Modeling Relations Between the Composition and Properties of French Light Water Reactor Waste Containment Glass
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MODELING RELATIONS BETWEEN THE COMPOSITION AND PROPERTIES OF FRENCH LIGHT WATER REACTOR WASTE CONTAINMENT GLASS D. GHALEB, J.L. DUSSOSSOY, C. FILLET, F. PACAUD AND N. JACQUET-FRANCILLON Commissariat6 I 'EnergieAtomique, Rh6ne Valley Research Center,BP 171, 30200 Bagnols-sur-C~ze Cedex, France ABSTRACT Models have been developed to calculate the density, molten-state viscosity and initial corrosion rate according to the chemical composition of glass formulations used to vitrify high-level fission product solutions from reprocessed light water reactor fuel. Developed from other published work, these models have been adapted to allow for the effects of platinoid (Ru, Pd, Rh) inclusions on the molten glass rheology. INTRODUCTION The density, viscosity and initial corrosion rate of a nuclear containment glass are directly related to the glass fabrication conditions (density and viscosity) or to its aqueous corrosion properties (initial corrosion rate). Controlling the density ensures that no glass overflow can occur from the canister as the material is cast. The viscosity is used to determine the casting rate and to ensure satisfactory flow inside the canister. The initial corrosion rate is indicative of the glass leaching resistance, although not necessarily of its long-term behavior. A number of published models describe these properties [1-61, but none of them allow for the effect [6-8] of incorporating platinoid elements (Ru, Rh and Pd) which result in heterogeneous inclusions and significantly affect certain properties of the sodium borosilicate glass used in France 19] for LWR waste containment purposes, notably its rheological characteristics in the molten state and its microscopic homogeneity. Based on previously published work [1,2] we developed a model valid for glass without platinoids (WoP) and adapted itto glass containing platinoids (WP) at concentrations of up to 3%. DENSITY The density calculation module was based on the model described by SCHOLZE [1]. The glass density
is determined using a barycenter relation : dW ___g__ 10[dwoP• omnn100 mi gp glass density coflioflents M, 9 m_"fraction of each component (wt%) i di • characteristic density of each basic glass component. To allow for the overall changes in structural parameters due to the transition from pure oxides to oxides in the glass, the dsio2 parameter for silica (the predominant glass component) was adjusted to 2.36 to fit the experimental results of a sensitivity study covering composition variations in over 80 glass samples without platinoids [10]. All the other di parameters were values fur pure oxides taken from a data base [11]. Figure 1 compares the calculated and measured values for glass without platinoids after experimental characterization[l 0].
Glass without platinoids ,
2.90 a w 2.80 * 2.70
-
2.60
O 2.50
2.50
Figure 1:
2.60
2.70
2.80
Me
red de nsity
Calculated versus results; model WoP.
Mat. Res. Soc. Symp. Proc. Vol. 353 0 1995 Materials Research Society
2.90
measured
108
The WoP model overestimated the density o
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