Jonny Rutqvist, Barry Freifeld, and Yvonne Tsang of the LBNL Earth Sciences Division have recently been awarded the 2010 American Rock Mechanics Association (ARMA) Case History Award for their paper entitled “Coupled Analysis of Change in Fracture Permeability during the Cooling Phase of the Yucca Mountain Drift Scale Test.” The paper was originally presented at the 42nd U.S. Rock Mechanics Symposium in San Francisco, in June 2008. This paper presents results from a coupled thermal, hydrological and mechanical analysis of thermally induced permeability changes during heating and cooling of fractured volcanic rock at the Drift Scale Test (DST) at Yucca Mountain, Nevada. At several test locations, changes in measured fracture permeability were found to indicate irreversible (inelastic) behavior. Analysis showed that such irreversible changes are consistent with either inelastic fracture shear dilation (where permeability increased) or inelastic fracture surface asperity shortening (where permeability decreased). These findings are important for bounding model predictions of possible thermally induced changes in rock-mass permeability at a potential Yucca Mountain repository. The award will be presented to each co-author (including Ki-Bok Min and Derek Elsworth of Penn State) at the Awards Reception and Banquet of the 44th U.S. Rock Mechanics Symposium, Salt Lake City, Utah, on June 29, 2010. Congratulations, Jonny, Barry, and Yvonne—all ESD is proud of you!