This, our country, and all its people, could be in danger of nuclear attack in
minutes by enemy missiles, in hours by enemy aircraft.
Our cities, our
farms, our factories.
Prime target would be our air bases.
With all our aircraft on the ground, our weapons of interception or retaliation
not instantly available, we might face another and infinitely more
costly Pearl Harbor.
To avoid surprise disaster, some of our aircraft must always be in the
sky or on the alert.
Carrying nuclear weapons.
These weapons are always unarmed.
They will be armed only following a decision by the
President of the United States.
Only these ready aircraft with nuclear weapons can form our first-line deterrent
force in peacetime, our sure striking force in case of attack.
We, the American people, understand
and accept this necessity for our survival.
But we want to know the facts about one question.
Do we live in danger of nuclear explosion and radioactive fallout if one of these
airplanes should crash or one of these nuclear weapons accidentally drop?
To give you the facts, the United States Air Force
presents...
This bomber carries a nuclear weapon.
It is a well-designed, carefully maintained, skillfully flown airplane.
But airplanes just like it have crashed and burned.
There was no nuclear explosion, no radioactive fallout.
These are the facts.
The bombardier watches over controls as safe as human ingenuity can make them to
prevent accidental bomb release.
But nuclear weapons have been dropped inadvertently.
There was no nuclear explosion, no radioactive fallout.
These are the facts.
And specially instrumented aircraft verify these facts in a continuing nuclear
safety program that tests our nuclear weapons under controlled conditions that
simulate every conceivable hazard.
Vital to this nuclear safety program is Air Force Special Weapons Center
at Albuquerque, New Mexico.
Here, in ultra-modern laboratory buildings, work scientists
in and out of uniform.
They work with the incredibly complex equations of nuclear physics, which derive
from Einstein's famous relationship of mass to energy.
These cryptic figures, programmed into lightning-fast computers, are the
theoretical base upon which these scientists, together with those of the Atomic
Energy Commission, can build nuclear weapon safety.
By research, design development,
and laboratory tests, they ensure weapons not yet built against
accidental nuclear explosion.
They have been doing this, successfully, since 1945, in safety conferences
with other Defense Department agencies and the Atomic Energy Commission.
In 13 years, there have been a few accidents, but not one has resulted in nuclear
explosion or radioactive fallout.
These are the facts.
What keeps our nuclear weapons safe?
To understand why there has never been an accidental nuclear explosion, you must
first know how these explosions can be produced, the general principles
of nuclear explosions.
Any explosion is the result of a very
rapid release of a great amount of energy.
Conventional explosions result from the rearrangement of whole atoms in
some explosive material.
For example, in TNT, the rearrangement of whole atoms of hydrogen, carbon,
nitrogen, and oxygen produces explosive force.
On the other hand, nuclear explosions result from the rearrangement
within each atom.
This may be a joining together or fusion, as in an H-bomb, or the splitting apart
or fission, as in an A-bomb.
At present, an H-bomb explosion starts with fission, so the splitting of the
nucleus of the atom is the basic principle of nuclear weapons.
All matter is composed of one or more of the 100 odd elements.
Of these, the atoms of the metals uranium and plutonium can be most readily
fission to cause nuclear explosion.
These elements are mildly radioactive.
They emit short-range, low-penetration alpha particles
while in their unfissioned state.
These alpha particles do not have the harmful effects of the longer range and
stronger gamma rays, which are given off by certain elements such as radium or
by the products of nuclear fission.
The atoms of uranium and plutonium are among the heaviest, heavy because the
nucleus of each atom contains large numbers of the fundamental particles
called protons and neutrons.
When a free neutron hits this nucleus, it splits into two parts, releasing more
neutrons which may go on to split other nuclei.
The resulting fission products become highly radioactive, emitting the long-range
and dangerous gamma rays.
The split nucleus weighs less than the whole one, and this difference in weight
is released in the form of energy, nuclear energy.
After fission, harmful gamma radiation. Before fission, innocuous
alpha radiation.
