Nuclear waste composition

Lumpkin, G. R., Colella, M., Smith, K. L., Mitchell, R. H. Larsen, A. 0.1998. Chemical composition, geochemical alteration, and radiation effects in natural perovskite. In McKinley, I. G. McCombie, C. (eds) Scientific Basis for Nuclear Waste Management XXL Materials Research Society Symposium Proceedings, 506, 207-214. 

This section is primarily intended to show that the relevant combination of the intrinsic physico-chemical and microscopic characteristics of HT materials, their behaviour under aggressive conditions of corrosion, and their modelled thermodynamic stability, yields a sound composite picture of these materials. On the basis of the knowledge acquired over decades on high-level nuclear waste glasses (Vernaz Dussosoy 1992 Bates et al. 1994 Thomassin 1995, 1996 Ewing 1996), these are the key parameters that may drastically influence the long-term durability of HT materials. 

Small-scale, tabletop nuclear fusion devices, known as compact accelerator neutron generators, are routinely used as a source of neutron radiation. By design, however, these devices consume more energy than they release. The beam of neutrons generated by these devices can be used to identify the elemental composition of amaterial.The coal industry uses such beams to measure the sulfur content of coal in real time as the coal moves over conveyor belts. The cement industry similarly uses these beams to judge the quality of cement mixes. These fusiongenerated neutrons are also used to identify the elemental composition of nuclear wastes and for the detection and identification of explosives. 

Scientists at PNNL have developed an automated radiochemical sample preparation-separation-detection system for the determination of total "Tc in nuclear-waste process streams.46 85 86 144145 This analyzer was designed to support a technetium removal process planned as part of the development of a nuclear-waste processing plant. The process stream composition is both complex and variable, with a high pH, high salt matrix. Depending on the source of the feed, the total base content, the concentration of organics, and complexant concentrations will vary, as will the aluminum, nitrate, nitrite, dichromate, and radionuclide composition. 

Figure 8. Auger surface spectrum of a corroded nuclear waste glass together with its compositional profile. Conditions (top and bottom) PNL glass composition 76-68, 90°C for 3 d in HgO, SA/V = 0.1 cm 1. Key (top) Si - 75 eV, B —...

The application of the linear model will be shown for cesium-137 and strontium-85 ions. Cs-137 and the different strontium isotopes, especially Sr-90, are important components of nuclear wastes. As seen previously in Table 3.2, the cesium ion has a different sorption property on bentonite samples from the Sajobabony deposit, depending on geological origin and composition. Similarly, different bentonite rocks from the Carpathian Basin (Table 3.4) show different sorption properties, including kinetics and equilibrium (Figure 3.4, Table 3.5 Nagy et al. 2003b Konya et al. 2005). 

PAN-KCoFC and PAN-4A composite adsorbents were prepared for the removal of cesium and strontium ions from acidic nuclear waste solutions. High porous spheri( composite adsorbents could be prepared using a dual nozzle technique. The acid and radiation stability tests showed that the both composite adsorbents were stable against acid solutions higher than pH - 2 and radiation dose less than 1.89 MGy, respectively. Adsorption tests showed that the PAN-KCoFC was selective for cesium ion and the PAN-zeolite 4A was for strontium ions, respectively. The ion exchange equilibrium isotherms were obtained and evaluated for the binary systems. 

Introduction actinide solubilities in reference waters. In this section, the environmental chemistry of the actinides is examined in more detail by considering three different geochemical environments. Compositions of groundwater from these environments are described in Tables 5 and 6. These include (i) low-ionic-strength reducing waters from crystalline rocks at nuclear waste research sites in Sweden (ii) oxic water from the J-13 well at Yucca Mountain, Nevada, the site of a proposed repository for high-level nuclear waste in tuffaceous rocks and (iii) reference brines associated with the WIPP, a repository for TRU in... 

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