The Weapon and Science II

Portable nuclear munitions

Caption: Special Atomic Demolition Munition (SADM), a Navy and Marine Corps project that was demonstrated as feasible in the mid-to-late 1960s. The package shown was intended to be used by UDT/Seal Special Forces, delivered into water by parachute along with a two man team, then floated to the target, set in place and armed by hand. Designed to attack a harbor or other strategic location that could be accessed from the sea.


The answer to the existence question is certainly yes, at least for “trunk size” devices. Unclassified sources have reported that small nuclear devices were developed by both the United States and the Soviet Union during the Cold War, a direct result of the work on tactical nuclear weapons. [..]

The U.S. developed a class of devices called “Atomic Demolition Munitions” (ADM), intended for use as atomic land mines. ADMs were in the U.S. inventory from the late 1950’s until such weapons were phased out by arms-control agreements in the 1980’s. A version of the ADM for use by Special Forces, the “Special Atomic Demolition Munitions” (SADM), was suitcase or duffle bag size, weighing less than 100 pounds [..] The top photo on this page is from a declassified film showing a demonstration of the SADM in the late 1960s. [..]

The Soviet Union’s small nuclear devices were developed for nuclear mines and possibly for Spetsnaz attacks (Special Forces). In 1997, General Aleksandr Lebed claimed that the Soviet Union created one hundred and fifteen atomic demolition munitions (ADMs), low-yield, one kiloton devices that were small, portable, and without safety devices to prevent unauthorized detonation. Lebed further raised the issue of whether the ADMs were all in proper custody and accounted for. Others have contradicted Lebed — the issue is unsettled, but it is most likely that the Soviets did produce small atomic munitions, similar to the U.S. SADM.

An important point is that all nuclear devices require routine maintenance to remain viable. Small devices are no exception and, in fact, may require more frequent maintenance than larger weapons. Therefore, a diverted weapon from military stocks will become ineffective in a matter of a few years even if its control systems can be bypassed. The main danger, after the device has lost its original effectiveness, is its use as a source of weapons grade plutonium.

Caption: SADM packing case small atomic munition

Caption: H-912 transport container for Mk-54 SADM.

Text: A suitcase nuke is a tactical nuclear weapon which uses, or is portable enough that it could use, a suitcase as its delivery method. Synonyms include suitcase bomb, backpack nuke, mini-nuke, or pocket nuke. [..]

The lightest nuclear warhead ever acknowledged to have been manufactured by the U.S. is the W54, which was used in both the Davy Crockett 120 mm recoilless rifle–launched warhead, and the backpack-carried version called the Mk-54 SADM (Special Atomic Demolition Munition). The bare warhead package was an 11 in by 16 in (28 cm by 41 cm) cylinder that weighed 51 lbs (23 kg). It was, however, small enough to fit in a footlocker-sized container.

Background on Suitcase Nukes

A “suitcase” bomb is a very compact and portable nuclear weapon and could have the dimensions of 60 x 40 x 20 centimeters or 24 x 16 x 8 inches. The smallest possible bomb-like object would be a single critical mass of plutonium (or U-233) at maximum density under normal conditions. The Pu-239 weighs 10.5 kg and is 10.1 cm across. It doesn’t take much more than a single critical mass to cause significant explosions ranging from 10-20 tons. These types of weapons can also be as big as two footlockers. The warhead consists of a tube with two pieces of uranium, which, when rammed together, would cause a blast. Some sort of firing unit and a device that would need to be decoded to cause detonation may be included in the “suitcase.”

Another portable weapon is a “backpack” bomb. The Soviet nuclear backpack system was made in the 1960s for use against NATO targets in time of war and consists of three “coffee can-sized” aluminum canisters in a bag. All three must be connected to make a single unit in order to explode. The detonator is about 6 inches long. It has a 3-to-5 kiloton yield, depending on the efficiency of the explosion. It’s kept powered during storage by a battery line connected to the canisters. Source: – Department of Homeland Security


050715suitcase.nuke (Dept of Homeland Security)

Too Few Labs To Test ‘Dirty Bomb’ Fallout

Report Finds U.S. Lagging In Resources To Test For Radiation Exposure

AP) The U.S. has a shortage of laboratories to test the thousands of people who might be exposed to radiation if a “dirty bomb” detonated in a major city, according to a recent congressional investigation.

The federal government established 15 disaster scenarios for federal, state and local officials to plan for, including one in which a dirty bomb goes off in a major downtown area and potentially exposes 100,000 people to radioactive materials.

A dirty bomb would contain some radioactive material that could cause contamination over a limited area but not create actual nuclear explosions.

Should this happen in real life, America would not be able to quickly conduct tests for these people, because there are few labs capable of doing so in the country; and the tests available only address six of the 13 radiological isotopes that would likely be used in a dirty bomb, according to the report prepared for the House Committee on Science and Technology. Instead, it would take four years to complete all these tests, according to the report to be released Thursday. [..] – Copyright AP WASHINGTON, Oct. 25, 2007

Caption: A congressional report found it would take four years to test the thousands of people who might be exposed to radiation of a dirty bomb detonated in a major downtown area. (CBS/AP)

Video: Declassified US Nuclear Test Film #31

VIDEO URL: Title: Declassified U.S. Nuclear Test Film _31 Dailymotion | Youtube | ArchiveOrg

“SADM Delivery by Parachutist/Swimmer (Special Atomic Demolition Munition) – The Special Atomic Demolition Munition (SADM) was a Navy and Marines project that was demonstrated as feasible in the mid-to-late 1960s, but was never used. The project, which involved a small nuclear weapon, was designed to allow one individual to parachute from any type of aircraft carrying the weapon package that would be placed in a harbor or other strategic location that could be accessed from the sea. Another parachutist without a weapon package would follow the first parachutist to provide support as needed.

The two-man team would place the weapon package in an acceptable location, set the timer, and swim out into the ocean where they would be retrieved by a submarine or other high-speed water craft. The parachute jumps and the retrieval procedures were practiced extensively.

The video shows a man in a wet suit donning his parachute, the weapon package, and a reserve parachute. After he jumps from the aircraft and is nearing the water, he drops the weapon package down on a 17-foot line to lessen the impact of his landing. He then floats the weapon package to the desired location.”

A still from that film:

VIDEO: American SADM

Dailymotion: American SADM. American Special Atomic Delivery Munitions. A shorter film (28 sec)

A still from that film:

Nuclear bunker buster – mini-nukes


The RNEP would be used on targets that may be immune to conventional weapons. Its backers claim it would create little contamination above ground, but critics say that it would produce huge amounts of nuclear fallout. The RNEP may also remove the distinction between a nuclear deterrent and conventional weapons, increasing the risk of a nuclear exchange.

US law prevents development of new “mini-nukes” that have an explosive yield of less than 5 kilotons. But the RNEP falls outside this ban because it is not a new weapon.

Rather, it will be a modification of an existing nuclear bomb, probably a highly modified B61, sources say, a weapon whose explosive yield can be set from anything between 0.3 and 340 kilotons. The bomb uses fission at low yields but is a fusion (hydrogen) bomb at high yields. The Hiroshima fission bomb had a yield of 12 kilotons.

Underground explosions are 10 to 15 times as effective against buried facilities as airbursts. A conventional bunker-buster is dropped from high altitude and hits the ground at enormous speed. It penetrates earth, rock and concrete before exploding. A nuclear version has the advantage of a far more powerful shock wave, increasing the depth of its destructive effect.

The US already has around fifty ‘penetrating’ nuclear weapons in its stockpile, but these can only reach a depth of six metres in earth. David Wright, a nuclear-weapons expert at the Union of Concerned Scientists in Washington DC, says this would not be nearly enough to contain the radioactivity.

