Method for detecting and characterising actinide-bearing micro-particles in soils and sediment of the Fukushima Prefecture, Japan

Abstract

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident released limited amounts of actinides on soils of Japan. Characterisation of these particles is essential to determine the fate of actinides in the environment. The method presented in this paper, based on α-tracks detections, microscope observations and mass-spectrometry measurements, was designed to identify and characterize actinide-bearing particles in soil samples. The method was tested on a 2 road dust sample collected in the main radioactive plume of the Fukushima region. Accordingly, α-tracks detection was demonstrated to provide a powerful technique to localise these particles and prepare their morphological, elemental and isotopic characterization.

Comparison of techniques to localise U-bearing particles in environmental samples

“…Regarding the naturally occurring U particles, they can be detected by all of three methods respectively with a full transmission of the α-nuclei for equivalent diameters larger than 15 µm for IP and BeaQuant ® , and larger than 2 µm for FT. By contrast, detection of irradiated U particles and reactor 3 MOX particles with equivalent diameters larger than 0.2 µm is possible even with the lowest transmission factor (ηα × η'α = 0.01) by means of the three tested methods. Actually, as explained by [45], a small fraction of Pu in U (in the 10 -3 -10 -2 range) strongly increases the number of α-emissions.…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…In a separate study, Jaegler et al used a combination of α-tracks detection, microscopic and mass spectrometric measurement to investigate the fate of actinide-bearing particles in environmental samples. 211 Detection using α-tracks was a useful technique for localising and characterising particles based on a test on a road dust sample collected in the Fukushima contaminated region. Multiple techniques were also used by Martin et al during the measurement of sub-mm particulate material from Fukushima power plant unit 1, to improve understanding of the accident and environmental legacy.…”

Analysis of particles containing alpha-emitters in stagnant water at torus room of Fukushima Dai-ichi Nuclear Power Station’s Unit 2 reactor

“…However, while these methods are effective for CsMPs with high radioactivity, it is difficult to selectively detect α-emitters that are present in small amounts and with low specific radioactivity. Therefore, we decided to use a combination of an automated particle measurement method using SEM-EDX 17 and a method for detecting particles containing α-emitters using solid-state track detectors 18 – 24 .…”