Uncertainty analysis with double heterogeneity treatment based on the generalized perturbation theory

Two generalized adjoint solution modules, the generalized adjoint transport equation solver and the generalized adjoint B1 equation solver, were implemented into DeCART for the general response uncertainty analysis on the doubly heterogeneous system. The generalized adjoint transport equation solver for the doubly heterogeneous system was implemented based on the Sanchez-Pomraning method. Moreover, the generalized adjoint B1 equation solution scheme was newly set up using the adjoint B1 equation for an efficient calculation. From the benchmark analysis on the MHTGR-350 Ex. I-1, it was confirmed that the two generalized adjoint solver can provide reliable results for the doubly heterogeneous region. Then, the uncertainties for the kinf and the microscopic cross sections on the same problem were evaluated using DeCART/MUSAD code system. The results reveal that the double heterogeneity does not have a significant effect on the kinf uncertainty but slightly increases the uncertainty of 238U capture compared with the homogeneous case.