Determination of plutonium,americium and curium isotopes in radioactive metal wastes deriving from nuclear decommissioning

A radiochemical analytical method, coupling different measurements techniques (alpha spectrometry, liquid scintillation counting and mass-spectrometry) for quantifying the content of the most significant plutonium and americium/curium isotopes in metal waste samples, is presented. The method based on the sequential determination of all the analytes of interest has the great advantage to perform the sample pre-treatment only once, resulting fast and cheap while maintaining sufficient selectivity and sensitivity. The mean values of radiochemical yields and the minimum detectable activities have been evaluated. Significant activity ratios between transuranic isotopes have been revealed and used to investigate the origin of the waste samples.

     

Preparation of "high specific activity" radiochemical forms of vanadium,manganese and thallium for metallo-toxicological studies

In this paper are presented the production methods for very "high specific activity" radionuclides (HSA-RN) of vanadium, manganese and thallium which have been developed in our laboratories for labelling different chemical forms of these elements present in the echo-systems in ultra-trace amounts, for metallo-toxicological and bio-kinetic studies. Use was made of both cyclotron and thermal nuclear reactor. If the nuclear reaction product has atomic number different from irradiated target, it is possible separating the radioactive nuclide from irradiated target, without addition of isotopic carrier. This kind of radionuclide is named No Carrier Added, NCA, and his specific activity, As is very high and can reach values close to the theoretical Carrier Free one, CF. The experimental determination of specific activity, chemical and radiochemical purities is mandatory for all these kinds of applications.     

"High specific activity" radiotracers for metallo-toxicological studies: cyclotron and nuclear reactor production,radiochemical separation and "quality control": platinum,iridium, gold,copper and gallium

Very High Specific Activity RadioNuclides, HSARN, are a powerful tool to label a wide variety of chemical elements and compounds present in the biosphere in ultra-trace amounts. Medium and high Z radionuclides, can be produced by irradiation in light-ions accelerator and sometimes nuclear reactor. If the nuclear reaction product has atomic number different from irradiated target, it is possible separating the radioactive nuclide from irradiated target, without addition of isotopic carrier. These kinds of radionuclides are named No Carrier Added, NCA, and their specific activity is very high and can reach values close to the theoretical Carrier Free one. The true specific activity must be determined by use of very sensitive radioanalytical techniques. If a low isotopic dilution factor is obtained, these radiotracers are used to label inorganic species and complexes of elements, which are presently introduced into the echo-systems by human activities. New production methods for NCA Pt, Ir, Au, Cu and Ga radiotracers are presented, with some details on radiochemistry and quality controls.     

Purification and separation of <Superscript>239+240</Superscript>Pu and <Superscript>241</Superscript>Am in biological samples by anion-exchange and extraction chromatography for high resolution alpha-spectrometry analyses

Many biological samples (urines and faeces) have been analyzed by means of chromatographic extraction columns, utilizing two different resins (AG 1-X2 resin chloride and TRU), in order to detect the possible internal contamination of ^239+240Pu and ²⁴¹Am for some workers of a reprocessing nuclear plant in the decommissioning phase. The results obtained show on one hand the great suitability of the first resin for the determination of plutonium, and on the other, the great selectivity of the second one for the determination of americium.     

Determination of plutonium and <Superscript>90</Superscript>Sr in air particulate samples

Within the surveillance program of the gaseous effluents coming from the nuclear reprocessing plant EUREX of ENEA (Italian National Agency for New Technologies Energy and Environment, CR Saluggia) in the North of Italy, the content of some radionuclides is continuously monitored. The so-called 1AW high-activity liquid waste (HLLW) is the aqueous raffinate of the first cycle of PUREX extraction process which was the starting point of the reprocessing activity of some MTR and CANDU spent fuel elements. Nowadays, 1AW-HLLW is stored in five tanks placed inside the EUREX plant site. This paper describes the sampling and radioanalytical methods employed to determine the activities of ²⁴¹Am, plutonium isotopes and ⁹⁰Sr in the total suspended particulate material (TSP) of the 1AW tank primary ventilation air circuit.     

Radioanalytical determination of 239+240Pu and 241Am in bioassay samples by anion exchange and extraction chromatography: Preliminary considerations about the two methods

During the radiation protection surveillance of exposed workers samples of urine and faeces were collected. Anion exchange chromatography was used for the separation of Pu. We investigated a technique to purify and separate Pu and Am isotopes using extraction chromatography with TRU resin. We tested different procedures to dissolve organic matter and eliminate interferences for chromatographic elution. At the end of the proces we have succeeded in electroplating the two radionuclides separately. We have also studied extraction chromatography with UTEVA resin to purify Pu isotopes and separate it from natural uranium radioisotopes, present in some biological samples. We validated a method for the determination of Pu in biological samples and a rather constant chemical yield and resolved peaks were obtained. The preliminary studies on TRU resin have indicated that it is possible to combine extraction and anion-exchange chromatography for analysing separately Pu and Am isotopes from the same sample aliquote.     

Determination of calibration curves for <Superscript>131</Superscript>I in thyroid tumour metabolic radiotherapy and other radionuclides used in SPECT imaging

Large columns containing aluminum oxide (Al₂O₃) or gel (e.g. zirconium molybdate) are needed to prepare ⁹⁸Mo(n,γ)⁹⁹Mo→^99mTc column chromatographic generators that results in large elution volumes containing relatively high ⁹⁹Mo impurity and low concentrations of ^99mTc. The decrease in radioactive concentration or specific volume concentration of ^99mTc places a limitation on some pharmaceutical kits (DTPA, MIBI, ECD, etc.) or clinical procedures. We report on the post elution concentration of ^99mTc using in house prepared lead cation-exchange and alumina columns. Using these columns high bolus volumes (10–60 mL 0.02M sodium sulfate) of ^99mTc can conveniently be concentrated in 1 mL of physiological saline. This approach also works very effectively to prepare high specific volume solutions of ^99mTc-pertechnetate from a fission based ⁹⁹Mo/^99mTc generator in the second week of its normal working life.     

Determination of 90Sr in urine samples and 89Sr/90Sr in water samples by chemical separation and Cherenkov counting with LSC system

Journal of Radioanalytical and Nuclear Chemistry - In order to determine radiostrontium with a satisfactory chemical yield, calculated by an external standard, and a low level of MDC a...     

Measurement of Actinides in Biological System; Radioanalytical determination of americium in human urines by extraction chromatography and high resolution alpha-spectrometry

Summary Within the radiation protection physical surveillance program of some workers, involved in the decommissioning operations of a nuclear reprocessing plant of the Italian National Agency for New Technologies Energy and Environment, CR Saluggia (ENEA) in the north of Italy, some radiotoxicological analyses, on human urines, have been carried out, in order to determine the possible internal contamination of ²⁴¹Am. After an in-depth study of a former extraction chromatographic method, based on the use of Microthene-722 supporting HDEHP, a more suitable method has been developed and adopted in our laboratory, based on the use of TRU-resin. This paper reports the results obtained with these two procedures as well as a comparison between them.