Introduction to Neutron Radiography Facilities at the Japan Research Reactor-3

Kurita, Keisuke; Iikura, Hiroshi; Tsuchikawa, Yusuke; Kai, Tetsuya; Shinohara, Takenao; Odaira, Naoya*; Ito, Daisuke*; Saito, Yasushi*; Matsubayashi, Masahito

Journal of Physics; Conference Series, 2605, p.012005_1 - 012005_6, 2023/10

https://doi.org/10.1088/1742-6596/2605/1/012005

The Japan Research Ractor-3 (JRR-3) is operation resumed on February 26, 2021, and the shared use was also restarted in July, 2021. With the resumption of JRR-3 operation, two imaging facilities called TNRF and CNRF have also resumed their utilization. In this presentation, we report the details of these two neutron facilities.

Development of tracer particles for thermal hydraulic experiment by neutron imaging

Saito, Yasushi*; Ito, Daisuke*; Odaira, Naoya*; Kurita, Keisuke; Iikura, Hiroshi

Journal of Physics; Conference Series, 2605, p.012028_1 - 012028_6, 2023/10

https://doi.org/10.1088/1742-6596/2605/1/012028

To observe flow velocity distributions by Neutron Imaging, suitable tracer is necessary. The requirements are its density, its visibility, and its wettability (if applied to liquid metal). Gold cadmium tracers have been developed for the Pb-Bi two-phase flow, however, the visibility have not been verified depending on the particle size and the measurement system. As the candidates of tracer particles, Ag, Cd, Au-Cd, and Ag-Cd have been tested by varying its compositions and its diameters. Results show enough visibility if the particles size is larger than 1mm. In addition, Cd tracer particles were applied to the fluidized bed, where the bed materials are metallic particle made of stainless steel, with 1mm diameter. The diameter of Cd trace is about 1.5 mm. From the neutron imaging, the visibility of the tracers is enough to measure the velocity distributions in the fluidized bed.

Visualization of gas-liquid interfacial behavior in a narrow channel using high-speed neutron imaging

Ito, Daisuke*; Odaira, Naoya*; Ito, Kei*; Saito, Yasushi*; Kurita, Keisuke; Iikura, Hiroshi

Konsoryu, 37(1), p.73 - 78, 2023/03

https://doi.org/10.3811/jjmf.2023.007

Gas-liquid two-phase flow is a very complicated flow phenomenon that involves the interaction between gas and liquid phases. Recently, an accurate simulation technique of two-phase flow has been developed. However, the validation of the simulated results is insufficient due to less experimental data. It is especially difficult to measure interfacial behavior with significant spatiotemporal fluctuation. To understand such phenomena, measurement methods with high spatial and temporal resolutions are required. Neutron imaging is a powerful tool for two-phase flow visualization. In this study, two-phase flow in the narrow rectangular channel was visualized by high-speed neutron imaging.

Measurements of pressure drop and void fraction of air-water two-phase flow in a sphere-packed bed

Yamamoto, Seishiro*; Odaira, Naoya*; Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Imaizumi, Yuya; Matsuba, Kenichi; Kamiyama, Kenji

Proceedings of 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS12) (Internet), 4 Pages, 2022/10

Status of LBE study and experimental plan at JAEA

Saito, Shigeru; Wan, T.*; Okubo, Nariaki; Obayashi, Hironari; Watanabe, Nao; Ohdaira, Naoya*; Kinoshita, Hidetaka; Yamaki, Kenichi*; Kita, Satoshi*; Yoshimoto, Hidemitsu*; et al.

JPS Conference Proceedings (Internet), 33, p.011041_1 - 011041_6, 2021/03

https://doi.org/10.7566/JPSCP.33.011041

An Accelerator Driven System (ADS) for waste transmutation investigated in JAEA employs lead-bismuth eutectic (LBE) as a neutron production target material and coolant. The neutrons are to be produced via the spallation with 1.5 GeV proton beam injection. As materials irradiation data are important for ADS development, JAEA plans to construct an irradiation facility with LBE neutron production target in J-PARC. There are many technical issues on LBE for practical use. In JAEA, various R&Ds are being carried out. Concerning corrosion study, conditioning operation and functional tests of OLLOCHI started. Oxygen concentration control technology has also developing. In the large scale LBE loop experiment, the operation for steady state and transient experiments was performed by using IMMORTAL. In the area of instrument, development of ultrasonic flow meter and freeze seal valve are progressing as a key technology for the LBE loop system. Investigation of behavior of impurities in LBE, which is important for design of the irradiation facility, started. In this paper, the status of the LBE studies and experimental plan will be presented.

