Thermal analysis of the cooling curves of small samples of uranium dioxide, laser heated in a high-pressure autoclave on a subsecond time scale to a temperature just below the melting point, reveals, in the case of nominally stoichiometric UO
2.00, a significant
-like heat capacity peak, indicating a premelting transition in this material. The results are discussed and a simple model is presented in terms of which the observed behavior can be described.
Key words heat capacity - laser heating - solid-solid transition - uranium dioxide
Summary of a paper presented at the Third Workshop on Subsecond Thermophysics, September 17–18, 1992, Graz, Austria. Because of its length, the full paper was published in a regular issue of this journal (Vol. 14, No. 2, 1993).