The Unsorted BBS Collection/thegreatunsorted.tar/thegreatunsorted/texts/anarchy_text_a-l/a-bomb.doc

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    ║  BUILD YOUR OWN A-BOMB AND WAKE UP THE NEIGHBORHOOD   ║
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     The following article is from the April, 1979 edition of
Analog Science Fiction, pages 36-52, and was written by George W.
Harper. For information on subscribing to Analog Science Fiction
or obtaining a back issue of this copy, please write:

                         Analog
                         Science Fiction/Science Fact
                         P.O. Box 5205
                         Boulder, Colorado 80233

                 =-=-=-=-=-=-=-==-=-=-=-=-=-=-=

     "Some months ago the newspapers carried an item about a
physics student who had designed his own A-bomb and was now in
hiding lest terrorists put the snatch on him and force him to
reveal the secret of a do-it-yourself bomb. A few months after
that there was a TV item on "Barney Miller" where the feds
impounded a private little A-bomb, which coincidentally just
happened to have been put together by a college student.

     Now we sympathize with the fears of students who feel
themselves jeopardized by their knowledge of exotic or arcane
arts and we would hate to think they cannot walk the streets
safely, simply because some terrorist might seize them and compel
them to serve as unwilling agents of mass destruction.
And since the best guarantee of their safety is to make the
knowledge so public that no terrorist would even bother to
impound some other person to do the job, we have decided to
provide a detailed, step-by-step method of constructing an A-
bomb. It is so simple that anyone who chooses -- even if he only
went to the fifth grade -- can build his own. This way the
undergrad students need no longer walk in fear and trembling lest
they be abducted by crazies and they can all rest a little more
peacefully. So if any of you have friends who feel like going
into the A-bomb business, please turn them on to this article and
leave the frightened college students alone.

     The theory of an A-bomb is simplicity itself. Merely take
two masses of the right material (usually either Uranium-235 or
plutonium) and hold them tightly together for a long enough
period of time. Everything else occurs on its own.

     The basic initial problem is determination of the minimum
quantity of fissile material needed to provide the bang. In this,
of course, the technological expertise of the manufacturer
necessarily plays a role. If you are an advanced engineering
student with access to exotic materials and the most advanced
triggering devices you can probably manage quite comfortably with
as little as twelve pounds of U-235. For our purpose here we will
assume you are not quite so capable and so will focus our
attention on the sort of bomb you can construct in an ordinary
home.

     For this type of bomb the amount of U-235 required should be
in the neighborhood of thirty pounds (about the size of a
baseball). Employing only easily acquired material, this type
bomb should be capable of demolishing everything within a radius
of one-third of a mile from ground zero and causing extensive
damage out to a distance of two-thirds of a mile. Lethal exposure
to radiation could occur within a radius of one and one-quarter
mile and people downwind of the fall-out might be sickened up to
a distance of forty or fifty miles.

     All in all, it would seem a most satisfactory device which,
if detonated in New York City, ought to kill perhaps 250,000
people and injure another 400,000. We believe this should be more
than adequate for the average terrorist and very possibly even
satisfying to a general, providing it was put in the right place.

     But we would also have to caution against the employment of
masses of U-235 exceeding some forty-five pounds. Beyond that
limit the problem of putting the pieces together in a timely and
efficient manner becomes too great for amateur mechanics. It
would be unfortunate if you started building one of these things
and it went off in your face before you finished it. Our personal
preference, therefore, would be a total mass of around thirty-six
or thirty-seven pounds. This will provide a comfortably large
bang while also leaving a certain margin for errors of
calculation in constructing the gadget.

     Once an adequate amount of material has been put together in
one place there is a need to keep them there for a period of
about half a second. The method of achieving this half-second
delay is the main problem confronting the manufacturer. Whenever
two masses which together will create a critical mass happen to
get too close they begin a rather violent interaction. The
immediate effect of this interaction is the appearance of massive
quantities of energy, all pushing outward. In a small fraction of
a second this energy will fling the two masses of U-235 apart.
The sole result of such an unconstrained approach is a squib
explosion, one which will make a mess of the immediate area but
will scarcely be felt a few hundred feet away. It is assumed any
self-respecting terrorist would wish for something more
spectacular so our immediate task is one of devising some method
which will keep the two masses of U-235 together long enough to
let bigger things happen.