“Even for a 0.3-kiloton explosion, you would need a burial depth of about 70 metres in dry soil and about 40 metres in dry, hard rock to contain the blast,” Wright says. An explosion at the maximum depth achievable so far would throw thousands of tonnes of highly radioactive debris into the air.

Nuclear bunker buster

Fig. 2 The Pentagon has a growing collection of high precision conventional weapons capable of defeating hardened targets. In this sled-driven test, the GBU-28 laser guided bomb with its improved BLU-113 warhead penetrates several meters of reinforced concrete.

Underground detonations limit collateral damage

Fig. 1 Diagrams like this one give the false impression that a low-yield earth penetrating nuclear weapon would “limit collateral damage” and therefore be relatively safe to use. In fact, because of the large amount of radioactive dirt thrown out in the explosion, the hypothetical 5-kiloton weapon discussed in the accompanying article would produce a large area of lethal fallout. (Philadelphia Inquirer/ Cynthia Greer, 16 October 2000.)

The B61-11 Nuclear Bomb

[M]ini-nuke advocates — mostly coming from the nuclear weapons labs — argue that low-yield nuclear weapons should be designed to destroy even deeper targets.

The US introduced an earth-penetrating nuclear weapon in 1997, the B61-11, by putting the nuclear explosive from an earlier bomb design into a hardened steel casing with a new nose cone to provide ground penetration capability. The deployment was controversial because of official US policy not to develop new nuclear weapons. The DOE and the weapons labs have consistently argued, however, that the B61-11 is merely a “modification” of an older delivery system, because it used an existing “physics package.”

The earth-penetrating capability of the B61-11 is fairly limited, however. Tests show it penetrates only 20 feet or so into dry earth when dropped from an altitude of 40,000 feet. Even so, by burying itself into the ground before detonation, a much higher proportion of the explosion energy is transferred to ground shock compared to a surface bursts. Any attempt to use it in an urban environment, however, would result in massive civilian casualties. Even at the low end of its 0.3-300 kiloton yield range, the nuclear blast will simply blow out a huge crater of radioactive material, creating a lethal gamma-radiation field over a large area.

Bunker buster in action

VIDEO: “CNN_bunkerbuster” Dailymotion (URL)

COMMENT: Notice that the blast is from a below ground explosion, similar to the WTC ones which were buried in the basement and were encased (in concrete and steel).

The fact that the explosions occur underground in the case of the bunker buster means that the effects of the nuclear explosion are all reduced (blast, thermal and radiation effects).

Bunker buster video

VIDEO Dailymotion: Nuclear bunker buster. From Federation of American Scientists. (“Nbbd_hi”)

Images from the video:

Robust Nuclear Earth Penetrator

VIDEO: “RNEPFallout” Dailymotion | Youtube

“This animation depicts a proposed weapon with a one megaton yield. The funding for this weapon was cut in 2005 defense appropriations. However, the United States still has a B61-11 nuclear ‘bunker buster’ in its arsenal which has a 400 kiloton yield, which could still cause hundreds of thousands of deaths and spread radiation to other countries.”

“The Bush Administration has again requested funding from Congress to research a new type of nuclear bomb. The Robust Nuclear Earth Penetrator (RNEP) is a nuclear weapon that would burrow a few meters into rock or concrete before exploding and thus generating a powerful underground shock wave. Its hypothetical targets are deeply buried command bunkers or underground storage sites containing chemical or biological agents.”

Fusion reaction – animation

Dailymotion: Nuclear fusion

“Nuclear fusion is the joining (or fusing) of the nuclei of two atoms to form a single heavier atom. At extremely high temperatures – in the range of tens of millions of degrees – the nuclei of isotopes of hydrogen (and some other light elements) can readily combine to form heavier elements and in the process release considerable energy.

For fusion to occur, the electrostatic repulsion between the atoms must be overcome. Creating these conditions is one of the major problems in triggering a fusion reaction.”

Animation: Fission reaction

Dailymotion: Fission reaction (“Fission”)

“In nuclear fission, a heavy atomic nucleus, such as that of uranium or plutonium, will break up into two lighter nuclei. In the fission process, a large quantity of energy is released, radioactive products are formed, and several neutrons are emitted.

The released neutrons can also induce fission in a nearby nucleus of fissionable material and release more neutrons that can repeat the sequence, causing a chain reaction.”


Animation: 3-D model of Fat Man

Dailymotion: Fat Man was used in the bombing of Nagasaki (“Fatman_vr”)

“The initial design for the plutonium bomb was also based on using a simple gun design (known as the “Thin Man”) like the uranium bomb. As the plutonium was produced in the nuclear reactors at Hanford, Washington, it was discovered that the plutonium was not as pure as the initial samples from Lawrence’s Radiation Laboratory. The plutonium contained amounts of plutonium 240, an isotope with a rapid spontaneous fission rate. This necessitated that a different type of bomb be designed. A gun-type bomb would not be fast enough to work. Before the bomb could be assembled, a few stray neutrons would have been emitted from the spontaneous fissions, and these would start a premature chain reaction, leading to a great reduction in the energy released.

Seth Neddermeyer, a scientist at Los Alamos, developed the idea of using explosive charges to compress a sphere of plutonium very rapidly to a density sufficient to make it go critical and produce a nuclear explosion.”

Animation: 3-D model of Little Boy

Dailymotion: Little Boy the bomb that was used in the bombing of Hiroshima (“Littleboy_vr”)

“In essence, the Little Boy design consisted of a gun that fired one mass of uranium 235 at another mass of uranium 235, thus creating a supercritical mass. A crucial requirement was that the pieces be brought together in a time shorter than the time between spontaneous fissions. Once the two pieces of uranium are brought together, the initiator introduces a burst of neutrons and the chain reaction begins, continuing until the energy released becomes so great that the bomb simply blows itself apart.”

Image from the video

The only secret about nuclear weapons is that there is no secret

When journalist Howard Morland wrote an article explaining how an “H-Bomb” is made, the US Government took him to court. The plates were seized to prevent publication, because US officials claimed American security would be jeopardized if classified details on such an explosive topic were revealed. But Morland won his case without even going to the Supreme Court by showing that all the vital information was available in the Encyclopedia Americana — in an item written by Dr. Edward Teller, the “Father of the H-Bomb”. This picture, taken on the steps of the Supreme Court, shows Morland holding a cut-away model of an H-bomb, with its plutonium trigger (the small black globe at the top). Morland believes that the only secret about nuclear weapons is that there are no secrets. He thinks it is a greater threat to global security to suppose there are secrets when there aren’t, than to discuss how the bombs are actually made, because such false beliefs contribute to a false sense of security and an atmosphere of complacency.

Photo by Robert Del Tredici from his book entitled
At Work In The Fields Of The Bomb (Harper and Row, 1987)

How To Make an H-Bomb (or Thermonuclear bomb)

Howard Morland wrote a magazine article explaining how an “H-Bomb” — or “thermonuclear bomb” — is made, using only publicly available information. In the photo, he is standing on the steps of the US Supreme Court holding a cut-away model of the H-bomb.

An H-bomb is a three-stage weapon: fission, fusion, and then fission again. The first stage, called the “trigger” (the black ball at the top), is a small plutonium bomb similar to the one dropped on Nagasaki in 1945. The energy release at this stage is mainly due to nuclear fission — because the atoms of plutonium are split. Tritium is often added to the centre of the plutonium core to “boost” the fission explosion with some additional fusion energy. Boosted or not, however, the only importance of this first-stage explosion is to irradiate and heat the material in the central column to 100 million degrees celsius so that a much more powerful fusion reaction can be started there.

