Quantum critical behavior of the hyperkagome magnet MnCoSi

Yamauchi, Hiroki; Sari, D. P.*; Yasui, Yukio*; Sakakura, Terutoshi*; Kimura, Hiroyuki*; Nakao, Akiko*; Ohara, Takashi; Honda, Takashi*; Kodama, Katsuaki; Igawa, Naoki; et al.

Physical Review Research (Internet), 6(1), p.013144_1 - 013144_9, 2024/02

https://doi.org/10.1103/PhysRevResearch.6.013144

The Effects of unburned-gas temperature and pressure on the unstable behavior of cellular-flame fronts generated by intrinsic instability in hydrogen-air lean premixed flames under adiabatic and non-adiabatic conditions; Numerical simulation based on the detailed chemical reaction model

Thwe Thwe, A.; Kadowaki, Satoshi; Nagaishi, Ryuji

Journal of Nuclear Science and Technology, 60(6), p.731 - 742, 2023/06

https://doi.org/10.1080/00223131.2022.2143448

In this study, we performed numerical calculations of unsteady reaction flow considering detailed chemical reactions, investigated the unstable behavior of hydrogen-air dilute premixed flame due to intrinsic instability, and clarified the effects of unburned gas temperature and pressure. I made it. The unstable behavior of the flame in a wide space was simulated, and the burning rate of the cellular flame was obtained. Then, the effects of heat loss and flame scale on flame unstable behavior were investigated. The burning velocity of a planar flame increases as the unburned-gas temperature increases and it decreases as the unburned-gas pressure and heat loss increase. The normalized burning velocity increases when the pressure increases and heat loss becomes large, and it decreases when the temperature increases. This is because the high unburned-gas pressure and heat loss promote the unstable behavior and instability of flame.

Development plan for coupling technology between high temperature gas-cooled reactor HTTR and hydrogen production facility, 1; Overview of the HTTR heat application test plan to establish high safety coupling technology

Nomoto, Yasunobu; Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; et al.

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 7 Pages, 2023/05

Toward long-term storage of nuclear materials in MOX fuels fabrication facility

Hirooka, Shun; Nakamichi, Shinya; Matsumoto, Taku; Tsuchimochi, Ryota; Murakami, Tatsutoshi

Frontiers in Nuclear Engineering (Internet), 2, p.1119567_1 - 1119567_7, 2023/03

https://doi.org/10.3389/fnuen.2023.1119567

Storage of plutonium (Pu)-containing materials requires extremely strict attention in terms of physical safety and material accounting. Despite the emphasized importance of storage management, only a few reports are available in the public, e.g., experience in PuO storage in the UK and safety standards in the storage of Pu-containing materials in the US. Japan also stores more U-Pu mixed oxide (MOX) mostly in powder form. Adopting an appropriate storage management is necessary depending on the characteristics of MOX items such as raw powder obtained by reprocessing of spent Light Water Reactor fuels, research and development on the remains of fuel fabrication, which can contain organic materials, and dry-recycled powder during fuel fabrication. Stagnation in fuel fabrications and experience in degradation of MOX containers during extended period of storage have led to the review of the storage method in the Plutonium Fuel Development Center in Japan Atomic Energy Agency. The present work discusses the various nuclear materials, storage methods, experience in degradation of containers that occur during storage, and strategies for future long-term storage.

Electronic properties of DNA-related molecules containing a bromine atom

Hirato, Misaki*; Onizawa, Misato*; Baba, Yuji*; Haga, Yoshinori; Fujii, Kentaro*; Wada, Shinichi*; Yokoya, Akinari*

International Journal of Radiation Biology, 99(1), p.82 - 88, 2023/01

https://doi.org/10.1080/09553002.2020.1800121

A 3D particle-based simulation of heat and mass transfer behavior in the EAGLE ID1 in-pile test

Zhang, T.*; Morita, Koji*; Liu, X.*; Liu, W.*; Kamiyama, Kenji

Annals of Nuclear Energy, 179, p.109389_1 - 109389_10, 2022/12

https://doi.org/10.1016/j.anucene.2022.109389

Preliminary deformation analysis of the reactor vessel due to core debris accumulation onto the reactor vessel bottom for sodium-cooled fast reactor

Onoda, Yuichi; Yamano, Hidemasa

Proceedings of 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS12) (Internet), 9 Pages, 2022/10

In Japan, sodium-cooled fast reactor design takes In-Vessel Retention (IVR) strategy to stably cool damaged core materials in the reactor vessel during a severe accident with various design measures. Although a possibility to fail IVR is extremely low, a probabilistic risk assessment study needs a wide variety of scenarios including the IVR failure. Therefore, in order to study a wide range of event spectra related to stable cooling of debris in the reactor vessel, this study numerically investigated the deformation and failure behavior of the reactor vessel due to the debris deposited onto the skirt of the core catcher using the FINAS-STAR structural analysis code. The analyses are conducted in two cases of power density with the aim of investigating failure conditions of the bottom of the reactor vessel. Reactor vessel deforms significantly when the temperature reaches about 1100 C and the reactor vessel reaches the failure criteria in high-power-density case.

Neutronic analysis of beam window and LBE of an Accelerator-Driven System

Nakano, Keita; Iwamoto, Hiroki; Nishihara, Kenji; Meigo, Shinichiro; Sugawara, Takanori; Iwamoto, Yosuke; Takeshita, Hayato*; Maekawa, Fujio

JAEA-Research 2021-018, 41 Pages, 2022/03

JAEA-Research-2021-018.pdf:2.93MB

Neutronic analysis of beam window of the Accelerator-Driven System (ADS) proposed by Japan Atomic Energy Agency (JAEA) has been conducted using PHITS and DCHAIN-PHITS codes. We investigate gas production of hydrogen and helium isotopes in the beam window, displacement per atom of beam window material, and heat generation in the beam window. In addition, distributions of produced nuclides, heat density, and activity are derived. It was found that at the maximum 12500 appm H production, 1800 appm He production, and damage of 62.1 DPA occurred in the beam window by the ADS operation. On the other hand, the maximum heat generation in the beam window was 374 W/cm. In the analysis of LBE, Bi and Po were found to be the dominant nuclides in decay heat and radioactivity. Furthermore, the heat generation in the LBE by the proton beam was maximum around 5 cm downstream of the beam window, which was 945 W/cm.

Direct temperature measurement for lamp-based heating device

Sumita, Takehiro; Sudo, Ayako; Takano, Masahide; Ikeda, Atsushi

Science and Technology of Advanced Materials; Methods (Internet), 2(1), p.50 - 54, 2022/02

https://doi.org/10.1080/27660400.2022.2035097

A 3D particle-based analysis of molten pool-to-structural wall heat transfer in a simulated fuel subassembly

Zhang, T.*; Morita, Koji*; Liu, X.*; Liu, W.*; Kamiyama, Kenji

Extended abstracts of the 2nd Asian Conference on Thermal Sciences (Internet), 2 Pages, 2021/10

For the Japanese sodium cooled fast reactor, a fuel subassembly with an inner duct structure (FAIDUS) was designed to avoid the re-criticality by preventing the large-scale pool formation. In the present study, using the finite volume particle method, the EAGLE ID1 test which was an in-pile test performed to demonstrate the effectiveness of FAIDUS was numerically simulated and the thermal-hydraulic mechanisms underlying the heat transfer process were analyzed.