     Over the years scientists have developed a number of methods
for bringing U-235 masses together and holding them there long
enough for an explosion to occur. One of the first such methods,
for example, required an implosion to trigger the final
explosion. In this method a mass of loosely compacted U-235 was
surrounded by quantities of high explosives. At the appropriate
instant the explosives were detonated, compressing the U-235 and
holding it in position long enough to complete the cycle (or at
least this is the sketched method which appeared in the
newspapers during the Rosenberg trial). We believe it probable
this was not the whole story however. Even a loosely compacted
mass of U-235 would be entirely too hot, both radioactively and
thermally, to be handled with any comfort. More likely the U-235
(or plutonium) was first machined into several segments which
together would approximate a sphere. Each segment would then be
placed in a single conduit, with a graphite or other moderator
separating the various segments. At the appropriate instant a
simultaneous detonation of several explosive charges would propel
the different segments down their conduits to an explosion
chamber.

     While this technique is theoretically quite workable, we
feel it would be entirely too difficult for terrorists to
construct using home-made equipment. Achieving the sort of
accuracy needed to bring all elements of the U-235 together at
the precise instant needed to obtain a satisfactory explosion
implies a "fail-safe" technology one or two orders of magnitude
greater than most terrorists can hope to achieve. For this reason
we have resolved on a simpler approach.

     We feel a quite acceptable device can be constructed
providing the terrorist has access to a two-story building with
basement, two sticks of dynamite (or the equivalent in black
powder or TNT), fifteen sacks of cement, twenty cubic yards of
sand and gravel and about a week to work. Total cost, apart from
building rental, should be in the vicinity of $3,000 (perhaps a
bit less if second hand or surplus materials are used). The final
requirement, which is a bit more difficult to come by, is the
necessary quantity of U-235 or plutonium. We will touch on this
matter later, but for the time being we will merely assume the U-
235 is on hand.

     Taking things in order, the first step is to make certain
the U-235 is divided into two or more approximately equal masses.
Rather obviously, it was not all together when brought into the
house, so we will assume it arrived in several small packages.
The immediate task is to get it into a form ready to become part
of an explosion. With two masses, each weighing eighteen to
eighteen-and-one-half pounds, it is necessary to machine a pair
of matching hemispheres. This requires an acetylene torch.

     Uranium has a melting temperature of approximately 3760
degrees Fahrenheit. An acetylene torch has a theoretical flame
temperature of 4770 degrees Fahrenheit, and even though this
theoretical limit is not reached, the flame temperature is still
comfortably above the melting point of uranium. Preferably you
should first construct a small kiln out of a few dozen fire
bricks and employ a bellows to add air to the system, but with a
bit of patience (and some luck since uranium happens to be
explosively flammable) the acetylene torch ought to be entirely
adequate.

     As the uranium melts it is allowed to flow into a
hemispherical depression created out of fire clay of the sort
obtainable in any ceramics outlet. Once the first hemisphere is
formed and cooled it can be moved away from the kiln and the
second hemisphere manufactured. It must be noted that in doing
this it is highly desirable to stay well clear of the area.
Uranium has a number of unpleasant characteristics. If you happen
to be in the same room while it is being melted down you are
certain to inhale some of the radioactive gasses, more than
enough to have a decidedly adverse effect on your life
expectancy, possibly reducing it to as little as a few hours.

     Assuming that as a terrorist you are not overwhelmingly
interested in personal survival, these matters can be neglected
providing you are willing to hurry a bit. Otherwise, to smelt the
uranium we would suggest you employ some reasonably good servo-
mechanisms, about five tons of lead and a distance of some fifty
feet or so between you and the U-235 being smelted. Given this
sort of protection there should be no problem, providing
appropriate peripheral precautions are taken.

     Keeping the two chunks of U-235 well separated from one
another (and in a lead casket to prevent excessive stray
radiation while you are about the business of completing the
bomb), we next cut a hole from the second floor down to the
basement. A couple of lengths of black iron pipe are now inserted
and joined so we have a three-inch cast pipe running from the
basement up to the second floor. This should give about a twenty
foot total length.

     Probably it would be a good idea to put about a six-inch
plug of cement in the base of the pipe, but if your floor is very
solid and the house rests on rock this may be dispensed with.
Before lowering the pipe down onto the plug we put one of the U-
235 hemispheres, flat side up, atop the plug. The pipe is then
seated and the first half of the bomb is complete.

