The Cobalt Bomb
Nuclear explosions seem horrible for many reasons. They were presented
to an unprepared world as a dramatic surprise—as the climax to the
slaughter of the Second World War. Their power of destruction is
fantastic. Before we had adjusted our thinking to atomic bombs, an even
more potent tool of warfare—the hydrogen bomb—was invented. Worst of
all: To the fear of destruction there was added the dread of the
unknown. It is not surprising that discussion of nuclear weapons has not
proceeded on a purely rational level.
To the nightmare of the atomic and hydrogen bombs has been added—not as
a reality but as a further threat—the cobalt bomb. The idea of such a
bomb is to intensify the most terrifying aspect of nuclear explosions:
the radioactivity. This radioactivity could be used to poison the enemy.
It could get out of hand and poison everyone.
Cobalt⁶⁰ is a radioactive isotope of the fairly common metal cobalt. It
can be easily produced by absorbing slow neutrons in the natural and
stable cobalt⁵⁹. It has a half-life of five years and it emits
penetrating gamma rays. These properties make it useful in cancer
therapy.
Many cancerous growths are more sensitive to radiation than healthy
tissue. Therefore radiation can be used to reduce—sometimes even to
destroy—dangerous tumors. The penetrating rays of cobalt⁶⁰ can reach the
cancer even deep inside the human body. The lifetime of cobalt⁶⁰ is long
enough so that this substance is easily installed in hospitals.
But the same properties which make cobalt⁶⁰ useful also make it
potentially dangerous. A nuclear explosion produces many neutrons and
these could be absorbed in ordinary cobalt. The radioactivity produced
in this way lives long enough to become widely distributed. Its ray can
easily penetrate a foot of masonry and several hundred feet of air. A
cobalt bomb would indeed be a most unpleasant object. (See pictures 7
and 8.)
One widely discussed possibility is that future nuclear tests will be
used to develop a cobalt bomb or other bombs for radiological warfare.
Actually tests have little to do with the cobalt bomb. Once one has a
powerful nuclear weapon, such as a hydrogen bomb, it is relatively easy
to make a radiological bomb. Further tests are not necessarily required.
To the extent that any testing need be carried out, it is only necessary
to activate a moderate amount of substance to find out in what way a
certain bomb would function as a tool of radiological warfare. Tests of
this kind would add only a negligible amount of radioactivity to the
atmosphere. Therefore, in connection with the test program we need not
worry about the cobalt bomb or any related experiment. The question of
the cobalt bomb or radiological warfare in general is not whether it is
feasible—it is—but rather whether it serves a useful military purpose.
It is not impossible that situations might arise in which radiological
warfare could be militarily advantageous. Instead of cobalt, other
materials may be placed near the nuclear bombs. In this way other
radioactive substances can be produced. By an appropriate choice of such
a substance one can get a radioactive material which, when deposited
near the point of explosion, will contaminate the site for a time which
can be adjusted to the military requirements. The lifetime of the
radioactive material may be long enough to give an opportunity to the
people to escape from the contaminated area. At the same time, one may
precipitate almost all the activity near the explosion so that distant
localities would not be seriously affected. It is conceivable,
therefore, that radiological warfare could be used in a humane manner.
By exploding a weapon of this kind near an island one might be able to
force evacuation without loss of human life. No instrument, not even a
weapon, is evil in itself. Everything depends on the way in which it is
used.
Public opinion has all but persuaded itself that nuclear weapons will be
used not for a military objective but to terrorize and kill the greatest
number of people. This is technically feasible. In fact, it does not
even require the atomic bomb. For the last hundred years this
possibility has been with us. Bacteriological warfare may cause
widespread destruction. Yet no one has resorted to this horrible way of
making war. We do not believe that anyone will expose his enemy and
ultimately himself to indiscriminate bacteriological or radiological
destruction. Our guarantee against this danger is not that it cannot be
done. Our guarantee is the better and saner part of human nature: the
will to survive and the feeling of common decency.