Pressure measurements in G-Tunnel

Transport of water in an unsaturated medium such as the proposed study site at Yucca Mountain, Nevada is very likely to be two-phase: vapor (or steam) and liquid water. Determination of partial vapor pressure in the medium is therefore desired for a model study of the transport mechanism. In this prototype test in G-Tunnel, the author commits to measure the relative humidity and moisture content of the rock around the heater. To determine the partial vapor pressure in the rock, he also needs to determine the total pressure in the medium. For that purpose, he decided to measure the pore-air (include steam or vapor) pressure in the boreholes where relative humidity will be determined (P1, P2, and P3). The total pore-air pressure will be measured by using a strain-gaged pressure transducer. Other purposes of this test are to try the pressure measuring technique and to investigate the long-term stability of sensitive pressure transducers. He also measures the barometric pressure in the alcove, outside the boreholes where total pressure is measured