     To assist in providing confinement we next fill the basement
with a mix of sand, cement and gravel, mixing thoroughly with
water from a hose in the process. Since this is to be a one-time
job there is no need to make a real production of the matter.
Slopping it together will do almost as well as trying to be
meticulous about the whole thing. What we are really interested
in is having enough external resistance around the pipe to
prevent it from rupturing and scattering uranium around the
basement before having it go boom. Even a semiliquid cement-sand-
gravel mix will be adequate for the purpose and any additional
strength will be largely wasted.

     We would also suggest a few sacks of cement and sand be
placed around the pipe where is passes up through the first
floor. This is probably not really necessary but a little extra
containment may well pay off in a higher yield. When finished,
this completes the receiver element of your bomb. [Note to
reader: a illustration is available in the original text]

     Construction of the firing element is a trifle more
difficult. The idea is to take the second U-235 hemisphere and
place it at the top section of the pipe so it can be fired
downward onto the receiver element. While the theory is
simplicity itself, there are certain inherent difficulties. For
one, it would be somewhat disconcerting if the trigger hemisphere
slipped during the final positioning. Lacking anywhere else to
go, it would promptly slide down the pipe and then come back up
again. This would be self-defeating. Not only would you be dead,
the publicity would be unfortunate. Terrorists who succeed only
in blowing themselves up are merely amusing and not at all
terrible.

     Our design is probably the simplest effective approach yet
devised. A thin wire screen (the same sort used to keep out flies
in the summer) is placed atop the bell of the pipe and then
stuffed loosely down into it, taking care that three or four
inches of the screen remain outside the lip of the bell. A four-
foot additional section of pipe is then seated on top of the bell
and welded firmly into place. For additional strength we would
also suggest one or two small holes be drilled into the joined
section of the pipe and steel pins inserted. [Note to reader: a
second illustration is available in the original copy of Analog
Science Fiction - Science Fact]

     Next you take a three-foot length of 2 1/2 inch copper pipe
and fill it with molten lead. The second hemisphere of U-235 is
then pinned into a form-fitting recess molded at the base of the
lead while a steel screw-rod is drilled into the opposite end of
the cylinder for a distance of perhaps a foot. The total mass of
this firing unit will be between eighty and ninety-five pounds,
depending on the amount of lead employed and the length of
trigger pipe used.

     A threaded cap is then screwed onto the pipe (note the need
to tap threads onto the pipe before affixing the cap). When the
cap is loose enough on the threads that you can screw it on and
off by hand it is then removed and a hole large enough to
accommodate the heel rod of the trigger unit is drilled into the
cap. Allow some six to eight inches of freedom and drill a small
hole in the heel rod, making it just large enough to accept a
small nail.

     Several nail sizes should be tried. The optimum size is a
nail barely large enough to hold the complete trigger when the
cap is suspended with the complete unit hanging from it. (Note:
this should not be tried atop the receiver pipe!) Once such a
nail has been found we are ready for final assembly. The TNT or
gunpowder is flaked and placed on a small tray, ideally a coffee
grounds holder from a small percolator. The flakes or powder
should be carefully tamped into place and either one or two
electric primers inserted. This is placed around the heel rod
with a pair of firing wires running up from the primers to the
outside of the unit. The whole assembly is now screwed on and
your A-bomb is complete. The wires are attached to a timer switch
and the lower safety pins are removed. You now have some twelve
hours to leave town before the town leaves.

     When the timer detonates the charge there is far more than
enough force to sheer the retaining pin and drop the trigger down
onto the receiver. Completely ignoring the acceleration imparted
by the powder explosion, a free fall of twenty feet by a mass of
ninety-five pounds will generate around 8 x 10^10 (8 times 10 to
the 10th power) erg/sec of kinetic energy at the point of impact.
Added to this is the thrust of the powder charge. The total
kinetic force should work out to something on the order of 10 ^12
(10 to the 12th power) erg/sec; which is fully adequate to keep
the two hemispheres in contact long enough to provide a
thoroughly satisfactory bang.

     The system is simplicity itself!

