Dissolution of Plutonium Metal in Sulfamic Acid at Elevated Temperatures.

摘要

The kinetics of the dissolution of plutonium metal in sulfamic acid at varying temperatures was determined. Hydrogen off-gas rates and plutonium concentrations were determined as functions of time for different dissolving conditions. Nominal 2.2kg Pu buttons (surface area, 171cm exp 2 ) should yield solutions containing 190to 260 g Pu/L and 3.3M sulfamate ion after a one-hour dissolving time at 70exp 0 C. Hydrogen off-gas rates were calculated to vary from a high of 2.7L of gaseous hydrogen per minute (STP) at the beginning of a dissolving cycle to 50 mL of hydrogen gas per minute at the end of a one-hour dissolving time. Sludge formation,which is a problem at ambient temperatures,does not occur at dissolving temperatures of 60to 80exp 0 C. Dissolution curves suggest that the mechanism of dissolution changes at about 50to 55exp 0 C. Below this temperature, a surface coating of plutonium hydride may form;above this temperature,plutonium metal appears to be converted directly to Pu exp 3+ . 13figures, 1table. (ERA citation 04:032521)