The second stage explosion is due to nuclear fusion in the central column. The main fusion reaction involves concentrated deuterium and tritium (both heavy isotopes of hydrogen) — which become spontaneously available when neutrons from the first stage explosion bombard a solid material called “lithium deuteride” located in the central column. When this hydrogen-rich mix is heated to 100 million degrees, the deuterium and tritium atoms “fuse” together, releasing enormous amounts of energy. This is the “H” or “thermonuclear” part of the bomb.

Then comes the third stage. The fusion reaction gives off an incredible burst of extremely powerful neutrons — so powerful that they can split or “fission” atoms of uranium-238 (called “depleted uranium”) — which is impossible at lower energy levels. This third stage more than doubles the power of the explosion, and produces most of the radioactive fallout from the weapon.

Unlike fission bombs, which rely only on nuclear fission, and which can achieve explosions equivalent to thousands of tons of TNT (“kilotons”), the power of an H-bomb or thermonuclear weapon has no practical limit — it can be made as powerful as you want, by adding more deuterium/tritium to the second stage. Most H-bombs are measured in “megatons” (equivalent to the explosive power of MILLIONS of tons of TNT — hundreds of times, or even a thousand times more powerful than a fission bomb).

American nuclear arsenal

This field full of ceramic cones represents, in miniature, the 25 000 warheads of the american nuclear arsenal. Plutonium is the principal nuclear explosive in most of these warheads. One of the greatest risks in using plutonium as a civilian nuclear fuel is the relative ease with which some of it could be stolen. Plutonium can be used — by anyone who gets their hands on it — to make nuclear weapons.

Photo by Robert Del Tredici from his book entitled At Work In The Fields Of The Bomb (Harper and Row, 1987)

Glass ball model of plutonium

This glass ball, 3.2 inches across, is the exact size of the plutonium core in the bomb that exploded over Nagasaki on August 9 1945 with a force equivalent to 22 thousand tons of TNT.

Photo by Robert Del Tredici
from his book entitled
At Work In The Fields Of The Bomb
(Harper and Row, 1987) (Canadian Coalition for Nuclear Responsibility)


This is a simple diagram illustrating an example of nuclear fission. A U-235 nucleus captures and absorbs a neutron, turning the nucleus into a U-236 atom. The U-236 atom experiences fission into Ba-141, Kr-92, three neutrons, and energy.

Fastfission, public domain


Caption: When neutrons are bombarded against uanium-235, the uranium-235 nucleus absorbs a neutron to be a uranium-236 and it splits into two fragments of almost equal masses with emitting some neutrons simultaneously and evolving a huge amount of energy larger than 200 MeV. This is nothing but one of the examples of fission of uranium-235. It does not always split into Ba and Kr but usually into two fragments with almost equal masses. The number of emitted neutrons is also not always constant but it distributes over one to several. Then the emitted energy is not always constant but is almost 200 MeV.

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The US Government’s Usage of Atomic Bombs — Domestic — WTC

By Ed Ward, MD

In 1993, Joe Vialls exposes some facts about single explosions that were very similar to the 2001 WTC bombing. [..] URL: Caption: Rare picture of damage from 6.3 tons of explosive from BLU-82

Another crater 22 feet wide and 5 feet deep is noted in the article Bali Micro Nuke – Lack of Radiation Confuses Experts. Within 48 hours the Bali government found traces of C4 explosive. Next came the revised explanation of explosives on top of gas containers. After that failed to explain noted facts, the next theory was explosives with napalm. The final explanation from London quoted a reliable source that an IRA style bomb mixture was used. Still, there were significant problems with the story as the IRA had detonated 1,000 pounds of the mixture and there was no crater produced. The US bomb, BLU-82 – used for clearing helicopter landing zones in the jungles of Vietnam – contains 6.3 tons of high grade military explosive with an aluminum additive for increased heat, but does not create a crater. The 1/4 inch steel encased explosive is parachuted to its target and detonated 1 to 2 feet above ground. Approximately 40 people close enough to be vaporized simply vanished without a trace. Insights on Israel’s .01 kt Dimona nuke are also related in this article. According to the information presented, the bomb uses highly enriched Plutonium 239, 99.78% pure, and only emits alpha radiation which is invisible to most Geiger counters.

Israel’s nuclear arsenal

Dimona nuclear reactor – Vanunu exposes

VIDEO: Dimona. Vanunu gave the a detailed account about the 60 photos he secretly took of the nuclear facility. URL:


‘Vanunu gave the “Sunday Times” a detailed description – 60 photos he secretly shot. We took that information and from that it was possible to learn about the nuclear compound. We took all 60 photos from different parts of the compound, composed it with the information Vanunu gave, processed through computerized simulation, to give a never before seen 3D tour of Israel’s nuclear facilities.

Let us watch.

Only from space can you take pictures of Israel’s top secret site. No plane is allowed within this airspace. Only one man’s testimony – Mordechai Vanunu – revealed what is going on within this row of buildings surrounded by palms, “The row of institutes” as it is referred to. This is Institute No. 1, Dimona’s symbol, the 20 meters high, nuclear reactor’s dome.
Until now only seen from afar, Vanunu took us inside, into the reactor.
A heavy water reactor built in the 50s by the French, declared capacity of 24 MW.

And this is Vanunu’s first revealed secret:

The reactor’s capacity is three – possibly even five times larger than assumed until now.

This reactor produces 40 kg of plutonium a year, enough to build 10 atom bombs.

Adjacent to the reactor is Institute No. 3. In here, the fuel rods powering the reactor are produced together with lithium 6, another ingredient of the bomb.

This is Institute No. 5, here the fuel rods are coated with aluminium.
Institute No. 6 is the power station of the compound.

The lab is in Institute No. 8 and inside is another secret Vanunu revealed:
this is where Israel produces enriched uranium. Like plutonium, it can serve as fissionable material for the bomb. The uranium is produced through gas centrifuges, just like the Iranians are now trying to produce.

By the size of the building, it appears that the amount of uranium produced here is insignificant.

Enriched uranium is also produced in Institute No. 9 using laser – an Israeli unique patent.

Institute No. 10 produces depleted uranium, an important component in the production of armor piercing shells.

Institute No. 4 handles the radioactive waste, prior to being disposed. And this long two story building, with no windows, is Dimona’s big secret – Institute No. 2.

Beneath the two innocent looking floors, hidden underground, are six additional floors.

Vanunu showed the world what no satellite could see. Here Israel set up a plutonium separationf facility, with one goal – manufacturing atomic bombs.
In the 60s, American inspectors visited the first floor. They saw the restaurant and the offices. A special wall was constructed, hiding the elevators leading to the underground levels.

Back outside, trucks bring in the processed uranium rods. Through the large doors, a crane grasps the rods and lowers them to the big workspace, 4 floors below.

The rods are dipped in nitrous acid tanks, cooked for about 30 hours, and then a system of pipes draws the water containing the uranium and plutonium.

Through a chemical process, the materials are separated and then baked in an oven, producing a small 130 gram plutonium ball, 1.7 kg a week. 4 kg and it’s a bomb. Just like this model shot by Vanunu.

The process can be viewed from level 2. A balcony was built for distinguished guests. Nicknamed Golda’s Balcony.

And that’s the control room as shot by Vanunu. Only 150 employees are authorized to enter it. Visits are limited to the prime minister, the minister of defense, and a small group of confidants. Equipped with a hidden camera, Vanunu walked about Institute No. 2 and took pictures of the different sections. Not only plutonium is produced here, at level 4, Vanunu revealed the production of tritium used in the production of thermo-nuclear bombs, which are more powerful than ordinary atom bombs.