     But in fairness to all concerned, we ought to mention a few
minor problems which should be considered by anybody wishing to
put one together. For example, we touched briefly on the
flammability of uranium when we mentioned the acetylene torch. We
should point out that any machining should be performed under a
`milk' bath. `Milk,' for those not knowledgeable of machining
techniques, is a milky appearing substance having many of the
properties of oil but lacking its flammability. It is readily
obtainable from any distributor of machine shop supplies with no
questions asked. Use of this `milk' will tend to minimize risk.

     Actually, it would be better if the uranium were melted and
machined in a pure nitrogen atmosphere, but with care and a bit
of luck you will most likely be able to manage without going to
any such extremes.

     The radiation problems are a bit more difficult to handle.
U-235 has certain expotentiation characteristics which cannot be
ignored. Assume for a moment that one gram of radium has a
characteristic radiation constant equal to X. Two grams of radium
would then have a radiation constant of 2X. Three grams would
equal 3X, and so on. With either U-235 or plutonium this is not
the case. It is this precise characteristic which makes them
explosive while radium is not. While one gram of U-235 may have a
radiation constant of 1X, two grams might turn out to have a
constant of 2.5X and three grams could well top 6X, etc. This can
be a problem.

     Since each of your hemispheres are in excess of half the
critical mass they are HOT! Simply staying in the same room with
one of these units for more than a few minutes is apt to be
highly lethal. Inhaling air containing dust motes made
radioactive by the U-235 is a reasonably quick way to saying
goodbye to the world. For these reasons we would suggest some
independent air supply for those working around the material.
Possibly scuba gear could be used to solve the breathing problem.
Solving the general radiation problem is a trifle more difficult,
but with a bit of determination, some ingenuity and some luck it
should be achievable.

     We would suggest something on the order of a lead-encased,
powered "wheelchair" which can be moved around the room with the
operator sitting securely inside. A small slit, covered with
leaded glass, provides the needed visibility. Leaded sleeves and
gauntlets will permit the operator to perform any needed
mechanical actions involving the U-235 providing he is cautious
and spends no more than a few minutes at a time working with the
material. As an added security against stray radiation we would
also suggest the laboratory be lead sheathed on both walls and
floors. The basement ceiling should also be shielded with lead to
avoid problems with the radiation from the receiver element. In
all, probably about six to eight tons of lead would have to be
used if even a minimal security is to be maintained. Since such a
weight would have to be fairly concentrated it would probably
also be necessary to shore up the flooring so the building
doesn't collapse. Once these precautions are taken, however, you
should be well prepared to go about building your bomb.

     There is still one more problem though; an old recipe for
rabbit stew begins with the practical injunction "first catch
your rabbit." Similarly, if you are going to build an A-bomb you
had better get your U-235 or your plutonium. Since plutonium is a
bit more difficult to lay hands on than U-235, we will begin by
assuming you want to take the easiest approach and will
concentrate on U-235.

     In this your task may have been made far simpler since any
number of newspapers and other scientific commentators have
repeatedly pointed out that the best available source of U-235 is
the local nuclear power reactor. By now there are nearly a
hundred of these scattered around the nation so all that's
necessary is to go in and steal a few of the control rods, smelt
them down, purify them to eliminate the nonexplosive U-238 and
then build your bomb.

     Getting into the reactor complex is probably reasonably
easy. Most campuses are only moderately guarded. Usually there is
a cyclone fence of some sort and one or two security guards at
the gate. It might be advisable to do a bit of discreet checking
in advance to determine whether or not there are electronic guard
devices around the grounds, but usually this is not the case.
Under ordinary circumstances there is no point in trying to come
in by the back way anyhow. Uranium has a rather considerable mass
and no one person, nor even a group of several people, are apt to
be able to carry out enough uranium reactor slugs to make much of
a difference, particularly since they would have to be wearing
protective armor to minimize the radiation hazards.

     As we see it the best approach is the most direct. Simply
steal a truck and semi-trailer and drive right up to the gate.
Take out the guards, leave a couple of your own people as
substitutes and drive right up to the reactor building, remove
what you wish and depart. Very simple, very direct and highly
effective.

     But there are a few minor problems here too. The actual
reactor itself is cased in a nickle-iron sphere which is immersed
in a water coolant/moderator. Since every reactor has crane
hoists and servo-mechanisms for use in working on the reactor
during maintenance periods at least a part of the problem is
already solved. These can be used to pick up the reactor core and
slide it over onto a powered dolly which can then load it onto
the truck.

