Comprehensive Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) Applied to a Subcritical Experimental Reactor Physics Benchmark

The Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) developed by Cacuci has been applied to compute deterministically the exact values of the 1st-order and 2nd-order sensitivities of the leakage response of a polyethylene-reflected plutonium (PoRP) experimental benchmark to the nuclear data characterizing this benchmark. The imprecisely known parameters underlying the nuclear data used in the neutron transport computational model for this benchmark include 180 group-averaged total microscopic cross sections, 21600 group-averaged scattering microscopic cross sections, 120 parameters describing the fission process, 60 parameters describing the fission spectrum, 10 parameters describing the system’s sources, and 6 isotopic number densities. Thus, this benchmark comprises 21976 first-order sensitivities of the leakage response with respect to the model parameters, and 482,944,576 second-order sensitivities. Computing these sensitivities exactly represents the largest sensitivity analysis endeavor ever attempted in reactor physics, and probably in any field, as well. Due to the symmetry of the 2nd-order sensitivities, only 241,483,276 are distinct from each other, and some of these turned out to be zero.<br>Data fie “sens_2nd_sigt_sigt.xlsx” is for “2nd-order sensitivities of the leakage response with respect to total/total microscopic cross sections.<br> Data fie “sens_2nd_sigt_sigs.xlsx” is for “2nd-order sensitivities of the leakage response with respect to total/scattering microscopic cross sections.<br> Data fie “sens_2nd_sigt_sigf.xlsx” is for “2nd-order sensitivities of the leakage response with respect to total/fission microscopic cross sections.<br> Data fie “sens_2nd_sigt_nu.xlsx” is for “2nd-order sensitivities of the leakage response with respect to total microscopic cross sections and average number of neutrons per fission (nu).<br> Data fie “sens_2nd_sigs_sigt.xlsx” is for “2nd-order sensitivities of the leakage response with respect to scattering/total microscopic cross sections.<br> Data fie “sens_2nd_unmixed_sigs_sigs.xlsx” is for “2nd-order sensitivities of the leakage response with respect to unmixed (i.e., to the same parameter) scattering/scattering microscopic cross sections.<br> Data fie “sens_2nd_sigs_sigf.xlsx” is for “2nd-order sensitivities of the leakage response with respect to scattering/fission microscopic cross sections.<br> Data fie “sens_2nd_sigs_nu.xlsx” is for “2nd-order sensitivities of the leakage response with respect to scattering microscopic cross sections and average number of neutrons per fission (nu).<br> Data fie “sens_2nd_sigf_sigt.xlsx” is for “2nd-order sensitivities of the leakage response with respect to fission/total microscopic cross sections.<br> Data fie “sens_2nd_sigf_sigs.xlsx” is for “2nd-order sensitivities of the leakage response with respect to fission/scattering microscopic cross sections.<br> Data fie “sens_2nd_sigf_sigf.xlsx” is for “2nd-order sensitivities of the leakage response with respect to fission /fission microscopic cross sections.<br> Data fie “sens_2nd_sigf_nu.xlsx” is for “2nd-order sensitivities of the leakage response with respect to fission microscopic cross sections and average number of neutrons per fission (nu).<br> Data fie “sens_2nd_nu_sigt.xlsx” is for “2nd-order sensitivities of the leakage response with respect to parameters underlying the average number of neutrons per fission (nu) and total microscopic cross sections.<br> Data fie “sens_2nd_nu_sigs.xlsx” is for “2nd-order sensitivities of the leakage response with respect to parameters underlying the average number of neutrons per fission (nu) and scattering microscopic cross sections.<br> Data fie “sens_2nd_nu_sigf.xlsx” is for “2nd-order sensitivities of the leakage response with respect to parameters underlying the average number of neutrons per fission (nu) and fission microscopic cross sections.<br> Data fie “sens_2nd_nu_nu.xlsx” is for “2nd-order sensitivities of the leakage response with respect to parameters underlying the average number of neutrons per fission (nu) and the average number of neutrons per fission (nu).<br><br>