Analysis actinide isotopes

Actinide isotope analysis method development using FI technique for column separation and preconcentration ICP-MS 138... 

The principal application of the actinide elements is in the production of nuclear energy. Although this is by far the most important use for any of the actinide elements, a surprising number of other uses have been found. These include the use of short-lived actinide isotopes as portable power supplies for satellites in ionization smoke detectors in the therapy of cancer in neutron radiography in mineral prospecting and oil-well logging as neutron sources in nuclear reactor start-up and as neutron sources in a variety of analytical procedures, the most important of which are neutron activation analysis and heavy-ion desorption mass spectroscopy. 

Potential fusion appHcations other than electricity production have received some study. For example, radiation and high temperature heat from a fusion reactor could be used to produce hydrogen by the electrolysis or radiolysis of water, which could be employed in the synthesis of portable chemical fuels for transportation or industrial use. The transmutation of radioactive actinide wastes from fission reactors may also be feasible. This idea would utilize the neutrons from a fusion reactor to convert hazardous isotopes into more benign and easier-to-handle species. The practicaUty of these concepts requires further analysis. 

Actinides were determined at the ultratrace level in moss samples collected from the eastern Italian Alps (1500 m a.s.l.). The frozen samples were cut into 1-2 cm sections and analyzed separately to obtain the distribution curves of the vertical concentrations. For plutonium and americium isotope analysis, 1-2 g of the samples were ashed, leached, separated with respect to analytes and analyzed by alpha spectrometry and LA-ICP-MS after the plutonium or americium had been electroplated on a stainless steel disk.23 Estimated limits of quantification of LA-ICP-MS for actinide radionuclides deposited on stainless steel plates after chemical separation are summarized in Table 9.45. For most of the long-lived radionuclides in moss samples, lower limits of determination were found at the 10 15gg 1 concentration level compared to those of a - spectrometry 23... 

Further applications of laser ablation inductively coupled plasma mass spectrometry for the trace and ultratrace and isotope analysis of long-hved radionuclides are discussed in references1 3,9actinide elements is presented by Geipel.91... 

Garcia Alonso, J. I., Determination of fission products and actinides by inductively coupled plasma mass spectrometry using isotope dilution analysis A study of random and systematic errors, Anal. Chim. Acta, 312, 57-78, 1995. 

There are many instances in which it is highly desirable to analyze the smallest possible sample. This is of obvious importance when radioactive species are involved, but it is also advantageous when analyzing smaller samples means processing smaller amounts of material for an analysis, as is often the case in geological applications, among others. Measurement of isotopic ratios from pico-gram or smaller quantities of analyte has been reported for technetium [70,71], actinide elements [72], and rare earth elements [73]. 

The nuclear area is one that has been heavily dependent upon isotope ratio mass spectrometry performed by thermal ionization. Applications in this area are among the major reasons for the continued push to analyze smaller and smaller samples. There are two primary reasons for this (1) maximum practicable reduction of the hazards associated with radioactivity and (2) presence of often only a very small amount of the target element available. Areas addressed include evaluation of uranium enrichment processes [86], isotopic analysis of transuranium elements (all elements through einsteinium have been analyzed) [87], and environmental monitoring for release of uranium and other actinides [88,89]. This last area has received renewed emphasis in the wake of the Gulf War [90]. 

Although ICP-MS has been used for analysis of nuclear materials, often the entire instrument must be in an enclosed hot enclosure [350]. Sample preparation equipment, inlets to sample introduction systems, vacuum pump exhaust, and instrument ventilation must be properly isolated. Many of the materials used in the nuclear industry must be of very high purity, so the low detection limits provided by ICP-MS are essential. The fission products and actinide elements have been measured by using isotope dilution ICP-MS [351]. Because isotope ratios are not predictable, isobaric and molecular oxide ion spectral overlaps cannot be corrected mathematically, so chemical separation is required. 

Many applications focus on the isotopic analysis of elements in environmental samples (water, rocks, soil, minerals), meteorites, biological tissues, and nuclear materials (such as nuclear fuels). A relatively new application has been the use of TIMS in nuclear safeguards and arms control treaty verification (IAEA, 2003). Of most interest to this discussion is the high quality isotopic analysis of actinide elements, especially U and Pu. Typical performance parameters are given in Table 17.6 for isotopic analysis of actinide elements and additional examples are given in Section 17.8. 

VII.63. The use of INF isotopics in the criticality safety analysis means that any computational methods used to predict the isotopics should be validated, preferably against measured data. The reduced reactivity in INF is due to the decrease in fissile inventory and the increase in parasitic, neutron absorbing nuclides (non-fissile actinides and fission products) that build up during bumup. Broadhead [V11.23] and DeHart [V11.24] provide information to help identify the important nuclides that affect the reactivity of PWR irradiated fuel. The INF nuclides that can be omitted from a safety analysis are the parasitic absorbers that can only decrease k jj further if included in the analysis. Neutron absorbers that are not intrinsic to the fuel material matrix (gases, etc.) must also be eliminated. 

The pre-det investigation of either an IND or RDD would seek to detect many of the same radionuclear analytes as for a post-det inquiry. Therefore, materials analysis of IND components would focus on actinide species and their isotopic ratios to estimate threat credibility. Fission products, perhaps at trace levels, could provide clues about radiochemical separation tactics used for reprocessed material. Even activation products, if the nuclear pit contained Pu, might supply information on the time elapsed since a device was assembled. 

With radiochemical forensic samples, isotopic carrying is used mainly for yielding the presence of excess isotopic carrier can interfere with subsequent mass-spectrometric and radiation-counting measurements. Non-isotopic carrying, however, has many applications to the radiochemical analysis of the actinides. Iron hydroxide is very effective in carrying the... 

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