Akio Yamamoto

A psychosocial stress task increases finger mechanical impedance

Manami Kumano, Shunsuke Yoshimoto, Akio Yamamoto

Abstract Stress monitoring during daily work can enable early detection of work-related stress. Conventional stress monitoring requires collecting biological samples or wearing sensors, while existing unobtrusive methods face challenges regarding context. To address the issue, this work focuses on finger joint stiffness …

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Simplified P 3 neutron transport calculation based on smoothed particle hydrodynamics with second-order accuracy for second derivatives

Tomohiro Endo, Akio Yamamoto, Kosuke Tsujita

In order to facilitate the treatment of deformed geometries for the multiphysics simulation in reactor physics, the Smoothed Particle Hydrodynamics (SPH) method is applied to the Simplified P3 (SP3) neutron transport calculation. To accurately perform the SP3 neutron transport calculation, the SPH …

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A Factorization Approach Using Adaptive Proper Orthogonal Decomposition for Kinetics Calculations

Kosuke Tsujita, Tomohiro Endo, Akio Yamamoto

A new kinetics calculation method using factorization and proper orthogonal decomposition (POD) is proposed. In the present method, discretized neutron balance equations that have fine and coarse time resolutions are derived using the factorization of the neutron flux. Then dimensionality reduction using …

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A Nonlinear Diffusion Acceleration Scheme for the S N Transport Equation with Anisotropic Scattering Using the Local Discontinuous Galerkin Method

Rikuto Kasama, Tomohiro Endo, Akio Yamamoto

A nonlinear diffusion acceleration (NDA) scheme is developed to efficiently solve the SN transport equation with anisotropic scattering. The spatial discretization of the high-order transport and low-order diffusion equations is based on the discontinuous Galerkin finite element method. A key innovation of …

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Burnup calculation using POD-based neutron spectrum reconstruction

Tomoaki Watanabe, Naoto Aizawa, Go Chiba, Kenichi Tada et autres

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Ikaros3D: a real-time 3D fine spatial mesh kinetics simulator using POD

Kosuke Tsujita, Kaito Ito, Tomohiro Endo, Akio Yamamoto

Toward the development of digital triplets for more effective reactor physics education, the present study develops a real-time 3D fine spatial mesh kinetics simulator based on the proper orthogonal decomposition (POD). The present simulator, Ikaros3D, is specifically designed for a simplified coupled …

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Verification of in-core power distribution reconstruction based on POD for high-temperature gas-cooled reactors using ex-core detectors

Yuki Urase, Akio Yamamoto, Tomohiro Endo

A reconstruction method of in-core power distribution using the proper orthogonal decomposition (POD) and the signal from ex-core detectors is proposed. POD can efficiently reconstruct the in-core power distribution from a small number of constraints (i.e. detectors) by expressing the power (≈ …

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Absolute measurement of subcriticality in dollar units based on lag-1 autocovariance of zero-power reactor noise

Ryoga Hirota, Taiyo Moribe, Tomohiro Endo, Akio Yamamoto et autres

The zero-power reactor noise analysis is often utilized to measure a kinetic parameter of the prompt neutron decay constant α for a target subcritical system in a steady state. There will be large uncertainties in the point kinetics parameters when detailed information …

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A deterministic transport calculation method of α-eigenvalue for non-multiplying system using framework of k-eigenvalue calculation

Akio Yamamoto, Kosuke Tsujita, Tomohiro Endo

A new α-eigenvalue calculation method for a non-multiplying system using the framework of conventional k-eigenvalue calculation of a deterministic transport code is proposed. The time-derivative or the time-absorption term in α-eigenvalue calculation is moved to the right-hand side of the transport equation …

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Hybrid data assimilation methods for nuclear-data-induced uncertainties

Shuhei Maruyama, Akio Yamamoto, Tomohiro Endo

This study proposes new hybrid data assimilation (DA) methods to effectively use experimental data represented in two different ways in the DA process for reducing nuclear-data-induced uncertainties. Conventional DA methods often assume a linear model, where data in a DA database are …

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Treatment of corner crossing ray-traces in CMFD acceleration of MOC

Akio Yamamoto, Tomohiro Endo

Treatment of corner crossing ray traces in the coarse-mesh finite-difference (CMFD) acceleration of a method of characteristics (MOC) transport calculation is discussed. The contribution of the corner crossing ray trace at a CMFD mesh is independently tallied as partial current at the …

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Impact of nuclear data updates from JENDL-4.0 to JENDL-5 on burnup calculations of light-water reactor fuels

Tomoaki Watanabe, Kenichi Tada, Tomohiro Endo, Akio Yamamoto

This study investigated the impact of nuclear data updates from JENDL-4.0 (J4) to JENDL-5 (J5) on the light-water reactor fuel burnup calculations. Burnup calculations were conducted with J4 and J5 for pressurized water reactor pin-cell and boiling water reactor (BWR) fuel assembly …

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