Development of a method utilizing drum headspace VOC concentration as a waste characterization tool

Pretest waste characterization for the bin-scale tests at the Waste Isolation Pilot Plant (WIPP) required sampling for volatile organic compounds (VOCS) from within transuranic (TRU) waste drums. Although the bin-scale tests have been postponed, the development and demonstration of accurate waste characterization methods continues. The objectives of extensive sampling of waste drums are to obtain a representative sample from each layer of confinement to identify volatile and gaseous constituents, verify process knowledge of the drum contents, and demonstrate compliance with regulatory requirements. A method to estimate the VOC concentration between layers of confinement from a single headspace sample collected beneath the drum filter of a vented waste drum is investigated. This method of characterizing the void space within a drum could eventually lead to a significant reduction in sampling time and cost. A model based on fundamental principles of transport phenomena is developed to estimate the VOC concentration throughout a waste drum based on the knowledge of the transport properties and the measured drum headspace VOC concentration. Model and experimental results are compared