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Thermonuclear weapon

The basics of the Teller–Ulam design for a thermonuclear 

weapon. Radiation from a primary fission bomb compresses a

secondary section containing both fission and fusion fuel. The

compressed secondary is heated from within by a second fission

explosion.

A thermonuclear weapon  is a  nuclear weapon that uses

the energy from a primary nuclear fission reaction to com-

press and ignite a secondary nuclear fusion reaction. The

result is greatly increased explosive power when com-

pared to single-stage fission weapons. It is colloquially re-

ferredto as a hydrogen bomb or H-bomb because it em-

ploys hydrogen fusion. The fission stage in such weapons

is required to cause the fusion that occurs in thermonu-

clear weapons.

[1]

The concept of the thermonuclear weapon was first devel-

oped and used in 1952 and has since been employed by

most of the world’s nuclear weapons.[2] The modern de-

sign of all thermonuclear weapons in the United States is

known as the  Teller-Ulam configuration for its two chief

contributors, Edward Teller and Stanislaw Ulam, who de-

veloped it in 1951[3] for the United States, with certain

concepts developed with the contribution of  John von

Neumann. The first test of a hydrogen bomb prototype

was the "Ivy Mike" nuclear test  in 1952, conducted by

the United States. The first ready-to-use thermonuclear

bomb "RDS-6s" (“Joe4”) was tested on August 12, 1953,

in the Soviet Union. Similar devices were developed bythe United Kingdom, China, and France.

As thermonuclear weapons represent the most efficient

design for  weapon energy yield   in weapons with yields

above 50  kilotons, virtually all the nuclear weapons de-

ployed by the five nuclear-weapon states under the NPT

today are thermonuclear weapons using the Teller–Ulam

design.[4]

The essential features of the mature thermonuclear

weapon design, which officially remained secret for

nearly three decades, are:

1. Separation of stages into a triggering “primary” ex-

plosive and a much more powerful “secondary” ex-

plosive.

2. Compression of the secondary by   X-rays   coming

from nuclear fission in the primary, a process called

the "radiation implosion" of the secondary.

3. Heating of the secondary, after cold compression,

by a second fission explosion inside the secondary.

The radiation implosion mechanism is a   heat engine

that exploits the temperature difference between the sec-

ondary stage’s hot, surrounding radiation channel and

its relatively cool interior. This temperature difference

is briefly maintained by a massive heat barrier called

the “pusher”, which also serves as an implosion  tamper,

increasing and prolonging the compression of the sec-

ondary. If made of uranium, as is almost always the case,

it can capture  neutrons produced by the fusion reaction

and undergo fission itself, increasing the overall explo-

sive yield. In many Teller–Ulam weapons, fission of thepusher dominates the explosion and produces radioactive

fission product fallout.

1

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3

inducing additional fission. Generally, a research pro-

gram with the capacity to create a thermonuclear bomb

has already mastered the ability to engineer boosted fis-

sion. When fired, the plutonium-239   (Pu-239) and/or

uranium-235   (U-235) core would be compressed to a

smaller sphere by special layers of conventional high ex-

plosives arranged around it in an explosive lens pattern,initiating the nuclear chain reaction that powers the con-

ventional “atomic bomb”.

The secondary is usually shown as a   column   of fu-

sion fuel and other components wrapped in many layers.

Around the column is first a “pusher-tamper”, a heavy

layer of  uranium-238   (U-238) or   lead  which serves to

help compress the fusion fuel (and, in the case of ura-

nium, may eventually undergo fission itself). Inside this

is the fusion fuel itself, usually a form of   lithium deu-

teride, which is used because it is easier to weaponize

than liquified tritium/deuterium gas (compare the suc-

cess of the cryogenic deuterium-based Ivy Mike exper-iment to the (over)success of the lithium deuteride-based

Castle Bravo   experiment). This dry fuel, when bom-

barded by neutrons, produces tritium, a heavy isotope of

hydrogen which can undergo  nuclear fusion, along with

the deuterium present in the mixture. (See the article on

nuclear fusion for a more detailed technical discussion of

fusion reactions.) Inside the layer of fuel is the “spark

plug”, a hollow column of fissile material (plutonium-239

or uranium-235) which, when compressed, can itself un-

dergo nuclear fission (because of the shape, it is not a

critical mass without compression). The tertiary, if one is

present, would be set below the secondary and probablybe made up of the same materials.[8][9]

Separating the secondary from the primary is the

interstage. The fissioning primary produces four types

of energy: 1) expanding hot gases from high explo-

sive charges which implode the primary; 2) superheated

plasma that was originally the bomb’s fissile material and

its tamper; 3) the  electromagnetic radiation; and 4) the

neutrons   from the primary’s nuclear detonation. The

interstage is responsible for accurately modulating the

transfer of energy from the primary to the secondary.

It must direct the hot gases, plasma, electromagnetic ra-

diation and neutrons toward the right place at the righttime. Less than optimal interstage designs have resulted

in the secondary failing to work entirely on multiple shots,

known as a “fissile fizzle”. The Koon shot of Operation

Castle is a good example; a small flaw allowed the neu-

tron flux from the primary to prematurely begin heating

the secondary, weakening the compression enough to pre-

vent any fusion.

Classified paper by Teller and Ulam on March 9, 1951:

On Heterocatalytic Detonations I: Hydrodynamic Lenses 

and Radiation Mirrors , in which they proposed their

revolutionary staged implosion idea. This declassified

version is extensively redacted.

There is very little detailed information in the open lit-

erature about the mechanism of the interstage. One of

the best sources is a simplified diagram of a British ther-

monuclear weapon similar to the American   W80   war-

head. It was released by  Greenpeace in a report titled

“Dual Use Nuclear Technology” .[10] The major compo-

nents and their arrangement are in the diagram, though

details are almost absent; what scattered details it does

include, likely have intentional omissions and/or inaccu-

racies. They are labeled “End-cap and Neutron Focus

Lens” and “Reflector Wrap"; the former channels neu-

trons to the U-235/Pu-239 Spark Plug while the latter

refers to an X-ray reflector; typically a cylinder made out

of an X-ray opaque material such as uranium with the

primary and secondary at either end. It does not reflect

like a  mirror; instead, it gets heated to a high temper-

ature by the X-ray flux from the primary, then it   emits

more evenly spread X-rays which travel to the secondary,

causing what is known as  radiation implosion. In Ivy

Mike, gold was used as a coating over the uranium to en-

hance the blackbody effect.[11] Next comes the “Reflec-

tor/Neutron Gun Carriage”. The reflector seals the gap

between the Neutron Focus Lens (in the center) and the

outer casing near the primary. It separates the primaryfrom the secondary and performs the same function as

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4   3 COMPRESSION OF THE SECONDARY 

the previous reflector. There are about six neutron guns

(seen here from  Sandia National Laboratories[12]) each

poking through the outer edge of the reflector with one

end in each section; all are clamped to the carriage and

arranged more or less evenly around the casing’s circum-

ference. The neutron guns are tilted so the neutron emit-

ting end of each gun end is pointed towards the centralaxis of the bomb. Neutrons from each neutron gun pass

through and are focused by the neutron focus lens towards

the centre of primary in order to boost the initial fission-

ing of the plutonium. A "Polystyrene  Polarizer/Plasma

Source” is also shown (see below).

