| Activation calculation can provide data support for material composition selection,shielding structure design,accident analysis and so on.It is an important link in reactor physics and source term calculation.At present,the optimal estimation model is more and more widely used in reactor design and safety analysis.The model requires the optimal estimation of parameters and its uncertainty.Therefore,it is of great significance to study the uncertainty in activation calculation.An important source of uncertainty in activation calculation is nuclear data such as nuclide half-life and neutron-induced reaction cross section,which are closely related to neutron irradiation patterns.Especially for the pulsed fusion reactor,the complex neutron irradiation mode makes the activation calculation and uncertainty analysis more difficult,and the related research at home and abroad is less,which is an important problem to be solved in this paper.In this paper the calculation methods of neutron activation(EP.SS.ESS,CP(SS),CP(ESS)under pulse condition are studiedfirstly.and the corresponding pulse processing module is added to the activation calculation program ABURN.The test results of activation examples show that the CP(ESS)method can effectively improve the computational efficiency under the typical pulse conditions of inertial confinement fusion(IFE)and magnetic confinement fusion(MFE).Subsequently,the uncertainty analysis method based on sampling is studied,and the overall process of uncertainty analysis is established,including sample generation.K-S test,sample substitution in activation program calculation,mathematical statistics of activation calculation results,and uncertainty analysis module is added to ABURN program.Finally,the uncertainties of neutron activation calculation under single-step constant flux activation,pure decay.Single-stage Pulse and multi-stage pulse conditions are calculated and analyzed.The results are as follows:By comparing with the results of FISPACT-2007 program uncertainty calculation,the rationality of the established uncertainty analysis process and the accuracy of the program calculation results are preliminarily proved.In the calculation process,the Latin hypercube sampling method is used to improve the sampling efficiency;CP(ESS)method can effectively improve the calculation efficiency on the premise of ensuring the analysis accuracy for the uncertainty analysis process under single-stage and multi-stage pulse conditions.In summary,this paper studies the calculation methods and uncertainty analysis methods of neutron activation under various working conditions(especially pulse working conditions),establishes the process and program modules of uncertainty analysis of neutron activation calculation based on sampling method,and tests and verifies them.The research results in this paper have certain research value,help to improve the accuracy of neutron activation calculation under complex conditions,and have broad engineering application prospects. |
