X‐ray fluorescence analysis of samples simulating blood collected from uranium‐contaminated wounds

Abstract

Personnel working in nuclear fuel handling facilities incur a finite risk of injury and uranium contamination in any resulting wounds. The accidental absorption of uranium from the likes of wounds can lead to a significant degree of internal exposure due to its hazardous nature. Although an appropriate surgical resection of tissue in the contaminated wound is useful for suppressing the additional intake of uranium, the rapid quantification of uranium in the wound is required to avoid unnecessary surgery. For surface contamination, the detection of uranium is usually performed using an α‐particle counting method. However, in the case of wound contamination, most of the α‐particles emitted from the uranium cannot pass through the blood oozing from the wound. Therefore, X‐ray fluorescence (XRF) analysis has been proposed as an alternative means of detecting uranium contamination because X‐rays can pass through several millimeters of blood or soft tissue. In the present study, we developed a new methodology for the rapid detection of uranium in wounds that is based on an XRF analysis of contaminated blood collected on filter paper. With XRF, the detection limit for uranium in blood is 0.45 ppm. This value is lower than those of commercially available α‐survey meters by a factor of ~103. Thus, the proposed method could be adopted for the rapid, on‐site detection of uranium in wounds.

Determination of trace levels of uranium in waste solutions by energy dispersive X‐ray fluorescence following adsorption on graphene oxide

“…To convert the units of the MDL from ng ml −1 to mBq cm −3 , the abundance ratios of 238 U, 235 U, and 234 U, for which the half‐lives are 4.47 × 10 9 , 7.04 × 10 8 , and 2.46 × 10 5 years, respectively, are required. As described in our previous reports, 19,20 when the abundance ratios of 235 U and 234 U (i.e., the isotopes with relatively short half‐lives) are higher, the value of the calculated radioactivity will be higher, thereby resulting in a conservative evaluation. In this study, we assumed the abundance ratio of 235 U to be 5%, which is slightly higher than the 3%–4% abundance ratio of 235 U in pre‐used nuclear fuel for light water reactors.…”

“…For the samples obtained using the 3% solution, measurements were also recorded for 300 s to ensure the suitability of this accumulation time (Figure 7a). Using the fitting results, the MDL for a target element can be calculated using the following equation 19–21,27–29 : where I net is the net intensity of the target element (cps), I BG is the background intensity in the same energy region (cps), c is the concentration of the target element (ng ml −1 ), and t is the measurement time (s). Based on the maximum value of the six MDLs obtained from the six data sets, the highest MDL was recorded, and subsequently, the variability of the peak fitting was accounted for to obtain the actual MDL as 0.37 ng ml −1 .…”

“…The basic strategy employed for peak fitting using multiple Gaussian functions was described in our previous studies. 19,27 Each Gaussian function has three parameters: the peak central energy, width, and intensity. The peak central energy can be fixed at previously reported values.…”

“…To clarify the characteristics of these peaks, a sample containing each individual element was prepared. According to our previous studies, 19,27 a bromine solution (10 μl) having a concentration of 100 μg ml À1 was dropped onto a 220 μm-thick filter paper (No. 5A, Toyo Roshi Kaisha, Ltd., Tokyo, Japan) that was cut to a diameter of 5.5 mm.…”

“…In contrast, X‐ray fluorescence (XRF) measurements are not significantly influenced by the presence of salts or organic matter, and XRF is also an analytical technique that is based on the number of atoms. Although the sensitivity of XRF analysis is approximately 5–6 orders of magnitude lower than that of ICP‐MS, 19 the equipment required for XRF analysis is inexpensive, and the operating costs are lower because, unlike in ICP‐MS, argon gas is not required. Furthermore, unlike in the case of ICP‐MS, where the sample is expended during the measurement, XRF analysis is non‐destructive, and the interiors of the instrument do not become contaminated with uranium.…”