The first U.S. government document to mention the in-

terstage was only recently released to the public promot-

ing the 2004 initiation of the Reliable Replacement War-

head Program. A graphic includes blurbs describing the

potential advantage of a RRW on a part by part level,

with the interstage blurb saying a new design would re-

place “toxic, brittle material” and “expensive 'special' ma-terial... [which require] unique facilities”.[13] The “toxic,

brittle material” is widely assumed to be beryllium, which

fits that description and would also moderate the neutron

flux from the primary. Some material to absorb and re-

radiate the X-rays in a particular manner may also be

used.[14]

The “special material” is thought to be a substance called

"FOGBANK", an unclassified codename, though it is of-

ten referred to as "THE   fogbank” (or "A   Fogbank”) as

if it were a subassembly instead of a material. Its com-

position is classified, though aerogel has been suggested

as a possibility. Manufacture stopped for many years;however, the Life Extension Program  required it to start

up again – Y-12  currently being the sole producer (the

“unique facility” referenced). The manufacturing process

used  acetonitrile as a solvent, which led to at least three

evacuations in 2006. Acetonitrile is widely used in the

petroleum and pharmaceutical industries. Like most sol-

vents, it is flammable and can be toxic.[15]

2.1 Summary

A simplified summary of the above explanation is:

1. An  implosion assembly type of fission bomb is ex-

ploded. This is the primary stage. If a small amount

of   deuterium/tritium  gas is placed inside the pri-

mary’s core, it will be compressed during the explo-

sion and a nuclear fusion reaction will occur; the re-

leased neutrons from this fusion reaction will induce

further fission in the plutonium-239 or uranium-235

used in the primary stage. The use of fusion fuel

to enhance the efficiency of a fission reaction is

called boosting. Without boosting, a large portion of

the fissile material will remain unreacted; the Little

Boy and  Fat Man bombs had an  efficiency of only1.4% and 17%, respectively, because they were un-

boosted.

2. Energy released in the primary stage is transferred

to the secondary (or fusion) stage. The exact mech-

anism whereby this happens is secret. This energy

compresses the fusion fuel and sparkplug; the com-

pressed sparkplug becomes critical and undergoes

a fission chain reaction, further heating the com-

pressed fusion fuel to a high enough temperature toinduce fusion, and also supplying neutrons that react

with lithium to create tritium for fusion.

3. The fusion fuel of the secondary stage may be sur-

rounded by   depleted uranium  or   natural uranium,

whose U-238 is not fissile and cannot sustain a chain

reaction, but which is  fissionable when bombarded

by the high-energy neutrons   released by fusion in

the secondary stage. This process provides consid-

erable energy yield (as muchas half of the total yield

in large devices), but is not considered a tertiary

“stage”. Tertiary stages are further fusion stages (seebelow), which have been only rarely used, and then

only in the most powerful bombs ever made.

Thermonuclear weapons may or may not use a boosted

primary stage, use different types of fusion fuel, and

may surround the fusion fuel with beryllium (or another

neutron reflecting material) instead of depleted uranium

to prevent early premature fission from occurring before

the secondary is optimally compressed.

3 Compression of the secondary

The basic idea of the Teller–Ulam configuration is that

each “stage” would undergo fission or fusion (or both)

and release energy, much of which would be transferred

to another stage to trigger it. How exactly the energy is

“transported” from the primary to the secondary has been

the subject of some disagreement in the open press, but

is thought to be transmitted through the X-rays which are

emitted from the fissioning primary. This energy is then

used to compress the  secondary. The crucial detail of

how the X-rays create the pressure is the main remainingdisputed point in the unclassified press. There are three

proposed theories:

•  Radiation pressure exerted by the X-rays. This was

the first idea put forth by Howard Morland  in the

article in The Progressive.

•  X-rays creating a plasma in the radiation case’s filler

(a polystyrene or "FOGBANK" plastic foam). This

was a second idea put forward by Chuck Hansen and

later by Howard Morland.

•   Tamper/Pusher   ablation. This is the concept best

supported by physical analysis.

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3.3 Tamper-pusher ablation   5

3.1 Radiation pressure

The radiation pressure exerted by the large quantity of X-

ray photons inside the closed casing might be enough to

compress the secondary. Electromagnetic radiation such

as X-rays or light carries momentum and exerts a force

on any surface it strikes. The pressure of radiation at theintensities seen in everyday life, such as sunlight striking

a surface, is usually imperceptible, but at the extreme in-

tensities found in a thermonuclear bomb the pressure is

enormous.

For two thermonuclear bombs for which the general size

and primary characteristics are well understood, the Ivy

Mike test bomb and the modern W-80 cruise missile war-

head variant of the W-61 design, the radiation pressure

was calculated to be 73 million bar (atmospheres) (7.3 T

Pa) for the Ivy Mike design and 1,400 million bar (140

TPa) for the W-80.[16]

3.2 Foam plasma pressure

Foam   plasma pressure is the concept which Chuck

Hansen introduced during the Progressive case, based

on research which located declassified documents listing

special foams as liner components within the radiation

case of thermonuclear weapons.

The sequence of firing the weapon (with the foam) would

be as follows:

1. The high explosives surrounding the core of the pri-mary fire, compressing the fissile material into a

supercritical state and beginning the fission chain re-

action.

2. The fissioning primary emits   X-rays, which “re-

flect” along the inside of the casing, irradiating the

polystyrene foam.

3. The irradiated foam becomes a hot plasma, pushing

against the tamper of the secondary, compressing

it tightly, and beginning the fission reaction in the

spark plug.

4. Pushed from both sides (from the primary and the

spark plug), the lithium deuteride fuel is highly

compressed and heated to thermonuclear temper-

atures. Also, by being bombarded with neutrons,

each  lithium−6 atom splits into one tritium atom

and one alpha particle. Then begins a fusion reac-

tion between the tritium and the deuterium, releas-

ing even more neutrons, and a huge amount of en-

ergy.

5. The fuel undergoing the fusion reaction emits a large

flux of neutrons, which irradiates the U-238 tamper

(or the U-238 bomb casing), causing it to undergoa fission reaction, providing about half of the total

energy.

This would complete the fission-fusion-fission sequence.

Fusion, unlike fission, is relatively “clean”—it releases en-

ergy but no harmful radioactive products or large amounts

of nuclear fallout. The fission reactions though, especially

the last fission reaction, release a tremendous amount of

fission products and fallout. If the last fission stage is

omitted, by replacing the uranium tamper with one madeof  lead, for example, the overall explosive force is re-

duced by approximately half but the amount of fallout

is relatively low. The neutron bomb is a hydrogen bomb

with an intentionally thin tamper, allowing as much radi-

ation as possible to escape.

A   B   C D E

Foam plasma mechanism firing sequence.

1. Warhead before firing; primary (fission bomb) at top, sec-

ondary(fusionfuel) at bottom, allsuspendedin polystyrene

 foam.

2. High-explosive fires in primary, compressing plutonium

core into supercriticality and beginning a fission reaction.

3. Fission primary emits X-rays which are scattered along the

inside of the casing, irradiating the polystyrene foam.

4. Polystyrene foam becomes plasma, compressing sec-ondary, and plutonium sparkplug begins to fission.

5. Compressed and heated, lithium-6 deuteride fuel produces 

tritium  and begins the fusion reaction. The neutron flux 

 produced causes the U-238 tamper to fission. A fireball 

starts to form.

Current technical criticisms of the idea of “foam plasma

pressure” focus on unclassified analysis from similar high

energy physics fields which indicate that the pressure pro-

duced by such a plasma would only be a  small multiplier 

of the basic photon pressure within the radiation case,

and also that the known foam materials intrinsically have

a very low absorption efficiency of the   gamma ray  and

X-ray  radiation from the primary. Most of the energy

produced would be absorbed by either the walls of the

radiation case and/or the tamper around the secondary.

Analyzing the effects of that absorbed energy led to the

third mechanism:  ablation.

3.3 Tamper-pusher ablation

The proposed tamper-pusher ablation mechanism is that

the primary compression mechanism for the thermonu-

clear secondary is that the outer layers of the tamper-pusher, or heavy metal casing around the thermonuclear

fuel, are heated so much by the X-ray flux from the pri-

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6   4 DESIGN VARIATIONS 

mary that they  ablate away, exploding outwards at such

high speed that the rest of the tamper recoils inwards at

a tremendous velocity, crushing the fusion fuel and the

spark plug.

Ablation mechanism firing sequence.

1. Warhead before firing. The nested spheres at the top are

the fission primary; the cylinders below are the fusion sec-

ondary device.

2. Fission primary’s explosives have detonated and collapsed 

the primary’s  fissile pit .

3. The primary’s fission reaction has run to completion, and 

the primary is now at several million degrees and radiat-

ing gamma and hard X-rays, heating up the inside of the

hohlraum and the shield and secondary’s tamper.

