Thorium nitrate, recovered from irradiated thorium metal processed in the ORNL Thorex Pilot Plant, was converted to thorium oxide and then to the fluoride in one pilot-plant-scale and two laboratory-scale runs. Activity distributions, decontamination factors, and safety of the process are treated. (D.L.C.)

Oscillations have been observed in a magnetically supported cylindrical rod of plasma. This rod of plasma can be the discharge occurring in the defining aperture of a Mode II, pressure gradient arc. Similar oscillations can also occur in the column of a Mode I arc. These oscillations appear to be the mechanism that drives the Mode II blowup phenomena.

Preliminary results from experiments on the dissolution of beryllium metal and sintered UO2-BeO fuel pellets are reported. In all cases the pellets were fired in hydrogen at 1650-1800°C. Uranium, from UO2-BeO pellets containing more than 60% UO2, is readily leached with boiling 6-13 M HNO3 in about 6 hr. The BeO in these pellets dissolves only slowly in nitric acid; however, in 8 M HNO3-0.2M NaF, it dissolves at about the same rate as the UO2. Sintered pellets containing less than 10% UO2 do not dissolve rapidly in common aqueous reagents. The highest rates are obtained in boiling acidic fluoride solutions; e.g., sintered BeO and BeO-8% UO2 are dissolved initially at a rate of about 1.7 mg min-1cm-2 (13 mils/hr) in boiling 5.8 M NH4HF2.