[1D05-07] Uncertainty Evaluation Method

11:35 AM - 11:50 AM JST(2:35 AM - 2:50 AM UTC)

[1D07] _{Influence of implicit effect for multi-group cross-section perturbation on random-sampling-based uncertainty propagation}

*Tatsuya Fujita¹ (1. JAEA)

Keywords:

random sampling,implicit effect,FRENDY,GENESIS,NJOY,JENDL-5,SERPENT

Past studies have mentioned that the treatment of implicit effect for cross-section perturbation affects the sensitivity coefficients and then the uncertainty propagation for neutronics parameters. The several approaches to consider the implicit effect have also been discussed for the random-sampling-based uncertainty propagation. In this study, continued from the presentation in the AESJ 2024 spring meeting, the influence of implicit effect for multi-group cross-section perturbation on random-sampling-based uncertainty propagation was evaluated for the k-infinity uncertainty in the multi-group neutron transport calculation. While the influence of the implicit effect was small on the UO₂ fuel pin-cell geometry, large influence was observed in the MOX fuel pin-cell geometry. However, it was considered that this influence could be reduced by refining the number of energy group in neutron transport calculation and cross-section covariance matrix.