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[en] On December 18, 1970, Baneberry, a 42-TJ (10-kt) nuclear device, was detonated at a depth of 278 m in hole U8d at the Nevada Test Site. A shock-induced fissure near ground zero opened and vented radioactive gases and debris into the atmosphere. Calculational results describe the sequence of dynamic phenomena that very likely produced the vent. The calculations predict the experimentally observed surface motion and long positive-velocity pulse. The surface fissure through which the material vented is approximately the same radial distance from ground zero as the maximum horizontal displacement is calculated to be. Also, the calculations indicate an explosive-induced extension of the Baneberry fault to the surface. This extension was observed in pictures of the surface motion and later confirmed by postshot on-site inspection. The final calculated cavity radius is very close to the measured Baneberry cavity radius. Finally, the calculations indicate that an open fracture path was generated that runs from the cavity to the Baneberry fault, up the fault to the spall region, and then vertically to the surface. This vent path predicted by the calculations is roughly consistent with the vent path found from the radioactivity in postshot drill holes. The extensions in computational capabilities in this work advance the state-of-the-art for numerical simulation of the containment aspects of underground nuclear tests

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[en] The Dining Car event was a Defense Nuclear Agency nuclear weapons test located in the U12e.18 drift of the E-tunnel complex, central Rainier Mesa, Area 12, Nevada Test Site. The main drift and bypass drift were mined in zeolitized tuff to a total length of 544 m (1,785 ft). The overburden thickness above the experiment is approximately 396 m (1,300 ft) in the U12e.18 area. The pre-Tertiary surface, which is most probably quartzite in this area, is located approximately 243.8 to 274.3 m (800 to 900 ft) below tunnel level. Site geology and geophysical investigations were made in one vertical and two horizontal drill holes prior to mining of the U12e.18 drift. Electric logs in the two horizontal holes indicate no extensive zones of argillization which might create problems in tunnelling. Geophysical logs in the vertical exploratory hole suggest that the tuff is saturated at a depth of about 244 m (800 ft). Electric logs in all three holes show a pronounced signature in tunnel bed 4J. Seismic velocities obtained in the tunnel after mining compare favorably with sonic velocities obtained in one hole by means of a sonic probe, indicating that the bulk geologic structure is not significant in affecting seismic-wave propagation. This condition is not always observed in such comparisons. A repeat seismic survey in the tunnel showed no change in seismic velocity 4 months after mining. In situ stresses determined by the overcore technique are within experience for the Rainier Mesa tunnel complex

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[en] The presented viewpoints have evolved from extensive interaction since 1963 with government and industry participants in the Plowshare program. During the first decade of the Atomic Energy Commission's Plowshare program, the scientific feasibility of industrial applications of underground nuclear explosive technology was established by the Rainier, Gnome, Hardhat, Shoal, Salmon and Handcar experiments. A new era for examination of the technical and economic feasibility of industrial applications of nuclear explosives began with the Gas-buggy detonation in 1967. This era must be accompanied by close coordination between government and industry which was not required when government alone was establishing scientific feasibility. This presentation on 'industry's view of underground nuclear engineering' will be concentrated on problems which must be resolved to make the transition from scientific feasibility to technical and economic feasibility. The distinctions between 'contained' and 'cratering' applications go far beyond the differences in technology. Cratering objectives have been defined, funded by the government, pursued with a readiness date in mind, and supported by a national policy. Thus far, underground nuclear engineering has enjoyed few of these benefits. Industry's objective in underground nuclear engineering is to establish a viable enterprise which will benefit the public

[en] The operational plan for conducting the final restoration work at the site of the first U.S. underground nuclear experiment for the stimulation of low-productivity natural gas reservoirs is given. The plan includes well plugging procedures, surface facilities decontamination and removal procedures, radiological guidelines, and environmental considerations