4. The primary’s reaction is over and it has expanded. The

surface of the pusher for the secondary is now so hot that 

it is also ablating or expanding away, pushing the rest of 

the secondary (tamper, fusion fuel, and fissile spark plug)

inwards. The spark plug starts to fission. Not depicted: 

the radiation case is also ablating and expanding outwards (omitted for clarity of diagram).

5. The secondary’s fuel has started the fusion reaction and 

shortly will burn up. A fireball starts to form.

Rough calculations for the basic ablation effect are rela-

tively simple: the energy from the primary is distributed

evenly onto all of the surfaces within the outer radiation

case, with the components coming to a   thermal equi-

librium, and the effects of that thermal energy are then

analyzed. The energy is mostly deposited within about

one X-ray optical thickness  of the tamper/pusher outer

surface, and the temperature of that layer can then becalculated. The velocity at which the surface then ex-

pands outwards is calculated and, from a basic Newtonian

momentum balance, the velocity at which the rest of the

tamper implodes inwards.

Applying the more detailed form of those calculations to

the Ivy Mike device yields vaporized pusher gas expan-

sion velocity of 290 kilometers per second and an implo-

sion velocity of perhaps 400 kilometers per second if 3/4

of the total tamper/pusher mass is ablated off, the most

energy efficient proportion. For the W-80 the gas expan-

sion velocity is roughly 410 kilometers per second and

the implosion velocity 570 kilometers per second. Thepressure due to the ablating material is calculated to be

5.3 billion bar (530 TPa) in the Ivy Mike device and 64

billion bar (6.4 PPa) in the W-80 device.[16]

3.4 Comparing the implosion mechanisms

Comparing the three mechanisms proposed, it can be

seen that:

The calculated ablation pressure is one order of magni-

tude greater than the higher proposed plasma pressures

and nearly two orders of magnitude greater than calcu-

lated radiation pressure. No mechanism to avoid the ab-

sorption of energy into the radiation case wall and the

secondary tamper has been suggested, making ablation

apparently unavoidable. The other mechanisms appear

to be unneeded.

United States Department of Defense  official declassifi-

cation reports indicate that foamed plastic materials are

or may be used in radiation case liners, and despite thelow direct plasma pressure they may be of use in de-

laying the  ablation  until energy has distributed evenly

and a sufficient fraction has reached the secondary’s

tamper/pusher.[17]

Richard Rhodes' book Dark Sun stated that a 1-inch-thick

(25 mm) layer of plastic foam was fixed to the lead liner

of the inside of the  Ivy Mike steel casing using copper

nails. Rhodes quotes several designers of that bomb ex-

plaining that the plastic foam layer inside the outer case is

to delay ablation and thus recoil of the outer case: if the

foam were not there, metal would ablate from the inside

of the outer case with a large impulse, causing the casingto recoil outwards rapidly. The purpose of the casing is

to contain the explosion for as long as possible, allowing

as much X-ray ablation of the metallic surface of the sec-

ondary stage as possible, so it compresses the secondary

efficiently, maximizing the fusion yield. Plastic foam has

a low density, so causes a smaller impulse when it ablates

than metal does.[17]

4 Design variations

A number of possible variations to the weapon designhave been proposed:

•   Either the tamper or the casing have been proposed

to be made of uranium-235 (highly enriched ura-

nium) in the final fission jacket. The far more ex-

pensive U-235 is also fissionable with fast neutrons

like the standard U-238, but its fission-efficiency is

higher than natural uranium, which is almost en-

tirely U-238. Using a final fissionable jacket of U-

235 would thus be expected to increase the yield of

any Teller-Ulam bomb above a U-238 (depleted ura-

nium) or natural uranium jacket design.

•   In some descriptions, additional internal structures

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7

exist to protect the secondary from receiving exces-

sive neutrons from the primary.

•   The inside of the casing may or may not be specially

machined to “reflect” the X-rays. X-ray “reflection”

is not like light reflecting off of a mirror, but rather

the reflector material is heated by the X-rays, caus-ing the material itself to   emit X-rays, which then

travel to the secondary.

Two special variations exist which will be discussed in a

further section: the cryogenically cooled liquid deuterium

device used for the Ivy Mike test, and the putative design

of the W88 nuclear warhead—a small, MIRVed version

of the Teller–Ulam configuration with a  prolate (egg or

watermelon shaped) primary and an elliptical secondary.

Most bombs do not apparently have tertiary “stages”—

that is, third compression stage(s), which are additional

fusion stages compressed by a previous fusion stage (the

fissioning of the last blanket of uranium, which provides

about half the yield in large bombs, does not count as a

“stage” in this terminology).

The U.S. tested three-stage bombs in several explosions

(see   Operation Redwing) but is only thought to have

fielded one such tertiary model, i.e., a bomb in which a fis-

sion stage, followed by a fusion stage, finally compresses

yet another fusion stage. This U.S. design was the heavy

but highly efficient (i.e.,   nuclear weapon yield  per unit

bomb weight) 25 Mt B41 nuclear bomb.[18] The Soviet

Union is thought to have used multiple stages (including

more than one tertiary fusion stages) in their 50 megaton

(100 Mt in intended use) Tsar Bomba (however, as with

other bombs, the fissionable jacket could be replaced with

lead in such a bomb, and in this one, for demonstration,

it was). If any hydrogen bombs have been made from

configurations other than those based on the Teller–Ulam

design, the fact of it is not publicly known. (A possible

exception to this is the Soviet early Sloika design).

In essence, the Teller–Ulam configuration relies on at

least two instances of implosion occurring: first, the

conventional (chemical) explosives in the primary would

compress the fissile core, resulting in a fission explosion

many times more powerful than that which chemical ex-

plosives could achieve alone (first stage). Second, the ra-

diation from the fissioning of the primary would be used

to compress and ignite the secondary fusion stage, re-

sulting in a fusion explosion many times more powerful

than the fission explosion alone. This chain of compres-

sion could then be continued with an arbitrary number

of tertiary fusion stages.[19][20] although this is debated

(see more:  Arbitrarily large yield debate). Finally, effi-

cient bombs (but not so-called neutron bombs) end with

the fissioning of the final natural uranium tamper, some-

thing which could not normally be achieved without the

neutron flux provided by the fusion reactions in secondaryor tertiary stages. Such designs are suggested to be capa-

ble of being scaled up to an arbitrary large yield (with

apparently as many fusion stages as desired),[19][20] po-

tentially to the level of a "doomsday device.” However,

usually such weapons were not more than a dozen mega-

tons, which was generally considered enough to destroy

even most hardened practical targets (for example, a con-

trol facility such as the Cheyenne Mountain Complex).

Even such large bombs have been replaced by smaller-yield bunker buster type nuclear bombs, see also nuclear

bunker buster.

As discussed above, for destruction of cities and non-

hardened targets, breaking the mass of a single missile

payload down into smaller MIRV bombs, in order to

spread the energy of the explosions into a “pancake” area,

is far more efficient in terms of area-destruction per unit

of bomb energy. This also applies to single bombs deliv-

erable by cruisemissile or other system, such as a bomber,

resulting in most operational warheads in the U.S. pro-

gram having yields of less than 500 kilotons.

5 History

Main article: History of the Teller–Ulam design

5.1 United States

Main articles: Ivy Mike and Operation Castle

The idea of a thermonuclear fusion bomb ignited by a

smaller fission bomb was first proposed by Enrico Fermi

to his colleague  Edward Teller   in 1941 at the start of

what would become theManhattan Project.[3] Teller spent

most of the Manhattan Project attempting to figure out

how to make the design work, to some degree neglect-

ing his assigned work on the Manhattan Project fission

bomb program. His difficult and devil’s advocate attitude

in discussions led Robert Oppenheimer to sidetrack him

and other “problem” physicists into the super program to

smooth his way.

Stanislaw Ulam, a coworker of Teller, made the first

key conceptual leaps towards a workable fusion design.

