A method for actinide determinations has been established which has considerable advantages over currently described procedures. The benefits are rapid sample throughput, good safety features with no compromise in data quality. A borate fusion is used for the sample digestion. Chemical separation is optimized by using a column of anion-exchange resin column stacked on a UTEVA column. Uranium was measured using thermal ionization mass spectrometry with a precision of 0.2% 2 sigma. Pu measurements were made using alpha-particle spectrometry. The procedure has been applied successfully to a wide range of sample types and other actinide elements (Th, Am, etc.) could also be included in the analytical scheme. The method has been thoroughly evaluated by measuring international reference samples. The method lends itself very well to large-scale environmental surveys.

Uranium isotopic composition and concentration have been determined on over 500 soil samples from the Greenham Common Air Base and surrounding Berkshire, UK, to detect potential contamination from nuclear sources. Due to the large number of samples involved in this study and the potentially subtle nature of the contamination a new method of analysis was developed which is both rapid and highly precise. Data are presented for international standard reference materials and soil samples for uranium content and 238U/235U measured by thermal ionisation mass spectrometry (TIMS) using a dynamic combination of Faraday and ion-counting detectors. Precision of the 238U/235U ratio was enhanced by correcting for mass bias as a function of ion beam intensity. In-run mass fractionation was controlled without recourse to double spiking by ensuring that sample loads were always in excess of 350 ng U. The resulting reproducibility for standards and soil samples was better than 0.2% at 2 standard deviations (sd). This precision means that an addition of ≥0.4 ng of enriched uranium (93 at% 235U) per gram of typical soil can be reliably identified. Subtle deviations from natural uranium composition have been recognised in a number of soil samples in the Aldermaston area.

A rapid and highly precise method, which uses a borate fusion, of U and Pu determination in soils, sediments and other materials is described. The chemical separation steps are optimised by using an anion resin column stacked on an extraction chromatography column (Eichrom Industries UTEVA resin). The whole procedure was streamlined to measure 700 soil samples in 10 weeks as part of an urgent environmental monitoring programme. Uranium was measured using thermal ionisation mass spectrometry with a precision of 0.2% at the 95% uncertainty level. Pu was measured using alpha spectrometry with a precision of approximately 10% at the 95% uncertainty level. The method can be applied successfully to a wide range of sample types and other actinide elements (Th, Am, etc.) can also be effectively included in the analytical scheme. The whole method has been critically evaluated by measuring a range of international reference samples.