Trace Amounts Of Plutonium Research Articles

Agile fusion method for the determination of Pu isotopes in diverse sediments

Atmospheric nuclear testing has occurred worldwide resulting in trace amounts of plutonium (Pu) isotopes in soils and sediments across the globe. Soils and sediments can vary greatly in both physical and chemical properties within close geographic regions presenting a major challenge for sample preparation in the analysis of fallout radionuclides. It is vital to have a rapid, agile method for the complete digestion of samples containing refractory Pu particles to address this challenge. A radioanalytical procedure for the analysis of Pu isotopes in soils/sediments has been developed improving sample preparation using fusion. This is done by eliminating the need for pre-dissolution combustion to remove organic material and providing greater application to a diverse range of samples including those of metal-bearing mineralogy. The integration of borate and peroxide flux materials creates a sample dissolution procedure that is greater than the sum of its parts. This method is applicable to the analysis of 239/240Pu in soil/sediment samples with a sample mass of 3 g, ranging from 0.05 to 5000 mBq/g achieving 242Pu tracer recoveries between 50 and 94%, with a trace-level detection limit of 0.04 mBq/g and measurement uncertainties down to 19%; adjustable to measurement priorities with variation in count time, background counts, chemical recovery and total activity of the sample. This sample preparation technique can be utilized with complementary analysis of alpha spectrometry or ICP-MS. Achieving these parameters provides a highly adaptable standard method for 239/240Pu in soil/sediment analysis applicable to samples from radioecological research at trace environmental levels to emergency response scenarios with 48-h turn-around producing highly repeatable, succinct and high-quality analysis.

Determination of trace amounts of plutonium in low-active liquid wastes from spent nuclear-fuel reprocessing plants by flow injection-based solid-phase extraction/electrochemical detection system

A flow injection-based electrochemical detection system coupled to a solid-phase extraction column was developed for the determination of trace amounts of plutonium in low-active liquid wastes from spent nuclear-fuel reprocessing plants. The oxidation state of plutonium in a sample solution was adjusted to Pu(VI) by the addition of silver(II) oxide. A sample solution was made up in 3 mol L−1 HNO3 and loaded onto a column packed with UTEVA® with 3 mol L−1 HNO3 as the carrier. Plutonium(VI) was adsorbed onto the resin, and interfering elements were removed by rinsing the column with 3 mol L−1 HNO3. Subsequently, the adsorbed Pu(VI) was eluted with 0.01 mol L−1 HNO3, and then introduced directly into the flow-through electrolysis cell with boron-doped diamond electrode. The eluted Pu(VI) was detected by an electrochemical amperometric method at a working potential of 0.1 V (vs. Ag/AgCl). The current produced on reduction of Pu(VI) was continuously monitored and recorded. The plutonium concentration was calculated from the relationship between the peak area and concentration of plutonium. The relative standard deviation of ten analyses was 1.1% for a plutonium solution of 25 μg L−1 containing 50 ng of Pu. The detection limit calculated from three-times the standard deviation was 0.82 μg L−1 (1.6 ng of Pu).

Formation of Unusual U, Pu, and Cf Oxide Species under Conditions of Gas Thermochromatography

Experiments were performed on the preparation of volatile oxidation products from trace amounts of plutonium and on thermochromatographic (TC) separation of these species, taking into account the previously obtained data on different behaviour of some micro- and macrocomponents in the gas phase. The volatility of products formed by thermal oxidation of traces of U and 249Cf with an He-O2 (1 : 1 vol.) mixture was studied with the aim to simulate the behavior of Pu(IV) and Pu(VI) oxides. Hollow quartz columns were used. Under the experimental conditions, volatile UO2, UO3, and 249CfO2 were formed; the dioxides were deposited at 450±25°C, and UO3, at 250±25°C. The enthalpies of adsorption -ΔH a 0 of these compounds on quartz were calculated. Experimental evidence of existence in the gas phase of volatile uranic acid was obtained. The TC behavior of 238,239Pu traces was studied under conditions of thermal oxidation in an He-O2 flow at the oxygen concentration cO 2 varied from 50 to 10- 7%. In the cO 2 range of 50-5 × 10- 2%, deposition of volatile Pu species at 460±25 and 250±25°C was observed. The identical deposition temperatures and close values of -ΔH a 0 of the products of U and Pu oxidation suggest the transfer of Pu in the form of PuO2 and PuO3. In the cO 2 range from 50 to 1%, an abnormally volatile Pu species was detected, which was deposited at -105±25°C. Its -ΔH a 0, 41±6 kJ mol- 1, was close to that of OsO4. The deposition zones of 185OsO4 and of the highly volatile Pu species were superimposed. As cO 2 decreased, the yield of the highly volatile Pu species decreased; a similar trend is also characteristic of OsO4. This volatile Pu species was tentatively identified as Pu(VIII) oxide, PuO4.

Effects of Fe(III) ions on the electrodeposition of trace amounts of plutonium and americium

The electrodeposition of Pu and Am onto stainless steel discs from 3.2M ammonium chloride solution is strongly affected by the iron concentration of the electrolyte. At Fe(III) concentrations of more than 0.1mM (≈30 μg Fe in 5 ml) only 30–40% of236Pu and 6% of241Am can be deposited. Tracer experiments with59Fe suggest that exchange processes take place between Fe from the surface layer of the cathode and from the electrolyte. Double tracer studies show increasing236Pu/59Fe- and decreasing241Am/59Fe-ratios with increasing iron content of the electrolyte, which may be due to different sorption properties on colloidal iron hydroxides formed at pH<3.6.

Inter-Element Interference Studies in the Determination of Trace Amounts of Plutonium by Inductively Coupled Plasma - Atomic Emission Spectrometry

Abstract Trace amounts of plutonium in aqueous solutions have been determined by an inductively coupled argon plasma-atomic emission spectrometric (ICP-AES) technique. Extensive studies have been carried out on interelement interference effects for two plutonium lines, viz., 300.06 nm and 453.6 nm, due to the presence of uranium, thorium, lanthanides and other metallic elements in the sample solutions. The analytical range obtained in the present case is 0.1–100 μg/ml with a precision of better than 1% R.S.D. The method ie checked for accuracy by analyzing two wellcharacterizd reference rtandards.

Investigation of the Fission Track Method for the Determination of Trace Amounts of Plutonium

Investigation of the Fission Track Method for the Determination of Trace Amounts of Plutonium