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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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Dry Ice Blasting: A Game-Changer for Safe Cleaning and Decontamination in Nuclear Power Plants
The nuclear energy industry is critical not only for meeting the world’s growing demand for electricity but also for advancing global decarbonization goals. As the sector evolves—through life extensions of existing plants, decommissioning, innovations like small modular reactors (SMRs) and microreactors, and new facility construction—the need for safe, efficient, and environmentally responsible maintenance and decommissioning continues to grow. Whether a plant is coming online, operating beyond its original design life, or entering decommissioning, cleanliness and operational integrity remain non-negotiable. That’s where dry ice blasting stands out—a powerful, safe cleaning method ideally suited for the high-stakes demands of nuclear environments.
Shigeki Shiba, Daiki Iwahashi, Tsuyoshi Okawa
Nuclear Technology | Volume 209 | Number 8 | August 2023 | Pages 1154-1163
Research Article | doi.org/10.1080/00295450.2023.2191588
Articles are hosted by Taylor and Francis Online.
From the viewpoint of criticality management in the fuel debris retrieval operation at the Fukushima Daiichi Nuclear Power Station, it is important in criticality safety analyses to consider the behavior of fuel debris particles as they fall into the water, given that the neutron moderation condition of the fuel debris can dramatically change. In this study, we evaluated a reactivity insertion while fuel debris particles dropped into the water. Specifically, we considered the effects of the fuel debris particle-size distribution in either an erroneous operation or a postulated accident in the fuel debris retrieval operation. Three types of fuel debris particle-size distribution were assumed: monodisperse, uniform, and Rosin-Rammler. The behaviors of the fuel debris particles during sedimentation were evaluated using the coupled Distinct Element Method–Moving Particle Simulation (DEM-MPS) code. The multiplication factors corresponding to the behaviors of the falling fuel debris were calculated by a continuous-energy Monte Carlo code MVP3.0 with JENDL-4.0. Consequently, the multiplication factors changed with the particle motions during the sedimentation, and the trends of the multiplication factors differed between the particle-size distributions. Especially, the 2-cm monodisperse particle-size distribution showed the highest multiplication factor during sedimentation, the trend of which differed from the others in the fuel debris particles dispersing and piled-up phases in the water.