Radioactive waste disposal measurements

Table 1. Sedimentation Rates and Curve Fitting of 210Pb Measurements in Cores Collected at the U. S. Radioactive Waste Disposal Sites Near the Farallon Islands 60 km off San Francisco and at the Hudson Canyon, 350 km off New York City.

Radioactive waste disposal—Risk assessment. 2. Hazardous wastes— Risk assessment. 3. Hazardous wastes—Classification. I. National Council on Radiation Protection and Measurements. II. Series. 

In addition to processes of the nuclear fuel cycle, release of uranium has been detected in surface water adjacent to a radioactive waste disposal site in Massachusetts (Cottrell et al. 1981). measurements indicated that surface water located adjacent to the waste disposal site had concentrations of up to 155 pCi/L. Additionally, groundwater measurements of and at the disposal site were 4,400 pCi/L and 2,400 pCi/L, respectively. These values were elevated compared to values obtained in a study performed for the EPA (Drury 1981). For the EPA study, a total of 35,000 surface water samples from across the United States were analyzed the average total uranium concentration was 1.1 pCi/L (range 0.01-582 pCi/E). Of these, 28,000 were considered samples of domestic water supplies. In this same study, 55,000 groundwater samples had a total mean uranium concentration of 3.2 pCi/L (range 0.01-635 pCi/L). 

Uranium isotopes have also been used to study local groundwater problems, in particular those related to the mobility of uranium in ground-water near radioactive waste disposal sites and the role of colloids in controlling the subsurface movement of uranium and its decay products (Ivanovich et al., 1988 Short et al., 1988 Suksi et al., 2001 Toulhoat et al., 1996 Hussain, 1995 Gomes and Cabral, 1981). Paces et al. (2002) used extensive measurements of... 

In addition to these analyses, a comparison of measured and computed values of temperature and degree of saturation for some selected points of the mid plane of hole number 1 have been presented. The results show that despite the large amount of parameters and the difficulties in characterising those materials, the simulation can reproduce the main aspects of the processes involved, as, for instance, the wetting-drying cycles of the zone close to the heater. This effect has been simulated thanks to the consideration of the vapour flow in the system. This result is also consistent with other THM simulations performed in the context of radioactive waste disposal problems. 

Absolute safety does not exist in any human activity, and much less so in industry. I believe, however, that nuclear power plants are every day safer and that radioactive waste disposal facilities will be safer still. Generally speaking it may be said that public concern for safety in this sector has forced those involved to enhance the measures takoi. It should also be pointed out, however, diat... 

Radiation — Safety measures. 2. Radioactive waste disposal — Safety measures. 3. Nuclear reactors — Safety measures. 4. Nuclear reactors — Design and construction. I. International Atomic Energy Agency. II. Series. 

All facilities where radiation sources need to be safely managed are covered by this Safety Guide, including those containing the sources shown in Table 1 in Section 3. The safety measures recommended are also applicable to radioactive sources in nuclear facilities or radioactive waste disposal facilities, while it is recognized that these facilities should in any case provide a high standard of source safety. 

After equilibration, the amount of bound and free-labeled antigen can be measured, and a calibration curve can be used to determine the analyte. Radioactive labels have been extensively used because of the sensitivity of the measurement however, they have several disadvantages, such as the waste disposal problem and the unstable nature of reagents. CL tags were therefore considered attractive alternatives due to their low (excellent) detectability, which was not fully provided by most fluorescent labels. 

Sediments in the Mississippi River were accidentally contaminated with a low-level radioactive waste material that leaked from a nuclear power plant on the river. Pore water concentrations of radioactive compounds were measured following the spill and found to be 10 g/m over a 2-mm depth. The water contamination was 30% radioactive cesium ( Cs), with a half-life of 30 years, and 70% radioactive cobalt ( °Co), with a half-life of 6 years. Objections by the local residents are preventing clean-up efforts because some professor at the local state university convinced them that dredging the sediments and placing them in a disposal facility downstream would expose the residents to still more radioactivity. The state has decided that the sediments should be capped with 10 cm of clay and needs a quick estimate of the diffusion of radioactive material through the clay cap (Figure E2.8.1). If the drinking water limit (10 g/m ) is reached at mid-depth in the cap, the state will increase its thickness. Will this occur ... 

To the extent that risk is used as a basis for waste classification, it is not used consistently. Different values for acceptable risk are assumed for different hazardous waste disposal situations. In addition, a variety of surrogate measures (e.g., ingestion toxicity, total radioactivity) having varying relationships to risk have been used to classify wastes. 

The chapters of this volume are organized into sections that cover the chemical aspects that are important to understanding the behavior of disposed radioactive wastes. These aspects include radionuclide sorption and desorption, solubility of radionuclide compounds, chemical species of radionuclides in natural waters, hydrothermal geochemical reactions, measurements of radionuclide migration, solid state chemistry of wastes, and waste-form leaching behavior. The information in each of these sections is necessary to predict the transport of radionuclides from wastes via natural waters and thus to predict the safety of the disposed waste. 

Cell harvesters were developed to capture multiple samples of cells on membrane filters, wash away unincorporated isotopes, and prepare samples for liquid scintillation counting on special equipment developed to process and count multiple samples. Despite miniaturization and improvements in efficiency of this technique, the disadvantages of multiple liquid handling steps and increasing costs for disposal of radioactive waste materials severely limit its usefulness. Although specific applications require measuring DNA synthesis as a marker for cell proliferation, much better choices are available for detecting viable cell number for HTS. 

Optical microscope observations have shown that zircons often exhibit extremely complex microstructures (on the scale of 1-100 /tm), in which changes of birefringence correlate with the distribution of U and Th (Chakoumakos et al. 1987). However, no attempts appear to have been made to relate these microstructures to other impurities (such as water-related species) and crystal defects, both of which may significantly influence the processes of metamictization and recrystallization. Such a study involving TEM might also provide important information about the diffusion and leaching of radioactive impurities (and the products of their decay), processes that have important implications for ceramic nuclear-waste disposal and for techniques of age determination based on measurements of Pb/U isotopic ratios. 

Martinez-Aguirre et al. (1994) have performed an extensive study of the presence of natural radioactivity around a phosphate fertilizer factory complex situated in an estuarine area of southwest Spain. The study has concluded that the wastes from such industries are the cause of the enhancement of natural radioactivity in the immediate environment. Thus, significantly high levels of U and Th-isotopes and Ra are detected in water and sediment samples collected in this area. These conclusions, based on the enhanced isotopic concentrations, are further supported by the measured U, Th and Ra isotopic activity ratios being quite different from any observed elsewhere in undisturbed estuaries. These isotope activity ratios appear to be very sensitive indicators of waste disposal practices in such environments. 

With the development of radioimmunoassays (RIAs) in the 1960s that used radioactive isotopes as labels (see Chapter 9), the measurement of radioactivity became a common and important practice in clinical laboratories. However, concerns about, and problems with, the safe handhng and disposal of radioactive reagents and waste have led to the development of immunoassays that use nonisotopic labels (see Chapter 9). The rapid acceptance and extensive use of nonisotopic immunoassays by the clinical laboratory have resulted in a decreased use of RIA and ultimately a decreased requirement for them to measure radioactivity. Because of this deemphasis on the necessity to measure radioactivity, only a brief discussion of the topic is presented here. Readers requiring more detail on this topic are referred to the chapter entitled Basic Principles of Radioactivity and Its Measurement that is included in a prior edition of this textbook, ... 

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