VAPORIZATION PROPERTIES OF SRUO3 AND BAUO3 IN ATMOSPHERES SIMULATING ACCIDENT CONDITIONS

Effects of various environments on vaporization characteristics of BaU O3 and SrUO3 have been studied by means of the Knudsen effusion mass s pectrometry. Three kinds of Knudsen cells were employed for simulating different accident atmospheres over temperature ranges from 1470 to 1 920 K. The vapor pressures obtained in a platinum Knudsen cell were us ed as the standard values, with which those obtained in other conditio ns were compared. A graphite Knudsen cell was utilized to simulate the graphite environment of high temperature gas-cooled reactors (HTGR). On the other hand, a specially designed Knudsen cell with a gas inlet system attached to its bottom was employed in order to introduce react ive gases such as D-2(g) or D2O(g) from the outside of the mass spectr ometer into the cell. In this way, the effects of hydrogen or water va por on the vaporization of fission products barium and strontium were examined. (C) 1997 Elsevier Science B.V.