Characterization of chemical composition and particle size distribution of aerosols released during laser cutting of fuel debris simulants

Microparticles with diverse sizes and morphologies from mechanical and laser cutting of fuel debris simulants and geopolymer as a covering material

“…However, large amount of powdery substance (<0.1 μm) can be observed as well, which cannot be observed from the particle generations from mechanical cuttings (Figures 4, 6 and 8). The powdery substance may be similar to the aerosol particles previously observed by researchers [5][6][7][8]. These powdery particles can exist as airborne aerosols and should be considered during the waste management of the defueling of FDNPP.…”

“…Characterization was carried out to investigate the aerosol mass concentration, particle size distribution, morphology and chemical composition [5][6][7][8]. In these studies, the size selection during the particle sampling was concerned with the specific pathological outcomes induced by the airborne particles generated, and the sampling section was on the top floor that was far away from the cutting cell.…”

“…In these studies, the size selection during the particle sampling was concerned with the specific pathological outcomes induced by the airborne particles generated, and the sampling section was on the top floor that was far away from the cutting cell. As a result, the detected aerodynamic mass median diameter was below 1 μm, with particle sizes generally 60-160 nm for air cutting conditions, and 300-400 nm for underwater cutting conditions [8]. Numerical studies have also been conducted on the behaviors of particle dispersion and agglomeration during the laser cutting [9].…”

“…As above-mentioned, previous studies were interested on the airborne particles with high thoracic and respirable fractions, so the sampling section was located meters away from the cutting cell along the exhaust line [5][6][7][8]. Therefore, although the collection efficiency of the sampling and characterization section was high enough for the airborne particles around or smaller than 1 μm, it can be inferred that most of the larger particle products (>10 μm) were not involved into the transport from the cutting cell to the sampling section and likely deposited in the cylindrical sampling line.…”

Observation and characterization of quasi-continuous wave kW-class laser interaction with metal and metal oxide targets using a high-speed camera and microscopes

“…At the same time, owing to the high energy density imparted to a laser irradiated material, fine particles, droplets and fragments from a laser interaction region are generated and dispersed away from the interaction region. This is an issue from the point of view of maintaining safe condition for workers especially for the decommissioning of atomic nuclear facilities [6][7][8] as well as clean material surfaces and safe working conditions in the industrial applications [9][10][11][12]. The laser techniques are expected to be one of the candidates in the debris retrieval technologies at the Fukushima Daiichi Nuclear Power Station [6].…”