Radionuclides determination

Example Problem Given the data plotted below for the decay of a single radionuclide, determine the decay constant and the half-life of the nuclide. 

The development of solvent-impregnated resins and extraction-chromatographic procedures has enabled the automation of radiochemical separations for analytical radionuclide determinations. These separations provide preconcentration from simple matrices like groundwater and separation from complex matrixes such as dissolved sediments, dissolved spent fuel, or nuclear-waste materials. Most of the published work has been carried out using fluidic systems to couple column-based separations to on-line detection, but robotic methods also appear to be very promising. Many approaches to fluidic automation have been used, from individual FI and SI systems to commercial FI sample-introduction systems for atomic spectroscopies. 

Lariviere, D., Taylor, V. F., Evans, R. D., and Cornett, R. J., Radionuclide determination in environmental samples by inductively coupled plasma mass spectrometry, Spectrochim. Acta, Part B, 61, 877-904, 2006. 

E. H. Evans, J. B. Truscott, L. Bromley, P. Jones, J. Turner, B. E. Fairman, in R. W. Morrow, J. S. Crain (Eds), Applications of Inductively Coupled Plasma-Mass Spectrometry to Radionuclide Determinations, ASTM Special Technical Publication, 1344 (1998), 79-88. 

Gross activity of main radionuclides generated in case of SNR at the moment of flash end will be 1.69xl0 Bq, maximmn activity after flash will be 1.82xl0 Bq. Activity escape into the atmosphere in accordance with radionuclides determining the radiation situation is 1.25xl0 Bq. 

Figure 1 A process for publicising of procedures for radionuclide determination in environmental samples...

Some of the reported ISP-MS applications to radionuclide determination are presented next. Kim et al. (1989a) measured the Pu/ Pu ratio in two soils and an estuary silt after performing radiochemistry. They also measured this ratio in these soils by the fission track-etch technique and found that ICP-MS gave better precision. They... 

The intercomparison exercises show a need for greater standardisation of the analytical techniques used for radionuclide determination. This is indicated in McGee (1992), where the bias and measurement errors in radioactivity data from four European radiation research laboratories were reported. 

Isotope ratios, as measured by mass spectrometry, along with the known amount of the tracer, are used to determine the amount of the analyte in the sample. Isotopically altered elements (sometimes consisting of nearly pure stable isotopes) and radioactive isotopes are commercially available for use as tracers. Nearly every element can be purchased as a solution whose atom concentration is known and traceable to NIST. Standard materials are also available with isotopic composition determined to a high degree of accuracy. Radioactive tracers, such as 233U and 244Pu, are available for tracing actinide elements that do not have stable isotopes. Because many of the samples analyzed in radionuclide determinations already have altered isotopic ratios, many times it is possible to use a natural isotope as the tracer. 

Because the only commercially available GD-MS systems use a DC glow discharge, the range of samples that can be analyzed has been somewhat limited, especially in the field of radionuclide determination. Once an RF GD-MS is available to purchase, it is possible that GD-MS could become more popular for these applications. 

Probst, T. U. 1996. Studies on the long-term stabilities of the background of radionuclides in inductively coupled plasma mass spectrometry (ICP-MS)—A review of radionuclide determination by ICP-MS. Fresen J Anal Chem 354(7-8), 782-787. 

Morrow RW and Crain JS (eds.) (1998) Applications of Inductively Coupled Plasma-Mass Spectrometry to Radionuclide Determinations. Chelsea, MI American Society for Testing and Materials. 

Besides specific radionuclide determinations, screening methods to determine radioactive elements levels are very useful tools prior to laborious and expensive analytical protocols allowing isotopic analysis. These screening tools could replace gross alpha and gross beta index providing information about total element concentration. In order to develop fully automated methodologies based on inexpensive instruments, and consequently affordable for any routine laboratory, spectrophotometric detection can be used for this purpose. 

Separation by extraction chromatographic materials appears as the most suitable technique to develop automated radiochemical methodologies followed by LLE. There are a large number of selective resins for radionuclides determination, e.g. Ra, Ni, Pb, Th, U, Np, Pu, Am, Cm, Sr, Tc, H, Fe and Pa [4], which have been largely included in protocols with online separation [5—8]. Automatic separation exploiting flow systems can also be carried out by LLE which involves the formation of complexes between several organic compounds and radionuclides [9—11]. 

As an example of a fully automated system for radionuclide determination, there is a method based on SIA technique developed for Tc determination, including microwave assisted treatment, solid phase extraction (SPE) and online detection (Figure 8.6) [21]. 

Another example of system for radionuclides determination using online detection is an SIA system with bead injection (Figure 8.7) [20]. The use of a renewable column packing with selective... 

Figure 15.1 Distribution of papers pubiished in the period 1989-2005 using ICP-MS for radionuclide determination by the isotope measured [5].

Preparative strategies have been a key factor in the development of new procedures for radionuclide determination by ICP-MS. Momoshima et al. [80] used ferric hydroxide coprecipitation to scavenge Tc from seawater after technetium had been reduced to its tetravalent oxidation state. Solvent extraction and ion exchange decrease the interferences caused by spectral overlap and the sample matrix. Hollenbach et al. [81] determined Tc, and in soil by using a combination of flow injection and extraction... 

Applications of Inductively Coupled Plasma to Radionuclide Determinations, R. W. Morrow and J. S. Crain, Eds., ASTM, West Conshohocken, PA, 1995. 

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