Atomic energy review最新文献

In recent years the demand for information about the distribution of elements at trace concentration levels in high purity materials and in biological, environmental and geological specimens has increased greatly. Neutron activation analysis can play an important role in obtaining the required information. Radiochemical separations are required in many of the applications mentioned. A critical review of the progress made over the last 15 years in the development and application of radiochemical separation schemes for multielement activation analysis and in their automation is presented. About 80 radiochemical separation schemes are reviewed. Advantages and disadvantages of the automation of radiochemical separations are critically analysed. The various machines developed are illustrated and technical suggestions for the development of automated machines are given.

Radioactive colloidal solutions and suspensions are being widely used in the diagnosis and treatment of various diseases. The author considers the behaviour or radioactive disperse preparations in the body and devotes particular attention to the reasons for isotope transition from the colloidal to the ionic state. Questions concerned with producing and investigating radioactive colloidal solutions are discussed. In the light of the physical and chemical properties of the radioisotopes and of the disperse systems themselves, the author considers methods of producing the more important radioactive disperse preparations: colloidal solutions of noble metals; colloidal solutions containing phosphorus-32, yttrium-90 and isotopes of the rare-earth elements; colloidal solutions with with indium-113m, gallium-68, technetium-99m and rhenium-186; suspensions (macroaggregates and microspheres) for the diagnosis of lung diseases; and radioactive colloidal solutions based on quaternary ammonium base compounds.

The review summarizes the present state of the involvement of relatively small computing devices in the collection and processing of gamma-ray spectrum data. An economic and utilitarian point of view has been chosen with regard to data collection in order to arrive at practically valuable conclusions in terms of feasibility of possible configurations with respect to their eventual application. A unified point of view has been adopted with regard to data processing by developing an information theoretical approach on a more or less intuitive level in an attempt to remove the largest part of the virtual disparity between the several processing methods described in the literature. A synoptical introduction to the most important mathematical methods has been incorporated, together with a detailed theoretical description of the concept gamma-ray spectrum. In accordance with modern requirements, the discussions are mainly oriented towards high-resolution semiconductor detector-type spectra. The critical evaluation of the processing methods reviewed is done with respect to a set of predefined criteria. Smoothing, peak detection, peak intensity determination, overlapping peak resolving and detection and upper limits are discussed in great detail. A preferred spectrum analysis method combining powerful data reduction properties with extreme simplicity and speed of operation is suggested. The general discussion is heavily oriented towards activation analysis application, but other disciplines making use of gamma-ray spectrometry will find the material presented equally useful. Final conclusions are given pointing to future developments and shifting their centre of gravity towards improving the quality of the measurements rather than expanding the use of tedious and sophisticated mathematical techniques requiring the limits of available computational power.

Fusion reactor design concepts are being pursued in the research and development programme of various countries and studies are being undertaken on the possible environmental impact of fusion power reactors. The paper reviews and summarizes the results of such environmental impact studies. Attention is restricted to deuterium-tritium fusion reactor concepts and a preliminary environmental impact assessment is presented. The possible inventory tritium and radioactive materials in the neutron-activated blanket structure of fusion power reactors is described and potential hazards posed by this radioactive materials inventory are discussed. Non-radiological implications and accident considerations are outlined. In conclusion, various areas still awaiting further investigation and research work are identified. The paper contains 8 tables and 50 references.

Reference materials (RMs) are useful to compare the accuracy and precision of laboratories and techniques. The desirable properties of biological reference materials are listed, and the problems of production, homogenization and storage described. At present there are only 10 biological RMs available compared with 213 geological and 520 metallurgical RMs. There is a need for more biological RMs including special materials for microprobe analysis and for in vivo activation analysis. A study of 650 mean values for elements in RM Kale, analysed by many laboratories, leads to the following conclusions. 61% of the values lie within +/- 10% of the best mean, and 80% lie within +/- 20% of the best mean. Atomic absorption spectrometry gives results that are 5-30% high for seven elements, while instrumental neutron activation analysis gives low and imprecise results for K. Other techniques with poor interlaboratory precision include neutron activation for Mg, polarography for Zn and arc-spectrometry for many elements. More than half the values for elements in Kale were obtained by neutron activation, confirming the importance of this technique and the need for RMs. As a rough estimate, 6 X 10(9) elemental analyses of biological materials are carried out each year, mostly by medical, agricultural and food scientists. It seems likely that a substantial percentage of these are inaccurate, a situation that might be improved by quality control using standard RMs.

The term 'emergency' applies to unplanned events that have generated, or had the potential to generate, radioactive wastes that could not be handled locally. Reports of past emergencies form the basis for discussion of future trends in emergency situations, the factors that influence waste management, the technology of waste management and personnel requirements. The number of past emergencies has been small and these have not increased the volume of radioactive wastes significantly. The majority of future emergencies are likely to be associated with reactors as they have been in the past. Little change in the nature of the waste is expected, although the greater use of separated plutonium may create some new problems. The factors that influence emergency waste management fall into two categories, those that are concerned with the location of the emergency event, and those concerned with the characteristics of the wastes. As in the past, it can be expected that in most emergencies proven waste management techniques will be adapted to suit the local circumstances but there is a need for simpler and more economic methods. Trained personnel and comprehensive planning are cited as key factors in successful waste management operations.

To find the optimum solution to the problem of how to protect the environment from pollution by industrial waste, it is necessary, first and foremost, to obtain information on the existing levels of various forms of pollution and the damage caused by them. In this review data are given on all the main sources of contamination of the environment by radioactive substances. The pathways by which these substances reach and affect the human body are discussed, the doses incurred are characterized and the possible consequences of existing levels of exposure are assessed in the light of the latest data on the dose-effect relationship. The wisdom of treating the evaluation of radiation hazards arising from the use of atomic energy not in isolation but as part of a whole complex of ecological factors - including the use of conventional fuels for power generation and transport - is duly noted.