     One note of caution here; if you merely hoist the reactor
sphere without pulling a few of the reactor slugs or inserting
the appropriate dampers it will not be possible for you to load
the device onto your truck. You will be dead in a minute or two
and the whole reactor will be a puddle on the floor. For this
reason we would suggest you take a prisoner or two and have them
instruct you in the proper technique for pulling the core and
removing the reactor unit.

     Additionally, it would be wise to have your semi-trailer
specially modified before you ever take it in. Total weight of
the system being removed is somewhere in the vicinity of fifty
tons, and since you would have to have at least six inches of
lead shielding inside the trailer to protect the driver in the
cab, the total cargo weight would gross out at about sixty-five
tons. The need for additional support members in the trailer is
obvious.

     Alternatively, if removal of the whole core unit seems
impractical, and if the power plant has enough spare slugs
available, you might simply remove about 1,200 pounds of reserve
slugs and load them onto the truck. This is quite a bit easier,
but you cannot neglect to carry along enough moderating material,
either graphite or lead, to prevent the slugs from building up
heat and melting through the bottom of the truck. It would be
embarrassing if you got all the way home and then discovered the
bottom had melted out of the truck and the contents were
scattered in a radioactive straight line all the way to your
hideout. Since you would probably already be dying of radioactive
poisoning by now there is little the police could do to make
things worse, but it would still be an ultimate humiliation. So
grab the 1,200 pounds of spare slugs and mix them with about
15,000 pounds of graphite and lead. This way you should get home
safely.

     Assuming now that you have gotten home and are not already
incapacitated by the onset of radiation sickness, your next task
is to set about converting the uranium slugs into A-bomb
material.

     Nuclear power reactor slugs are enriched with U-235. Natural
uranium consists of some 99.5% U-238 and some 0.5% U-235. When
prepared for use in a reactor the U-238 is mixed with enough U-
235 to bring the U-235 fraction up to about 3%. This is a very
considerable improvement, but it is not even approximately good
enough to give you a bomb. Bomb grade uranium must consist of at
least 97+% U-235, otherwise it simply cannot explode. It will get
hot at 3%. If enough of the 3% mix is piled in one spot it will
boil away merrily and ultimately blow itself around the room, but
there is no way it can give you a genuine A-Bomb. To get one of
those you have to refine the U-235 out of the mix.

     The 1,200 pounds of enriched slugs you acquired can be
expected to provide you with the needed 36 pounds of U-235,
providing you have the time, the patience and the expertise to
separate it all out. Should you have any doubts of your ability
to perform a total separation you should plan in advance to
increase the number of slugs removed from the power plant
accordingly. If you feel you can obtain something on the order to
50% efficiency you might figure on picking up 2,400 pounds. If
you are more pessimistic you might plan on 33% and grab 3,600.

     Generally, with the best current techniques and several
passes of the material, a refining efficiency of 25% is easily
achievable. To go above that requires materials and equipment not
apt to be available. This would suggest you ought to abduct a
minimum of 4,800 pounds, with 9,600 pounds being an optimum
target. Together with the shielding necessary to transport all
this mass of uranium with a degree of safety you should figure on
a total mass on the order of 150,000 pounds, or 75 tons.

     Presuming this has been taken care of and you now have
secure possession of approximately 5 to 10 tons of uranium slugs,
you next have the problem of finding some place (or places) to
store them while you set about extracting the needed U-235. For
this we suggest you rent a small warehouse and move your
operation there. You may keep your two-story building as your
ground-zero site, but it is showing signs of being a trifle
impractical as a refinery, particularly in view of the difficulty
of separating the two isotopes of uranium. As a good estimate,
you should probably figure on acquiring a structure containing a
minimum of 20,000 square feet of floor space if you are serious
about going into the uranium refining business. It is simply too
difficult to cram the needed equipment into any smaller space.
After all, if it takes hundreds of acres to refine out U-235 at
such places as Oak Ridge, Tennessee or Hanford, Washington, we
hardly feel we are out of line in settling for a scant 20,000
square feet here. You will be cramped but it should be possible.

     Now that you have your floor space you have to decide which
technique you are going to use to separate out the U-235. Several
of these are now available, but they tend to be mutually
exclusive so you must pick one at the beginning and stick with it
through out.

