Versatile chemical handling to confine radioactive cesium as stable inorganic crystal.

The present paper describes an extremely efficient, reproducible and inexpensive chemical handling method for converting the nuclear wastes contaminated by radioactive cesium to stable inorganic crystal, pollucite (CsAlSi2O6), which is promising as a form of the final storage. In this processing, the clays are used as a source for aluminum and silicon, and it is important to get a well-mixed homogenous solution by the aid of some heat and pressure. The present method proposes the use of ethylene glycol as a solvent, rather than water. It has been found that one can obtain crystalline pollucite by heating up to 350 °C in a high-pressure container (~15 MPa), mixed with montmorillonite - an abundant natural clay and ethylene glycol. It has been found that the reduction of the amount of water helps to achieve very high confinement rate in a reasonable time of few~20 h. This will be fairly important in processing contaminated water in the nuclear power plant. The influence of seawater has been also examined.

Micro X-ray fluorescence imaging without scans: toward an element-selective movie.

Micro X-ray fluorescence imaging is a promising method for obtaining positional distribution on specific elements in a nondestructive manner. So far, the technique has usually been performed by a 2D positional scan of a sample against a collimated beam. However, the total measuring time can become quite long, since a number of scanning points are needed in order to obtain a high-quality image. The present report discusses a completely different way of performing imaging of elements much more quickly. A combination of grazing-incidence geometry using a rather wide beam and parallel optics for detecting X-rays can produce an X-ray fluorescence image with approximately 1 M pixels and with approximately 20-microm resolution in 1-2 min or less. The technique has the potential to open up new frontiers in X-ray imaging, particularly in element-selective movie applications.

Wavelength-dispersive total-reflection X-ray fluorescence with an efficient Johansson spectrometer and an undulator X-ray source: detection of 10-16 g-level trace metals.

The present paper reports significant enhancement of the detection power for total-reflection X-ray fluorescence (TXRF). The employment of an efficient wavelength-dispersive spectrometer rather than a conventional Si(Li) detector, as well as the use of a quasi-monochromatic undulator X-ray source, completely changed the quality of X-ray florescence spectra. The energy resolution is 20 times better, which effectively contributes to reducing the low-energy tail of the scattering background and to separating neighboring X-ray florescence peaks. Another advantage is its capability with respect to high-counting-rate measurements, which ensure the detection of weak signals from trace materials. The absolute and relative detection limit for nickel are 3.1 x 10(-16) g and 3.1 ppt (pg/g) for a 0.1-microL droplet of pure water, respectively, which is nearly 50 times better than the current best data achieved by conventional energy-dispersive TXRF using a Si(Li) detector system.