Background ventilation studies for TRU-waste retrieval

This report presents results from a series of experiments performed to give engineering background information for a ventilation system that will be used during retrieval of transuranic (TRU) buried waste. The retrieval project is part of the Environmental Restoration Program and will involve a double containment with an inner and outer building. The retrieval of buried wastes within the inner containment building may result in TRU contaminated particulates being suspended in the air. The ventilation system will help remove these contaminated particles. To study the behavior of airborne TRU contaminated particulates in a ventilation flow, a scaled wind tunnel was designed and constructed at INEL. Experiments discussed in this report include: (a) a study of eddy patterns and backflow around a scale-model excavator and dig face, (b) evaluation of innovative filter media as a possible pre-filter to extend the service life of the primary HEPA filters, and (c) a study of deposition of TRU contaminated dust as a function of duct velocity (0--100 fpm). These experiments involved soils contaminated with small amounts of plutonium and americium (500 pCi/g). Results include high speed photographs and video tape of the air pattern experiments and tabulated results and graphs of measured dust massmore » deposition and radiochemical analysis of samples taken during the pre-filter and downwind deposition experiments. 5 refs., 20 figs., 9 tabs.« less