Development of corrosion-stable dual-Si-layered membranes for hydrogen production via thermochemical iodine-sulfur process

Myagmarjav, O.; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Ono, Masato; Nomura, Mikihiro*; Takegami, Hiroaki

Progress in Nuclear Science and Technology (Internet), 7, p.235 - 242, 2025/05

https://doi.org/10.15669/pnst.7.235

Development of a method for distinguishing alpha particles from other types of radiation using a high-resolution alpha imager

Morishita, Yuki; Sagawa, Naoki; Fujisawa, Makoto; Kurosawa, Shunsuke*; Sasano, Makoto*; Hayashi, Masateru*; Tanaka, Hiroki*

Radiation Measurements, 181, p.107371_1 - 107371_5, 2025/02

https://doi.org/10.1016/j.radmeas.2024.107371

The effects of different types of radiation on a high-resolution alpha imager developed using an electron multiplying charge-coupled device (EMCCD) camera were investigated. This imager was originally developed to visualize alpha particles from Pu oxide particles at decommissioning sites. Other types of radiation such as beta particles, gamma rays, and neutrons are also present. The purpose of this study is to investigate the effects of these background radiations on the imager and to develop a method to discriminate between alpha particles and other types of radiation. When measuring gamma rays, and neutrons, the sensor of the EMCCD camera generated high intensity signals due to gamma rays and neutrons. These radiations were identified by image processing. The image values were binarized and the findContours function was applied to count the number of alpha particle spots. The results showed that alpha and gamma (neutron) radiation can be discriminated by using differences in intensity. This method will be useful for visualizing alpha particles at decommissioning sites.

Developing an online composition prediction for an HI-I-HO system using deep neural network

Tanaka, Nobuyuki; Takegami, Hiroaki; Noguchi, Hiroki; Kamiji, Yu; Myagmarjav, O.; Ono, Masato; Sugimoto, Chihiro

Chemical Engineering Science, 299, p.120479_1 - 120479_11, 2024/11

https://doi.org/10.1016/j.ces.2024.120479

We developed a deep neural network method to predict the composition of the iodine-sulfur process of thermochemical water-splitting hydrogen production using measurable properties. Unlike conventional titration analysis, this approach allows a quick understanding of fluid composition, providing essential information for controlling operating conditions. This study focused on the HI-I-HO three-component system within the IS process. Using Gibbs phase rule, the DNN model was constructed using online measurable parameters, such as temperature, pressure, and density, as input conditions. The model was trained with experimental data, and the structural parameters were tuned. Composition prediction using actual trend data demonstrated good correlation with titration analysis measurements. Furthermore, the local interpretable model-agnostic explanations method was incorporated to gain insights into the significance of input parameters for compositions from the DNN model, providing valuable information on crucial parameters for effective composition control.

R&D status of digital technology on inverse estimation of radioactive source distributions and related source countermeasures; Fast Digital Twin Tech. in Decommissioning Field: 3D-ADRES-Indoor FrontEnd

Machida, Masahiko; Yamada, Susumu; Kim, M.; Tanaka, Satoshi*; Tobita, Yasuhiro*; Iwata, Ayako*; Aoki, Yuto; Aoki, Kazuhisa; Yanagisawa, Kenichi*; Yamaguchi, Takashi; et al.

RIST News, (70), p.3 - 22, 2024/09

Inside the Fukushima Daiichi Nuclear Power Plant (1F), there are many locations with high radiation levels due to contamination by radioactive materials that leaked from the reactor. These pose a significant obstacle to the smooth progress of decommissioning work. To help solve this issue, the Japan Atomic Energy Agency (JAEA), under a subsidy from the Ministry of Economy, Trade, and Industry's decommissioning and contaminated water management project, is conducting research and development on digital technologies to improve the radiation environment inside the decommissioning site. This project, titled "Development of Technology to Improve the Environment Inside Reactor Buildings (Enhancing Digital Technology for Environment and Source Distribution to Reduce Radiation Exposure)," began in April of FY 2023. In this project, the aim is to develop three interconnected systems: FrontEnd, Pro, and BackEnd. The FrontEnd system, based on the previously developed 3D-ADRES-Indoor (prototype) from FY 2021-2022, will be upgraded to a high-speed digital twin technology usable on-site. The Pro system will carry out detailed analysis in rooms such as the new office building at 1F, while the BackEnd system will serve as a database to centrally manage the collected and analyzed data. This report focuses on the FrontEnd system, which will be used on-site. After point cloud measurement, the system will quickly create a 3D mesh model, estimate the radiation source from dose rate measurements, and refine the position and intensity of the estimated source using recalculation techniques (re-observation instructions and re-estimation). The results of verification tests conducted on Unit 5 are also presented. Furthermore, the report briefly discusses the future research and development plans for this project.

Development of DynamicMC for PHITS Monte Carlo package

Watabe, Hiroshi*; Sato, Tatsuhiko; Yu, K. N.*; Zivkovic, M.*; Krstic, D.*; Nikezic, D.*; Kim, K. M.*; Yamaya, Taiga*; Kawachi, Naoki*; Tanaka, Hiroki*; et al.