Ulam’s two innovations which rendered the fusion bomb

practical were that compression of the thermonuclear fuel

before extreme heating was a practical path towards the

conditions needed for fusion, and the idea of staging or

placing a separate thermonuclear component outside a

fission primary component, and somehow using the pri-

mary to compress the secondary. Teller then realized that

the gamma and X-ray radiation produced in the primary

could transfer enough energy into the secondary to create

a successful implosion and fusion burn, if the whole as-

sembly was wrapped in a  hohlraum or radiation case.[3]

Teller and his various proponents and detractors later dis-puted the degree to which Ulam had contributed to the

theories underlying this mechanism. Indeed, shortly be-

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8   5 HISTORY 

Operation Castle thermonuclear test, Castle Romeo shot.

fore his death, and in a last-ditch effort to discredit Ulam’s

contributions, Teller claimed that one of his own “gradu-

ate students” had proposed the mechanism.

The “George” shot of Operation Greenhouse of 9 May

1951 tested the basic concept for the first time on a very

small scale. As the first successful (uncontrolled) release

of nuclear fusion energy, which made up a small fractionof the 225kt total yield,[21] it raised expectations to a near

certainty that the concept would work.

On November 1, 1952, the Teller–Ulam configuration

was tested at full scale in the "Ivy Mike" shot at an is-

land in the Enewetak Atoll, with a yield of 10.4 megatons

(over 450 times more powerful than the bomb dropped on

Nagasaki during World War II). The device, dubbed the

Sausage, used an extra-large fission bomb as a “trigger”

and liquid deuterium—kept in its liquid state by 20 short

tons (18 metric tons) of cryogenic equipment—as its fu-

sion fuel, and weighed around 80 short tons (70 metric

tons) altogether.The liquid deuterium fuel of Ivy Mike was impractical

for a deployable weapon, and the next advance was to

use a solid lithium deuteride fusion fuel instead. In 1954

this was tested in the "Castle Bravo" shot (the device was

code-named the Shrimp), which had a yield of 15 mega-

tons (2.5 times higher than expected) and is the largest

U.S. bomb ever tested.

Efforts in the United States soon shifted towards develop-

ing miniaturized Teller–Ulam weapons which could eas-

ily outfit intercontinental ballistic missiles and submarine-

launched ballistic missiles. By 1960, with the   W47

warhead[22] deployed on   Polaris ballistic missile sub-marines, megaton-class warheads were as small as 18

inches (0.5 m) in diameter and 720 pounds (320 kg) in

weight. It was later found in live testing that the Polaris

warhead did not work reliably and had to be redesigned.

Further innovation in miniaturizing warheads was accom-

plished by the mid-1970s, when versions of the Teller–

Ulam design were created which could fit ten or more

warheads on the end of a small MIRVed missile (see the

section on the W88 below).[7]

5.2 Soviet Union

Main articles: Joe 4 and RDS-37

See also:  Soviet atomic bomb project

The first Soviet fusion design, developed by   Andrei

Sakharov and Vitaly Ginzburg in 1949 (before the Soviets

had a working fission bomb), was dubbed the  Sloika, af-

ter a Russian layer cake, and was not of the Teller–Ulam

configuration. It used alternating layers of fissile mate-

rial and lithium deuteride fusion fuel spiked with tritium

(this was later dubbed Sakharov’s “First Idea”). Though

nuclear fusion might have been technically achievable, it

did not have the scaling property of a “staged” weapon.

Thus, such a design could not produce thermonuclear

weapons whose explosive yields could be made arbitrar-

ily large (unlike U.S. designs at that time). The fusion

layer wrapped around the fission core could only mod-

erately multiply the fission energy (modern Teller–Ulam

designs can multiply it 30-fold). Additionally, the whole

fusion stage had to be imploded by conventional explo-

sives, along with the fission core, multiplying the bulk ofchemical explosives needed substantially.

Their first Sloika design test, RDS-6s, was detonated in

1953 with a yield equivalent to 400 kilotons of TNT (15–

20% from fusion). Attempts to use a Sloika   design to

achieve megaton-range results proved unfeasible. After

the U.S. tested the "Ivy Mike" bomb in November 1952,

proving that a multimegaton bomb could be created, the

Soviets searched for an additional design. The “Second

Idea”, as Sakharov referred to it in his memoirs, was a

previous proposal by Ginzburg in November 1948 to use

lithium deuteride in the bomb, which would, in the course

of being bombarded by neutrons, produce tritium  andfree deuterium.[23] In late 1953 physicist   Viktor Davi-

denko  achieved the first breakthrough, that of keeping

the primary and secondary parts of the bombs in separate

pieces (“staging”). The next breakthrough was discovered

and developed by Sakharov and  Yakov Zel'dovich, that

of using the  X-rays  from the fission bomb to compress

the  secondary   before fusion (“radiation implosion”), in

early 1954. Sakharov’s “Third Idea”, as the Teller–Ulam

design was known in the USSR, was tested in the shot

"RDS-37" in November 1955 with a yield of 1.6 mega-

tons.

The Soviets demonstrated the power of the “staging” con-cept in October 1961, when they detonated the massive

and unwieldy Tsar Bomba, a 50 megaton hydrogen bomb

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5.4 China   9

that derived almost 97% of its energy from fusion. It was

the largest nuclear weapon developed and tested by any

country.

5.3 United Kingdom

Operation Grapple on  Christmas Island  was the first British hy-

drogen bomb test.

In 1954 work began at Aldermaston to develop the British

fusion bomb, with Sir William Penney  in charge of the

project. British knowledge on how to make a thermonu-

clear fusion bomb was rudimentary, and at the time the

United States was not exchanging any nuclear knowledge

because of the  Atomic Energy Act of 1946. However,

the British were allowed to observe the American Castle

tests and used sampling aircraft in the mushroom clouds,

providing them with clear, direct evidence of the com-pression produced in the secondary stages by radiation

implosion.

Because of these difficulties, in 1955 British prime min-

ister Anthony Eden agreed to a secret plan, whereby if

the Aldermaston scientists failed or were greatly delayed

in developing the fusion bomb, it would be replaced by

an extremely large fission bomb.

In 1957 the   Operation Grapple tests were carried out.

The first test,   Green Granite   was a prototype fusion

bomb, but failed to produce equivalent yields compared

to the Americans and Soviets, only achieving approxi-

mately 300 kilotons. The second test Orange Herald wasthe modified fission bomb and produced 720 kilotons—

making it the largest fission explosion ever. At the time

almost everyone (including the pilots of the plane that

dropped it) thought that this was a fusion bomb. This

bomb was put into service in 1958. A second prototype

fusion bomb Purple Granite was used in the third test, but

only produced approximately 150 kilotons.

A second set of tests was scheduled, with testing recom-mencing in September 1957. The first test was based on

a "… new simpler design. A two stage thermonuclear

bomb which hada much more powerful trigger”. This test

Grapple X Round C was exploded on November 8 and

yielded approximately 1.8 megatons. On April 28, 1958

a bomb was dropped that yielded 3 megatons—Britain’s

most powerful test. Two final air burst tests on Septem-

ber 2 and September 11, 1958, dropped smaller bombs

that yielded around 1 megaton each.

American observers had been invited to these kinds of

tests. After their successful detonation of a megaton-

range device (and thus demonstrating their practical un-derstanding of the Teller–Ulam design “secret”), the

United States agreed to exchange some of their nuclear

designs with the United Kingdom, leading to the 1958

US–UK Mutual Defence Agreement. Instead of contin-

uing with their own design, the British were given access

to the design of the smaller American Mk 28 warhead

and were able to manufacture copies.

5.4 China

Main article: Test No. 6

The People’s Republic of China detonated its first hydro-

gen bomb on June 17, 1967, 32 months after detonating

its first fission weapon, with a yield of 3.31 Mt. It took

place in the Lop Nor Test Site, in northwest China.[24]

5.5 France

Very little is known about France’s development of the

Teller–Ulam design beyond the fact that France detonated

a 2.6 Mt device in the "Canopus" test in August 1968.