To build up a nuclear energy release, the fissionable material must be of a
certain size, shape, or density.
Then one of the neutrons escaping from a split atomic nucleus will in turn split
another, and a chain reaction is set up.
The mass is now releasing nuclear energy but not quickly enough
to cause a nuclear explosion.
This condition is called critical.
If the mass is now suddenly increased so that more neutrons are trapped each time
an atomic nucleus is split, a multiplying chain reaction is maintained.
Now the mass is supercritical, causing a nuclear explosion.
Density of the fissionable material can be as important as mass in
building up a nuclear explosion.
The same sphere can be compressed so that the atoms are closer together and
neutrons split more atomic nuclei, making the smaller mass critical.
If compressed still more, a multiplying chain reaction sets in, causing the mass
to become supercritical in a nuclear explosion.
Nuclear weapons make use of both of these principles.
A gun-type device can increase the mass of fissionable material to a
supercritical state instantaneously.
One subcritical mass is propelled forcibly into another by
an ordinary powder charge.
The increased mass becomes supercritical.
A multiplying chain reaction builds up until the nuclear explosion.
Obviously, if any mechanical device keeps these two subcritical masses apart,
the weapon is nuclear safe.
Applications of this fact prevent accidental nuclear explosions
in gun-type weapons.
Another kind of nuclear weapon is the implosion type.
It compresses the fissionable material to greater
density to make it supercritical.
To do this, the sphere is enclosed by a shell of ordinary explosive designed to
direct its explosive force inward.
This effect is called implosion.
The detonators attached to the explosive are connected to a complex firing
device, which can fire every detonator simultaneously.
When all the explosive is detonated simultaneously, the nuclear material is
compressed into a supercritical mass, which results in a nuclear explosion.
Implosion-type weapons are nuclear safe because only the specially designed
firing device can produce the simultaneous detonation of all the ordinary
explosive, a deliberate effect possible only by the precise firing mechanism.
Should a single detonator be fired accidentally, whether by malfunction, crash
impact, or fire, the explosive would not provide the all-around
compression necessary for implosion.
Instead, it might push the nuclear material out of the shell, break it into small
pieces, or even burn it.
This unfission material emits only alpha particles because no nuclear
explosion has taken place.
These alpha particles do not penetrate the skin.
The simplest precautions can prevent their intake into the body, and the simplest
cleanup measures can remove them.
So you see, each type of nuclear weapon has its own safeguards against
accidental nuclear explosion.
These are the facts, and they are based upon practice as well as theory.
Specially instrumented aircraft fly the tests that verify what happens inside a
weapon, what accident hazards the nuclear components may have to withstand.
The nuclear safety is everybody's business.
Although Air Force flies the test missions, scientists and technicians from the
Atomic Energy Commission and other services man the test range and evaluate the
findings of the elaborate instrumentation.
Drop tests measure impact characteristics of various weapon types.
They are made without nuclear components, so that this precious
material is not wasted.
They supplement the detonation tests that have been made with the
complete nuclear weapons.
Impact, or shock, does not cause nuclear explosion or radioactive fallout.
What has exploded is the ordinary explosive,
which is an essential part of nuclear weapons.
The ordinary explosive in a nuclear weapon can be a hazard, exactly
as in a conventional bomb.
Depending upon the amount and location of the explosive and the speed and height
of the drop, we may experience a variety of ordinary explosions.
Large ones, small ones, or none
at all from impact of the bomb.
Beside the hazard of impact, frequent tests are run on the hazard of fire.
To learn what temperatures and pressures would be created inside a weapon by an
aircraft fire, various types of bombs are subjected to a flame
bath of burning fuel.
Because fire would also destroy the precious nuclear material,
it is replaced by instruments.
Their readings are compared with known characteristics of the fissionable
material to assure that temperatures higher than any aircraft fire will not set
off a nuclear explosion.
The characteristic white flame indicates that the ordinary explosive
is burning in the weapon.
