Neutron noise calculated from the neutron noise equation in the frequency domain is governed by the cross section and kinetic parameters. Deterministic and stochastic methods to obtain the sensitivity coefficient of neutron noise with respect to the abovementioned parameters are proposed. | Progress in Nuclear Energy 145 2022 104130 Contents lists available at ScienceDirect Progress in Nuclear Energy journal homepage locate pnucene Deterministic and stochastic methods for sensitivity analysis of neutron noise Toshihiro Yamamoto a Hiroki Sakamoto b a Institute for Integrated Radiation and Nuclear Science Kyoto University 2 Asashiro-Nishi Kumatori-cho Sennan-gun Osaka 590-0494 Japan b Radiation Dose Analysis and Evaluation Network 4-13-14 Kokubunji-shi Tokyo 185-0001 Japan A R T I C L E I N F O A B S T R A C T Keywords Neutron noise calculated from the neutron noise equation in the frequency domain is governed by the cross Neutron noise section and kinetic parameters. Deterministic and stochastic methods to obtain the sensitivity coefficient of Sensitivity coefficient neutron noise with respect to the abovementioned parameters are proposed. As a deterministic method a Diffusion equation diffusion equation for the first derivative of neutron noise with respect to a cross section or kinetic parameter is Monte Carlo derived by differentiating the neutron noise diffusion equation. As a stochastic method the differential operator sampling method which is a well-established Monte Carlo technique is applied to calculate the sensitivity co efficient. Neither method requires adjoint mode calculations and can be expanded to higher-order derivatives. Based on verifications performed in this study it is discovered that these techniques yield accurate sensitivity coefficients. The methods developed in this study eliminates a large number of calculations that need to be performed in the random sampling method. 1. Introduction the neutron noise by solving the frequency-domain diffusion or trans port equation for neutron noise. The frequency-domain method is Neutron noise in an operating power reactor core . inherent typically limited to diffusion approximation. A Monte Carlo method was fluctuations in neutron flux detected by in-core or ex-core .