Two other essential materials for the bomb are produced here: lithium and deuterium. All these ingredients are taken to level 5, to Unit MD2 – Metal Department 2, where they are assembled into a bomb.

One level down is a recreation room, where Vanunu shot what experts identified as a model of an Israeli thermo-nuclear bomb, 10 times more powerful than the bomb dropped on Hiroshima.

Experts that analyzed Vanunu’s testimony, determined that by the 80s, Israel had produced 100-200 atom bombs.

This ranks Israel as the 6th or even 5th nuclear power in the world.
This presentation was based solely on data delivered by Vanunu to the “Sunday Times”. ‘


Still from the video

Closeup of the Dimona nuclear plant


The Dimona Reactor Dome. (Courtesy of Mordechai Vanunu).


Mockup of a Dimona bomb. (Photo courtesy of Mordechai Vanunu)

Two Mordechai Vanunu photos.


Control room of the Machon 2 plutonium separation plant. (Photo courtesy of Mordechai Vanunu)


Revealed: the secrets of Israel’s nuclear arsenal URL: Caption: On 5 October 1986, the British newspaper The Sunday Times ran Mordechai Vanunu’s story on its front page under the headline: “Revealed: the secrets of Israel’s nuclear arsenal”

Sunday October 5, 1986: Headline: Revealed – the secrets of Israel’s nuclear arsenal/ Atomic technician Mordechai Vanunu reveals secret weapons production

THE SECRETS of a subterranean factory engaged in the manufacture of Israeli nuclear weapons have been uncovered by The Sunday Times Insight team.

Hidden beneath the Negev desert, the factory has been producing atomic warheads for the last 20 years. Now it has almost certainly begun manufacturing thermo-nuclear weapons, with yields big enough to destroy entire cities.

Information about Israel’s capacity to manufacture the bomb come from the testimony of Mordechai Vanunu, a 31-year-old Israeli who worked as a nuclear technician for nearly 10 years in Machon 2 – a top secret, underground bunker built to provide the vital components necessary for weapons production at Dimona, the Israeli nuclear research establishment.

Vanunu’s evidence has surprised nuclear weapons experts who were approached by Insight to verify its accuracy because it shows that Israel does not just have the atom bomb – which has been long suspected – but that it has become a major nuclear power.

Vanunu’s testimony and pictures, which have been scrutinised by nuclear experts on both sides of the Atlantic, show that Israel has developed the sophisticated and highly classified techniques needed to build up a formidable nuclear arsenal. They confirm that:

Israel now ranks as the world’s sixth most powerful nuclear power, afterAmerica, the Soviet Union, Britain France and China – with an arsenal far greater than than those other countries, such as India, Pakistan and South Africa, which have also been suspected of developing nuclear weapons.

It has possessed its secret weapons factory for more than two decades, hiding its plutonium extraction processes from spy satellites and independent inspections during the 1960s by burying it beneath an innocuous, little used building.

The plant is equipped with French plutonium extracting technology, which transformed Dimona from a civilian research establishment to a bomb production facility. Plutonium production rates amount to 40 kilograms a year, enough to build 10 bombs. In the past six years Israel has added further equipment to make components for thermo-nuclear devices.

The 26 megawatt reactor, also built by the French, has been expanded and is probably now operating at 150 megawatts to allow it to extract more plutonium. An ingenious cooling system disguises the output.

The nuclear scientists consulted by The Sunday Times are convinced by Vanunu’s evidence. They calculate that at least 100 and as many as 200 nuclear weapons of varying destructive power have been assembled – 10 times the previously estimated strength of Israel’s nuclear arsenal.

One of the pictures Vanunu took URL: Caption: This is a photo of a plutonium separation plant’s control room, with equipment recognizable by nuclear scientists as part of a nuclear weapons production facility. Dimona Nuclear Weapons Facility Machon 2, Negrev Desert, Israel (courtesy M. Vanunu)

Israeli nuclear ‘power’ exposed

Sunday, 16 March, 2003, 01:47 GMT by Olenka Frankiel URL: Caption: Israel has enforced Vanunu’s silence for 16 years

Mordechai Vanunu, Israel’s nuclear whistleblower, was jailed in 1986 for publishing photographs of Israel’s nuclear bomb factory at Dimona. Olenka Frenkiel reveals the extent of Israel’s nuclear gagging.

Vanunu has spent 17 years in jail, 11 of which were in a minute solitary confinement cell – and he has just had his appeal for parole denied.

He will stay in jail until 2004, when his term is expected to end.


Caption: Revelations hit the press in October 1986 Image: URL:

Sunday Times journalist Peter Hounam heard rumours in 1986 that an Israeli whistleblower was offering proof of what the world had long suspected.

Vanunu was that whistleblower.

His revelations confirmed that Israel was building advanced nuclear weapons

After the Sunday Times published this scoop, Vanunu was lured to Italy and kidnapped by Mossad agents and illegally smuggled back to Israel.

He was tried in secret and convicted of treason and spying.

Security chief exposed

In court, at his parole hearing, Avigdor Feldman, Vanunu’s lawyer, argued that his client had no more secrets and should be freed.

But the prosecutor had a new argument: the imminent war with Iraq.

After the hearing Mr Feldman told Correspondent: “The prosecutor said that if Vanunu were released, the Americans would probably leave Iraq and go after Israel and Israel’s nuclear weapons – which I found extremely ridiculous.”

The real force blocking Vanunu’s release is a man who was known only as “Y”.

In 2001, “Y” was exposed as Yehiyel Horev and it is said that the only thing he fears is publicity.

Mr Horev is the head of Israel’s most powerful intelligence service, dealing with nuclear and military secrets.

_38953133_150yehiyel_horev URL: Caption: Yehiyel Horev unmasked, here, for the first time

His accountability has only been to the many prime ministers he has watched come and go in the 16 years he has built his power base.

He has been likened to the head of the FBI, J Edgar Hoover – an autocrat out of control.

Ronen Bergman, security correspondent for one of Israel’s leading newspapers – Yediot Ahronoth – says: “Horev is a grave danger to Israeli democracy.

“He operates with no law, no real scrutiny and no monitoring by the Israeli parliament.

“Horev was afraid that veterans of the Israeli intelligence and the Israeli nuclear effort would try to maintain their footprint in the history of Israel and tell their story.

“He wanted to frighten them.”

Acting with impunity

Israel never confirms or denies claims that it has nuclear, chemical and biological weapons.

The country positions itself outside international treaties, which would make it subject to inspection.

Uzi Even

Uzi Even – Dimona should be shut down

For 40 years, most Israelis have been content with this policy – known as “nuclear ambiguity”.

But there are some in Israel who argue this policy has had its day.

They say the costs of such secrecy to Israeli democracy are too great.

Uzi Even, was a young scientist working, in the 60s, at Dimona – Israel’s nuclear reactor – as did Vanunu.

Today, Mr Even says it should be shut down.

Forty-year-old reactors tend to have accidents and he believes that Dimona, which is beyond the reach of the Israeli parliament, needs to be brought into a system of accountability and public scrutiny.

Mr Even explained: “You should have an outside watchdog.

“The secrecy more or less created an extra- territorial area in Israel where standard procedures of safety monitoring are not implemented.

“So worker safety, environmental questions and industrial safety procedures, are not covered, and there are thousands of people working there.”

Enforced silence

Nothing illustrates this better than the sensitive issue of Dimona’s cancer victims.