     As a terrorist one of the best methods for your purposes is
the gaseous diffusion approach. This was the one used for the
earliest A-bombs, and in many respects it is the most reliable
and requires the least sophisticated technology. It is, however,
a bit expensive and does require certain chemicals apt to raise a
few eyebrows. You have to start with something on the order of a
dozen miles of special glass-lined steel tubing and about sixty
tons of hydrofluoric acid which can be employed to create the
compound uranium-hexafluoride. Once your uranium has been
converted into hexafluoride it can be blown up against a number
of special low-porosity membranes. The molecules of uranium-
hexafluoride which contain an atom of U-238 are somewhat heavier
that those containing an atom of U-235. As the gas is blown
across the membranes more of the heavier molecules are trapped
than the light ones. The area on the other side of the membrane
is thus further enriched with the U-235 containing material,
possibly by as much as 1/2% per pass. Repeat this enough times
and you wind up with uranium hexafluoride containing virtually
100% core atoms of U-235. You then separate the fluorine from the
uranium and arrive at a nice little pile of domesticated U-235.
From there its all downhill.

     Since hydrofluoric acid is expensive and probably difficult
to obtain without somebody asking the wrong sort of questions it
would be best to steal it if you are genuinely determined on this
method, either that or first steal a few million dollars, then
set up your plant as a cover and not bother getting the uranium
until you are ready to start the final phase of your operations.

     Alternatively, if you decide the gaseous diffusion method is
too cumbersome, you might merely construct a breeder-reactor pile
somewhere out in the woods and use the enriched uranium to create
plutonium. The plutonium could then be separated out by purely
chemical techniques, thereby avoiding all the difficulties
implicit in the gaseous approach.

     Setting up a breeder pile is simplicity itself, and any of a
dozen easily obtained college texts will spell out equally good
methods so there is no need to go into them here. Suffice it to
say there are not theoretical problems in putting a breeder
reactor together. There may be a few practical problems, but if
you happen to have access to a small private river, a few train
car loads of sodium, a considerable quantity of stainless steel
tubing and about a hundred acres of secluded land you should be
able to manage it nicely.

     There might be a few problems in maintaining secrecy from
low flying aircraft carrying radiation detectors, but if your
building is properly shielded there shouldn't be too much of a
problem and you might very well escape detection altogether.

     Should neither of these approaches appeal to you, you might
consider trying your hand at some of the interesting new
techniques for isolating U-235 out of a conventional mix. One of
these, for example, starts with a requirement for a cryogenic
magnet capable of sustaining a 20,000 gauss flux inside a liquid
helium bath. From there it starts getting complicated. A simpler
approach utilizes a laser separation technique. U-235, being
lighter in mass than U-238, departs with a slightly different
vector when excited by a laser beam. You spray a thin mist of
uranium atoms at right angles through a laser beam. The U-235 is
driven out at a somewhat steeper angle than the U-238 so the task
is fairly simple.

     In principle it is easy and reliable. It is, however, a bit
slow. Using any readily obtainable laser you could probably
process as much as twenty pounds of uranium per day with a 12.5%
efficiency. The resulting mix at the U-235 end, would probably
run about 10% U-235 after the first pass so a total of nine
separate runs would be needed if the material is to reach bomb
grade. Assuming you started with 9,600 pounds of slugs you should
be able too come up with the needed 36 pounds of 97+% pure U-235
in just under four years.

     This would be something of a problem in its own right.
Almost certainly you would have picked up a lethal dose of
radiation during the initial theft and transfer phases of the
operation, so you would not have four years to complete the
refinement. On this basis it would probably be wise to have at
least one, and preferably two or three back-up crews of
volunteers to replace you and your original crew as you die off.
You will not live to see the end of your project but, with a
little bit of luck and no curiosity on the part of any of your
neighbors, your successors should be able to create a pretty fair
bang before they too die of radiation poisoning.

     Should you anticipate serious difficulty in finding enough
volunteers to carry through a long range project of this sort you
might consider a few other alternatives. One of the more
attractive, darkly hinted at by Ralph Nader and other such
reliable sources, is considerably more direct. Rather than
raiding the reactor plant and stealing the uranium, why not
merely short-circuit the safety systems so the station itself
goes up, taking a few square miles, plus you, along with it, or
at least poisoning the neighborhood with some thoroughly nasty
radiation?

