A high-temperature installation for the thermomechanical testing of refractories

Abstract

diam., 5.5 nun; height, 5 mm; density, 9 g/cm 3) of a solid solution of 8570 UO 2 and 15% PuO 2 and produced by mixing the oxides by mechanical means, molding the tablets from the mix, and firing them in vacuo at 1750~The tablets of (U, Pu)O2 and the zircon cylinders were tested in a molybdenum ampoule in an inert atmosphere at 1500~ for 20 h with the specimens in contact under a load of 2 kgf/cm 2. Radiographic and chemical analyses revealed slight migration of U (up to 0.03%) and Pu (up to 0.02%) into the zircon composition and of the components of the refractory composition (Zr, Si, A1, and Cr) into the nuclear fuel (up to 0.01% of the original amount), and the absence of caking between the zircon specimens and the (U, Pu)O 2 tablets. These findings make it possible to recommend the ACP-bonded zircon composition for the production of crucibles for the melting unit of installations for the thermal stripping of spent fuel elements. CONCLUSIONSAn investigation was carried out of the physic,-and thermomechanical properties of ACP-bonded zircon ramming compounds, of the conditions for their drying and firing processes, and of their solid-solution interaction with a mixed (U, Pu)O 2 nuclear fuel.The optimal composition of the ramming compound is as follows: 95?0 zircon of particle-size fraction 0.06-3.0 ram, 5% refractory clay finer than 0.5 ram, and 7% ACP binder of density 1.5 g/cm 3 (on 100%). The composition is characterized by high strength and low porosity and water absorption.

A study of the thermomechanical properties of the graphite-bearing refractores

“…I specimens and the specimens drawn from the imported monoblock-stopper was determined at 1970~ using a previously described [2] machine.…”

“…The heating elements, the loading pads, and the protective screens of the heating chamber of the test set-up were made from graphite [2]. For determining the ultimate compressive strength, cylindrical specimens measuring 50 mm in height and 36 mm in diameter were heated at a rate of 180~ up to 1470~ at a rate of 720-900~ in the 1470-1770~ range, and at a rate of 120-180~ up to 18200K; at a given test temperature, the isothermal holding period amounted to 0.5 h. Table 2 shows the test results along with the data on the ultimate tensile strength obtained using the radial (diametric) compression method [3].…”