5.6 Other countries

5.6.1 India

Main article: India and weapons of mass destruction

On May 11, 1998, India reportedly detonated a ther-

monuclear bomb in its  Operation Shakti tests ("Shakti-

1", specifically).[26] Dr.   Samar Mubarakmand  asserted

that Shakti-1 was a successful test, but if it was a ther-

monuclear device as claimed, then it failed to producecertain results that were to be expected of a thermonu-

clear device.[26] The yield of India’s hydrogen bomb re-

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10   5 HISTORY 

The detonation of Shakti-1 produced a nuclear yield  of 45 kt.[25]

mains highly debatable among the Indian science com-

munity and the international scholars.[27] The question of

politicisation and disputes between Indian scientists fur-ther complicated the matter.[28]

Director for the 1998 test site preparations, Dr. K. San-

thanam, reported the yield of the thermonuclear explo-

sion was lower than expected, although his statement

has been disputed by other Indian scientists involved in

the test.[29] Indian sources, using local data and citing a

United States Geological Survey report compiling seismic

data from 125 IRIS stations across the world, argue that

the magnitudes suggested a combined yield of up to 60

kilotonnes, consistent with the Indian announced total

yield of 56 kilotonnes.[30][31] However, several indepen-

dent experts have reported lower yields for the nucleartest and remained skeptical about the claims,[26] and oth-

ers have argued that even the claimed 50 kiloton yield was

low for confirmation of a thermonuclear design.[26][32]

5.6.2 Israel

Main articles:   Nuclear weapons and Israel   and   Vela

Incident

Israel is alleged to possess thermonuclear weapons of the

Teller–Ulam design,[33] but is not known to have testedany nuclear devices, although it is widely speculated that

the Vela Incident of 1979 may have been a joint Israeli-

South African nuclear test.[34][35] It is well established

that American scientist, Edward Teller (father of the hy-

drogen bomb), is said to have advised and guided the Is-

raeli establishment on general nuclear matters for some

twenty years.[36] Between 1964 and 1967, Teller made

six visits to Israel where he lectured at the Tel Aviv Uni-

versity on general topics in theoretical physics.[37] It tookhim a year to convince the CIA about Israel’s capability

and finally in 1976, Carl Duckett of the CIA testified in

the  U.S. Congress, after receiving credible information

from an “American scientist” (Edward Teller), on Israel’s

nuclear capability.[35] Sometime in 1990, Teller came to

confirm the speculations in media that it was during his

visits, three decades ago, that he concluded to the CIA

that Israel was in possession of nuclear weapons.[35] Af-

ter he conveyed the matter to the higher level of the U.S.

government, Teller reportedly said: “They [Israel] have

it, and they were clever enough to trust their research and

not to  test, they know that to test would get them intotrouble.”[35]

5.6.3 Pakistan

Main article: Pakistan and weapons of mass destruction

According to the scientific data received and published

by PAEC, the Corps of Engineers, and Kahuta Research

Laboratories (KRL), in May 1998, Pakistan carried out

six underground nuclear tests in Chagai Hills and KharanDesert  in  Balochistan Province  (See the code-names of

the tests,   Chagai-I   and   Chagai-II ).[26] None of these

boosted fission devices   was the thermonuclear weapon

design, according to KRL and PAEC.[26] In March 2000,

a leading Pakistani theoretical physicist reciprocated Mu-

nir Khan’s statement that both India and Pakistan pos-

sess the scientific capability to produce a hydrogen bomb,

which could be studied and developed “within a time lag

of three to six years.”[33] The scientist maintained that

Pakistan’s policy on hydrogen bombs comes under its

“moral ethics”,[33] and it is a “very dangerous game” since

it would have a destructive impact on the area covering a

radius of about 40–45 miles.[33]

5.6.4 North Korea

Main article: North Korea and weapons of mass destruc-

tion

North Korea’s three nuclear tests (2006, 2009 and 2013)

were relatively low yield and do not appear to have been

of a thermonuclear weapon design. The  South Korean

Defense Ministry  has speculated that North Korea maybe trying to develop a “hydrogen bomb” and such a device

may be North Korea’s next weapons test.[38][39]

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6.2   The Progressive case   11

6 Public knowledge

The Teller–Ulam design was for many years considered

one of the top nuclear secrets, and even today it is not

discussed in any detail by official publications with ori-

gins “behind the fence” of  classification.   United States

Department of Energy (DOE) policy has been, and con-

tinues to be, that they do not acknowledge when “leaks”

occur, because doing so would acknowledge the accuracy

of the supposed leaked information.

Photographs of warhead casings, such as this one of the  W80

nuclear warhead, allow for some speculation as to the relative

size and shapes of the   primaries  and  secondaries  in U.S. ther-

monuclear weapons.

Aside from images of the warhead casing, most informa-

tion in the public domain about this design is relegated to

a few terse statements by the DOE and the work of a few

individual investigators.

6.1 DOE statements

In 1972 the United States government declassified a state-

ment that “The fact that in thermonuclear (TN) weapons,

a fission 'primary' is used to trigger a TN reaction in ther-

monuclear fuel referred to as a 'secondary'", and in 1979

added, “The fact that, in thermonuclear weapons, radia-tion from a fission explosive can be contained and used to

transfer energy to compress and ignite a physically sep-

arate component containing thermonuclear fuel.” To this

latter sentence they specified that "Any elaboration of this 

statement will be classified .”[40] The only statement which

may pertain to the   spark plug  was declassified in 1991:

“Fact that fissile and/or fissionable materials are present

in some secondaries, material unidentified, location un-

specified, use unspecified, and weapons undesignated.” In

1998 the DOE declassified the statement that “The fact

that materials may be present in channels and the term

'channel filler,' with no elaboration”, which may refer tothe polystyrene foam (or an analogous substance).[41]

Whether these statements vindicate some or all of the

models presented above is up for interpretation, and of-

ficial U.S. government releases about the technical de-

tails of nuclear weapons have been purposely equivocat-

ing in the past (see, e.g., Smyth Report). Other informa-

tion, such as the types of fuel used in some of the early

weapons, has been declassified, though of course precise

technical information has not been.

6.2   The Progressive case

Main article: United States v. The Progressive

Most of the current ideas on the workings of the

Teller–Ulam design came into public awareness after the

Department of Energy (DOE) attempted to censor a mag-

azine article by U.S. antiweapons activist Howard Mor-

land in 1979 on the “secret of the hydrogen bomb”. In

1978, Morland had decided that discovering and expos-ing this “last remaining secret” would focus attention onto

the arms race  and allow citizens to feel empowered to

question official statements on the importance of nuclear

weapons and nuclear secrecy. Most of Morland’s ideas

about how the weapon worked were compiled from highly

accessible sources—the drawings which most inspired his

approach came from none other than the   Encyclopedia

Americana. Morland also interviewed (often informally)

many former Los Alamos scientists (including Teller and

Ulam, though neither gave him any useful information),

and used a variety of interpersonal strategies to encour-

age informative responses from them (i.e., asking ques-tions such as “Do they still use spark plugs?" even if he

was not aware what the latter term specifically referred

to).[42]

Morland eventually concluded that the “secret” was that

the  primary  and  secondary  were kept separate and that

radiation pressure from the primary compressed the sec-

ondary before igniting it. When an early draft of the arti-

cle, to be published in The Progressive magazine, was sent

to the DOE after falling into the hands of a professor who

was opposed to Morland’s goal, the DOE requested that

the article not be published, and pressed for a temporary

injunction. The DOE argued that Morland’s informationwas (1) likely derived from classified sources, (2) if not

derived from classified sources, itself counted as “secret”

information under the "born secret" clause of the 1954

Atomic Energy Act, and (3) was dangerous and would

encourage nuclear proliferation.

Morland and his lawyers disagreed on all points, but the

injunction was granted, as the judge in the case felt that

it was safer to grant the injunction and allow Morland,

et al., to appeal, which they did in   United States v. The

Progressive  (1979).

