Rapid detection of plutonium contamination with and without uranium contamination in wounds by x-ray fluorescence.

In the event of an accident at a nuclear fuel handling facility, the wounds of affected workers may be contaminated with plutonium. The current approach for identifying plutonium contamination is by detecting α-particles in the blood stream. However, the applicability of this approach is impeded due to the α-particles being easily shielded by the bodily fluid components. In this study, we investigate a contamination testing method for such cases that involves the collection of blood with a small piece of filter paper, sealing the sample with thin films, and performing x-ray fluorescence analysis. Our previous study on collecting uranium-contaminated blood with filter paper and performing x-ray fluorescence analysis revealed that the effects arising from blood components could be completely removed by peak fitting, and thus water instead of blood was used as a solvent here. Samples containing various amounts of plutonium as well as samples with 150 Bq of plutonium and uranium were prepared with a mass ratio of 0 to 500 times greater than that of plutonium. x-ray fluorescence measurements showed a high linearity and reproducibility of the Pu Lα peak intensity and plutonium radioactivity, and it was clarified that the signal intensity of the Pu Lα peak did not depend on the amount of coexisting uranium. This method will allow for the simple and rapid assessment of plutonium contamination in wounds.

Rapid detection of heavy elements in blood extracted from wounds using x-ray fluorescence analysis.

In radiation emergency situations involving persons having plutonium (Pu)-contaminated wounds, rapid assessment of the degree of Pu contamination is required to determine the appropriate course of treatment. Currently, rapid on-site detection of Pu is usually performed by analysis of α-particles emitted from the adhesive tape peeled off the wound. However, the detection of α-particles is difficult, especially in traumatic skin lesions with oozing blood, because of the low permeability of α-particles in blood. Therefore, we focused on x-ray fluorescence (XRF) analysis because x-rays easily pass through several millimetres of blood. In this study, we developed a new methodology for the rapid detection of heavy elements in wounds based on XRF analysis of the contaminated blood collected by gauze patch and filter paper, using stable lead (Pb) as a model contaminant substitute for Pu. Mouse blood samples contaminated with Pb were dropped on gauze patches or absorbed by filter papers and were subjected to XRF measurement. Small pieces of filter paper served as more suitable extraction materials than gauze patches because the entire amount of blood absorbed could be measured. When we used filter paper, the signal intensity of the Pb Lα peak was proportional to the Pb concentration in the blood. With a measurement time of 30 s, the minimum detection limit of Pb in blood collected by filter paper was 2.4 ppm.

Development of Methods to Evaluate Several Levels of Uranium Concentrations in Drainage Water Using Total Reflection X-Ray Fluorescence Technique.

As a country's law stipulates the effluent standard uranium concentration in drainage water, the uranium concentration must be determined when drainage water is released from a uranium handling facility, such as the Fukushima Daiichi nuclear power plant. The maximum allowable limit for uranium release at each facility is defined taking into consideration the situation of the facility, such as 1/10 to 1/100 of this effluent standard value. Currently, the uranium concentration of drainage water is commonly determined by α-particle spectrometry, in which several liters of drainage water must be evaporated, requiring about half of a day followed by 2-3 h of measurements, due to the low specific radioactivity of uranium. This work proposes a new methodology for the rapid and simple measurement of several levels of uranium in drainage water by a total reflection X-ray fluorescence (TXRF) analysis. Using a portable device for TXRF measurements was found to enable measurements with 1/10 the sensitivity of the effluent standard value by 10 times condensation of the uranium-containing sample solution; a benchtop device is useful to measure uranium concentrations <1/100 of the effluent standard value. Therefore, the selective usage of methods by a portable and benchtop devices allows for screening and precise evaluation of uranium concentrations in drainage water.