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Title: Hydrogeology of the Faultless site, Nye County, Nevada

Technical Report ·
OSTI ID:5969050

The Faultless event was the detonation of an intermediate-yield nuclear device on January 19, 1968, at a depth of 975 m below the surface of Hot Creek Valley, Nevada. This report presents details of the hydrogeology of the rubble chimney and radiochemical monitoring in re-entry hole UC-1-P-2SR. The surface location of re-entry hole UC-1-P-2SR is about 91 m north of the emplacement hole, UC-1. Re-entry hole UC-1-P-2SR was drilled to a total depth of about 1097 m. The hole penetrated Quaternary and Tertiary valley-fill sediments above the rubble chimney, as well as Quaternary and Tertiary valley-fill and Tertiary tuffaceous sediments within the chimney and rubble-filled cavity. Monitoring of the water level in re-entry hole UC-1-P-2SR indicated that, from 1970 to 1974, the water level was 695 m below land surface. During filling of the rubble chimney from 1974 to 1983, the water level rose slowly to a depth of 335.1 m. The 1983 level was about 167 m below the pre-event level that was about 168 m below land surface. Water with temperatures ranging from 37 to 61/sup 0/C occurred at the bottom of the re-entry hole at depths ranging from 728 to 801 m. A temperature of 100/sup 0/C at a depth of 820 m was projected from temperature logs. The hydraulic connection between the re-entry hole and the rubble chimney is considered poor to fair. Chemical analyses of water samples indicate that the water predominantly was a sodium bicarbonate type. Chemical and radiochemical analyses indicated that, although the constituents generally increased with increasing depth, three distinct water-quality zones have lasted for more than 16 years, even during the rising water level. The hot, radioactive water from the Faultless event apparently rose into the lower zone concomitant with the rising water level, as the rubble chimney was being filled. This general rise was interrupted by the apparently major dilution from colder water descending from the upper zone during 1975 and 1977.

Research Organization:
Geological Survey, Denver, CO (USA)
DOE Contract Number:
AI08-78ET44802
OSTI ID:
5969050
Report Number(s):
USGS/WRIR-86-4342; ON: DE88001305
Country of Publication:
United States
Language:
English