Radioactive Fallout Will be the Killer
Like the more than 160 million Americans
who live within the danger zones, your greatest concern
following a nuclear attack comes from radioactive fallout.
That's the main reason you will need a
well-constructed, underground bomb shelter.
Bomb Shelter Writing Supplies
Are writing supplies available,
including pens or pencils and printed forms or paper,
for keeping records of radiation exposure?
Watching for Fallout to Arrive Near the Bomb Shelter
When a nuclear weapon explodes anywhere
within several hundred miles, there will be many signs to
indicate it. By that time, people should be on the way to,
or already at, their bomb shelter.
Use of the Penalty Table as a Guide for Bomb Shelter
Operations
The Penalty Table was developed to
provide a simple guide when decisions must be made that will
involve some risk.
Group Dosimetry: Keeping Track of Radiation Exposure
The radiation hazard will be worst
throughout the first 24 hours after each fallout cloud
arrives. It is important to start keeping track of
everyone’s radiation exposure right away, as soon as
fallout begins to arrive.
Time-Averaging Method
Used to compare the radiation levels
between two or more locations in a bomb shelter when the
radiation levels are climbing rapidly and when you have only
one survey meter.
Space in the Bomb Shelter
Is there going to be enough room for
all of the people at this bomb shelter in the locations
of best protection?
Restroom and Water Locations in the Bomb Shelter
After fallout has arrived, he or she
should check the radiation levels at these locations. Some
of them may have to be blocked off until the radiation
decays to a safer level.
Radiation Safety Improvement in Bomb Shelters
As you go through your bomb shelter
looking for the places that appear to provide the best
shielding from gamma radiation, you should also look for
ways to improve the shielding.
Organization of the Bomb Shelter Population
Organization of the bomb shelter
population into bomb shelter units, each with its own Unit
Leader, is necessary not only for good management but also
for keeping a radiation exposure record for each person in
the bomb shelter.
Materials for Shielding the Bomb Shelter
You may have improved the radiation safety of the bomb
shelter to the best of your judgment and capability, as
discussed earlier. But after fallout arrives, you may
find with the use of your survey meter that gamma
radiation is shining through at some unexpected
location.
Light Sources in the Bomb Shelter
Electricity may fail in many locations
due to a wide-scale nuclear attack. Most of the bomb
shelters with the highest FPF’s will also have the least
daylight reaching them. If the power goes out, these bomb
shelters may be pitch black.
Informing the People in the Bomb Shelter about Radiation
Exposure
Even if people are frightened, it is
better not to hold back information. The policy of “what
they don’t know won’t hurt them” has never worked with the
American public.
Getting and Checking the Bomb Shelter Instruments
If you are selected to be an RM after you arrive at the
bomb shelter, you may have to find out where the
radiation instruments are, and you may have to make a special trip
to get them. Instructions on how to use the instruments
may be given at the place where they are issued.
Gamma Shielding by using People in the Bomb Shelter
The shielding effect of human bodies can
be used to provide extra protection. This protection would
be of particular benefit to those people with the greatest
sensitivity to radiation, namely, children and pregnant
women.
Forecasting Radiation Exposure
When the survey meter readings level
off and then continue to decrease, the arrival of
fallout from that particular cloud at your location has
almost ended. If no more fallout clouds arrive, the
radiation levels will continue to decrease rapidly.
Finding the Places with the Lowest Radiation Levels in the
Bomb Shelter
Use the survey meter to find the places
that have the lowest radiation levels. The people in the
bomb shelter should be gathered at the locations that are
estimated to have the lowest radiation levels.
Finding and Covering up Leaks in Bomb Shelter Gamma
Shielding
After the safest locations have been
found in the bomb shelter and the people have moved
there (if they weren’t there already), use the survey
meter to make detailed measurements of the radiation
levels in and around the area where the people are
located.
Dosimeter Locations: Where to Place Dosimeters
In some bomb shelters where the FPF is
high and about the same everywhere, as in deep underground
bomb shelters, caves, and mines, only a few dosimeters need
to be mounted or hung where people will be located, to get
an idea of what total exposures they are getting, if any.
Decontamination of People Caught in Radioactive Fallout
Fallout arriving within a few hours after
a nuclear explosion is highly radioactive. If it collects on
the skin in large enough quantities it can cause beta burns
Checking Radiation Levels Outside the Bomb Shelter Area
Sometime no later than 24 - 30 hours
after fallout has begun to come down, you (the RM)
should take the survey meter and check the radiation levels
in rooms next to the bomb shelter area and on the way to the
outside.
Checking Out the Bomb Shelter
Some bomb shelters may have many rooms,
some of them on different levels, and others may have just
one large room. The problems of providing the best radiation
safety will be a little different in each bomb shelter.
Best Bomb Shelter Protection
Which locations within the bomb shelter appear to offer the
best protection against fallout? Sketch a bomb shelter
floor plan and mark these locations.
Bomb Shelter Openings and Ventilation
Are there openings to be baffled or
covered to reduce the amount of radiation coming through
them? Will these changes allow enough air to flow
through to keep people from getting too hot when they
are crowded? |
Bomb Shelter Location
The location you choose for your bomb
shelter should be one which gives you the greatest
protection possible. Just placing an underground bomb
shelter in your back yard is not enough.
Bomb Shelter Design
What should your underground bomb shelter
look like? What materials should it consist of?
How should it be designed? These are all important
considerations when planning the construction of an
underground bomb shelter.
