technology based on metamorphic relations is applied to verify program correctness,and has been widely used in numerical computing,bioinformatics,machine learning and other fields.The technology can indirectly verify the correctness according to the correspondence between the input mode and the output mode(the metamorphic relations)of the program by running multiple times without knowing the expected output value of the software.And it can also be based on the existing test cases to calculate new test cases,according to the metamorphosis relations.Therefore,this technology has significant advantages in solving problems of Oracle test problems and insufficient test case sets,and it is a promising test technology.In-depth research has not yet been carried out in nuclear software verification.Core neutron diffusion program is the important program of nuclear design.It provides key parameters for reactor design and analysis by calculating the neutron diffusion eigenvalue equation.The correctness of the program calculation has an important impact on the quality of the nuclear design.This thesis will carry out in-depth research on the metamorphic test technology and application of the core neutron diffusion calculation program.Discovering or constructing metamorphic relations is the premise and basis for conducting this research.Therefore,firstly,the metamorphic relations between the physics and computational model of the neutron diffusion equation are studied and revealed.Then,the benchmark problem derivative technology based on the metamorphic relations is studied.Finally,the related application of metamorphic test technique is studied.The main work and innovations are as follows.Firstly,this thesis analyzes the classical mathematical properties in the physical model of the core neutron diffusion equation.On this basis,through mathematical reasoning,the equivalent reasoning and perturbation method are used to obtain the relevant deductions,that is,the pairs of specific input mode and the output mode,thus deriving various metamorphic relations implied by the physical model.Secondly,this thesis analyzes the classical mathematical properties in the calculation model of the core neutron diffusion equation.On this basis,through mathematical reasoning,the Richardson extrapolation method is used to obtain the relevant deductions.The mode pairs are used to derive the metamorphic relations contained in the computational model.These above metamorphic relations are a new type of mathematical property that contributes to the verification of correctness of the procedures,and a new understanding of the mathematical properties of physical models and computational models from a new perspective of program verification.Thirdly,this thesis analyzes the test case derivative principle based on the metamorphosis relations,and classifies the metamorphosis relations,and proposes the benchmark devirative technique,and designs benchmark problem automatic derivative solver algorithm and tool according the characteristics of the benchmark question.Experiments show that the benchmark derivative technology provides test cases for program sufficiency verification.It is a low-cost,high-efficiency benchmark problem derivative method.Forthly,in this thesis,a metamorphic test technique based on metamorphic relation and benchmark problem is proposed,which applies to the verification test of the autonomous Core neutron diffusion program.Compared with the traditional verification test technology,this technology plays the role of the existing benchmark problems,and generates derivative benchmark problems that satisfy the test sufficiency according to the metamorphic relations.The research work and results of this thesis will provide new methods and technical support for verification testing of core nuclear design software,and can also be applied to the verification of other similar nuclear power design procedures.It has good engineering application value and importance meaning for enhancing the quality of the autonomous nuclear power software.