Radiation Protection Dosimetry, 200(2), p.130 - 142, 2024/02

https://doi.org/10.1093/rpd/ncad278

Previously, we have developed DynamicMC for modelling relative movement of ORNL phantom in a radiation field for MCNP. Using this software, 3-dimensional dose distributions in a phantom irradiated by a certain mono-energetic source can be deduced through its graphical user interface (GUI). In this study, we extended DynamicMC to be used in combination with the PHITS by providing it with a higher flexibility for dynamic movement for a less sophisticated anthropomorphic phantom. We anticipate that the present work and the developed open-source tools will be in the interest of nuclear radiation physics community for research and teaching purposes.

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

Development of ARKADIA for the innovation of advanced nuclear reactor design process (Overview of optimization process development in design optimization support tool, ARKADIA-Design)

Tanaka, Masaaki; Doda, Norihiro; Yokoyama, Kenji; Mori, Takero; Okajima, Satoshi; Hashidate, Ryuta; Yada, Hiroki; Oki, Shigeo; Miyazaki, Masashi; Takaya, Shigeru

Dai-26-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 5 Pages, 2022/07

https://doi.org/10.1299/jsmepes.2022.26.A221

To assist conceptual studies of various reactor systems conducted by private sectors in nuclear power innovation, development of an innovative design system named ARKADIA (Advanced Reactor Knowledge- and AI-aided Design Integration Approach through the whole plant lifecycle) is undergoing to achieve the design of an advanced nuclear reactor as a safe, economic, and sustainable carbon-free energy source. In this paper, focusing on the ARKADIA-Design as a part of it, the progress in the development of optimization processes on the representative problems in the fields of the core design, the plant structure design, and the maintenance schedule planning are introduced.

Development of numerical analysis codes for multi-level and multi-physics approaches in an advanced reactor design study

Tanaka, Masaaki; Doda, Norihiro; Mori, Takero; Yokoyama, Kenji; Uwaba, Tomoyuki; Okajima, Satoshi; Matsushita, Kentaro; Hashidate, Ryuta; Yada, Hiroki

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 16 Pages, 2022/03

Japan Atomic Energy Agency is developing an innovative design system named ARKADIA to achieve the design of an advanced nuclear reactor as a safe, economic, and sustainable carbon-free energy source. In the first phase of its development, ARKADIA-Design for design study and ARKADIA-Safety for safety assessment will be developed individually. In this paper, focusing on the ARKADIA-Design, the concept of the system is described and numerical analysis codes to be used for the multi-level and multi-physics analyses are introduced. Descriptions of the practical functions composed by the analysis codes and the representative problems in application studies for validation are introduced.

Introduction of loop operating system to improve the stability of continuous hydrogen production for the thermochemical water-splitting iodine-sulfur process

Tanaka, Nobuyuki; Takegami, Hiroaki; Noguchi, Hiroki; Kamiji, Yu; Myagmarjav, O.; Kubo, Shinji

International Journal of Hydrogen Energy, 46(55), p.27891 - 27904, 2021/08

https://doi.org/10.1016/j.ijhydene.2021.06.072

The thermochemical water-splitting iodine-sulfur (IS) process enables producing hydrogen. In a previous operation procedure, after the components of the unit operations were individually started, they were connected at the same time. However, it was challenging to stably interconnect the components. This study introduces a new loop operation, subdividing the process configuration into four sections before transferring the continuous operation. The proposed loop operation was validated analyzing the material and heat balances of each section. The calculated results showed that the material balances of respective loop sections were closed. The loop operation mode would transfer to the continuous operation by connect all sections. Regarding the switching of operation modes, the material and heat balance showed no or little difference, indicating that two operation modes could only be changed by switching the pipelines. Consequently, the loop sections could be individually operated to stabilize the IS process system, and the loop operation could be smoothly transferred to the continuous operation.

Hydrogen production using thermochemical water-splitting iodine-sulfur process test facility made of industrial structural materials; Engineering solutions to prevent iodine precipitation

Noguchi, Hiroki; Kamiji, Yu; Tanaka, Nobuyuki; Takegami, Hiroaki; Iwatsuki, Jin; Kasahara, Seiji; Myagmarjav, O.; Imai, Yoshiyuki; Kubo, Shinji

International Journal of Hydrogen Energy, 46(43), p.22328 - 22343, 2021/06

https://doi.org/10.1016/j.ijhydene.2021.02.071

An iodine-sulfur process offers the potential for mass producing hydrogen with high-efficiency, and it uses high-temperature heat sources, including HTGR, solar heat, and waste heat of industries. R&D tasks are essential to confirm the integrity of the components that are made of industrial materials and the stability of hydrogen production in harsh working conditions. A test facility for producing hydrogen was constructed from corrosion-resistant components made of industrial materials. For stable hydrogen production, technical issues for instrumental improvements (i.e., stable pumping of the HIx solution, improving the quality control of glass-lined steel, prevention of I precipitation using a water removal technique in a Bunsen reactor) were solved. The entire process was successfully operated for 150 h at the rate of 30 L/h. The integrity of components and the operational stability of the hydrogen production facility in harsh working conditions were demonstrated.