Sensitivity analysis for neutron multiplication parameters of accelerator driven subcritical system

Chiba, Go; Nishihara, Kenji  ; Endo, Tomohiro*

Sensitivity calculations are carried out for some neutronic parameters on neutron multiplication in subcritical systems. Sensitivities of the subcriticality multiplication rate and the generation-wise neutron multiplication rate , which is a new neutronic parameter proposed in the present paper, are calculated, and these sensitivities are compared with the sensitivities which have been conventionally used for sensitivity works. The present sensitivity calculations show that the sensitivities of and in small values of are significantly different from the sensitivities. This result indicates that the sensitivity analyses focusing only on the solution of the eigenvalue equation cannot provide full information on the core properties of subcritical systems, and that the sensitivities of the other neutronic parameters describing real neutron multiplication are essential.