Proceedings of the 12th International Conference on Nuclear Criticality Safety (ICNC2023); October 1-6, 2023, Sendai International Center, Sendai, Miyagi, Japan

Suyama, Kenya; Gunji, Satoshi; Watanabe, Tomoaki; Araki, Shohei; Fukuda, Kodai; Shimada, Kazuya; Fujita, Tatsuya; Ueki, Taro; Nguyen, H. H.

JAEA-Conf 2024-001, 40 Pages, 2024/07

JAEA-Conf-2024-001.pdf:1.28MB
JAEA-Conf-2024-001-appendix(CD-ROM).zip:163.97MB

The 12th International Conference on Nuclear Criticality Safety (ICNC2023) was held from October 1 to October 6, 2023, at the Sendai International Center (Aobayama, Aoba-ku, Sendai, Miyagi-prefecture 980-0856, Japan), organized by Japan Atomic Energy Agency (JAEA) and co-organized by the Reactor Physics Division of the Atomic Energy Society of Japan (AESJ) and the Nuclear Energy Agency of the Organization for Economic Co-operation and Development (OECD/NEA). 224 presentations passed peer review and 273 technical session registrations, bringing the total number of registered participants to 289, including accompanying persons. Technical tours were also conducted to i) Fukushima Daiichi Nuclear Power Station of TEPCO holdings and Interim Storage Facility Information Center, ii) Nuclear Science Research Institute of JAEA (STACY Renewable Reactor and FCA), iii) NanoTerasu of Tohoku University (synchrotron radiation facility) and Onagawa Nuclear Power Station of Tohoku Electric Power Co., Inc. This report summarizes the conference and compiles the papers that were presented and agreed to be published in the Proceedings.

Identification of hydrogen species on Pt/AlO by inelastic neutron scattering and their reactivity with ethylene

Yamazoe, Seiji*; Yamamoto, Akira*; Hosokawa, Saburo*; Fukuda, Ryoichi*; Hara, Kenji*; Nakamura, Mitsutaka; Kamazawa, Kazuya*; Tsukuda, Tatsuya*; Yoshida, Hisao*; Tanaka, Tsunehiro*

Catalysis Science & Technology, 11(1), p.116 - 123, 2021/01

https://doi.org/10.1039/D0CY01968B

Removal of radioactive cesium from surface soils solidified using polyion complex; Rapid communication for decontamination test at Iitate-mura in Fukushima Prefecture

Naganawa, Hirochika; Kumazawa, Noriyuki*; Saito, Hiroshi*; Yanase, Nobuyuki; Mitamura, Hisayoshi; Nagano, Tetsushi; Kashima, Kaoru*; Fukuda, Tatsuya*; Yoshida, Zenko; Tanaka, Shunichi*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.227 - 234, 2011/12

https://doi.org/10.3327/taesj.J11.017

no abstracts in English

Experimental investigation of bubbling in particle beds with high solid holdup

Cheng, S.*; Hirahara, Daisuke*; Tanaka, Yohei*; Gondai, Yoji*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; et al.

Experimental Thermal and Fluid Science, 35(2), p.405 - 415, 2011/02

https://doi.org/10.1016/j.expthermflusci.2010.11.003

The current experiments were conducted under two dimensional (2D) and three dimensional (3D) conditions separately, in which water was used as liquid phase, and bubbles were generated by injecting nitrogen gas from the bottom of the viewing tank. Various particle-bed parameters were varied, including particle-bed height (from 30 mm to 200 mm), particle diameter (from 0.4 mm to 6 mm) and particle type (beads made of acrylic, glass, alumina and zirconia). Under these experimental conditions, three kinds of bubbling behavior were observed for the first time using digital image analysis methods that were further verified by quantitative detailed analysis of bubbling properties including surface bubbling frequency and surface bubble size under both 2D and 3D conditions.

Experimental investigation on self-leveling behavior in debris bed

Cheng, S.*; Tanaka, Yohei*; Gondai, Yoji*; Kai, Takayuki*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; et al.