Blast and Fallout Concerns
The blast wind produced by a nuclear bomb
will reach 2,000 mph within the first half mile from ground
zero, drop to about 1,000 mph at 2 miles, and will still be
at hurricane force (200 mph) several miles out.
Get an
Underground Bomb Shelter, Hop in, Now What?
You are going to need a complete underground bomb shelter plan,
and you want to make sure such a plan has been scrutinized
thoroughly.
Before
Fallout Arrives
It may not be possible to do all these tasks before fallout
arrives at the bomb shelter or fallout shelter, and in that
case, those tasks that can be done inside the bomb shelter
can be done later while fallout is arriving.
Types of Nuclear Explosions
The immediate phenomena associated with a nuclear explosion,
as well as the effects of shock and blast and of thermal and
nuclear radiations, vary with the location of the point of
burst in relation to the surface of the earth. For
descriptive purposes five types of burst are distinguished,
although many variations and intermediate situations can
arise in practice.
Sources of Radiation
Blast and thermal effects occur to some
extent in all types of explosions, whether conventional or
nuclear. The release of ionizing radiation, however, is a
phenomenon unique to nuclear explosions and is an additional
casualty producing mechanism superimposed on blast and
thermal effects.
Time Scale of a Fission Explosion
An interesting insight into the rate at which the energy is
released in a fission explosion can be obtained by treating
the fission chain as a series of “generations.” Suppose that
a certain number of neutrons are present initially and that
these are captured by fissionable nuclei; then, in the
fission process other neutrons are released.
Thermonuclear Fusion Reactions
From experiments made in laboratories with
charged-particle accelerators, it was concluded that the
fusion of isotopes of hydrogen was possible.
Thermal Radiation
The observed
phenomena associated with a nuclear explosion and the
effects on people and materials are largely determined by
the thermal radiation and its interaction with the
surroundings. It is desirable, therefore, to consider the
nature of these radiations somewhat further.
Fission Products
Many different
initial fission product nuclei, i.e., fission fragments, are
formed when uranium or plutonium nuclei capture neutrons and
suffer fission. There are 40 or so different ways in which
the nuclei can split up when fission occurs; hence about 80
different fragments are produced.
Fission Energy
The
significant point about the fission of a uranium (or
plutonium) nucleus by means of a neutron, in addition to the
release of a large quantity of energy, is that the process
is accompanied by the instantaneous emission of two or more
neutrons.
Critical Mass for a Fission Chain
Although two to three neutrons are produced in the fission
reaction for every nucleus that undergoes fission, not all
of these neutrons are available for causing further
fissions. Some of the fission neutrons are lost by escape,
whereas others are lost in various nonfission reactions.
Attainment of Critical Mass in a Nuclear Explosion
In order to produce an explosion,
the material must then be made “supercritical,” i.e., larger
than the critical mass, in a time so short as to preclude a sub-explosive change in the configuration, such as by
melting.
Residual Radiation
The residual radiation hazard from a
nuclear explosion is in the form of radioactive fallout and
neutron-induced activity.
Radiation and Fallout
Radioactive fallout will fall in a manner
similar to that following a volcanic eruption. It will
be flaky in appearance and its size may reduce to dust
particles or smaller. Expect it to be thicker near the
detonation site and thinner as it travels down wind.
Initial Radiation
About 5% of the energy released in a
nuclear air burst is transmitted in the form of initial
neutron and gamma radiation. The neutrons result almost
exclusively from the energy producing fission and fusion
reactions, while the initial gamma radiation includes that
arising from these reactions as well as that resulting from
the decay of short-lived fission products.
General Principles of Nuclear Explosions
An explosion, in general,
results from the very rapid release of a large amount of
energy within a limited space. This is true for a
conventional “high explosive,” such as TNT, as well as for a
nuclear (or atomic) explosion, although the energy is
produced in quite different ways.
Worldwide and Local Fallout
The radiobiological hazard of worldwide
fallout is essentially a long-term one due to the potential
accumulation of long-lived radioisotopes, such as
strontium-90 and cesium-137, in the body as a result of
ingestion of foods which had incorporated these radioactive
materials.
Energy Yield of Nuclear Explosions
The “yield” of a nuclear weapon is a measure of the amount
of explosive energy it can produce. It is the usual practice
to state the yield in terms of the quantity of TNT that
would generate the same amount of energy when it explodes.
Distribution of Energy in Nuclear Explosions
The basic
reason for this difference is that, weight for weight, the
energy produced by a nuclear explosive is millions of times
as great as that produced by a chemical explosive.
Atomic Structure and Isotopes
A less
familiar element, which has attained prominence in recent
years because of its use as a source of nuclear energy, is
uranium, normally a solid metal.
Thermal Radiation
The observed phenomena associated with a nuclear explosion
and the effects on people and materials are largely
determined by the thermal radiation and its interaction with
the surroundings. It is desirable, therefore, to consider
the nature of these radiations somewhat further. Thermal
radiations belong in the broad category of what are known as
“electromagnetic radiations.”
Understanding Radiation
What is radiation, you ask?
Radiation
in physics is the process of emitting energy in the form of
waves or particles. Various types of radiation may be
distinguished, depending on the properties of the emitted
energy/matter, the type of the emission source, properties
and purposes of the emission, etc.
Bomb Shelter Entranceway Problems
One problem that could develop is that
the bomb shelter entrance could be blocked by people who
have stopped just inside the entrance.
Minimizing Exposure to Radiation
It's people like you and me (hopefully) that will survive
the initial blast. Our greatest concern is
radioactive
fallout. Fallout will kill as many, if not much more
than the blast itself. And how long you have before
fallout arrives depends on three things. |
