Prototype Engineered Barrier System Field Test (PEBSFT); Final report

Modeling of thermally driven hydrological processes in partially saturated fractured rock

“…Buscheck and Nitao [1991] also applied the effective continuum concept to model a field test [ Ramirez et al , 1991] involving a heater horizontally emplaced within a borehole in the G‐Tunnel complex of the Nevada Test Site. Two alternative models in two dimensions were invoked.…”

“…Thermal tests conducted in granite at Climax, Nevada, in the early 1980s included a spent‐fuel test involving eleven fuel canisters and six electrical heaters [ Majer and McEvilly , 1985; Patrick , 1986; Wilder and Yow , 1987]. Other tests carried out in the G‐Tunnel of the Nevada Test Site in volcanic tuff included the heated block experiments [ Zimmerman et al , 1986a], the small diameter experiments [ Zimmerman et al , 1986b], and a prototype engineered barrier test [ Ramirez et al , 1991]. In the middle and late 1990s, with the construction of the Exploratory Studies Facility, an underground testing laboratory at Yucca Mountain located within a tunnel 8 m in diameter and 8 km in length, the Department of Energy Yucca Mountain Project developed a unified thermal testing strategy, initiating three large‐scale field tests, all conducted in the welded, fractured rock that will host the repository.…”

Drift Scale Test Design and Forecast Results

“…Each of the thirty heaters can be switched on or off independent of the others; however, the primary and back-up elements in each heater cannot be energized at the same time. Experience in the G-Tunnel thermal test (Ramirez et al 1991) indicates that sealing the electrical terminals and connectors from ambient moisture is essential for prolonging heater life. Potting at d the heater end of the lead wires and covering the terminal strips (at the lead wirdpower cable connection) with high temperature epoxy are intended to avoid galvanic effects and potential initiation of corrosion.…”

Preliminary near-field environment report; Volume 1, Technical bases for EBS design

“…If the fracture networks at the repository horizon have limited connected path lengths, then the imbibition of mining/drilling will be confined to the scale of the connected fracture path lengths. The experience of Ramirez et al (1991) indicates that drilling fluids had a negligible impact on the ambient saturation conditions in the vicinity of the G-Tunnel heater.…”

“…The work performed at the G-Tunnel proto type test (Ramirez et al, 1991) also indicates that the time for rehydration of the rock once it has been dried out is longer than the time for the original dry-out. The elevated temperatures will raise the partial pressure of the water, and so it is likely that the environment will remain dry for a considerably longer period than that period when the temperatures exceed the boiling point.…”