In an Israeli documentary in 2002, Dimona workers said accidents had been routine.

They spoke of explosions, fires and liquid and toxic gas leaks that they had to clean, often without protection.

_38958193_150reactor.jpg URL: Caption: Accidents were ‘routine’ at Dimona

The authorities denied they had worked with radioactive materials.

They have refused to compensate them or their families for their years of loyal service.

Because of the strict secrecy rules they were even unable to fight for their rights.

When Correspondent approached one of the workers, who was dying of cancer, he refused to be interviewed – but with some regret.

Unaware he was being filmed, he said: “I wanted to talk to you but I have been silenced.

“They came from intelligence and told me not to talk.

“They said I would be like Vanunu.”

Vanunu has another year in jail.

When his sentence is finished he hopes to emigrate to America.

But Mr Horev has clearly let it be known he never intends to let Vanunu leave Israel. URL: Caption: Completed Dimona complex as seen by US Corona satellite on November 11, 1968

Caption: Mordechai Vanunu’s photograph of a Negev Nuclear Research Center glove box containing nuclear materials in a model bomb assembly, one of about 60 photographs he later gave to the British press. URL:

The Third Temple’s Holy Of Holies: Israel’s Nuclear Weapons

by Warner D. Farr, LTC, U.S. Army September 1999


This paper is a history of the Israeli nuclear weapons program drawn from a review of unclassified sources. Israel began its search for nuclear weapons at the inception of the state in 1948. As payment for Israeli participation in the Suez Crisis of 1956, France provided nuclear expertise and constructed a reactor complex for Israel at Dimona capable of large-scale plutonium production and reprocessing. The United States discovered the facility by 1958 and it was a subject of continual discussions between American presidents and Israeli prime ministers. Israel used delay and deception to at first keep the United States at bay, and later used the nuclear option as a bargaining chip for a consistent American conventional arms supply. After French disengagement in the early 1960s, Israel progressed on its own, including through several covert operations, to project completion. Before the 1967 Six-Day War, they felt their nuclear facility threatened and reportedly assembled several nuclear devices. By the 1973 Yom Kippur War Israel had a number of sophisticated nuclear bombs, deployed them, and considered using them. The Arabs may have limited their war aims because of their knowledge of the Israeli nuclear weapons. Israel has most probably conducted several nuclear bomb tests. They have continued to modernize and vertically proliferate and are now one of the world’s larger nuclear powers. Using “bomb in the basement” nuclear opacity, Israel has been able to use its arsenal as a deterrent to the Arab world while not technically violating American nonproliferation requirements.

Mini-nukes and micro-nukes

According to brave activist, Howard Morland, in his article The Holocaust Bomb: a Question of Time, second generation atomic bombs got their start in 1950 and came to fruition in 1956 with Eisenhower’s announcement of a 95% clean bomb. In 1958 the Mk-41C was tested for a 9.3 Megaton yield, 4.8% of the energy was from fission with 95.2% from fusion. Less radioactive (more fusion and less fission energy) or semi-clean H-bombs were known then and were used for testing purposes only. The more powerful, mostly fission bombs were deployed for usage in a cognitive effort to produce maximum destruction on ‘enemies’ for generations and no forethought of the worldwide consequences. Among various other types of hydrogen bomb warheads, the W54 nuke was developed in 1961. The W54 was a micro-nuke that weighed 51 pounds and could be fired from a slightly modified ordinary bazooka. Different versions of the W54 ranged from .01 kt to 1 kt yield. Between the mid 1950’s and the mid 70’s both types (large yield dirty and small yield clean), of 2nd generation H-bombs were refined.

Focused nuclear explosions were envisioned in 1959 as a possible concept for propulsion of the spacecraft Orion. The mere directing of the yield was obviously known prior to 1959. Samuel Cohen has stated that a low yield neutron bomb may be tailored to direct yield and proposed the concept more than 35 years ago. An underground detonation causes shaping of the direction of yield as well.


Nine nuclear and chemical weapons sites in Israel––according to this Hezbollah video

VIDEO: Nine Israeli Nuclear And Chemical Sites مواقع المفاعلات النووية الإسرائيلية  ArchiveOrg


Medium Atomic Demolition Munitions (MADM)

Caption: scientists displaying the warhead (left) and packing container for the Medium Atomic Demolition Munition (MADM), a low-yield (1- to 15-kiloton) nuclear land mine designed to be deployed behind enemy lines and destroy tunnels, bridges, dams, and disrupt enemy troop movements. The entire unit (including warhead) weighed less than 400 pounds and was deployed from 1965 to 1986.

Another view of the MADM, showing (from left) the packing container, warhead, code-decoder unit, and firing unit.

The carrying case for the W54 Special Atomic Demolition Munition (SADM). The SADM had a yield of 0.01, or 0.02-1 kiloton and was operationally deployed between 1964 and 1988. The entire unit weighed less than 163 pounds (74 kilograms).

Images: Credit: Department of Defense (courtesy Natural Resources Defense Council) (Brookings)

BBC documentary on Vanunu – Israel’s Terror WMD Facilities

Youtube: “Vanunu told the world that Israel had developed between one hundred to two hundred atomic bombs, and had gone on to develop neutron bombs and thermonuclear weapons – enough to destroy the entire Middle East, and nobody has done anything about it since.”

“Today proliferation experts report Israel has the sixth largest nuclear arsenal with small tactical nuclear weapons, nuclear land mines as well as medium range nuclear missiles launchable from air land and sea …”

Israel and the Schiphol plane crash

Dirty and clean weapons

“Dirty” and “Clean” Weapons

Whether to make a fission-fusion weapon into a fission-fusion-fission weapon is one of the most basic design issues. A fission-fusion weapon uses an inert (or non-fissionable) tamper and will obtain most of its yield from the fusion reaction directly. A fission-fusion-fission weapon will obtain at least half of its yield (and often far more) from the fusion neutron induced fission of a fissionable tamper.

The basic advantage of a fission-fusion-fission weapon is that energy is extracted from a tamper which is otherwise deadweight as far as energy production in concerned. The tamper has to be there, so a lighter weapon for a given yield (or a more powerful weapon for the same weight) can be obtained without varying any other design factors. Since it is possible to do this at virtually no added cost or other penalty, compared to an inert material like lead, by using natural or depleted uranium or thorium there is basically no reason not to do it if the designer is simply interested in making big explosions.

Fission of course produces radioactive debris – fallout. Fallout can be reduced by using a material that does not become highly radioactive when bombarded by neutrons (like lead or tungsten). This requires a heavier and more expensive weapon to produce a given yield, but is also considerably reduces the short and long term contamination associated with that yield.

This is not to say that the weapon is “clean” in any commonsense meaning of the term. Neutrons escaping the weapon can still produce biohazardous carbon-14 through nitrogen capture in the air. The primary and spark plug may still contribute 10-20% fission, which for a multi-megaton weapon may still be a megaton or more of fission. Significant contamination may also occur from the “inert” tamper radioisotopes, and even from the unburned tritium produced in the fusion stage. Reducing these contributions to the lowest possible level is the realm of “minimum residual radiation” designs discussed further below.

During the fifties interest in both the US and USSR was given to developing basic design that had both clean and dirty variants. The basic design tried to minimize the essential fission yield by using a small fission primary, and spark plug sizes carefully chosen to meet ignition requirements for each stage, without being excessive (note that although only part of the spark plug will fission to ignite the fusion stage, the essentially complete fission of the remainder by fusion neutrons is inevitable). These weapons appear to have all been three-stage weapons to allow multi-megaton yields (even in the clean version) with a relatively small primary. The dirty version might simply replace the inert tamper of the tertiary with a fissionable one to boost yield.

