Radiochemicals analysis

Radio antennas Radio astronomy Radioautogiaphy Radiochemical analysis Radiochemical technology Radiofibrosis Radio frequency... 

The difficulties include the inconvenience of handling radioactivity and the necessity for obtaining an accurate radiochemical analysis of two phases containing several elements (which often involves complicated spectra). Highly sensitive instrumentation is required for the analysis e.g. a Li-Si surface barrier detector for a particles, a 2 r gas counter for (3-radiation and a Li-Ge detector for 7-radiation. Great care is required during source preparation, which is best done by electrodeposition. 

A slightly different example is the separate determination of rates of reaction of nC and 14C labeled methyl iodide with N,N-dimcthyl-/>-toluidine as illustrated in Fig. 7.3. Again the method takes advantage of the convenience of radiochemical analysis. If, as likely, the KIE of interest is ki2/ki4, it can be obtained to sufficiently good approximation by applying a modified Swain-Schaad rule, ln[ki2/ki4]/ln[kn/ki4] = [(12/14)/(11/14)]1/2 obtained from the law of the geometric mean (see Section 10.5). 

Radiochemical analysis of meta-studtite from an SNF test indicated that 237Np was associated with the U6+ peroxide (Table 3). Plutonium, Cm, and Am were found to be in lower concentration in the secondary U phases however, 5-6% of the available Pu and Am, based on reactor code estimates, was co-precipitated with the U phase. The radiochemical data for the collected alteration products from the SNF samples (Table 3) are presented as pg-analyte per g U for comparison to the reactor inventory code calculation for 30MW/d burn-up fuel at 20 y (extracted from Guenther et al. 1988). 

Tahiti 3. Radiochemical analysis oj corrosion products Jrom spent fuel ajtvr 1.5 v of immersion in wilier... 

The spectrometer has also been applied successfully to the counting of environmental samples contaminated with worldwide fallout, reactor effluent, and debris from nuclear cratering experiments. In addition, it has been possible to carry out a variety of laboratory experiments not practical in the past because of the need for laborious radiochemical analysis such experiments have involved the analysis of several hundred samples each containing up to 20 isotopes. 

X-ray and Coincidence Spectrometry Applied to Radiochemical Analysis of Environmental Samples... 

In Table IV, the atom ratio data obtained by radiochemical analysis of a series of aerial filter and fallout samples are presented. The analyses were performed by the Radiochemistry Division at Lawrence Radiation Laboratory, Livermore. The atom ratios, which we designate by rxA in... 

Prior to radiochemical analysis the samples were ashed and separated into size fractions by means of procedures described by Nathans et al. The determinations of the fraction weights and of the mean diameters of the particles in the fractions have also been described extensively in the same paper. An aliquot of each size fraction was dissolved and subjected to a separation procedure to isolate Sr, Ru, Sb, Cs, Ce, Pm, U, and Pu fractions. The procedure is sketched in Figure 1. Further decontamination of Ru and Ce was carried out only with the Johnie Boy sample. The Sb and Pu fractions were set aside for later analysis. After complete analysis of the Cs fractions, anomalies were found in the data for the coral samples. These samples had been ashed at about 475°C. Apparently some Cs had volatilized at this temperature. Such a behavior explained the anomalies, and this was confirmed by Heft by more extensive experimentation (4). Thus, Cs data are reported only for the Johnie Boy sample, which was ashed at low temperature in a Tracerlab low temperature asher. 

Ruzicka, J. and J. Stray. Substoichiometry in Radiochemical Analysis, Pergamon, Oxford, 1968. 

Since not many natural radioactive elements are in existence analysis by radiochemical methods was rather limited until it became possible to "induce radioactivity artificially in some of the non-radioactive elements, as was first done in 1934 by I. Curie F.Joliot(Ref 1). This discovery greatly broadened the application of radiochemical analysis. The first application of artificial radio activation for the identification of constituents in a mixt was reported by Meinke (Ref 16) to have been done in 1936 by Hevesy 8t Levi (Ref 2). 

Morrison, G. H., and J. F. Cosgrove Symposium on Radiochemical Analysis, 136. Meeting ACS, 1959. New York American Chemical Society. 

Monk, R. G., and K. C. Steed Microchemical Methods in Radiochemical Analysis. VI. Determination of Chemical Yields by Micro-Coulometry. Anal. Chim. Acta 26, 305 (1962). 

Q Automation of Extraction Chromatographic and Ion Exchange Separations for Radiochemical Analysis and Monitoring... 

Both radiometric and mass spectrometric detection approaches have been used in automated radiochemical analysis, depending on the radionuclides of interest and the capabilities of the laboratory involved. The tradeoffs between radiation counting and atom counting have been described.14 16 17 Short-lived fission products may be advantageously detected with radiation detection, whereas long-lived (low specific activity) radionuclides can be determined with better sensitivity using ICP-MS. 

Solid-Phase Separation Materials for Radiochemical Analysis... 

Laboratory robotics represents an attractive approach for the automation of sample preparation and separation steps in radiochemical analysis, and for many years, such methods have been routinely used by laboratories serving the analytical needs of the International Atomic Energy Association.64 68-72 However, there are currently a limited number of published studies containing technical details on the radiochemical separations and how they were automated. Accordingly, the remainder of this chapter will focus on fluidic approaches. 

Although best known for simple serial assays in homogeneous solution, such as colorimetric reactions, FI methods have also been developed that perform separations or utilize solid phases.33 34,42 73 -76 The use of solid-phase separation columns in FI or SI systems for radiochemical analysis gathered momentum in the 1990s. 

By the late 1990s and into the 2000s, a number of additional groups became involved in automated fluidic separations for radiochemical analysis, especially as a front end for ICP-MS. Published journal articles on fluidic separations for radio-metric or mass spectrometric detection are summarized in Tables 9.1 through 9.5. The majority of such studies have used extraction chromatographic separations, and these will be the main focus of the remainder of this chapter. Section 9.4 describes methods that combine separation and detection. Section 9.5 describes a fully automated system that combines sample preparation, separation, and detection. 

Conventional radiochemical analysis of nuclear process or waste samples in the laboratory entails three primary activities sample preparation, radiochemical separation, and detection. Each of these activities may entail multiple steps. The automated fluidic methods described above, typically also carried out in the laboratory, link separation and detection. Sample preparation has, in many cases, been carried out first by manual laboratory methods. 

Radiochemical analysis will continue to be important in many aspects of the use of nuclear fuels, including spent-fuel analysis monitoring reprocessing for process performance or safeguards analyzing environmental samples for contamination and... 

Egorov, O., Grate, J. W., and Ruzicka, J., Automation of radiochemical analysis by flow injection techniques Am-Pu separation using TRU-resin sorbent extraction column, J. Radioanal. Nucl. Chem., 234, 231-235, 1998. 

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