Chapter 3—Containing Underground Nuclear Explosior
Figure 3-6—Vessel|
point room, a muffler, a modified auxiliary
(MAC), a gas Seal auxiliary closure (GSAC)
Vessel 1
tunnel and pipe seal (TAPS). All these closu
End of stemming
ag pe
Mechanical
closurg
Working point
Mechanica!
closure
(MAC)
M “re
echanica
closure
“#— Bypass drift
eg LOS rift
Test chamber
End of stemming
(GSAC)
Key: GSAC =gas seal auxiliary closure; MAC = moditied auxiliary
closure; TAPS =Tunnel and pipe seal
The HLOS Vessel | is designed to protect the experimental
equipment after allowing radiation to travel down the pipe.
SOURCE: Modified trom Defense Nuclear Agency.
the test chamber.*4 The entire pipe is vacuum
pumpedto simulate the conditions of space and to
minimize the attenuation of radiation. The bypass
drift (an access tunnel). located next to the line of
sight pipe, is created to provide access to the closures
and to different parts of the tunnel system. These
drifts allow for the nuclear device to be placed in the
zero room and for late-time emplacement of test
equipment. After the device has been emplaced at
the working point, the bypass drift is completely
filled with grout. After the experiment, parts of the
bypass drift will be reexcavated to permit access to
the tunnel system to recoverthe pipe and experimental equipment.
The area around the HLOSpipe is also filled with
grout, leaving only the HLOS pipe as a clear
pathway between the explosion and the test chamber. Near the explosion, grout with properties similar
to the surrounding rock is used so as notto interfere
with the formation of the stress containmentcage.
Near the end of the pipe strong grout or concrete is
used to support the pipe and closures. In between,
the stemming is filled with super-lean grout designed to flow under moderate stress. The super-lean
grout is designed to fill in and effectively plug any
fractures that may form as the ground shock
collapses the pipe and creates a stemming plug.
Asillustrated in figure 3-6, the principal components of an HLOS pipe system include a working
24On occasion, the diameter of the pipe has increased 10 20 feet
installed primarily to protect the experimenta.
ment. The closures are designed to shut off t
after the radiation created by the explosi
traveled down to the test chamber, but
material from the blast can fly down the pi
destroy the equipment.
The working point room is a box desig
house the nuclear device. The muffler is
pandedregion of the HLOSpipe thatis desi;
reduce flow down the pipe by allowing ex]
and creating turbulence and stagnation. The
(figure 3-7(a)) is a heavy steel housing thatc
two 12-inch-thick forged-aluminum doors d
to close openings up to 84 inches in diamet
doors are installed opposite each other, perp
lar to the pipe. The doors are shut by high p
gas that is triggered at the time of detc
Although the doors close completely with
seconds (overlapping so that each door f
tunnel), in half that time they have metin the
and obscure the pipe. The GSACis similai
MACexceptthatit is designed to providea g:
closure. The TAPS closure weighs 40 tons |
design (figure 3-7(b)) resembles a largetoil
The door, which weighs up to 9 tons, is hinge:
top edge and held in the horizontal (open) p
Whenthe dooris released, it swings down by
and slams shut in about 0.75 seconds. Any f
remaining in the pipe pusheson the door mal
seal tighter. The MAC and GSAC will wi
pressures up to 10,000 pounds per square in
TAPSis designed to withstand pressures up |
pounds per square inch, and temperature:
1,000 °F.
Whenthe explosion is detonated radiatior
down the HLOS pipe at the speed of lig
containmentprocess(figure 3-8(a-e). trigger
time of detonation, occurs in the following s:
to protect experimental equipment and
radioactive material produced by the explos
e After 0.03 seconds (b), the cavity create
explosion expands and the shock wav:
away from the working point and apf
the MAC. The shock wave collapses 1
squeezing it shut, and forms a st
**plug.’* Both the MAC and the GSAC