The three-stage Bassoon and Bassoon Prime devices tested in Redwing Zuni (27 May 1956, 3.5 Mt, 15% fission) and Redwing Tewa (20 July 1956, 5 Mt, 87% fission) are US tests of this concept. Clearly though, the second test was not simply a copy of the first with a different tamper. The fusion yield dropped from 3 Mt to 0.65 Mt, and the device weight increased from 5500 kg to 7149 kg between the two tests. The inference can be made that the tertiary in the first used a large volume of relatively expensive (but light) Li-6D in a thin tamper, which was replaced by a heavier, cheaper tertiary using less fusion fuel, but a very thick fissionable tamper to capture as many neutrons as possible.

The 50 Mt three stage Tsar Bomba (King of Bombs) tested by the Soviet Union on 30 October 1961 was the largest and cleanest bomb ever tested, with 97% of its yield coming from fusion (fission yield approximately 1.5 Mt). Assuming a primary of 250 kt (to keep the fissile content relatively low for safety reasons), we might postulate secondary and tertiary stages of 3.5 Mt and 46 Mt respectively. This fusion stages would require 1700 kg of Li6D (at 50% fusion efficiency), and something like 250 kt of fission for reliable ignition. If the initial spark plug firings were 25% efficient, later fission would release another 750 kt – placing the total at 1.25 Mt (close enough to the claimed parameters to match within the limits of accuracy).

This was a design though for a 100-150 Mt weapon! A lead tamper was used in the tested device, which could have been replaced with U-238 for the dirty version (thankfully never tested!).

Minimum Residual Radiation (MRR or “Clean”) Designs

It has been pointed out elsewhere in this FAQ that ordinary fission-fusion- fission bombs (nominally 50% fission yield) are so dirty that they merit consideration as radiological weapons. Simply using a non-fissile tamper to reduce the fission yield to 5% or so helps considerably, but certainly does not result in an especially clean weapon by itself. If minimization of fallout and other sources of residual radiation is desired then considerably more effort needs to be put into design.

Minimum residual radiation designs are especially important for “peaceful nuclear explosions” (PNEs). If a nuclear explosive is to be useful for any civilian purpose, all sources of residual radiation must be reduced to the absolute lowest levels technologically possible. This means elimination of neutron activation of bomb components, of materials outside the bomb, and reducing the fissile content to the smallest possible level. It may also be desirable to minimize the use of relatively hazardous materials like plutonium.

The problems of minimizing fissile yield and eliminating neutron activation are the most important. Clearly any MRR, even a small one, must be primarily a fusion device. The “clean” devices tested in the fifties and early sixties were primarily high yield strategic three-stage systems. For most uses (even military ones) these weapons are not suitable. Developing smaller yields with a low fissile content requires considerable design sophistication – small light primaries so that the low yields still produce useful radiation fluxes and high-burnup secondary designs to give a good fusion output.

Minimizing neutron activation form the abundant fusion neutrons is a serious problem since many materials inside and outside the bomb can produce hazardous activation products. The best way of avoiding this is too prevent the neutrons from getting far from the secondary. This requires using an efficient clean neutron absorber, i.e. boron-10. Ideally this should be incorporated directly into the fuel or as a lining of the fuel capsule to prevent activation of the tamper. Boron shielding of the bomb case, and the primary may be useful also.

It may be feasible to eliminate the fissile spark plug of a MRR secondary by using a centrally located deuterium-tritium spark plug similar to the way ICF capsules are ignited. Fusion bombs unavoidably produce tritium as a by- product, which can be a nuisance in PNEs.

Despite efforts to minimize radiation releases, PNEs have largely been discredited as a cost-saving civilian technology. Generally speaking, MRR devices still produce excessive radiation levels by civilian standards making their use impractical.

MRRs may have military utility as a tactical weapon, since residual contamination is slight. Such weapons are more costly and have lower performance of course.

This leads to another reason why PNEs have lost their attractiveness – there is no way to make a PNE device unsuitable for weapons use. “Peaceful” use of nuclear explosives inherently provides opportunity to develop weapons technology. As the saying goes, “the only difference between a PNE and a bomb is the tail fins”. – Nuclear Weapons Frequently Asked Questions Version 2.04: 20 February 1999 COPYRIGHT CAREY SUBLETTE

Low Yield Weapons

This represents one extreme of the weapon design spectrum – nuclear devices intend to make “small” explosions. Low yield in this context generally means yields much less than the 20 kts of a nominal fission weapon – say, 1-1000 tons. These are, of course, always very large compared to any other types of weapon of remotely similar size. They are small only in comparison to the potential capabilities of nuclear weapons.

The smallest nuclear weapons actually deployed have had yields around 10 tons (like the W54), and have been intended for short range tactical or nuclear demolition use (e.g. blowing up roads and bridges).

A low yield weapon can be made simply by taking an existing weapon and reducing its efficiency in some manner – like reducing the amount of explosive to create a weak implosion. But this likely result in a low-yield the weapon with unnecessarily high mass, volume, and cost.

A weapon designer will probably want to optimize a low yield weapon toward one of two design goals: minimizing its size or minimizing its cost (basically this means minimizing the fissile content of the device). Real weapons typically try to strike a balance between the two extremes.

Minimum Size

A low yield minimum mass or volume weapon would use an efficient fissile material (plutonium or U-233), a low mass implosion system (i.e. a relatively weak one), and a thin beryllium reflector (thickness no more than the core radius). Since volume increases with the cube of the radius, a thick layer of anything (explosive or reflector) surrounding the fissile core will add much more mass than that of the core itself.

Referring to the Reflector Savings Table we can see that for beryllium thicknesses of a few centimeters, the radius of a plutonium core is reduced by 40-60% of the reflector thickness. Since the density difference between these materials is on the order of 10:1, substantial mass savings can be achieved. At some point though increasing the thickness of the reflector begins to add more mass than it saves, this marks the point of minimum total mass for the reflector/core system.

In general, minimum mass and minimum volume designs closely resemble each other. The use of a hollow core adds negligibly to the overall volume.

At the low end of this yield range (tens of tons) simply inducing the delta -> alpha phase transition in a metastable plutonium alloy may provide sufficient reactivity insertion. In this case a classical implosion system is not even necessary, a variety of mechanisms could be used to produce the weak 10-20 kilobar shock required to collapse the crystal structure.

Since the fissile core would be lightly reflected, and weakly compressed, a relatively large amount of fissile material is required: perhaps 10 kg for even a very low yield bomb. The efficiency is of course extremely poor, and the cost relatively high.

The absolute minimum possible mass for a bomb is determined by the smallest critical mass that will produce a significant yield. Since the critical mass for alpha-phase plutonium is 10.5 kg, and an additional 20-25% of mass is needed to make a significant explosion, this implies 13 kg or so. A thin beryllium reflector will reduce this, but the necessary high explosive and packaging will add mass, so the true absolute minimum probably lies in the range of 10-15 kg.

The W54 warhead used in the Davy Crockett had a minimum mass of about 23 kg, and had yields ranging from 10 tons up to 1 kt in various mods (probably achieved by varying the fissile content). The warhead was basically egg-shaped with the minor axis of 27.3 cm and a major axis of 40 cm. The W-54 probably represents a near minimum diameter for a spherical implosion device (the U.S. has conducted tests of a 25.4 cm implosion system however).

