Sensitivity and uncertainty analysis of burnup reactivity for an accelerator-driven system

岩元 大樹; Mathias, M.*; 西原 健司

no journal, , 

A burnup calculation is carried out for an accelerator-driven system (ADS) proposed by the Japan Atomic Energy Agency (JAEA) with the fourth version of JENDL, JENDL-4.0 and the previous one, JENDL-3.3. Considerable differences are seen in burnup reactivity between the nuclear data libraries for an initial phase (first burnup cycle) and an equilibrium phase (tenth burnup cycle). The differences in these values are investigated using two methods: a method by replacing a nuclear data library by nuclide and a sensitivity analysis technique. Among many contributors to them for the both phases, we identify major ones; (i) the initial phase: fission cross section and fission neutron multiplicity of Pu, capture cross section of Am, and(ii) the equilibrium phase: capture cross section of Cm and Am, and inelastic scattering cross section of Pb. The uncertainty analysis shows that uncertainties in the bunrup reactivity deduced from the JENDL-4.0 covariance data are comparable in magnitude to the differences between the nuclear data libraries, and are dominated by nuclear data parameters of Pu. Finally, we show the necessity of uncertainty evaluation of the branching ratio of Am capture reaction.