if you can, some 3,100 cubic meters of concrete and over 2,000 metric
tons of reinforcing steel. "ThatŐs enough concrete and steel to
build the frame of a 16- by 18-meter, 60-story office building,"
says Rick Visoria, project manager for the new Contained Firing
Facility (CFF) at Site 300, Livermore's experimental test site.
"Those are the quantities we used to build the firing chamber at
the CFF, which is also 16 by 18 meters. But, it's only 10 meters
Those huge amounts of materials
for a relatively small structure say a lot about the thickness of
the firing chamber's concrete walls, the denseness of its reinforcing
steel, and the thickness of its steel liners. Those thicknesses
and densities are needed for tests inside that will use as much
as 60 kilograms of high explosives—enough explosive to demolish
that hypothetical 60-story building frame.
The inside surfaces of the
firing chamber are protected by 50-millimeter-thick steel plates
from a spray of shrapnel traveling as fast as 1.5 kilometers per
second—that's three times the speed of a bullet. The chamber's main
structural elements are designed to remain elastic when blasted
by explosives, so that repetitive firings are possible.
The CFF, including the firing
chamber, support area, diagnostic equipment area, and new offices
and conference room, adds almost 3,200 square meters to Bunker 801
at Site 300. Bunker 801 houses the Flash X Ray—one of the
most powerful x-ray machines in the world—and other diagnostic
tools that have been used for many years to examine weapon components
during hydrodynamic and other tests (see S&TR, March
1997, Site 300's
New Contained Firing Facility, and March
1999, Site 300
Keeps High-Explosives Science On Target).
Construction of the firing
chamber and its support facilities began in April 1999 and was virtually
complete by the end of 2000. Acceptance testing of the building
and its many new systems is under way. During construction, Bunker
801 has been unusable, but by fall, its real work is expected to
begin. The project's goal was to limit bunker downtime to 28 months.
Says Visoria, "We'll be coming in almost exactly on schedule, and
on budget, too."
The CFF will be an essential
tool of the Department of Energy's Stockpile Stewardship Program
to assure that our nation's nuclear arsenal remains safe and reliable
as weapons age beyond their designed lifespan. Computer modeling
provides considerable information about how a nuclear weapon will
behave, but test data are needed to validate the codes used in modeling.
300 has been used since 1955 to perform experiments that measure
variables important to nuclear weapon safety, conventional ordnance
designs, and possible accidents (such as fires) involving explosives.
To date, these experiments have been performed in the open air.
The CFF will dramatically reduce emissions to the environment and
minimize the generation of hazardous waste, noise, and blast pressures.
While emissions from open-air testing at Site 300 are within current
environmental standards, use of the CFF ensures that testing can
continue even if environmental requirements change. Future residential
development not far from Site 300 will also benefit from these environmental
Visoria says, "Indoor testing
will allow experimenters to perform tests at virtually any time
and in any kind of weather, offering greater flexibility in scheduling
and better control of the testing environment. Setting up experiments
will also be easier on a steel floor rather than on an outdoor gravel
a Test Facility
The completed construction
project is being subjected to an array of tests to assure that all
systems are in working order. For example, tests are planned to
assure that the CFF can withstand huge explosions of sometimes hazardous
materials while remaining a safe place to work.
After construction was completed,
Livermore personnel and the construction contractor, Neilsen Dillingham
Builders Inc. of Pleasanton, California, conducted site acceptance
tests of the CFF's state-of-the-art mechanical, electrical, safety,
and process control systems. These tests culminated in the Firing
Sequence of Operations, an integrated system test that checked out
all the steps associated with firing an experiment. Several Firing
Sequence of Operations tests were run, sometimes under irregular
conditions, such as when power to the facility was abruptly shut
The next step was the Structural
Qualification Test Series to examine the integrity of the overall
structure and the firing chamber in particular. A series of five
high-explosive shots was conducted. The shots ranged from 25 to
125 percent of the explosive weight of 60 kilograms of high explosives.
Data on the structural integrity tests are preliminary but indicate
that all is well.
A spherical firing chamber
structure would have been best for resisting blast effects. But
a sphere is difficult to design and build because it does not use
conventional construction methods. Engineering tests in the mid-1990s
on a one-quarter-scale model of the firing chamber demonstrated
that a rectangular, conventionally reinforced, concrete structure
would have the structural strength to contain the blast effects
of a high-explosive detonation. An essential requirement was that
the chamber exhibit an almost totally elastic response to detonations
within it, meaning that the chamber would not incur any permanent
changes to its size or shape over time. Strain gauges installed
in the thick walls, floor, and ceiling of the firing chamber are
supplying the data needed to show that the full-scale facility meets
the specified structural strength and elasticity response.
The last tests prior to putting
Bunker 801 back to work will take about a month. They will assure
that new CFF systems and those in the existing bunker are properly
Aerial view of firing chamber construction on August 31, 1999,
just prior to pouring the floor slabs for the firing chamber.
This pour required deliveries by more than 100 concrete trucks.
The protruding end of the Flash X Ray bullnose can be seen in
the upper right. (b) The final concrete pour was for the roof
slab of the firing chamber. Note the denseness of the reinforcing
steel in both photos.
CFF is the largest explosives chamber in the world. That means that
no one at the Laboratory or anywhere else is experienced in bringing
such a large indoor testing facility on line.
Lloyd Multhauf, a deputy
division leader in the Defense and Nuclear Technologies Directorate,
which will be using the CFF, says, "Our first task will be to learn
how to work with hazardous materials indoors. We will begin with
less hazardous test shots and work up to those with more hazardous
purge the air in the firing chamber after a shot, the chamber is
equipped with an air intake and exhaust system that can perform
10 air changes in half an hour. Exhaust air goes through a series
of filters before being released into the atmosphere.
Personnel who then enter
the firing chamber will be fully suited up to protect against any
remaining hazardous materials. After removing the remains of the
experiment, they will turn on a wash water system as necessary to
remove any particulate matter from the walls and floor.
Says Multhauf, "Anyone entering
the chamber will be in full personal protective equipment until
we know for sure that the protective systems we've installed really
There is much important work
to do once Bunker 801 is fully operational. The Department of Energy
recently assigned Livermore to perform work required to extend the
lifespan of the W80 nuclear weapon, which was originally designed
by Los Alamos National Laboratory. This effort will be similar to
the W87 Life Extension Project that Livermore is completing. As
design and engineering get under way to make the weapon more robust
and able to withstand a longer time in the stockpile, hydrodynamic
tests in the CFF will be numerous. But this time around, they will
be indoors and much quieter.
Contained Firing Facility (CFF), hydrodynamic testing, Site 300,
Stockpile Stewardship Program, W80 Stockpile Life Extension Project.
For For further
information contact Rick Visoria (925) 423-0939 (firstname.lastname@example.org).