Through a variety of more complicated circumstances,

the DOE case began to wane as it became clear thatsome of the data they were attempting to claim as “se-

cret” had been published in a students’ encyclopedia a few

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12   7 VARIATIONS 

years earlier. After another H-bomb speculator, Chuck

Hansen, had his own ideas about the “secret” (quite dif-

ferent from Morland’s) published in a Wisconsin news-

paper, the DOE claimed that  The Progressive  case was

moot, dropped its suit, and allowed the magazine to pub-

lish its article, which it did in November 1979. Mor-

land had by then, however, changed his opinion of howthe bomb worked, suggesting that a foam medium (the

polystyrene) rather than radiation pressure was used to

compress the secondary, and that in the secondary there

was a spark plug of fissile material as well. He published

these changes, based in part on the proceedings of the ap-

peals trial, as a short erratum in The Progressive a month

later.[43] In 1981, Morland published a book about his ex-

perience, describing in detail the train of thought which

led him to his conclusions about the “secret”.[42][44]

Morland’s work is interpreted as being at least partially

correct because the DOE had sought to censor it, one of

the few times they violated their usual approach of not ac-knowledging “secret” material which had been released;

however, to what degree it lacks information, or has in-

correct information, is not known with any confidence.

The difficulty that a number of nations had in developing

the Teller–Ulam design (even when they apparently un-

derstood the design, such as with the United Kingdom),

makes it somewhat unlikely that this simple information

alone is what provides the ability to manufacture ther-

monuclear weapons. Nevertheless, the ideas put forward

by Morland in 1979 have been the basis for all the current

speculation on the Teller–Ulam design.

7 Variations

There have been a few variations of the Teller–Ulam de-

sign suggested by sources claiming to have information

from inside of the fence of classification. Whether these

are simply different   versions  of the Teller–Ulam design,

or should be understood as contradicting the above de-

scriptions, is up for interpretation.

7.1 Richard Rhodes’s “Ivy Mike” device inDark Sun

In his 1995 book  Dark Sun: The Making of the Hydro-

 gen Bomb, author Richard Rhodes describes in detail the

internal components of the "Ivy Mike"  Sausage  device,

based on information obtained from extensive interviews

with the scientists and engineers who assembled it. Ac-

cording to Rhodes, the actual mechanism for the com-

pression of the secondary was a combination of the radi-

ation pressure, foam plasma pressure, and tamper-pusher

ablation theories described above; the radiation from the

primary heated the polyethylene foam lining the casing toa plasma, which then re-radiated radiation into the sec-

ondary’s pusher, causing its surface to ablate and driving

In the W88  warhead, the primary (top) and  secondary (bottom)

have switched positions, to allow the  secondary to be larger than

in the otherwise similar W87.

it inwards, compressing the primary and causing the fu-

sion reaction; the general applicability of this principle is

unclear.[11]

7.2 W88 revelations

In 1999 a reporter for the  San Jose Mercury News   re-

ported that the U.S.   W88   nuclear warhead, a small

MIRVed warhead used on the  Trident II SLBM, had a

prolate (egg or watermelon shaped) primary (code-named

Komodo) and a spherical secondary (code-named Cursa)

inside a specially shaped radiation case (known as the

“peanut” for its shape).[45] A story four months later

in  The New York Times   by William Broad[46] reported

that in 1995, a supposed double agent from the People’s

Republic of China delivered information indicating that

China knew these details about the W88 warhead, sup-posedly through espionage.[47] (This line of investigation

eventually resulted in the abortive trial of Wen Ho Lee.)

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13

In the W87  warhead, the heavier  secondary (top) is placed for-

ward of the lighter  primary   (bottom) to promote aerodynamic 

stability during reentry.

If these stories are true, it would explain the reported

higher yield of the W88, 475 kilotons, compared with

only 300 kilotons for the earlier W87 warhead.

The   reentry cones   for the two warheads are the samesize, 1.75 meters (69 in) long, with a maximum diam-

eter of 55 cm. (22 in).[48] The higher yield of the W88

implies a larger secondary, which produces most of the

yield. Putting the secondary, which is heavier than the

primary, in the wider part of the cone allows it to be

larger, but it also moves thecenter of mass aft, potentially

causing aerodynamic stability problems during reentry.

Dead-weight ballast must be added to the nose to move

the center of mass forward.

To make the primary small enough to fit into the nar-

row part of the cone, its bulky  insensitive high explo-

sive charges must be replaced with more compact “non-insensitive” high explosives which are more hazardous to

handle. The higher yield of theW88, which is thelast new

warhead produced by the United States, thus comes at a

price of higher warhead weight and higher workplace haz-

ard. The W88 also contains tritium, which has a half life

of only 12.32 years and must be repeatedly replaced.[49]

8 See also

•   Pure fusion weapon

9 References

[1] The misleading term “hydrogen bomb” was already in

wide public use before fission product fallout from the

Castle Bravo test in 1954 revealed the extent to which the

design relies on fission.

[2] From National Public Radio Talk of the Nation, Novem-

ber 8, 2005, Siegfried Hecker of Los Alamos, “the hydro-

gen bomb – that is, a two-stage thermonuclear device, as

we referred to it – is indeed the principal part of the U.S.

arsenal, as it is of the Russian arsenal.”

[3] Teller, Edward; Ulam, Stanislaw (March 9, 1951).   “On

Heterocatalytic Detonations I. Hydrodynamic Lenses and

Radiation Mirrors”  (PDF). LAMS-1225. Los Alamos

Scientific Laboratory. Retrieved September 26, 2014. on

the Nuclear Non-Proliferation Institute  website. This is

the original classified paper by Teller and Ulam propos-

ing staged implosion. This declassified version is heavily

redacted, leaving only a few paragraphs.

[4] Carey Sublette (July 3, 2007).  “Nuclear Weapons FAQ

Section 4.4.1.4 The Teller–Ulam Design”.   Nuclear 

Weapons FAQ . Retrieved 17 July 2011. “So far as is

known all high yield nuclear weapons today (>50 kt or so)

use this design.”

[5] Broad, William J. (23 March 2015).   “Hydrogen Bomb

Physicist’s Book Runs Afoul of Energy Department”.

New York Times . Retrieved 20 November 2015.

[6] Greene, Jes (25 March 2015).   “A physicist might be in

trouble for what he revealed in his new book about the H

bomb”.  Business Insider . Retrieved 20 November 2015.

[7]   “Complete List of All U.S. Nuclear Weapons”. 1 October

1997. Retrieved 2006-03-13.

[8] Hansen, Chuck (1988).  U.S. nuclear weapons: The secret 

history. Arlington, TX: Aerofax. ISBN 0-517-56740-7.

[9]   Hansen, Chuck   (2007).   Swords of Armageddon: U.S.

Nuclear Weapons Development Since 1945  (PDF) (CD-

ROM & download available) (2 ed.). Sunnyvale, Califor-

nia: Chukelea Publications.   ISBN 978-0-9791915-0-3.

2,600 pages.

[10]  “Figure 5 – Thermonuclear Warhead Components”. Re-

trieved 27 August 2010. A cleaned up version:   “BritishH-bomb posted on the Internet by Greenpeace”. Federa-

tion of American Scientists. Retrieved 27 August 2010.

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[11] Rhodes, Richard (1995).   Dark Sun: The Making of the

Hydrogen Bomb. New York:  Simon & Schuster.   ISBN

0-684-80400-X.

[12]   http://nuclearweaponarchive.org/Usa/Weapons/

W76NeutronTube1200c20.jpg

[13]   “Improved Security, Safety & Manufacturability of the

Reliable Replacement Warhead”, NNSA March 2007.

[14]   A 1976 drawing which depicts an interstage that absorbs

and re-radiates X-rays. From Howard Morland, “The Ar-

ticle”, Cardozo Law Review, March 2005, p 1374.

[15]   [Fogbank] Speculation on Fogbank, Arms Control Wonk 

[16]   “Nuclear Weapons Frequently Asked Questions 4.4.3.3

The Ablation Process”. 2.04. 20 February 1999. Re-

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[17]   “Nuclear Weapons Frequently Asked Questions 4.4.4 Im-

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[18]   “The B-41 (Mk-41) Bomb – High yield strategic ther-

monuclear bomb”. 21 October 1997. Retrieved 2006-

03-13.

[19] Winterberg, Friedwardt (2010).   The Release of Ther-

monuclear Energy by Inertial Confinement: Ways To-

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9814295914.

[20] Croddy, Eric A.; Wirtz, James J.; Larsen, Jeffrey, Eds.

