Download Free The Volatility Of Uo2 X And Phase Relations In The Uranium Oxygen System Book in PDF and EPUB Free Download. You can read online The Volatility Of Uo2 X And Phase Relations In The Uranium Oxygen System and write the review.

The volatility of UO/sub 2 plus or minus x/ and the phase relations in the uranium-oxygen system were studied using thermogravimetric techniques. Chemical reactions describing the loss of uranium from UO/sub 2 plus or minus x/ at temperatures between 1100 and 2200 deg C in oxygen pressures between approximately 10 and 10/sup -6/ torr are proposed. The uranium-bearing vapor species above UO/sub 2 plus or minus x/ appears to be UO/sub 4/(g). Evidence supporting the existence of UO/sub 4/(g) included the volatilization of material with an oxygen-to-uranium ratio of 4 during the decomposition of UO/sub 2 plus or minus x/ (0.2> x> 0) to near-stoichiometric UO/sub 2/ in vacuum above 1500 deg C and the dependence of the evaporation rate of the uranium dioxide on the oxygen pressure between 1200 and 1500 deg C. The equilibrium oxygen pressures over compositions between UO/sub 2.02/ and UO/sub 2.63/ in the UO/sub 2+x/ and U/ sub 3/O/sub 8/- regions and over the boundary between these phases were measured between 1000 and 1600 deg C. The equilibrium oxygen-to-uranium ratio of UO/sub 2 plus or minus x/ was less than 2 above 1700 deg C in vacuum. (auth).
Urania-lanthana compositions were studied by x-ray diffraction, chemical analysis, and polished-section techniques to determine cubic fluorite solubility, lattice parameter values, stoichiometry, and microstructure. An appreciable variation in fluorite lattice parameter with composition existed for vacuum, hydrogen, and oxidizing heat treatments. The volatility behavior of urania-lanthana solid solutions was investigated by heating for extended time intervals in an oxidizing atmosphere.
In the beginning of the 1990’s, in the course of the events which were rapidly cha- ing the political con?guration of the East European countries, the crisis which - vested the vast research apparatus of the former Soviet Union was entailing con- quences whose dimension and depth were immediately realized by the international scienti?c community. In the same years, however, the most important branch of nuclear energy - searchanddevelopment,inparticularthatconcerning?ssionreactor,wasworldwide undergoing a substantial reduction due to a variety of decisional situations. Yet, paradoxically, it was a very good fortune that a number of concerns on the future of nuclear research were shared by East- and West-European scientists, especially those who were working in advanced ?elds. In fact, the only hope for coping with an uncertain future was to erect bridges between similar institutions and employ safeguarding tactics linked to a long term collaboration strategy. A decade later, this proved to be a winning decision, since the revival of nuclear energy is presently starting from a basis of common intentions and a network of established cooperation, whose seeds are to be searched in those initial, individual e?orts.