Year
1986
Abstract
We have studied methods of determining alpha activity in transuranic waste from the gamma rays produced by the reactions (a,ny), ( and (Q,C*'Y) or produced directly by the alpha-emitting isotopes. Gamma-ray spectra were acquired for 20 drums of waste at the Stored Waste Examination Pilot Plant at Idaho National Engineering Laboratory with a high-purity germanium detector. To assist in the analysis, gamma-ray spectra were also acquired from the following standard neutron sources: 238Pu/Li, 241Am/Li, 24lAm/Be, 241Am/B, 241AM/13C, 238PuO2 and 241AmF. Neutron measurements on the 20 drums were made in a combined passive and active neutron assay system for transuranic waste in Idaho. Representative gamma-ray spectra, line intensities, and calculated alpha activities for the drums are presented. In most matrix types, the alpha activity can be estimated from the neutron assay system results alone or from the reaction gamma-ray outputs. This work demonstrates a method of certifying the alpha activity, as well as the fissile content, of transuranic waste for the Waste Isolation Pilot Plant.