(2005).   Weapons of Mass Destruction: An Encyclope-

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[21]  The “George” shot, Comprehensive Test Ban Treaty Or-

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[22]   “Photograph of a W47 warhead” (JPG). Retrieved 2006-

03-13.

[23] Holloway, David (1994). Stalin and the bomb: The Soviet 

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[24]   https://www.ctbto.org/specials/testing-times/

17-june-1967-chinas-first-thermonuclear-test

[25]   “Forces gung-ho on N-arsenal”. Times of India. Re-

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[26] Khan, Kamran (30 May 1998).   “Tit-for-Tat: Pakistan

tested 6 nuclear devices in response to Indian’s tests.”.  The

News International . Retrieved 10 August 2011. “None

of these explosions were thermonuclear, we are doing re-

search and can do a fusion test if asked, said by   Abdul

Qadeer Khan. “These boosted devices are like a half way

stage towards a thermonuclear bomb. They use elements

of the thermonuclear process, and are effectively stronger

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[27] PTI, Press Trust of India (September 25, 2009).   “AECex-chief backs Santhanam on Pokhran-II”.   The Hindu,

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[28] Carey Sublette, et. al. “What are the real yield of India’s

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[29]   “Former NSA disagrees with scientist, says Pokhran II

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[30]   India tested H-bomb, says New Scientist

[31]   "?". Rediff.com. Retrieved 27 August 2010.

[32] Arms Control Today May 1998, pp. 7–13; Terry C. Wal-

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[33] Samdani, Zafar (25 March 2000).   “India, Pakistan can

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[34]   Hersh 1991, p. 271.

[35] Cohen, Avner (October 15, 1999). “The Battle over the

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[36] Karpin, Michael (2005).  The Bomb in the Basement . New

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[37] Gábor Palló (2000). “The Hungarian Phenomenon in Is-

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[38] Kim Kyu-won (February 7, 2013). “North Koreacould bedeveloping a hydrogen bomb”. The Hankyoreh. Retrieved

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[39] Kang Seung-woo, Chung Min-uck (February 4, 2013).

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[40] emphasis in original

[41]   Restricted Data Declassification Decisions, 1946 to the

 present, Volume 7 . United States Department of Energy.

January 2001.

[42] Morland, Howard (1981).  The secret that exploded . New

York: Random House. ISBN 0-394-51297-9.

[43]   “The H-Bomb Secret: How we got it and why we’re telling

it”.  The Progressive 43  (11). November 1979.

[44] Alexander De Volpi, Jerry Marsh, Ted Postol, and George

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ISBN 0-08-025995-2.

[45] Dan Stober and Ian Hoffman (2001).   A convenient spy: 

Wen Ho Lee and the politics of nuclear espionage . New

York: Simon & Schuster.  ISBN 0-7432-2378-0.

[46]   “Spies versus sweat, the debate over China’s nuclear ad-vance”.   The New York Times . 7 September 1999. Re-

trieved 2011-04-18.

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15

[47] Christopher Cox, chairman (1999).  Report of the United 

States House of Representatives Select Committee on U.S.

National Security and Military/Commercial Concerns with

the People’s Republic of China., esp. Ch. 2, “PRC Theft

of U.S. Thermonuclear Warhead Design Information”.

[48]   “The W88 Warhead – Intermediate yield strategic SLBM

MIRV warhead”. 1 October 1997. Retrieved 2006-03-

13.

[49] Morland, Howard (February 2003). The holocaust bomb: 

A question of time.

9.1 Bibliography

Basic principles

•   “Engineering and Design of Nuclear Weapons” from

Carey Sublette’s Nuclear Weapons FAQ.

•   Hansen, Chuck,  U.S. nuclear weapons: The secret 

history   (Arlington, TX: Aerofax, 1988).   ISBN 0-

517-56740-7

•   Hansen, Chuck (2007).   Swords of Armaged-

don: U.S. Nuclear Weapons Development Since

1945   (PDF) (CD-ROM & download available) (2

ed.). Sunnyvale, California: Chukelea Publications.

ISBN 978-0-9791915-0-3. 2,600 pages.

•   Dalton E. G. Barroso,   The physics of nuclear ex-

 plosives , in Portuguese. (São Paulo, Brazil: Editora

Livraria da Física, 2009).  ISBN 978-85-7861-016-6

History

•   DeGroot, Gerard, “The Bomb: A History of Hell

on Earth”, London: Pimlico, 2005.  ISBN 0-7126-

7748-8

•   Peter Galison and Barton Bernstein, “In any light:

Scientists and the decision to build the Superbomb,

1942–1954”  Historical Studies in the Physical and 

Biological Sciences   Vol. 19, No. 2 (1989): 267–

347.

•  German A. Goncharov, “American and Soviet H-

bomb development programmes: historical back-

ground” (trans. A.V. Malyavkin), Physics—Uspekhi 

Vol. 39, No. 10 (1996): 1033–1044.  Available on-

line (PDF)

•   David Holloway,  Stalin and the bomb: The Soviet 

Union and atomic energy, 1939–1956  (New Haven,

CT: Yale University Press, 1994).   ISBN 0-300-

06056-4

•   Richard Rhodes,   Dark sun: The making of thehydrogen bomb   (New York: Simon and Schuster,

1995). ISBN 0-684-80400-X

•  S.S. Schweber,   In the shadow of the bomb: Bethe,

Oppenheimer, and the moral responsibility of the sci-

entist   (Princeton, N.J.: Princeton University Press,

2000). ISBN 0-691-04989-0

•   Gary Stix, “Infamy and honor at the Atomic Café:

Edward Teller has no regrets about his contentiouscareer”, Scientific American (October 1999): 42–43.

Analyzing fallout

•  Lars-Erik De Geer, “The radioactive signature of

the hydrogen bomb”   Science and Global Security

Vol. 2 (1991): 351–363.  Available online (PDF)

•   Yulii Borisovich Khariton  and Yuri Smirnov,   The

Khariton version   Bulletin of the Atomic Scientists 

Vol. 49, No. 4 (May 1993): 20–31.

10 External links

Principles

•   “Hydrogen bomb / Fusion weapons” at GlobalSecu-

rity.org (see also links on right)

•   “Basic Principles of Staged Radiation Implosion

(Teller–Ulam)"   from Carey Sublette’s Nuclear-

WeaponArchive.org.

•   “Matter, Energy, and Radiation Hydrodynamics”

from Carey Sublette’s Nuclear Weapons FAQ.

•   “Engineering and Designof NuclearWeapons” from

Carey Sublette’s Nuclear Weapons FAQ.

•   “Elements of Thermonuclear Weapon Design” from

Carey Sublette’s Nuclear Weapons FAQ.

•   Annotated bibliography for nuclear weapons design

from the Alsos Digital Library for Nuclear Issues

History

•   PBS: Race for the Superbomb: Interviews and Tran-scripts (with U.S. and USSR bomb designers as well

as historians).

•   Howard Morland on how he discovered the “H-

bomb secret” (includes many slides).

•   The Progressive   November 1979 issue   – “The H-

Bomb Secret: How we got it, why we're telling” (en-

tire issue online).

•   Annotated bibliography on the hydrogen bomb from

the Alsos Digital Library

•   University of Southampton, Mountbatten Centre forInternational Studies, Nuclear History Working Pa-

per No5.

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16   10 EXTERNAL LINKS 

•  Peter Kuran’s “Trinity and Beyond” – documentary

film on the history of nuclear weapon testing.