The Analytical study of inventories and physicochemical configuration of spallation products produced in Lead-Bismuth Eutectic of Accelerator Driven System

Miyahara, Shinya*; Ohdaira, Naoya*; Arita, Yuji*; Maekawa, Fujio; Matsuda, Hiroki; Sasa, Toshinobu; Meigo, Shinichiro

Nuclear Engineering and Design, 352, p.110192_1 - 110192_8, 2019/10

https://doi.org/10.1016/j.nucengdes.2019.110192

Lead-Bismuth Eutectic (LBE) is used as a spallation neutron target and coolant materials of Accelerator Driven System (ADS), and many kinds of elements are produced as spallation products. It is important to evaluate the release and transport behavior of the spallation products in the LBE. The inventories and the physicochemical composition of the spallation products produced in LBE have been investigated for an LBE loop in the ADS Target Test Facility (TEF-T) in J-PARC. The inventories of the spallation products in the LBE were estimated using the PHITS code. The physicochemical composition of the spallation products in the LBE was calculated using the Thermo-Calc code under the conditions of the operation temperatures of LBE from 350C to 500C and the oxygen concentrations in LBE from 10 ppb to 1 ppm. The calculation showed that the 5 elements of Rb, Tl, Tc, Os, Ir, Pt, Au and Hg were soluble in LBE under the all given conditions and any kinds of compound were not formed in LBE. It was suggested that the oxides of Ce, Sr, Zr and Y were stable as CeO, SrO, ZrO and YO in the LBE.

Research on physicochemical composition of spallation products in lead-bismuth eutectic in ADS, 1; Estimation of inventories of spallation products

Maekawa, Fujio; Matsuda, Hiroki; Meigo, Shinichiro; Sasa, Toshinobu; Miyahara, Shinya*; Arita, Yuji*; Ohdaira, Naoya*

no journal, , 

To assess physicochemical composition of spallation products in Lead-Bismuth Eutectic (LBE) alloy which was to be used as a spallation neutron target and coolant materials of Accelerator Driven nuclear transmutation Systems (ADS), inventories of spallation products in an LBE loop of J-PARC ADS Target Test Facility (TEF-T) were evaluated.

Stress minimization procedure for stainless steel tube produced by phase transition of solidified lead-bismuth eutectic

Ohdaira, Naoya; Saito, Shigeru; Wan, T.; Obayashi, Hironari; Sasa, Toshinobu

no journal, , 

J-PARC plans to install a lead-bismuth eutectic (LBE) spallation target to study the irradiation effects of structural materials in flowing LBE environment. A freeze seal valve is to be used for the LBE circulation system. LBE is known as a material which expands after solidification; hence the solidified LBE in freeze seal part will be deformed and tube in freeze seal part might be broken by the imposed stress consequently. To minimize the stress at freeze seal valve, deformation of stainless steel (SS) generated by LBE expansion in different cooling conditions were studied. It was found that annealing at a certain temperature for 24 hours is effective to reduce the stress.

Visualization of gas-liquid two-phase flow in a packed bed of spheres

Fujitsu, Akito*; Odaira, Naoya*; Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Imaizumi, Yuya; Matsuba, Kenichi; Kamiyama, Kenji

no journal, , 

no abstracts in English

Effect of pressure gradient along axial direction of vortex-core on gas entrainment flow rate

Torikawa, Tomoaki*; Odaira, Naoya*; Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Matsushita, Kentaro; Ezure, Toshiki; Tanaka, Masaaki

no journal, , 

On free surface of a sodium cooled fast reactor, gas entrainment can be caused by free surface vortices, which may result in disturbance in core power. It is important to develop an evaluation model to predict accurately entrained gas flow rate. In this study, the effect of pressure gradient in vortex axis direction on the gas entrainment flow rate is investigated in a simple gas experimental apparatus, in which upper and lower tanks are connected by a suction pipe. As a result, it was observed that there are two flow regime: swirling annular flow regime shows the tendency that only the gas entrainment flow rate increases with almost constant pressure gradient, then, when liquid plug is induced by the development of free surface disturbance, the gas entrainment flow rate increases as the pressure gradient increases. In addition, it was confirmed that the transformation of those two flow regimes is advanced by higher liquid level in the upper tank.