SR studies on copper minerals

Fujihara, Masayoshi; Okabe, Hirotaka*; Koda, Akihiro*

Interactions (Internet), 245(1), p.13_1 - 13_6, 2024/12

https://doi.org/10.1007/s10751-024-01856-7

Quantum states are difficult to observe experimentally. In addition, ideal model materials have not been found for some of the lattice systems in which exotic quantum states are predicted to be realized. Numerous candidates for low-dimensional quantum magnets are hidden in copper minerals, and the number of candidates is increasing every year. We succeeded to synthesize seven copper minerals by imitating the environment where they are discovered and reported their quantum states. The properties of pulsed muons are very suitable for investigating the spin state of artificial copper minerals.

User's manual and analysis methodology of probabilistic fracture mechanics analysis code PASCAL Ver.5 for reactor pressure vessels

Takamizawa, Hisashi; Lu, K.; Katsuyama, Jinya; Masaki, Koichi*; Miyamoto, Yuhei*; Li, Y.

JAEA-Data/Code 2022-006, 221 Pages, 2023/02

JAEA-Data-Code-2022-006.pdf:4.79MB

As a part of the structural integrity assessment research for aging light water reactor (LWR) components, a probabilistic fracture mechanics (PFM) analysis code PASCAL (PFM Analysis of Structural Components in Aging LWR) has been developed in Japan Atomic Energy Agency. The PASCAL code can evaluate failure probabilities and failure frequencies of core region in reactor pressure vessel (RPV) under transients by considering the uncertainties of influential parameters. The continuous development of the code aims to improve the reliability by introducing the analysis methodologies and functions base on the state-of-the-art knowledge in fracture mechanics and domestic data. In the first version of PASCAL, which was released in FY2000, the basic framework was developed for analyzing failure probabilities considering pressurized thermal shock events for RPVs in pressurized water reactors (PWRs). In PASCAL Ver. 2 released in FY 2006, analysis functions including the evaluation methods for embedded cracks and crack detection probability models for inspection were introduced. In PASCAL Ver. 3 released in FY 2010, functions considering weld-overlay cladding on the inner surface of RPV were introduced. In PASCAL Ver. 4 released in FY 2017, we improved several functions such as the stress intensity factor solutions, probabilistic fracture toughness evaluation models, and confidence level evaluation function by considering epistemic and aleatory uncertainties related to influential parameters. In addition, the probabilistic calculation method was also improved to speed up the failure probability calculations. To strengthen the practical applications of PFM methodology in Japan, PASCAL code has been improved since FY 2018 to enable PFM analyses of RPVs subjected to a broad range of transients corresponding to both PWRs and boiling water reactors, including pressurized thermal shock, low-temperature over pressure, and normal operational transients. In particular, the stress intensi

Enhancement of uniform elongation by temperature change during tensile deformation in a 0.2C TRIP steel

Tsuchida, Noriyuki*; Harjo, S.

Metals, 11(12), p.2053_1 - 2053_16, 2021/12

https://doi.org/10.3390/met11122053

Martensitic transformation in CrCoNi medium-entropy alloy at cryogenic temperature

Naeem, M.*; Zhou, H.*; He, H.*; Harjo, S.; Kawasaki, Takuro; Lan, S.*; Wu, Z.*; Zhu, Y.*; Wang, X.-L.*

Applied Physics Letters, 119(13), p.131901_1 - 131901_7, 2021/09

https://doi.org/10.1063/5.0067268

Stacking fault driven phase transformation in CrCoNi medium entropy alloy

He, H.*; Naeem, M.*; Zhang, F.*; Zhao, Y.*; Harjo, S.; Kawasaki, Takuro; Wang, B.*; Wu, X.*; Lan, S.*; Wu, Z.*; et al.

Nano Letters, 21(3), p.1419 - 1426, 2021/02

https://doi.org/10.1021/acs.nanolett.0c04244

Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

EPJ Web of Conferences, 239, p.06006_1 - 06006_4, 2020/09

https://doi.org/10.1051/epjconf/202023906006

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and copper was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.

Neutron diffraction study of temperature-dependent elasticity of B19' NiTi; Elinvar effect and elastic softening

Ahadi, A.*; Khaledialidusti, R.*; Kawasaki, Takuro; Harjo, S.; Barnoush, A.*; Tsuchiya, Koichi*

Acta Materialia, 173, p.281 - 291, 2019/07

https://doi.org/10.1016/j.actamat.2019.05.027

Reversible elastocaloric effect at ultra-low temperatures in nanocrystalline shape memory alloys

Ahadi, A.*; Kawasaki, Takuro; Harjo, S.; Ko, W.-S.*; Sun, Q. P.*; Tsuchiya, Koichi*

Acta Materialia, 165, p.109 - 117, 2019/02

https://doi.org/10.1016/j.actamat.2018.11.035

Evaluation of the cryogenic tensile properties for aramid fiber rod

Saito, Toru; Okubo, Toshikazu*; Izumi, Keisuke*; Okawa, Yoshinao*; Kobayashi, Norihiro*; Yamazaki, Toru; Kawano, Katsumi; Isono, Takaaki

Teion Kogaku, 50(8), p.400 - 408, 2015/08

https://doi.org/10.2221/jcsj.50.400

Aramid fiber-reinforced plastic (AFRP) has been developed as a structural material that has the advantages of light weight and high strength. In this study, tensile tests were carried out to measure the tensile properties of AFRP rod on the market for reinforcement of concrete at room temperature, 77 K and 4.2 K. Especially at cryogenic temperatures, it is difficult to perform a tensile test of the bar because the specimen slips through the jig grip. To prevent the rod from slipping, tensile tests were carried out with some filling conditions. The applicable and appropriate tensile test conditions were established by modifying the jig grip, treating the surface of the rod and using cryogenic epoxy infill to grip the rod. They were more than 1100 MPa. Additionally, the AFRP rod included a temperature dependence in which the Young's modulus increased as the test temperature decreased. It was confirmed that the Young's modulus increased because aramid fiber was more dominant than epoxy.

Numerical analysis for the emergency discharge of the hydrogen loop of JSNS

Hasegawa, Shoichi; Kato, Takashi; Aso, Tomokazu; Ushijima, Isamu*; Tatsumoto, Hideki; Otsu, Kiichi*; Ikeda, Yujiro

LA-UR-06-3904, Vol.2, p.402 - 407, 2006/06

In JSNS, the hydrogen of super critical state is adopted as moderators. Therefore the cryogenic hydrogen system is prepared, which consists of hydrogen circulating unit and transfer lines to moderators. The hydrogen system will immediately discharge hydrogen when an off-normal event occurs. In case of emergency, helium gas will be inputted to an insulation vacuum of the transfer line in order to enhance the heat transfer and the hydrogen discharge time should be shortened. Then, it is impotant to estimate the behaviour of pressure and velocity of discharging hydrogen in the emergency. During hydrogen discharge, the pressure rise in the discharge piping should be kept below the design pressure of 0.1 MPa. The result of analysis shows that the pressure of helium gas injection is suitable less than 0.04Mpa, and that the maximum hydrogen discharge flow is evaluated to be 0.047 kg/s after around 150 seconds. After five minutes with this condition, the hydrogen of around 90% in the moderator piping is discharged. Safety hydrogen release in the case of emergency can be established.