An apparatus of high-pressure differential thermal analysis has been constructed. It operates under constant pressure up to 200MPa in the temperature range between 100K and 350K. Liquid 3-methylpentane is used as the pressure medium. Two holes symmetrically drilled in a copper-beryllium alloy block are fitted with sample and reference cells. The cell, made of stainless steel, has a re-entrant copper sheath soldered at the center of the bottom for accepting the thermocouple junction. The pressure inside of the block is sealed by the metallic cone connections and kept constant to within 0.1MPa during measurement by an automatic pressure control system. These contrivances made the sample replacement easy and increased the stability of the baseline. The results on ND₄Br crystals showed the apparatus to be sensitive enough for use in most of the phase transition studies in the crystalline state. The heat capacity change≈10JK^-1 mol^-1 in the ND₄Br crystal was resolved as a signal a few times larger than the noise level.

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The aim of the review is to introduce the recent advances in high temperature mass spectrometry; activity measurements, expanding upper limit of measurement temperature, improving in sensitivity and accuracy, using in atmospheres, electrichemical Knudsen cell and application to preparing a phase diagram.

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Radioactive waste management has been briefly reviewed. Then, thermal properties of radioactive waste glass such as thermal conductivity, concentration redistribution under temperature gradient, stored energy and its release properties, and thermal performance of metamict state have been reviewed and discussed, including authors' latest data.

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