Rapid Mass Spectrometry Method For Uranium And Plutonium

A new, rapid sample preparation method to improve the assay of uranium and plutonium by mass spectrometry has been developed at the Westinghouse Savannah River Site (SRS). The method is applied to the analysis of mixed plutonium-uranium oxide materials but can be applied to low-level mass spectrometry analyses as well. The new method uses a single extraction chromatographic column to separate and purify both uranium and plutonium for isotopic assay by thermal ionization mass spectrometry. A dual uranium/plutonium spike isotope dilution technique is used to allow rapid analysis of uranium/plutonium content and isotopics. A single UTEVA Resin column is utilized to simultaneously separate both uranium and plutonium from the sample matrix. The plutonium and uranium can rapidly removed from the column separately or eluted together for analysis. This new method combines sample preparation into a single, effective separation step that significantly reduces sample preparation time and costs.

Techniques have been developed which permit rapid, high-precision analyses of uranium and plutonium by multiple-filament thermal ionization mass spectrometry utilizing a commercial multicollector instrument. The salient feature of the method is volatilization of the entire sample while simultaneously integrating the signal from each isotope, thus virtually eliminating the effects of isotope fractionation in the evaporation process. The method permits the analysis of samples much smaller than required for conventional techniques using Faraday collectors and is expected to have application in the analysis of many elements in addition to uranium and plutonium. Run-to-run reproducibilities of

A new rapid fusion method for the determination of plutonium in large rice samples has been developed at the Savannah River National Laboratory (Aiken, SC, USA) that can be used to determine very low levels of plutonium isotopes in rice. The recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid, reliable radiochemical analyses for radionuclides in environmental and food samples. Public concern regarding foods, particularly foods such as rice in Japan, highlights the need for analytical techniques that will allow very large sample aliquots of rice to be used for analysis so that very low levels of plutonium isotopes may be detected. The new method to determine plutonium isotopes in large rice samples utilizes a furnace ashing step, a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a column separation process with TEVA Resin cartridges. The method can be applied to rice sample aliquots as large as 5 kg. Plutonium isotopes can be determined using alpha spectrometry or inductively-coupled plasma mass spectrometry (ICP-MS). The method showed high chemical recoveries and effective removal of interferences. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory plutonium particles are effectively digested. The MDA for a 5 kg rice sample using alpha spectrometry is 7E-5 mBq g−1. The method can easily be adapted for use by ICP-MS to allow detection of plutonium isotopic ratios.

A six-inch radius mass spectrometer has been constructed and demonstrated to adequately analyze water samples for uranium concentrations down to 5 to 10 ng/liter (ppt). The precision and accuracy of the isotope-dilution, thermal emission method is sufficient to meet the needs of the Uranium Resources Evaluation (URE) project. A single analyst can analyze in excess of 50 samples per day, including all preparation and instrument time. This analysis rate will meet the economic constraints of the URE analytical program.

A new method that allows rapid preconcentration and separation of plutonium and neptunium in water samples was developed for the measurement of 237Np and Pu isotopes by inductively-coupled plasma mass spectrometry (ICP-MS) and alpha spectrometry; a hybrid approach. 238U can interfere with 239Pu measurement by ICP-MS as 238UH mass overlap and 237Np via peak tailing. The method provide enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then moving Pu to DGA resin for additional removal of uranium. The decontamination factor for uranium from Pu is almost 100,000 and the decontamination factor for U from Np is greater than 10,000. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration is performed using a streamlined calcium phosphate precipitation method. Purified solutions are split between ICP-MS and alpha spectrometry so that long and short-lived Pu isotopes can be measured successfully. The method allows for simultaneous extraction of 20 samples (including QC samples) in 4 to 6 hours, and can also be used for emergency response. 239Pu, 242Pu and 237Np were measured by ICP-MS, while 236Pu, 238Pu, and 239Pu were measured by alpha spectrometry.