Diesel emissions and ventilation exhaust sampling in the North Ramp of the Yucca Mountain Project Exploratory Studies Facility

A series of ventilation experiments have been performed to assess the potential retention of diesel exhaust constituents in the North Ramp of the Yucca Mountain Site Characterization Project's Exploratory Studies Facility (ESF). Measurements were taken to help evaluate the potential impact of retained diesel exhaust constituents on future in-situ experiments and long-term waste isolation. Assessment of the diesel exhaust retention in the ESF North Ramp required the measurement of air velocities, meteorological measurements, quantification of exhaust constituents within the ventilation air stream, multiple gas sample collections, and on-line diesel exhaust measurements. In order to assess variability within specific measurements, the experiment was divided into three separate sampling events. Although somewhat variable from event to event, collected data appear to support pre-test assumptions of high retention rates for exhaust constituents within the tunnel. The results also show that complete air exchange in the ESF does not occur within the estimated 16 to 20 minutes derived from the ventilation flowrate measurements. Because the scope of work for these activities covered only measurement and acquisition of data, no judgment is offered by the author as to the implications of this work. Final analyses and decisions based upon the entire compendium of data associated with this investigation is being undertaken by the Repository and ESF Ventilation Design Groups of the Yucca Mountain Site Characterization Project