Development of a 3D-printed two-stage virtual impactor for radioactive aerosol size classification and direct analysis

Laffolley, H.; Tsubota, Yoichi; Kuroe, Ayame; Kato, Tomoaki

ACS Omega (Internet), 11(30), p.45423 - 45438, 2026/08

https://doi.org/10.1021/acsomega.6c04521

Radioactive aerosol size classification is crucial for exposure assessment during nuclear decommissioning. This study presents SPLIT, a two-stage 3D-printed virtual impactor separating aerosols into three aerodynamic classes (10 m, 110 m, and 1 m) while enabling direct analysis on integrated filters. This low-cost, disposable device eliminates hazardous cleaning and metallic waste by allowing incineration after use. Flow paths were optimized via computational fluid dynamics, and prototypes were fabricated by stereolithography. Simulations predicted sharp separation with cutoff diameters of 9.0 m and 1.3 m, despite minor cross-flow particle contamination. Prototype measurements revealed shrinkage and corner rounding, necessitating fabrication compensation. Experiments with incense smoke confirmed submicrometric particles collected mostly in the 1 m class. Tests using Rn-progeny-bearing NaCl particles (1.70 m mean diameter) showed the highest activity on the 110 m filter, confirming the expected classification. These results validate this lightweight, low-cost impactor for simultaneous size classification and direct radioactive particle analysis.

Development of the technology for preventing radioactive particles' dispersion during the fuel debris retrieval (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*

JAEA-Review 2022-010, 155 Pages, 2022/06

JAEA-Review-2022-010.pdf:9.78MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of the technology for preventing radioactive particles' dispersion during the fuel debris retrieval" conducted from FY2018 to FY2021 (this contract was extended to FY2021). Since the final year of this proposal was FY2021, the results for four fiscal years were summarized. The present study aims to clarify the behavior of microparticles in gas and liquid phases in order to steadily confine radioactive microparticles during fuel debris retrieval in Fukushima Daiichi Nuclear Power Station, TEPCO. As measures to prevent dispersion of microparticles, (1) a method to suppress the dispersion with minimum amount of water utilizing water spray etc., and (2) a method to suppress the dispersion by solidifying fuel debris were evaluated by experiments and simulation. The applicability of these methods to the actual plants was also evaluated.

Characterization of radionuclides formed by high-energy neutron irradiation

Yokoyama, Sumi; Sato, Kaoru; Noguchi, Hiroshi; Tanaka, Susumu; Iida, Takao*; Furuichi, Shinya*; Kanda, Yukio*; Oki, Yuichi*; Kaneto, Taihei*

Radiation Protection Dosimetry, 116(1-4), p.401 - 405, 2005/12

https://doi.org/10.1093/rpd/nci020

The physicochemical property of radionuclides suspended in the air is an important parameter to evaluate internal doses due to the inhalation of the airborne radionuclides and to develop the air monitoring system in high-energy proton accelerator facilities. This study focuses on the property of radioactive airborne chlorine (Cl and Cl) and sulfur (S) formed from Ar gas by irradiation with high-energy neutrons. As a result of the irradiation to a mixture of Ar gas and dry air, Cl and Cl existed as non-acidic gas and S was present as acidic gas. Further, it was found that in the high-energy neutron irradiation to aerosol containing-Ar gas, the higher the amount of radioactive aerosols becomes, the lower that of radioactive acidic gas becomes.

Adsorption of radioactive I gas onto atmospheric aerosol

Noguchi, Hiroshi; Murata, Mikio;

Hoken Butsuri, 25, p.209 - 219, 1990/00

https://doi.org/10.5453/jhps.25.209

no abstracts in English