Overview of HTGR Hydrogen production system and current status of R&Ds

Kubo, Shinji

Kinzoku, 95(1), p.25 - 33, 2025/01

no abstracts in English

Quantitative evaluation of leakage flow rate in the sealing part using graphite gland packing to mount a hydrogen separation membrane tube for HI decomposition membrane reaction

Sugimoto, Chihiro; Myagmarjav, O.; Tanaka, Nobuyuki; Noguchi, Hiroki; Takegami, Hiroaki; Kubo, Shinji

International Journal of Hydrogen Energy, 95, p.98 - 107, 2024/12

https://doi.org/10.1016/j.ijhydene.2024.10.334

France-Japan collaboration on severe accident studies in sodium-cooled fast reactors, 2; Methodologies and calculations of severe accident phases

Sogabe, Joji; Ishida, Shinya; Tagami, Hirotaka; Okano, Yasushi; Kamiyama, Kenji; Onoda, Yuichi; Matsuba, Kenichi; Yamano, Hidemasa; Kubo, Shigenobu; Kubota, Ryuzaburo*; et al.

Proceedings of International Conference on Nuclear Fuel Cycle (GLOBAL2024) (Internet), 4 Pages, 2024/10

In the frame of France-Japan collaboration, the calculational methodologies were defined and assessed, and the phenomenology and the severe accident consequences were investigated in a pool-type sodium-cooled fast reactor.

Development of severe accident simulation code for sodium-cooled fast reactors: SIMMER-V, 1; Overview of the SIMMER-V code development

Tagami, Hirotaka; Ishida, Shinya; Okano, Yasushi; Yamano, Hidemasa; Kubo, Shigenobu; Payot, F.*; Saas, L.*; Trotignon, L.*; Gubernatis, P.*; Dufour, E.*; et al.

Proceedings of 11th European Review Meeting on Severe Accident Research Conference (ERMSAR 2024) (Internet), 12 Pages, 2024/05

https://doi.org/10.5445/IR/1000174165

JAEA has been developing the SIMMER-V code in collaboration with CEA to perform severe accident (SA) simulations of future sodium-cooled fast reactors (SFRs) including a unique core design with large-scale heterogeneous cores. An SA sequence in SFRs has been analyzed by: the SAS4A code for the Initiation Phase (IP), in which fuel pin disruption and vertical fuel dispersion occur in individual fuel subassemblies; and the two-dimensional SIMMER-III or three-dimensional SIMMER-IV code for the Transition Phase (TP), in which core disruption extends to the whole core. The joint development of SIMMER-V is of limited scope but aims at significantly expanding the code applicability by providing flexible interfaces to couple a SIMMER-V calculation with other computational domains or other codes, and by adding new advanced physical models such as a detailed fuel pin model and a model of flexible treatment of fuel isotopic composition. The former tasks are conducted by CEA the latter tasks by JAEA. In parallel to the code development, verification and validation of the new models and methods have been performed. This paper describes the objectives and overall framework of SIMMER-V code development program, representative new elements, and recent development progress.

Radiation monitoring via manned helicopter around the nuclear power station in the fiscal year 2022 (Contract research)

Futemma, Akira; Sanada, Yukihisa; Nagakubo, Azusa; Kawasaki, Yoshiharu*; Iwai, Takeyuki*; Hiraga, Shogo*; Haginoya, Masashi*; Matsunaga, Yuki*; Akutsu, Yuichiro*; Arai, Yoshinori*; et al.

JAEA-Technology 2023-027, 146 Pages, 2024/03

JAEA-Technology-2023-027.pdf:18.12MB

By the accident at Tokyo Electric Power Company's (TEPCO's) Fukushima Daiichi Nuclear Power Station (FDNPS), caused by tsunami triggered by the 2011 off the Pacific coast of Tohoku Earthquake, a large amount of radioactive material was released into the surrounding environment. After the accident, Airborne Radiation Monitoring (ARM) via manned helicopter has been applied as a method to quickly and extensively measure the distribution of radiation. Japan Atomic Energy Agency (JAEA) has continuously conducted ARM via manned helicopter around FDNPS. In this report, we summarize the results of the ARM around FDNPS in the fiscal year 2022, evaluate the changes of ambient dose rates and other parameters based on the comparison to the past ARM results, and discuss the causes of such changes. In order to contribute to improve the accuracy of ambient dose rate conversion, we analyzed the ARM data taking into account undulating topography, and evaluated the effect of this method. Furthermore, the effect of radon progenies in the air on the ARM was evaluated by applying the discrimination method to the measurement results.