Proceedings of 7th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-7) (CD-ROM), 7 Pages, 2010/11

Self-leveling onset criteria in debris beds

Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu

Journal of Nuclear Science and Technology, 47(4), p.384 - 395, 2010/04

https://doi.org/10.3327/jnst.47.384

Criteria for occurrence of self-leveling in the debris bed

Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu

Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 15 Pages, 2009/09

Although the decay heat from fuel debris drives the coolant boiling in fast reactor accident conditions, the present experiments were conducted by employing depressurization boiling of water to simulate axially increasing void distribution in a debris bed instead of conventional heating or gas injection from the debris bottom. Good agreements on self-leveling occurrence were obtained between model predictions and experimental results. Extrapolation of the present model was also discussed against reactor conditions.

Experimental study of self-leveling behavior in debris bed

Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu

Proceedings of 6th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-6) (USB Flash Drive), 8 Pages, 2008/11

In the present study, characteristics of self-leveling behaviors were investigated experimentally with simulant materials. The present experiments employed depressurization boiling of water to simulate axially increasing void distribution in a debris bed, which consists of solid particles of alumina or lead with different density. The particle size (from 0.5 mm to 6 mm in diameter) and shape (spherical or non-spherical particles) were also taken as experimental parameters. A rough criteria for self-leveling occurrence is proposed and compared with the experimental results.

Fundamental study on flow characteristics of disrupted core pool at a low energy level (Joint research)

Morita, Koji*; Liu, P.*; Matsumoto, Tatsuya*; Fukuda, Kenji*; Tobita, Yoshiharu; Sato, Ikken

JAEA-Research 2007-032, 47 Pages, 2007/03

JAEA-Research-2007-032.pdf:4.04MB

Dynamic behaviors of solid particle beds in a liquid pool against pressure transients were investigated to model the mobility of core materials in a low-energy disrupted core of a liquid metal fast reactor. A series of experiments was performed with a particle bed of different heights, comprising different monotype solid particles, where variable initial pressures of the originally pressurized nitrogen gas were adopted as the pressure source. Computational simulations of the experiments were performed using SIMMER-III, a fast reactor safety analysis code. Experimental analyses using the SIMMER-III code show that physical models and methods used in the code can reasonably represent the transient behaviors of multiphase flows with rich solid phase as observed in the experiments. The validation of several key models of SIMMER-III was also discussed for treating transient behaviors of the solid-particle phase in multiphase flows.

Experimental verification of fast reactor safety analysis code SIMMER-III for transient bubble behavior with condensation

Morita, Koji*; Matsumoto, Tatsuya*; Fukuda, Kenji*; Tobita, Yoshiharu; Yamano, Hidemasa; Sato, Ikken

Proceedings of Technical Meeting on Severe Accident and Accident Management (CD-ROM), 13 Pages, 2006/03

Experimental verification of a reactor safety analysis code, SIMMER-III, was performed for transient behaviors of large-scale bubbles with condensation. The objective of the present study is to verify the code for numerical simulations of relatively short-time-scale multi-phase, multi-component hydraulic problems, among which vaporization and condensation, or simultaneous heat and mass transfer, play an important role. In this study, a series of transient bubble behavior experiments, which are dedicated to condensation phenomena with noncondensable gases, was performed. In the experiments, pressurized mixture of noncondensable gas and steam was discharged as a large-scale single bubble into a cylindrical pool filled with stagnant subcooled water. Concentrations of noncondensable gas were taken as an experimental parameter as well as the species of noncondensable gas. The characteristics of transient behavior of large-scale bubbles with condensation observed in the experiments were clarified through experimental analyses using SIMMER-III. In the experiments with steam condensation, dispersion of the vapor phase discharged into the liquid pool was accompanied by the vapor condensation at the gas/liquid interface. SIMMER-III simulations suggest that there is much less inhibiting effect of noncondensable gas in the mixture on large-scale bubble condensation. This is considered to be a different characteristic of condensation in small-scale bubbles as observed in our previous experiments.