Evaluation of FTIR-based analytical methods for the analysis of Hanford Site waste

摘要

Sampling and chemical characterization of mixed high-level waste stored in underground tanks at the Hanford Site is currently in progress. Waste tank safety concerns have provided impetus to analyze this waste. A major safety issue is the possibility of significant concentrations of fuel (ferrocyanide and/or organic compounds) in contact with oxidizers (nitrates and nitrites) that under dry conditions and elevated temperatures could undergo rapid exothermic reactions. To maintain the tanks in a safe condition, data are needed on the moisture and fuel concentrations in the waste. Because of the highly radioactive nature of the waste, non-radioactive waste simulants mimicking actual waste are used to provide an initial basis for identifying realistic waste tank safety concerns. Emphasis has been placed on the use of new or existing Fourier transform infrared (FTIR)-based systems with potential for field or tank deployment to perform in situ remote waste characterization. Three FTIR-based analytical methods have been evaluated. These include (1) fiber optics, (2) modular transfer optics using light guides equipped with non-contact sampling peripherals, and (3) photoacoustic spectroscopy. The attributes of each method for analysis of actual radioactive waste are discussed.