In Situ Testing of Waste Glass in Clay

ABSTRACTThe actual status of an in-situ test programme exposing different waste glass samples directly to Boom clay is reviewed. Corrosion test tubes have been retrieved after residence for 5 years at 16° C, 2 years at 90° C, and 5 years at 170° C. The corrosion is interpreted in terms of mass loss, surface analysis by SEM and profiling by EPMA and SIMS. At 16° C, glasses dissolve about 0.02 – 0.08 µm per year. At higher temperature dissolution is more than two orders of magnitude larger. A good agreement is obtained between the mass losses and the surface analyses. The advantages and limitations of the Belgian in-situ tests are compared with the conclusions of an international expert group.</jats:p

Geochemical Modeling of the Interaction of HLW Glass With Boom Clay Media

ABSTRACTA geochemical model has been developed to describe the interactions of the main elements released from the COGEMA R7T7 SON68 glass with the Boom Clay environment and predict the formation of secondary phases which may influence the glass corrosion. It is based on two submodels: a model describing the interaction between the clay and its porewater, and a model for glass corrosion in groundwater. According to the calculations, no secondary minerals are predicted to precipitate when glass dissolves in the Boom Clay. The oncentrations of the main elements released from the glass are controlled by stable phases present in the Boom Clay (a.o. Si, Al) or by cation exchange reactions (e.g. Na). The concentration of silica in solution can be maintained below the glass silicon solubility limit. Therefore, the Boom Clay can suppress the saturation of silica, explaining the enhancing effect of Boom Clay on glass corrosion. The influence of the presence of clay on the other components of the glass is also discussed.</jats:p

Parametric Study of the Corrosion Behaviour in Static Distilled Water of Simulated European Reference High Level Waste Glasses

AbstractThe corrosion behaviour in distilled water of five simulated European reference high level waste glasses has been investigated for times up to 8 months. The glasses were chosen in accordance with the Joint European Community research programme on HLW form characterization: two French glasses (SON58, SON64), one British glass (UK209) and two glasses designed to incorporate HLW stored at the Eurochemic plant in Belgium (SM58 and SAN60). In the reference condition (90°C, SA.V−1 = 1 cm−1) the leaching was characterized mainly by diffusion processes and by the onset of saturation in the leachate (these saturation effects were found to depend on glass composition). In more dilute conditions (SA.V−1 = 0.1 cm−1), matrix dissolution was the rate controlling mechanism. Increasing the leachant temperature to 150°C and higher lead to pronounced surface crystallization and, at least for one glass (SAN60), to an increased corrosion.</jats:p

Urine erythrocyte morphology in patients with microscopic haematuria caused by a glomerulopathy

The evaluation of urinary erythrocyte morphology (UEM) has been proposed for patients with isolated microscopic haematuria (IMH) to early orientate the diagnosis towards a glomerular or a nonglomerular disease. However, to date, the role of this test in patients with IMH has very rarely been investigated. Sixteen patients (ten children, six adults) with persistent IMH classified as glomerular on the basis of repeated UEM evaluations (55 urine samples, two to eight per patient) were submitted to renal biopsy. This showed a glomerular disease in 14/16 patients (87.5%) (nine thin basement membrane disease; three Alport syndrome; two other), whereas in two patients, no abnormalities were found. Of four microscopic criteria investigated to define a IMH as glomerular, > 80% dysmorphic erythrocytes were not found in any sample, >= 40% dysmorphic erythrocytes alone were seen in seven samples (12.7%), >= 5% acanthocytes alone in 15 samples (27.3%) and erythrocytic casts in six samples (10.9%). There was >= 40% dysmorphic erythrocytes associated with >= 5% acanthocytes in 25 samples (45.5%). Sensitivity and positive predictive values in diagnosing a glomerular haematuria were 59.2% and 90.6%, respectively, for >= 40% dysmorphic erythrocytes, 69.4% and 85% for >= 5% acanthocytes/G1 cells and 12.2% and 100% for erythrocytic casts. Our findings demonstrate that the evaluation of UEM is useful to identify patients with an IMH of glomerular origin