The test devices for this design fired in Hardtack Phase II (shots Hamilton and Humboldt on 15 October and 29 October 1958) weighed only 16 kg, impressively close to the minimum mass estimated above. These devices were 28 cm by 30 cm, Humboldt used PBX-9404 as the explosive. – Nuclear Weapons Frequently Asked Questions Version 2.04: 20 February 1999 COPYRIGHT CAREY SUBLETTE

Davy Crockett weapon – From Wikipedia: Davy Crockett


Caption: The Davy Crockett (shown here at the Aberdeen Proving Ground in Maryland in March 1961) was the smallest and lightest nuclear weapon ever deployed by the U.S. military. It was designed for use in Europe against Soviet troop formations.

The M-28 or M-29 Davy Crockett Weapon System(s) was a tactical nuclear recoilless gun for firing the M388 nuclear projectile that was deployed by the United States during the Cold War. Named after American soldier, congressman and folk hero Davy Crockett, it was one of the smallest nuclear weapon systems ever built. [..]

Img: URL: Caption: A Davy Crockett casing preserved in the United States Army Ordnance Museum

The M-388 round used a version of the W54 warhead, a very small sub-kiloton fission device. The Mk-54 weighed about 51 lb (23 kg), with a selectable yield equivalent to 10 or 20 tons of TNT (very close to the minimum practical size and yield for a fission warhead). The complete round weighed 76 lb (34.5 kg). It was 31 in. (78.7 cm) long with a diameter of 11 in. (28 cm) at its widest point; a subcaliber piston at the back of the shell was inserted into the launcher’s barrel for firing

The World’s Smallest Nuke

VIDEO: The World’s Smallest Nuke  Dailymotion

W54 – From Wikipedia: W54

The W54 was the smallest nuclear warhead deployed by the United States. It was a very compact implosion-type nuclear weapon design, designed for tactical use and had a very low yield for a nuclear weapon. [..]

Img: URL: Caption:The W54 nuclear warhead was used in the man-portable M-388 Davy Crockett projectile. The unusually small size of the warhead is apparent

There were four distinct models of the basic W54 design used, each with different yield, but the same basic design. These were:

  • Mk-54 (Davy Crockett) — 10 or 20 ton yield, Davy Crockett artillery warhead
  • Mk-54 (SADM) — variable yield 10 ton to 1 kiloton, Special Atomic Demolition Munition device
  • W-54 — 250 ton yield, warhead for AIM-26 Falcon air to air missile
  • W72 — 600 ton yield, rebuilt W-54 (Falcon warhead) for AGM-62 Walleye

All four variants share the same basic core: a nuclear system which is 10.75 inches diameter (270 mm), about 15.7 inches long (400 mm), and weighs around or slightly over 50 pounds (23 kg). [..]

Though small compared to most other nuclear weapons, whose yields are usually measured in the thousands of tons of TNT (kilotons), in human terms they are still extremely large. By comparison, the smallest yield version of the W54 (10 tons) is two to four times as powerful as the 1995 Oklahoma City bombing, making the 250 ton version 50 to 100 times as powerful. [..]

The W54 style warhead was known to be used on the M-388 Davy Crockett, a tactical nuclear recoilless rifle projectile that was deployed by the United States during the Cold War.

The W54 is small enough to be deployed as a SADM (Special Atomic Demolition Munition) or so called “Backpack Nuke”. It was the closest thing the U.S. is known to have to developed to a so-called “suitcase bomb”.

Img: URL: Caption: The W54 would have fit into the Special Atomic Demolition Munition (“Backpack Nuke”) casing

The W54 was tested for use in a U.S. Navy SEALs project that was demonstrated as feasible in the mid-to-late 1960s, designed to attack a harbor or other strategic location that could be accessed from the sea. The SEALs version would be delivered into water by parachute along with a two man team, then floated to the target, set in place and armed by hand.

Thermonuclear devices – Wikipedia Nuclear Weapon Design

Two-stage thermonuclear weapons are essentially a chain of fission-boosted fusion weapons [..] usually with only two stages in the chain. The second stage, called the “secondary,” is imploded by x-ray energy from the first stage, called the “primary.” This radiation implosion is much more effective than the high-explosive implosion of the primary. Consequently, the secondary can be many times more powerful than the primary, without being bigger. The secondary can be designed to maximize fusion energy release, but in most designs fusion is employed only to drive or enhance fission, as it is in the primary. More stages could be added, but the result would be a multi-megaton weapon too powerful to serve any plausible purpose. [..]

The term thermonuclear refers to the high temperatures required to initiate fusion. It ignores the equally important factor of pressure, which was considered secret at the time the term became current. [..]

Pure fission or fusion-boosted fission weapons can be made to yield hundreds of kilotons, at great expense in fissile material and tritium, but by far the most efficient way to increase nuclear weapon yield beyond ten or so kilotons is to tack on a second independent stage, called a secondary.

In the 1940s, bomb designers at Los Alamos thought the secondary would be a canister of deuterium in liquified or hydride form. [..] Mathematical simulations showed it wouldn’t work, even with large amounts of prohibitively expensive tritium added in.

The entire fusion fuel canister would need to be enveloped by fission energy, to both compress and heat it, as with the booster charge in a boosted primary. The design breakthrough came in January 1951, when Edward Teller and Stanisław Ulam invented radiation implosion. [..]

In radiation implosion, the burst of X-ray energy coming from an exploding primary is captured and contained within an opaque-walled radiation channel which surrounds the nuclear energy components of the secondary. The radiation quickly turns the plastic foam that had been filling the channel into a plasma which is mostly transparent to X-rays, and the radiation is absorbed in the outermost layers of the pusher/tamper surrounding the secondary, which ablates and applies a massive force [..] causing the fusion fuel capsule to implode much like the pit of the primary. As the secondary implodes a fissile “spark plug” at its center ignites and provides heat which enables the fusion fuel to ignite as well. The fission and fusion chain reactions exchange neutrons with each other and boost the efficiency of both reactions. The greater implosive force, enhanced efficiency of the fissile “spark plug” due to boosting via fusion neutrons, and the fusion explosion itself provides significantly greater explosive yield from the secondary despite often not being much larger than the primary.

Clean bombs – From Wikipedia: Nuclear Weapon Design

[..] In response to the public alarm over fallout, an effort was made to design a clean multi-megaton weapon, relying almost entirely on fusion. Since the energy produced by fission is essentially free, using the vital tamper as a source of extra energy, the clean bomb needed to be much larger for the same yield. For the only time, a third stage, called the tertiary, was added, using the secondary as its primary. The device was called Bassoon. It was tested as the Zuni shot of Operation Redwing, at Bikini on May 28, 1956. With all the uranium in Bassoon replaced with a substitute material such as lead, its yield was 3.5 megatons, 85% fusion and only 15% fission. The records for devices that produced the highest proportion of their yield via fusion only reactions, known in the public domain are, the Redwing Navajo test at 95% Fusion, The Hardtack Poplar test at 95.2% & the 97% Tsar bomba.

Tsar Bomba – from Wikipedia: Tsar Bomba

Tsar Bomba (Russian: Царь-бомба) is the nickname for the AN602 hydrogen bomb, the most powerful nuclear weapon ever detonated. Also known as Kuz`kina Mat` (Russian: Кузькина мать, Kuzma’s mother).

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Developed by the Soviet Union, the bomb was originally designed to have a yield of about 100 megatons of TNT (420 PJ); however, the bomb yield was reduced to 50 megatons—one quarter of the estimated yield of the 1883 eruption of Krakatoa—in order to reduce nuclear fallout. This attempt was successful, as it was one of the cleanest (relative to its yield) atomic bombs ever detonated. Only one bomb of this type was ever built and it was tested on October 30, 1961, in the Novaya Zemlya archipelago. [..]

