Assessment of hydrologic transport of radionuclides from the Gnome underground nuclear test site, New Mexico

Site Characterization Work Plan for the Gnome-Coach Site, New Mexico (Rev. 1, January 2002)

“…An initial analysis of the subsurface hazard represented by the site is given by Gardner and Sigalove (1970). More recently, Desert Research Institute assessed radionuclide transport from the site (Earman et al, 1996), and performed two evaluations of transport related to the tracer test (Pohlmann and Andricevic, 1994;Pohll and Pohlmann, 1996 …”

“…A previous evaluation of a release scenario from the Gnome cavity (Earman et al, 1996) compiled readily available information pertaining to the underground test and failure scenario. This included the physical test configuration and radionuclide inventories (Rawson et al, 1965), and the record of underground disposal operations that were performed in conjunction with surface cleanup activities (DOE/NV, 1981).…”

“…Rather, the release analysis of Earman et al (1996) will be combined with any additional data located to determine the threat posed to the Culebra aquifer from the Gnome test. If a modeling effort appears beneficial in the course of the investigation, it will likely focus on transport through the Culebra dolomite and/or optimization of monitoring in the Culebra.…”

Assessment of hydrologic transport of radionuclides from the Rulison Underground Nuclear Test Site, Colorado

“…For this reason, a version of the solute flux model which incorporates source size into its calculations was used to perform all the modeling described in this report. Other offsite nuclear test area hydrologic assessments (Earman et al, 1996a(Earman et al, , 1996b were able to use the point-source model because the source size was considered small relative to the correlation scale. It should be emphasized that neither the source size nor the correlation scale are known values; they are simply estimated, based on the cavity diameter and the general relationship of correlation scale to transport distance, respectively.…”

Value of Information Analysis Project Gnome Site, New Mexico

“…The two contaminant sources in the deep subsurface (Gnome cavity and the tracer test) are fundamentally different from each other in terms of both their stratigraphic location and release mechanisms, and are accordingly treated separately in the work plan. The only release scenario identified for the Gnome cavity is hypothetical and dependent on a system failure involving an assumed failed borehole seal, sufficient fluid to dissolve and transport contaminants, and the timing of sufficient pressure build-up prior to salt creep sealing the pathway (Earman et al, 1996). As a result, the strategy for the nuclear cavity concentrates on evaluating completion and stemming data for the subsurface workings and using that information to assess migration potential.…”