Recovery Of Americium Research Articles

An Anion Exchange Process for Americium–Curium Recovery from Plutonium Process Waste

S>An anion exchange process for the recovery of americium, curium, and rare earths contained in the waste effluent from plutonium processing was developed and tested on a laboratory scale. In the process the waste, which is a solution of americium, curium, aluminum, and fission products, in concentrated nitric acid, is concentrated by evaporation until a temperature of 140 deg C is reached. This removes excess acid, and the proper feed concentration of 2,34 M Al(NO/sub 3/)/sub 3/ is obtained by dilution. The americium, curium, and rare earths are sorbed on Dowex 1-10X resin; aluminum is washed from the column with 8 M LiNO/sub 3/; and the americium, curium, and rare earths are eluted with 0.65 M HNO/sub 3/. In laboratory demonstrations of the process made with americium tracer and macro amounts of rare earths, americium losses were undetectable, aluminum decontamination factors were 250, and rare earth concentration in the product was as great as 8.5 gm/liter. (auth)

The determination of americium in Plutonium Alloy fuels for fast reactors

Summary For the determination of americium in fast-reactor plutonium fuels, a method is required which is quantitative and which gives a product free of either alpha or gamma contaminants, since either alpha or gamma counting may be used for the detection of Am241. In the present method, americium, plutonium, and the rare-earth fission products are precipitated as hydroxides from an HCl solution of the fuel sample, after the addition of lanthanum as a carrier. Ceric sulfate is added to the acidified hydroxide precipitate to oxidize plutonium to the hexavalent state. The hexavalent plutonium remains in solution when americium and the rare-earth fluorides are precipitated. After the fluoride precipitate is dissolved in HNO3 and H3BO3, a second hydroxide precipitation is performed to remove fluoride. This precipitate is dissolved in a small quantity of HNO3 and transferred to an ion-exchange column packed with Dowex 50-X4, 200- to 400-mesh resin. Americium and the rare-earth elements are eluted with 5 % NH4NO3 saturated with ethylenediaminetetra-acetic acid at a pH of 2.3. The americium is eluted after the yttrium and just prior to the elution of the europium fractions. In fresh samples (less than 2 days old), the americium may be contaminated with Eu156, but it is free of all other rare-earth elements, permitting alpha counting in a sample with low beta activity. Recovery of americium is better than 98 %, with less than 2 % plutonium alpha activity and with a gamma decontamination factor of 2 × 104. If the sample has aged sufficiently to allow the short-half-lived rare-earth elements to disappear, the americium may be determined by counting the gamma activity.