Chapter 2—The Nuclear Testing Program e 19
Figure 2-3—Drill-Back Operation
Drill rig
Surfaced
a
3
Ny
oa
Phot credit: Department of Energy
“ane of
interest
Emplacement Tower for Vertical Drill Hole Test
1/2 up to 7 ft; while Livermore typically uses 8-ft
diameter holes and an occasional 10-ft diameter
hole.2° Livermore usually places its experimental
devices above the watertable to avoid the additional
time and expense required to case holes below the
water table.
Whenthe device is detonated at the bottom of a
vertical drill hole, data from the test are transmitted
through electrical and fiber-optic cables to trailers
containing recording equipment. Performanceinformation is also determined from samples of radioactive material that are recovered by drilling back into
the solidified melt created by the explosion (figure
2-3). On rare occasions, vertical drill holes have
been used for effects tests. One such test, ‘‘Huron
King,’ used an initially open, vertical ‘‘line-of-
sight’” pipe that extended upwards to a large
-~- X-eae cae ce ee nhTillie caer ee my ey come me ee ne se, se cams eon,
TE Te ee ee ey oR RY OE GERD Se we
ground zero
SOURCE: Modified from Michael W. Butler, Pastshot Driling Hancdboc
Lawrence Livermore National Laboratory. Jan. 19, 1984,
enclosed chamberlocated at the surface. The chan
ber contained a satellite inside a vacuum to simula
the conditions of space. The radiation from tt
explosion was directed up the hole at the satellit
The explosion was contained by a series of mecha
ical pipe closures that blocked the pipe immediate
after the initial burst of radiation. The purpose of U
test was to determine how satellites might !
affected by the radiation produced by a nucle
explosion.
Tunnel tests occur within horizontal tunnels tr
are drilled into the volcanic rock of Rainier
Aqueduct Mesa. From 1970 through 1988, the
20Livermore has considered the use of 12 ft diameter holes, but has not yet used one.