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To reveal the triton transport and the tritium migration in a deuterium plasma experiment in the Large Helical Device (LHD), the distribution of the remaining tritium in divertor tiles made of graphite after the first deuterium plasma experimental campaign in 2017 was investigated. In this study, tritium contents in divertor tiles have been measured by using a full-combustion method. The asymmetric tritium retention in divertor tiles located at symmetric positions, which was found in the previous study by the surface tritium measurement using an imaging plate technique, has been confirmed by the results of the full-combustion method. The asymmetry is considered to be attributed to the asymmetric distribution of lost-points of energetic tritons in divertor. A depth profile of remaining tritium in a divertor tile estimated by using a combination of the imaging plate technique and a sputtering treatment shows that the peak of the profile locates at several micro-meters from the surface. This result suggests that the majority of the remaining tritium impinged upon the divertor tile as energetic tritons. In this study, a distribution of lost-points of energetic tritons has been calculated by using a Lorentz orbit following code (LORBIT) with taking into account divertor components. The obtained distribution has been compared with measured tritium distributions on divertor tiles. The measured and calculated distributions are similar to each other, but they are not the same. The difference between them can be attributed to plasma exposures during and after the deuterium plasma campaign.

This paper describes the use of a photostimulable phosphor screen imaging technique to detect radioactive contamination in the leaves of wormwood (Artemisia vulgaris L) and fern (Dryopteris filix-max CL. Schoff) plants affected by the Chernobyl nuclear power plant accident. The imaging plate technology is well known for many striking performances in two-dimensional radiation detection. Since imaging plate comprises an integrated detection system, it has been extensively applied to surface contamination distribution studies. In this study, plant samples were collected from high- and low-contaminated areas of Ukraine and Belarus, which were affected due to the Chernobyl accident and exposed to imaging technique. Samples from the highly contaminated areas revealed the highest photo-stimulated luminescence on the imaging plate. Moreover, the radio nuclides detected in the leaves by gamma and beta ray spectroscopy were 137Cs and 90Sr, respectively. Additionally, in order to assess contamination, a comparison was also made with leaves of plants affected during the JCO criticality accident in Japan. Based on the results obtained, the importance of imaging plate technology in environmental radiation monitoring has been suggested.

A tritium imaging plate technique has been applied to visualize hydrogen distribution and examine hydrogen solubility and diffusivity in a proton-conducting oxide, Y-doped BaCeO 3 (BaCe 0.9 Y 0.1 O 3 − α ). Tritium charging of the BaCe 0.9 Y 0.1 O 3 − α specimens was carried out by a gas absorption method using partially tritiated water vapor (HTO, 3 kPa, T/H ~ 10 − 6 ) at temperatures ranging from 673 K to 873 K for a given time. After charging, tritium distributions of the surface and cross section of the halved specimens were visualized using an imaging plate technique. From the tritium concentration and distributions of the surface and cross section, hydrogen solubility and hydrogen (tritium) diffusivity of the BaCe 0.9 Y 0.1 O 3 − α specimens were determined. [ABSTRACT FROM AUTHOR]

Abstract: A tracer technique using 14C, which is a β-decaying radioactive isotope, is being planed to understand the carbon migration behavior in fusion devices. An imaging plate (IP), which is a radiation image detector successfully applied for the tritium analysis of plasma-facing walls, easily detects β-electrons from 14C and would give a detailed 14C deposition profiles, hence the IP method can be one of the postmortem measurements of the 14C deposition. However, since β-electrons from tritium would superpose those from 14C, it is essential to differentiate β-electrons of 14C from those of tritium. To do this, we have developed a film insertion technique in which a thin film is inserted between a specimen and IP to prohibit lower energy electrons passing through the film. It is found that 14C concentrations as small as 10Bq/cm2 (∼2.6×1012 14C/cm2) can be detected, indicating that this technique keeps the advantage of 14C as a high sensitivity tracer, and making two-dimensional 14C profiling possible without any disturbance of co-existing tritium. [Copyright &y& Elsevier]