     This is a good idea. We recommend it, both for the
directness of approach and the simplicity. Why go through all the
bother of acquiring and refining tons of reactor-grade uranium
just to get a few pounds of bomb-grade U-235?

     Of course there is the fact that it is only reactor-grade
stuff, which means there is no possible way for you to get an
explosion out of the thing. That is simply impossible no matter
what you do. But this does not mean you could not come up with a
distinctly impressive melt-down which will release all sorts of
radioactivity in the neighborhood.

     Should you decide on this you will have to make definitive
advance plans and work with split second timing, otherwise you
are apt to discover all your efforts have gone for naught. The
basic problem here is that most of the data concerning nuclear
reactors comes either from newspaper reporters or Ralph Nader,
and as such they ought to be accepted uncritically or not at all.

     As we mentioned earlier, the core unit of a reactor consists
of uranium slugs and moderators in a stainless steel sphere. As
the moderator rods are slipped out of the reactor, the neutrons
released by decaying U-238 and U-235 atoms are captured by other
atoms, triggering fissions there too. The trouble is, the process
is relatively slow since the U-238 atoms are reasonably stable.
The result is the sort of a chain reaction which cannot complete
a real explosion. All it can do is build up heat and expand
somewhat so the space between atoms serves as its own moderator.

     The reactor itself produces power essentially as a steam
generator. The heat of the core is used to create superheated
steam which in turn drives turbines. To prevent overheating, the
core is placed in a special sink which floods automatically
whenever the temperature starts to exceed a critical level. As
there are also automatic moderator control rods and equally
automatic fuel-slug removal devices, this water flooding system
seldom requires any sort of attention. It is merely a third level
back-up in case the first two fail. In order to force a melt-
down, therefore, it is necessary to override the automatic slug
removal system, the automatic moderator system and the flooding
system. Once this is done the meltdown goes to completion.

     Now comes the question of specific goals in mind. Are you,
as a terrorist, primarily interested in causing a maximum amount
of immediate dislocation in society? Are you rather more
interested in knocking a nuclear power plant out of operation for
some indefinite period of time? Is your concern with proving a
point, say that you don't like nuclear power and that you wish to
convince everyone it is simply too dangerous to play with?

     Assuming you are mainly interested in causing a maximum
immediate dislocation, it would probably be easier and simpler
just to dynamite a few hundred high-tension power lines coming
into New York City. Two dozen, strategically placed conventional
small bombs would probably black out everything from Washington,
D.C. north. A day or two would be required to mend matters and by
that time you could be ready to blast some more.

     This would be genuinely effective! It could seriously
inconvenience 35 million people for a whole summer if done
properly. On the other hand, if a solitary nuclear plant were
disrupted there is a good likelihood no one would even notice.
Power from other sources would automatically be fed into the grid
and things would go on much as before. A few months later, say in
the middle of winter, there might be a shortage of power to some
industrial plants, but the overall direct effect would be
negligible.

     If your purpose is limited to knocking out the power plant
for an indefinite period, then by all means tackle the main
place. When the newspapers catch up with the story the nation
will be deluged with panic headlines about the "narrowly averted"
tragedy so the resulting publicity will be highly rewarding to
your successors in the movement. Apart from the fear generated,
about all it will do is prompt the authorities to take additional
precautions to make it more difficult for the next group to break
in. Since terror works best when it becomes cumulative this would
appear to be a bit self-defeating. A persistent blasting of high-
tension lines would be more effective in the long run.

     So we assume your concern is in proving a point. You want to
demonstrate conclusively that nuclear power cannot be permitted
in America. You wish to generate so much fear and horror that
every plant will be closed down and the nation will rise up in
arms against the "Atomic Monster." You wish to knock out a
nuclear power plant and do it in the most deadly manner possible,
releasing clouds of radioactivity over the neighborhood and
killing as many people as you possibly can.

     This is something entirely different from a mere disruption
of the plant and an uncomplicated core meltdown. To explain,
suppose you simply pull all the safety systems and let the thing
take off on its own. Temperature inside the steel core
immediately starts building up. Within three or four minutes the
steel around the core turns cherry red, then becomes white hot.
In another minute it would commence deforming and flowing as the
melting point of steel was reached. Within minutes it would be a
bubbling puddle on the floor of the reactor chamber. Mostly the
puddle would consist of iron, nickle, chromium, U-238, U-235,
graphite and some odds and ends of other elements, including
minute quantities of plutonium plus fission end-products.

