Investigating eutectic behavior and material relocation in BC-stainless steel composites using the improved MPS method

Ahmed, Z.*; Wu, S.*; Sharma, A.*; Kumar, R.*; Yamano, Hidemasa; Pellegrini, M.*; Yokoyama, Ryo*; Okamoto, Koji*

International Journal of Heat and Mass Transfer, 250, p.127343_1 - 127343_17, 2025/11

https://doi.org/10.1016/j.ijheatmasstransfer.2025.127343

Core degradation behavior under ULOF transient on CFV-type core equipped SFR

Onoda, Yuichi; Kubota, Ryuzaburo*; Yamano, Hidemasa

Proceedings of 2025 International Congress on Advances in Nuclear Power Plants (ICAPP 2025) (Internet), 11 Pages, 2025/09

Reaction behavior between sodium and molten salt caused by the heat transfer tube failure for sodium-cooled fast reactor coupled to thermal energy storage system

Sato, Rika; Kondo, Toshiki; Umeda, Ryota; Kikuchi, Shin; Yamano, Hidemasa

Progress in Nuclear Science and Technology (Internet), 8, p.137 - 142, 2025/09

https://doi.org/10.15669/pnst.8.137

In a sodium-cooled fast reactor (SFR) coupled to thermal energy storage (TES) system, the reaction between nitrate molten salt as thermal energy storage medium and sodium (Na) as reactor coolant might occur under postulated accidental conditions. Thus, the reaction behavior of Na-nitrate molten salt is one of the important phenomena in terms of safety assessment of the SFR with TES system. In this study, reaction experiments on Na-solar salt were performed. It was found that Na-solar salt reaction occurred after the NaNO-KNO eutectic melting. Based on the measured reaction temperature, the kinetic parameters and rate constant were obtained and compared with the sodium-water reaction. From the results of kinetic analysis, it could be assumed that Na-solar salt reaction occurs in the time frame of the accident such as the failure of heat transfer tube of sodium-molten salt heat exchanger.

Characterization of relocated solidified eutectic melt of BC-stainless steel composite under severe reactor conditions

Ahmed, Z.*; Kumar, R.*; Yokoyama, Ryo*; Okamoto, Koji*; Pellegrini, M.*; Yamano, Hidemasa

Proceedings of 21st International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-21) (Internet), 15 Pages, 2025/08

Density, surface tension, and viscosity of molten Ni-based superalloys using the maximum bubble pressure and oscillating crucible methods

Nishi, Tsuyoshi*; Matsumoto, Saori*; Yamano, Hidemasa; Hayashi, Kiichiro*; Endo, Rie*; Bell, M. R.*; Neubert, L.*; Volkova, O.*

Steel Research International, 96(5), p.2300766_1 - 2300766_6, 2025/05

https://doi.org/10.1002/srin.202300766

The density of Ni-based superalloys is measured using the maximum bubble pressure (MBP) method. The viscosity is evaluated using the oscillating crucible method. The surface tension is simultaneously measured using the MBP method.

Density of a molten stainless steel-BC alloy measured in the electrostatic levitation furnace onboard the international space station

Ishikawa, Takehiko*; Oda, Hirohisa*; Koyama, Chihiro*; Shimonishi, Rina*; Ikeuchi, Rumiko*; Paradis, P.-F.*; Okada, Jumpei*; Fukuyama, Hiroyuki*; Yamano, Hidemasa

International Journal of Microgravity Science and Application, 42(2), p.420202_1 - 420202_10, 2025/04

https://doi.org/10.15011/jasma.42.420202

Density, surface tension, and viscosity of liquid low-sulfur manganese-boron steel via maximum bubble pressure and oscillating crucible methods

Bell, M. R.*; Neubert, L.*; Sherstneva, A.*; Yamamoto, Taisei*; Nishi, Tsuyoshi*; Yamano, Hidemasa; Weinberg, M.*; Volkova, O.*

Steel Research International, p.2400252_1 - 2400252_10, 2025/00

https://doi.org/10.1002/srin.202400252

In this study, the thermophysical properties of low-sulfur manganese-boron steel with varying boron and sulfur contents at different temperatures are investigated.

A Preliminary study for boron mixing effect on severe accident scenario in sodium-cooled fast reactor

Yamano, Hidemasa; Morita, Koji*

Proceedings of 13th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS13) (Internet), 9 Pages, 2024/11

SIMMER-III and SIMMER-IV; Computer codes for LMFR core disruptive accident analysis

Kondo, Satoru; Tobita, Yoshiharu*; Morita, Koji*; Kamiyama, Kenji; Yamano, Hidemasa; Suzuki, Toru*; Tagami, Hirotaka; Sogabe, Joji; Ishida, Shinya

JAEA-Research 2024-008, 235 Pages, 2024/10

JAEA-Research-2024-008.pdf:4.77MB

The SIMMER-III and SIMMER-IV computer codes, developed at the Japan Atomic Energy Agency are the codes with two- and three-dimensional, multi-field, multi-component fluid-dynamics models, coupled with a space- and time-dependent neutron kinetics model. The codes have been used widely for simulating complex phenomena during core-disruptive accidents in liquid-metal fast reactors. Advanced features of the codes in comparison with the former codes include: stable and robust fluid-dynamics algorithm with up to 8 velocity fields, improved representation of structures and multi-phase flow topology, comprehensive treatment of complex heat and mass transfer processes, accurate analytic equations of state, a stable and efficient neutron flux shape solution method and decay heat model. This report describes the models and methods of SIMMER-III and SIMMER-IV. For those individual models, the details of which have been reported elsewhere, only the outlines of the models are presented. The reports of code verification and validation have been already published.

Development of failure mitigation technologies for improving resilience of nuclear structures

Kasahara, Naoto*; Yamano, Hidemasa; Nakamura, Izumi*; Demachi, Kazuyuki*; Sato, Takuya*; Ichimiya, Masakazu*

International Journal of Pressure Vessels and Piping, 211, p.105298_1 - 105298_6, 2024/10

https://doi.org/10.1016/j.ijpvp.2024.105298