Year
2002
Abstract
Spent-fuel dissolver solutions are the input to the main chemical process where separation and purification occurs. In general, dissolver solutions contain high levels of fission products and uranium. Plutonium concentrations are generally about 1% of uranium concentrations. For input accountability analysis and on-site verification, the concentrations of plutonium and uranium in the dissolver solutions need to be determined. Direct determination of plutonium and uranium from the dissolver solutions by gamma-ray spectrometry is impossible because of the very large number of gamma rays from fission products. Thus, the fission products must be removed from the sample before gamma-ray measurement can take place. The U/TEVA·Spec method is used to separate fission products and recover both uranium and plutonium in the resin from dissolver solutions. Unfortunately, the U/Pu ratio is altered during the fission-product separation phase. It is, therefore, necessary to develop a method that could correct for this effect and accurately determine the U/Pu ratio before the fission product separation. Such a method was developed using the unique decay properties of 241Pu to both 237U and 241Am. The technique is incorporated into the FRAM/IDGS software to allow the determinations of both the plutonium and uranium isotopes in the dissolver solutions in one single step.