R&D progress of thermochemical hydrogen production iodine-sulfur process in JAEA

Kubo, Shinji

Nihon Enerugi Gakkai Kikan-Shi Enerumikusu, 102(4), p.428 - 438, 2023/07

https://doi.org/10.20550/jieenermix.102.4_428

no abstracts in English

Evaluation of container using hybrid technique for thermochemical water-splitting iodine-sulfur process

Ioka, Ikuo; Kuriki, Yoshiro*; Iwatsuki, Jin; Kubo, Shinji; Yokota, Hiroki*; Kawai, Daisuke*

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 5 Pages, 2023/05

A thermochemical water-splitting iodine-sulfur processes (IS process) is one of candidates for the large-scale production of hydrogen using heat from solar power. Severe corrosive environment which is thermal decomposition of sulfuric acid exists in the IS process. A hybrid material with the corrosion-resistance and the ductility was made by a plasma spraying and laser treatment. The specimen had excellent corrosion resistance in the condition of 95 mass% boiling sulfuric acid. This was attributed to the formation of SiO on the surface. A corrosion test of the container was performed in 95 mass% boiling sulfuric acid until 500 hours to evaluate the corrosion characteristic of the container. No peeling was observed on the inner surface of the container after the corrosion test. The container had excellent corrosion resistance in the condition of 95 mass% boiling sulfuric acid.

New approach to understanding the experimental Cs NMR chemical shift of clay minerals via machine learning and DFT-GIPAW calculations

Okubo, Takahiro*; Takei, Akihiro*; Tachi, Yukio; Fukatsu, Yuta; Deguchi, Kenzo*; Oki, Shinobu*; Shimizu, Tadashi*

Journal of Physical Chemistry A, 127(4), p.973 - 986, 2023/02

https://doi.org/10.1021/acs.jpca.2c08880

The identification of adsorption sites of Cs on clay minerals has been studied in the fields of environmental chemistry. The nuclear magnetic resonance (NMR) experiments allow direct observations of the local structures of adsorbed Cs. The NMR parameters of Cs, derived from solid-state NMR experiments, are sensitive to the local neighboring structures of adsorbed Cs. However, determining the Cs positions from NMR data alone is difficult. This paper describes an approach for identifying the expected atomic positions of Cs adsorbed on clay minerals by combining machine learning (ML) with experimentally observed chemical shifts. A linear ridge regression model for ML is constructed from the smooth overlap of atomic positions descriptor and gauge-including projector augmented wave (GIPAW) ab initio data. The Cs chemical shifts can be instantaneously calculated from the Cs positions on any clay layers using ML. The inverse analysis from the ML model can derive the atomic positions from experimentally observed chemical shifts.

Present status of JAEA's R&D toward HTGR deployment

Shibata, Taiju; Nishihara, Tetsuo; Kubo, Shinji; Sato, Hiroyuki; Sakaba, Nariaki; Kunitomi, Kazuhiko

Nuclear Engineering and Design, 398, p.111964_1 - 111964_4, 2022/11

https://doi.org/10.1016/j.nucengdes.2022.111964

Japan Atomic Energy Agency (JAEA) has been promoting the research and development (R&D) of High Temperature Gas-cooled Reactor (HTGR). R&D on reactor technologies is carried out by using High Temperature engineering Test Reactor (HTTR). The HTTR was resumed without significant reinforcements in 2021. On January 2022, a safety demonstration test under the OECD/NEA LOFC project was carried out. JAEA is promoting R&D on a carbon-free hydrogen production by thermochemical water splitting Iodine-Sulfur process (IS process). JAEA conducts design study for various HTGR systems toward commercialization. A new test program about demonstration of hydrogen production by the HTTR was launched. Steam methane reforming hydrogen production system was selected for the first demonstration by 2030.

Sodium-cooled Fast Reactors

Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.

Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07

https://shop.elsevier.com/books/sodium-cooled-fast-reactors/morishita/978-0-12-824076-2

This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.