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11 Text and image sources, contributors, and licenses

11.1 Text

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Bryan Derksen, Tedernst, Patrick, Michael Hardy, Ixfd64, GTBacchus, Ahoerstemeier, William M. Connolley, Julesd, Palfrey, Evercat,

Schneelocke, Andrewman327, Katana0182, LMB, Finlay McWalter, Auric, Carnildo, Fastfission, Dratman, Leonard G., Nomad~enwiki,

Malyctenar, Prosfilaes, Brockert, Matt Crypto, Btphelps, Gadfium, Xmnemonic, ConradPino, Beland, Oneiros, Thincat, Nickptar, Klemen

Kocjancic, Ehamberg, Trevor MacInnis, Vivacissamamente, Discospinster, Rich Farmbrough, ArnoldReinhold, Jnestorius, CheekyMon-

key, Ylee, El C, AreJay, Sietse Snel, Shenme, Scott Ritchie, Aquillion, Kjkolb, PiccoloNamek, Pharos, Eddideigel, Alansohn, Arthena,

Ronline, Andrew Gray, Jaardon, Snowolf, RJFJR, DV8 2XL, Gene Nygaard, Djsasso, Ashujo, Crosbiesmith, LOL, Before My Ken, Former

user 2, Kralizec!, Wayward, Joke137, GraemeLeggett, Deansfa, Tslocum, Magister Mathematicae, BD2412, Bunchofgrapes, Jclemens,

Rjwilmsi, Jivecat, Strait, Bruce1ee, Ligulem, Krash, Rbeas, Titoxd, Mumblingmynah, Nivix, Mark Sublette, Gurch, RobyWayne, Or-

borde, Wongm, Alphachimp, Miffy900, Chobot, Gwernol, YurikBot, JWB, RussBot, Arado, Limulus, Hellbus, Hydrargyrum, Shaddack,

ENeville, Welsh, Ino5hiro, Voidxor, Emersoni, Tony1, Ospalh, Bozoid, Lockesdonkey, Doncram, Anttin, Emesik, Georgewilliamherbert,

Petri Krohn, Jrstewart, JLaTondre, Mais oui!, Criticality, SmackBot, Roger Hui, Prodego, Elminster Aumar, WookieInHeat, Eaglizard,

Boris Barowski, Man with two legs, HalfShadow, Gilliam, Brianski, Ohnoitsjamie, Chris the speller, Master Jay, TimBentley, Rampart,

Jprg1966, Sbharris, Frap, Rrburke, Wen D House, Cybercobra, Glover, Jon Awbrey, DMacks, Ultor Solis, Neil9327, Will Beback, John,

Mgiganteus1, Arhon, Mr. Vernon, Stanley011, TJ Spyke, BranStark, Iridescent, Bockspur, Igoldste, Domitori, Tuttt, Courcelles, Neuril-

lon, Chetvorno, Flubeca, Canis Enigmas, J Milburn, J Forget, Sohebbasharat, Phreadom, Tomw91, CMG, UncleBubba, Gogo Dodo, Corpx,

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sterlopithecus, Igodard, PhilKnight, Parsecboy, Bongwarrior, VoABot II, Hullaballoo Wolfowitz, JNW, Kosmopolis, CTF83!, Roches, TheAnomebot2, Robotman1974, DerHexer, Warren Dew, Cdecoro, S3000, MartinBot, Paracel63, TheEgyptian, CommonsDelinker, Nono64,

Cian584, J.delanoy, JamesR, Maurice Carbonaro, Wikip rhyre, Algotr, Ignatzmice, Ryan Postlethwaite, Ash sul, Robertmclean2, Bobian-

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Utvik old, Nirvana888, AnomieBOT, Kingpin13, Citation bot, Kalamkaar, Frankenpuppy, LilHelpa, TomB123, Sionus, Capricorn42,

Armbrust, Miesianiacal, Brylan, ProtectionTaggingBot,میرز سینی  مد

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Legobot III, God94, FrescoBot, Paine Ellsworth, WPANI, DivineAlpha, DrilBot, HRoestBot, Supreme Deliciousness, Merwat, Skiff,

Refycul, Xeworlebi, Rotblats09, Poliphile, Saintonge235, Trappist the monk, Bangbangbear, Benefactordyr, Katerenka, Mr.98, Suffu-

sion of Yellow, DARTH SIDIOUS 2, RjwilmsiBot, Bento00, Tytung, Genesiser, EmausBot, 478jjjz, Ncsr11, Omegaman99, GoingBatty,

Tommy2010, Dcirovic, K6ka, Yes sey yes127, Ida Shaw, Fæ, Josve05a, MazinX, Ask2264230, Jasuko, MajorVariola, Peterh5322, L Kens-

ington, Epicstonemason, Orange Suede Sofa, Bomazi, GermanJoe, RockMagnetist, Wackjob101, Whoop whoop pull up, Miguel.baillon,Petrb, Xanchester, Vceinc, ClueBot NG, Gareth Griffith-Jones, Stwheel1, Vance&lance, Deer*lake, DarthXavius, Tideflat, Frietjes, Car-

oleHenson, AlexB531, MerlIwBot, Helpful Pixie Bot, Strike Eagle, Wbm1058, BG19bot, MusikAnimal, 220 of Borg, Comfr, BattyBot,

Guanaco55, Dec22, Standardengineer, Childish Gaines, Morganson691, T0000000000, MSUGRA, Editfromwithout, Irondome, Hmains-

bot1, Webclient101, Aymankamelwiki, Cerabot~enwiki, Lugia2453, I am One of Many, Abishai 300, Debouch, Wistchars, Zenibus,

Slgonzalez, JaconaFrere, TheGuyWhoIsOnTheStreet, Monkbot, Volker Siegel, Vozul, BethNaught, Jamesnottingham, Wikiornah, WC

Jay, Jaffacakemonster53, Ericwilloughby, RealFAKER, I know everything man!, Endaine and Anonymous: 444

11.2 Images

•   File:Ambox_important.svg  Source:  https://upload.wikimedia.org/wikipedia/commons/b/b4/Ambox_important.svg  License:  Public do-

main  Contributors:  Own work, based off of Image:Ambox scales.svg Original artist:  Dsmurat (talk ·  contribs)

•  File:BombH_explosion.svg   Source:    https://upload.wikimedia.org/wikipedia/commons/d/df/BombH_explosion.svg  License:    CC-BY-

SA-3.0  Contributors:  ?  Original artist:  ?

•   File:Commons-logo.svg Source:  https://upload.wikimedia.org/wikipedia/en/4/4a/Commons-logo.svg License:  ?   Contributors:  ?  Original artist:  ?

• File:Edward_Teller_&_Stanislaw_Ulam_1951_On_Heterocatalytic_Detonations_-_Secret_of_hydrogen_bomb_-_p_1.png

Source:    https://upload.wikimedia.org/wikipedia/commons/4/40/Edward_Teller_%26_Stanislaw_Ulam_1951_On_Heterocatalytic_

Detonations_-_Secret_of_hydrogen_bomb_-_p_1.png   License:    Public domain   Contributors:    Retrieved October 6, 2014 from <a

data-x-rel='nofollow' class='external text' href='http://www.nuclearnonproliferation.org/LAMS1225.pdf'>Edward Teller, Stanislaw Ulam,

On Heterocatalytic Detonations I: Hydrodynamic Lenses and Radiation Mirrors , Report LAMS-1225, Los Alamos Scientific Laboratory,

March 9, 1951, declassified version, p. 1</a> on Nuclear Nonproliferation Institute website Original artist:  Edward Teller and Stanislaw

M. Ulam

• File:Edward_Teller_&_Stanislaw_Ulam_1951_On_Heterocatalytic_Detonations_-_Secret_of_hydrogen_bomb_-_p_3.png

Source:    https://upload.wikimedia.org/wikipedia/commons/3/30/Edward_Teller_%26_Stanislaw_Ulam_1951_On_Heterocatalytic_

Detonations_-_Secret_of_hydrogen_bomb_-_p_3.png   License:    Public domain   Contributors:    Retrieved October 6, 2014 from <a

data-x-rel='nofollow' class='external text' href='http://www.nuclearnonproliferation.org/LAMS1225.pdf'>Edward Teller, Stanislaw Ulam,

On Heterocatalytic Detonations I: Hydrodynamic Lenses and Radiation Mirrors , Report LAMS-1225, Los Alamos Scientific Laboratory,

March 9, 1951, declassified version, p. 3</a> on Nuclear Nonproliferation Institute website Original artist:  Edward Teller and Stanislaw

M. Ulam

•  File:Edward_Teller_(1958)-LLNL.jpg   Source:    https://upload.wikimedia.org/wikipedia/commons/c/cf/Edward_Teller_%281958%

29-LLNL.jpg  License:  Public domain  Contributors:  ?  Original artist:  ?

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