The definition of true crater dimensions by post-shot drilling /
Nicholas M. Short.

Description

Main Author

Short, Nicholas M.

Related Names

U.S. Atomic Energy Commission.

Language(s)

English

Published

Livermore, California : Lawrence Radiation Laboratory, University of California, 1964.

Subjects

Nuclear explosions.
Nuclear excavation.
Blast effect.

Summary

Core samples from all three holes examined thusly over 1-ft intervals revealed these microfractures to occur consistently at points 35-38 ft radially from the shot point. A radius of 36+2 feet is therefore assigned to the explosion cavity. The true crater (cavity) surface is a hemisphere radially symmetrical about the shot point at depths below approximately 110 ft. Fixing this radius relative to calculated cavity expansion curves and to the probable time of venting aids in the understanding of history and mechanisms of cavity growth, from which speculative treatments of the behavior of rock and water vapors in the growing cavity and of a possible origin of vesiculated glass found in the crater throwout rubble have been developed.
The Danny Boy event of March 5, 1962, was a nuclear cratering explosion of 0.42-kt yield at a depth of 110 ft in a basalt flow capping Buckboard Mesa in Area 18, Nevada Test Site. In May-June 1962, three slant holes were drilled from the northwest side of the crater lip base into the vicinity of the shot point for purposes of recovering samples for radiochemical yield determination, assessing the fracture state in the inelastic zone, and locating the true crater surface at several points in order to estimate the explosion cavity radius at the time of venting. Percent core recovery data and radiation logs failed to define the fallback-true crater interface nor was any radioactive glass lining the cavity surface found in the cores. Rock in a 2-ft-thick zone immediately beyond this surface was intensely crushed and fractured in a manner readily discernible by a petrographic microscope examination.

Note

Accession No.: 54029.
Misc. No.: WT-1834.
"March 2, 1964."--Title page.
"Issued 6 July 1964."--Cover.
"Project Danny Boy Nevada Test Site 5 March 1962, Final Report."

Physical Description

59 pages : illustrations ; 28 cm.

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