A combined method for the determination of the isotopic vector of plutonium isotopes in environmental samples

A combination of alpha-spectrometry, liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS) was used for the determination of plutonium isotopes. 238Pu and 239+240Pu were measured by alpha-spectrometry after separation of Pu by anion-exchange using 236Pu tracer as recovery monitor. After alpha-measurement, one part of the sample was dissolved for determining 241Pu by LSC. Another part was used for the measurement of the 240Pu/239Pu atom ratio by AMS at VERA. Thus, it was possible to obtain complete information on the Pu isotopic composition of the samples. This method was applied to environmental reference samples and samples contaminated from nuclear reprocessing

Collection and behaviour of radon progenies on thin Mylar foils

Thin Mylar foils are often used to protect detectors from contamination. However, these foils can be electrostatically charged, possibly leading to their contamination with airborne radon progenies. In the present work, the collection and behaviour of radon progenies on Mylar foils was investigated in detail using alpha spectrometry. The radon progenies collection rate of a small Mylar foil (3 cm2) is equivalent to an air sampler with a flow rate of approximately 0.1 m3/h. It was demonstrated that such contamination may jeopardise the validity of the entire analysis if not interpreted correctly.JRC.E-Institute for Transuranium Elements (Karlsruhe

Determination of U, Pu and Am isotopes in Irish Sea sediment by a combination of AMS and radiometric methods

Samples from a marine sediment core from the Irish Sea (54.416 N, 3.563 W) were analyzed for the isotopic composition of uranium, plutonium and americium by a combination of radiometric methods and AMS. The radiochemical procedure consisted of a Pu separation step by anion exchange, subsequent U separation by extraction chromatography using UTEVA® and finally Am separation with TRU® Resin. Additionally to radiometric determination of these isotopes by alpha spectrometry, the separated samples were also used for the determination of 236U/238U and plutonium isotope ratios by Accelerator Mass Spectrometry (AMS) at the VERA facility

Characterisation of environmental radioactive particles

Control samples produced as 1µm size uranium oxide particles are described for the calibration of the instrumental techniques when applied for the characterisation of environmental radioactive particles. The efficiency of nuclear track methods is demonstrated for the location of hot spots in swipe and environmental samples. Examples of the characterisation in terms of morphology, structure, elemental and isotopic composition of radioactive environmental particles detected in sediments and soil samples from different origin are illustrated. The characteristics of the particles are related with the source term and the release scenarios. Correlation between measurements of bulk samples and particles are given

Investigation of the 236 U/ 238 U isotope abundance ratio in uranium ores and yellow cake samples

Uranium ores and yellow cake samples of known geographic origin were investigated for their n(236U)/n(238U) isotope abundance ratio. Samples from four different uranium mines in Australia, Brazil and Canada were selected. Uranium was separated by UTEVA

Vertical distribution of 238Pu, 239(40)Pu, 241Am, 90Sr and 137Cs in Austrian soil profiles

The occurrence of 238Pu, 239(40) Pu, 241Am, 90Sr and 137Cs in the region of Nassfeld (Salzburg, Austria) is discussed at four different locations by evaluating a depth profile for each radionuclide. Furthermore, the plutonium separated from the soil samples was measured by Accelerator Mass Spectrometry (AMS) to get information on the isotope ratio 240Pu/239Pu. The radiochemical procedure consisted of a Pu separation step from Am and Sr by anion exchange in 8 M HNO3 after oxidation state adjustment to Pu(IV). Am and Sr were coprecipitated with calcium oxalate. Am was separated from Sr by extraction chromatography using TRU-resin. The Sr separation was performed also by extraction chromatography using Sr-resin; after coprecipitation as oxalate, 90Sr was measured in a gas proportional counter. For the determination of 239(40)Pu and 241Am by «-spectrometry thin sources were prepared by microprecipitation with NdF3. With the respective Pu isotope ratios, it was possible to identify the global fallout as source of the contamination. This was confirmed by the ratio 241Am/239(40)Pu. From the activity ratio 90SrZ137Cs, it could be shown that most of these radionuclides stem from the reactor accident in Chernobyl