Catalytic decomposition of methane is considered as a prospective pro-ecological method of hydrogen production. The main drawback of this method is fast deactivation of the catalyst by an inactive carbonaceous deposit formed in the reaction. In this study, a series of experiments have been made to check the effect of the presence of carbon dioxide in the reaction system on the reduction of the catalyst deactivation. The reaction of methane decomposition was carried out in two variants for 4 h in the presence of a carbon catalyst obtained from pine wood biomass. In the first variant, CO2 and methane were alternately dosed into the reaction system, while in the second variant, CO2 and methane were introduced simultaneously. The second variant reaction was performed at three temperatures, 750, 850, or 950 °C, and for the reaction mixture containing 5−50% CO2, while in the first variant reaction, the methane decomposition and the catalyst regeneration by CO2 were carried out at the same (750, 850, or 950 °C) or different temperatures. The results proved that the introduction of CO2 into the reaction system permits a considerable reduction of the catalyst deactivation, leading to an increasing content of hydrogen in the postreaction gases. The efficiency of the catalyst regeneration with CO2 introduced into the reactor simultaneously with methane is a resultant of the rates of the following main processes: carbon deposition (as a consequence of methane decomposition), gasification of the deposit and destruction of its structure by CO2, and partial gasification of the carbon catalysts.

a b s t r a c tSeveral U-based intermetallic compounds (UCoGe, UNiGe with the TiNiSi structure type and UNiAl with the ZrNiAl structure type) and their hydrides were studied from the point of view of compressibility and thermal expansion. Confronted with existing data for the compounds with the ZrNiAl structure type a common pattern emerges. The direction of the U-U bonds with participation of the 5f states is distinctly the "soft" crystallographic direction, exhibiting also the highest coefficient of linear thermal expansion. The finding leads to an apparent paradox: the closer the U atoms are together in a particular direction the better they can be additionally compressed together by applied hydrostatic pressure.

Intermediate level waste containers are used for the storage of an assortment of radioactive waste. This waste is heatgenerating and needs monitoring and so this work was undertaken to determine whether the mean internal container temperature can be inferred from the temperature of the vent. By using two independent thermometry techniquesphosphor thermometry and thermal imaging -the internal temperature was demonstrated to be proportional to the vent temperature as measured by both methods. The correlation is linear and given suitable characterisation could provide robust indication of the internal bulk temperature.

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