     Still the heat continues to build until the uranium starts
vaporizing as a high density "steam." As each atom of uranium is
flung outward the distance between it and each other atom of
uranium naturally increases, and with the increased distance the
probability of neutron capture decreases. This cools the mass and
reduces the temperature.

     In general, the distance factor for the radioactive material
can be calculated to a good degree of precision. We assume a
vaporization temperature for uranium at around 4,500 degrees
Fahrenheit. We also assume the sphere was formed from Durimet B,
which consists of: 48% iron, 35% nickle, 12% chromium, 5% silicon
and a trace of carbon. The melting point of Durimet B is right at
4,950 degrees Fahrenheit. These two factors, when combined,
provide for an understanding of the meltdown physics. Since the
sphere containing the fission material melts at a higher
temperature then the contents, once the safeguards have been
disrupted the core rapidly becomes molten. The heat continues
building up until the outer sphere melts, releasing the core
material. Once the core material has escaped, however, the metal
of the sphere quickly solidifies. But since it is lighter than
the uranium it forms a crust atop the still molten fission
material. This gives us three different areas to consider, the
molten substance which consists of uranium, the surface crust
consisting of iron, nickle and chromium, and the diffused uranium
which escaped as a vapor before the crust formed. Somewhere in
this mix there are also a number of fission byproducts, but for
the most part they can be neglected.

     The uranium trapped beneath the solidified container metals
will remain extremely hot until it is broken up and separated so
it can cool. A surface temperature in the vicinity of 3,000
degrees Fahrenheit is a reasonably good estimate. But so far as
radiation hazards are concerned there is not much to worry about.
The region immediately around the reactor room will remain
unusable for a year or so while automated machinery picks up the
pieces and takes them out for refining, but it is not going to
hurt anyone outside. Only that portion of the radioactive
material which escapes the reactor complex and gets out into the
surrounding countryside is going to be able to cause casualties,
and with a conventional meltdown most of the material which could
escape is going to be buried under the solidifying nickle-iron-
chromium jacket. Only if you can get the uranium on the outside
of the jacket, so it vaporizes and escapes first, will you be
able to do much.

     Since we presume you want to release as much radioactivity
as possible, this means you must also take some secondary steps.
One of these might be to break into one nuclear power plant and
steal as many fuel rods as you can. Then bring them over to a
second plant and place them around the core before starting the
meltdown. This would be effective and you could die happy in the
knowledge your martyrdom probably killed fifty or sixty people in
the hundred or so acres downwind of the complex. A second, and
even more effective plan, would be to break into some military
installation and simply steal one of their A-bombs. Bring this
into the power station and you find you have achieved a genuine
bang.

     Of course, if you've broken into the military installation
and already have your own A-bomb then there is really very little
reason to go through all the other rigamarole with the power
station to begin with. Just take your little treasure, figure out
how the trigger operates and set it off.

     Alternatively, if you find it too difficult to obtain an A-
bomb from the U.S. military, you might try to contact the
Palestine Liberation Organization, the Red Brigades in Italy or
the Provisional Irish Republican Army in Belfast. These are all
well-financed, well-organized groups which have been in existence
for years. Since we have shown how simple it is for you to build
your own A-bomb, then rather obviously they must have a few dozen
of their own stashed away in the woods somewhere and since they
are not using them surely they would be willing to offer you one
or two in a good cause.

     Should they prove to be selfish about the whole thing and
pretend they have none of their own then you will either have to
fall back on one of the alternatives I have suggested here or set
about creating a terror weapon which does not involve nuclear
weaponry.

     In this regard may I suggest biological warfare. Several
years ago the United States discontinued its research in germ
warfare and presumably dumped its supplies. Since it is necessary
to perform enough research to know what sort of plagues you can
manufacture before you can discover how to stop the plagues
someone else manufactures then there is every likelihood the
nation would be virtually defenseless against a first-class
biological attack.

     Spray a little anthrax bacillus in the air-conditioning
system of the U.N. building, for instance, and within a week or
so people will be dropping like flies. Let a few thousand people
die in an artificial plague of this sort and the panic would
easily match that of an A-bomb, and it would certainly be a lot
easier to make.