Polarization analysis for small-angle neutron scattering with a He spin filter at a pulsed neutron source

Okudaira, Takuya; Ueda, Yuki; Hiroi, Kosuke; Motokawa, Ryuhei; Inamura, Yasuhiro; Takata, Shinichi; Oku, Takayuki; Suzuki, Junichi*; Takahashi, Shingo*; Endo, Hitoshi*; et al.

Journal of Applied Crystallography, 54(2), p.548 - 556, 2021/04

https://doi.org/10.1107/S1600576721001643

Neutron polarization analysis (NPA) for small-angle neutron scattering (SANS) experiments using a pulsed neutron source was successfully achieved by applying a He spin filter as a spin analyzer for the scattered neutrons. The He spin filter covers a sufficient solid angle for performing SANS experiments, and the relaxation time of the He polarization is sufficient for continuous use over a few days, thus reaching the typical duration required for a complete set of SANS experiments. Although accurate evaluation of the incoherent neutron scattering, which is predominantly attributable to hydrogen atoms in samples, is practically difficult using calculations based on the sample elemental composition, the developed NPA approach with consideration of the influence of multiple neutron scattering enabled reliable decomposition of the SANS intensity distribution into the coherent and incoherent scattering components. To date, NPA has not been well established as a standard technique for SANS experiments at pulsed neutron sources. This work is anticipated to greatly contribute to the accurate determination of the coherent neutron scattering component for scatterers in various types of organic sample systems in SANS experiments at J-PARC.

Homogeneity of neutron transmission imaging over a large sensitive area with a four-channel superconducting detector

Vu, TheDang; Shishido, Hiroaki*; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Miyajima, Shigeyuki*; Oku, Takayuki; Soyama, Kazuhiko; Aizawa, Kazuya; et al.

Superconductor Science and Technology, 34(1), p.015010_1 - 015010_10, 2021/01

https://doi.org/10.1088/1361-6668/abc2af

Development of spin-contrast-variation neutron reflectometry for structural analyses of multilayer films

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Suzuki, Junichi*; Torikai, Naoya*

Hamon, 30(4), p.207 - 211, 2020/11

We developed a technique of spin-contrast-variation neutron reflectivity (SCV-NR) for structural analyses of multilayer films. The SCV-NR curves of the polystyrene monolayer film were precisely reproduced using a common set of structural parameters and neutron scattering length density at each proton polarization. This result ensures that SCV-NR curves are not deformed by inhomogeneous PH due to the spin-diffusion mechanism. The number of structural parameters of the lamellar microphase-separated poly(styrene-block-isoprene) thin film is too large to determine with a single unpolarized reflectivity curve only. However, these parameters converged through the global analysis of the SCV-NR curves. In this manner, SCV-NR determines the structure of multilayer films while excluding the incorrect structural model that accidentally accounts for a single unpolarized reflectivity curve only.

JAEA activities related to the use of computer programs and databases in the nuclear field

Suzuki, Yoshio; Otani, Takayuki; Sakamoto, Kensaku; Takakura, Masahiro*; Kuwabara, Yasuhiro*

Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.287 - 294, 2020/10

HPC Technology Promotion Office, Center for Computational Science and e-systems (CCSE) of Japan Atomic Energy Agency (JAEA) is responsible for the administration of computer programs (CPs) and databases (DBs) developed in JAEA to disseminate R&D results in JAEA to the outside and improve R&D efficiency. The information of these CPs and DBs can be found using Program and Database retrieval System (PRODAS) (https://prodas.jaea.go.jp), which is developed by our team. Those in Japan can also obtain CPs and DBs in the nuclear field possessed in OECD NEA Data Bank (NEADB), Radiation Safety Information Computational Center (RSICC) in the United States, and International Atomic Energy Agency (IAEA). In this paper, the recent situation of possession and dispatch of CPs and DBs developed within JAEA and the frameworks to obtain and provide CPs and DBs in nuclear field worldwide are presented.

Numerical simulation of two-phase flow in 44 simulated bundle

Ono, Ayako; Yamashita, Susumu; Suzuki, Takayuki*; Yoshida, Hiroyuki

Mechanical Engineering Journal (Internet), 7(3), p.19-00583_1 - 19-00583_12, 2020/06

https://doi.org/10.1299/mej.19-00583

JAEA is implementing the 3D detailed nuclear-thermal-coupled analysis code to analyze the transition state of the core and to reduce the likelihood of the design. In the development plan, the computational fluid dynamics code based on the VOF method, JUPITER, is applied for TH part of the 3D detailed nuclear-thermal-coupled analysis code.

Study on the two-phase flow in simulated LWR fuel bundle by CFD code

Ono, Ayako; Yamashita, Susumu; Suzuki, Takayuki*; Yoshida, Hiroyuki

Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.666 - 677, 2019/08

An evaluation methodology of critical heat fluxes (CHFs) based on a mechanism for fuel assemblies in light water reactors (LWRs) is needed in order to design and evaluate the safety for the fuel assemblies in LWRs. In our study, the numerical simulation with surface-tracking will be applied for the two-phase flow in fuel assemblies in order to obtain the detail data relating to the size and velocity of bubbles in the subchannel, which is needed to predict the CHF based on the mechanism. In this study, the numerical simulation of two-phase flow in 44 bundle was implemented by using JUPITER in order to establish the evaluation method of the size and velocity of bubbles by the numerical simulation, which is the multi-physics simulation code and enable to track the gas-liquid surface. The simulation results are validated by the curve of flow regime for air-water under the adiabatic condition. The bubble and velocity of bubbles obtained by simulation results are analyzed.

Measurement of water-steam flow behavior and pressure distribution in venturi scrubber

Uesawa, Shinichiro; Horiguchi, Naoki; Suzuki, Takayuki*; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 11 Pages, 2018/10

Development of simultaneous evaluation method of bubble behavior and electric field distribution around WMS by using TPFIT and EMSolution

Uesawa, Shinichiro; Suzuki, Takayuki*; Yoshida, Hiroyuki

Konsoryu Shimpojiumu 2018 Koen Rombunshu (Internet), 2 Pages, 2018/08

no abstracts in English

Numerical study on effect of pressure on behavior of bubble coalescence by using CMFD simulation

Ono, Ayako; Suzuki, Takayuki*; Yoshida, Hiroyuki

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 6 Pages, 2018/07

The mechanism of critical heat flux (CHF) for higher system pressure remains to be clarified, even though it is important to evaluate the CHF for the light water reactor (LWR) which is operated under the high pressure condition. In this study, the process of bubble coalescence was simulated by using a computational multi-fluid dynamics (CMFD) simulation code TPFIT under various system pressure in order to investigate the behavior of bubbles as a basic study. The growth of bubbles was simulated by blowing of vapor from a tiny orifice simulating bubble bottom. One or four orifices were located on the bottom surface in this simulation study. The numerical simulations were conducted by varying the pressure and temperature.

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, 3; Neutron devices and computational and sample environments

Sakasai, Kaoru; Sato, Setsuo*; Seya, Tomohiro*; Nakamura, Tatsuya; To, Kentaro; Yamagishi, Hideshi*; Soyama, Kazuhiko; Yamazaki, Dai; Maruyama, Ryuji; Oku, Takayuki; et al.

Quantum Beam Science (Internet), 1(2), p.10_1 - 10_35, 2017/09

https://doi.org/10.3390/qubs1020010

Neutron devices such as neutron detectors, optical devices including supermirror devices and He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.