Sometimes the explosive detonates because of close confinement and intense heat.
The effects of such explosions are measured and compared with those
in an actual nuclear weapon.
Fire and ordinary explosives do not create the conditions necessary
for nuclear explosion.
These are the facts.
And on the vast desert ranges of the Atomic Energy Commission, the facts are
verified by safety testing live prototypes of all new weapons before they go into
production for our stockpile.
The tests are costly in money and manpower, even more costly in the fissionable
materials on which our nuclear strength depends.
But they do provide insurance against nuclear accidents, which make them
a bargain at any price.
Some take place deep in the earth.
Fantastically complex instruments replace the five senses.
They record what happens when some of the explosive that surrounds the nuclear
material of a new weapon is deliberately detonated.
They record only an ordinary explosive blast.
A random detonation has not created the implosion which would compress the
nuclear material to a supercritical mass.
There was no nuclear explosion, no radioactive fallout.
Each new design must be proved nuclear safe, able to withstand accident,
fire, or random explosive.
Other tests with nuclear weapons are made above ground.
These are also designed to test the nuclear safety of new weapon types by
intentionally detonating the explosive which surrounds the fissionable material.
Sometimes these tests also provide data on the side effects to be expected
if the fissionable material is broken up by the explosion.
Air samplers and test pads are used to gauge the area intensity and
duration of these side effects.
In this way, they learn not only what does not happen when a charge is
deliberately fired, but what does.
The explosive does break up the nuclear material and scatter
parts of it over a small area.
This fissionable material is mildly radioactive.
If the explosion or fire should suspend any of this material in dust or smoke, it
should not be inhaled or otherwise taken into the body in quantity.
That is why the trained monitoring and cleanup crews may wear respirators until
air samplers or alpha counters have determined that no injurious
concentration exists.
The alpha particles emitted do not penetrate skin or clothing, so this material
is harmless when on the ground.
Only simple cleanup measures are necessary, plus an effort to find and
save the valuable material.
The findings from all tests set up to measure possible radiological hazard are no
external radioactive hazard from material on the ground, slight radioactive
hazard from prolonged inhalation of material suspended in a small area near the
accident, but none from the short exposures necessary for firefighting, rescue,
or cleanup of the small area involved.
These are the facts, facts that have dispelled the fearsome myths about accidents
involving nuclear weapons.
For anyone near an accident, whether or not the crashed airplane carries a
nuclear weapon, here are the safe and simple rules.
Stay away from the crash unless you are needed for rescue.
Bystanders endanger themselves and hamper others.
To be safe, keep at least a quarter of a mile away from any burning airplane.
At this distance, you are safe from the flames, which may explode the jet fuel,
from detonating explosives, and from flying debris.
These are the real dangers in rescue or firefighting, as they have always been.
The trained men who bear these responsibilities know how to do their job and get
quickly away from all these hazards.
After the emergency is over, the area is monitored for radioactive material, and
if necessary, cleaned up by specially trained teams.
Other specialists care for burned or undetonated pieces of ordinary explosive.
Until this is done, access to any crash area is controlled to prevent
accidents and speed up the work.
The tests you have seen have proved the safety of our nuclear weapons program
over and over again.
But the grim reality is the payoff. How safe is a nuclear bomber
coming in for a crash landing?
Not the impact of the crash landing, nor the fire which often follows.
Not even detonation of the ordinary explosive in the weapon caused nuclear
explosion or radioactive fallout.
The safety that was designed in during research, built in during development,
proved in the laboratory and on the range, has withstood the
ultimate tragic test.
These are the facts. They prove that you, the American people, can stay both
safe and strong.
Safe, because the weapons your air force must carry have
been tested nuclear safe.
The possibility of an accidental nuclear explosion is so small as to be
practically non-existent.
Strong, because an air force, nuclear armed and combat ready, stands guard
against surprise attack.
Under this shelter, you and your family may live in peace, free from the fear
of nuclear accidents.