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The tsar was a three-stage Teller–Ulam design hydrogen bomb with a yield of 50 megatons (Mt). This is equivalent to 1,400 times the combined power of the two nuclear explosives used in World War II (Little Boy (13–18 kilotons) and Fat Man (21 kilotons), the bombs that destroyed Hiroshima and Nagasaki), or 10 times the combined power of all the explosives used in WWII. A three-stage H-bomb uses a fission bomb primary to compress a thermonuclear secondary, as in most H-bombs, and then uses energy from the resulting explosion to compress a much larger additional thermonuclear stage. However, there is evidence that the Tsar Bomba had a number of third stages rather than a single very large one.

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The initial three-stage design was capable of approximately 100 Mt, but would have caused too much radioactive fallout. To limit fallout, the third stage and possibly the second stage had a lead tamper instead of a uranium-238 fusion tamper (which greatly amplifies the reaction by fissioning uranium atoms with fast neutrons from fusion reaction). This eliminated fast fission by the fusion-stage neutrons, so that approximately 97% of the total energy resulted from fusion alone (as such, it was one of the “cleanest” nuclear bombs ever created, generating a very low amount of fallout relative to its yield). There was a strong incentive for this modification since most of the fallout from a test of the bomb would fall on populated Soviet territory.

Img: URL: URL: Caption: The Tsar Bomba mushroom cloud

Tsar Bomb – The King of the bombs URL: Caption: Tsar Bomba – King of the Bombs. On October 23, 1961, Soviet pilot A. E. Durnovtsev guides his Tu-95 Bomber towards the Arctic Sea above Novaya Zemlya Island. This day will make atomic history, not as an advancement in nuclear science, but rather as a statement of intimidation by the Soviet Union to the United States in those tense days now known as The Cold War.

The bomber is carrying a secret cargo that will soon make the world take notice of Russia as a serious nuclear threat to the survial of mankind. For on this day a nuclear weapon rides into history as the largest thermonuclear bomb ever constructed and detonated named, “Tsar Bomba…King of the Bombs.”

Teller-Ulam design – from Wikipedia: Teller-Ulam design

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The Teller–Ulam design is the nuclear weapon design concept used in most of the world’s nuclear weapons. [..] It is named for its two chief contributors, Edward Teller and Stanisław Ulam, who developed it in 1951 for the United States. It was first used in multi-megaton-range thermonuclear weapons. As it is also the most efficient design concept for small nuclear weapons, today virtually all the nuclear weapons deployed by the five major nuclear-armed nations use the Teller–Ulam design.

Its essential features, which officially remained secret for nearly three decades, are: 1) separation of stages into a triggering “primary” explosive and a much more powerful “secondary” explosive, 2) compression of the secondary by X-rays coming from nuclear fission in the primary, a process called the “radiation implosion” of the secondary, and 3) heating of the secondary, after cold compression, by a second fission explosion inside the secondary.

The radiation implosion mechanism is a heat engine exploiting the temperature difference between the hot radiation channel, surrounding the secondary, and the relatively cool interior of the secondary. This temperature difference is briefly maintained by a massive heat barrier called the “pusher”. The pusher is also an implosion tamper, increasing and prolonging the compression of the secondary, and, if made of uranium, which it usually is, it undergoes fission by capturing the neutrons produced by fusion. In most Teller–Ulam weapons, fission of the pusher dominates the explosion and produces radioactive fission product fallout. [..] URL:

The basic principle of the Teller–Ulam configuration is the idea that different parts of a thermonuclear weapon can be chained together in “stages”, with the detonation of each stage providing the energy to ignite the next stage. At a bare minimum, this implies a primary section which consists of a fission bomb (a “trigger”), and a secondary section which consists of fusion fuel. Because of the staged design, it is thought that a tertiary section, again of fusion fuel, could be added as well, based on the same principle of the secondary. The energy released by the primary compresses the secondary through the concept of “radiation implosion”, at which point it is heated and undergoes nuclear fusion. [..]



A simplified summary of the above explanation would be:

1. An implosion assembly type of fission bomb is exploded. This is the primary stage. If a small amount of deuterium/tritium gas is placed inside the primary’s core, it will be compressed during the explosion and a nuclear fusion reaction will occur; the released 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 only 1.4% and 14%, respectively, because they were unboosted.

2. Energy released in the primary stage is transferred to the secondary (or fusion) stage. The exact mechanism whereby this happens is unknown. This energy compresses the fusion fuel and sparkplug; the compressed sparkplug becomes critical and undergoes a fission chain reaction, further heating the compressed fusion fuel to a high enough temperature to induce fusion, and also supplying neutrons that react with lithium to create tritium for fusion. Generally, increasing the kinetic energy of gas molecules contained in a limited volume will increase both temperature and pressure (see gas laws).

3. The fusion fuel of the secondary stage may be surrounded 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.

Actual designs of thermonuclear weapons may vary. For example, they 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 further fission from occurring. [..]

Fusion, unlike fission, is relatively “clean”—it releases energy 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 made of lead, for example, the overall explosive force is reduced by approximately half but the amount of fallout is relatively low. [..]

Tamper-pusher ablation

The tamper-pusher ablation proposed mechanism is that the primary compression mechanism for the thermonuclear 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 primary 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. uRL:

Nuclear reactions

Nuclear fission splits heavier atoms to form lighter atoms. Nuclear fusion bonds together lighter atoms to form heavier atoms. Both reactions generate roughly a million times more energy than comparable chemical reactions, making nuclear bombs a million times more powerful than non-nuclear bombs. [..]


When a free neutron hits the nucleus of a fissionable atom like uranium-235 ( 235U), the uranium splits into two smaller atoms called fission fragments, plus more neutrons. Fission can be self-sustaining because it produces more neutrons of the speed required to cause new fissions.

The uranium atom can split any one of dozens of different ways, as long as the atomic weights add up to 236 (uranium plus the extra neutron). The following equation shows one possible split, namely into strontium-95 ( 95Sr), xenon-139 (139Xe), and two neutrons (n), plus energy:

235U + n = 95Sr + 139Xe + 2n + 180MeV

The immediate energy release per atom is 180 million electron volts (MeV), i.e. 74 TJ/kg, of which 90% is kinetic energy (or motion) of the fission fragments, flying away from each other mutually repelled by the positive charge of their protons (38 for strontium, 54 for xenon). Thus their initial kinetic energy is 67 TJ/kg, hence their initial speed is 12,000 kilometers per second, but their high electric charge causes many inelastic collisions with nearby nuclei. The fragments remain trapped inside the bomb’s uranium pit until their motion is converted into x-ray heat, a process which takes about a millionth of a second (a microsecond).

This x-ray energy produces the blast and fire which are normally the purpose of a nuclear explosion.

After the fission products slow down, they remain radioactive. Being new elements with too many neutrons, they eventually become stable by means of beta decay, converting neutrons into protons by throwing off electrons and gamma rays. Each fission product nucleus decays between one and six times, average three times, producing a variety of isotopes of different elements, some stable, some highly radioactive, and others radioactive with half-lives up to 200,000 years. In reactors, the radioactive products are the nuclear waste in spent fuel. In bombs, they become radioactive fallout, both local and global.

Meanwhile, inside the exploding bomb, the free neutrons released by fission strike nearby U-235 nuclei causing them to fission in an exponentially growing chain reaction (1, 2, 4, 8, 16, etc.). Starting from one, the number of fissions can theoretically double a hundred times in a microsecond, which could consume all uranium up to hundreds of tons by the hundredth link in the chain. In practice, bombs do not contain that much uranium, and, anyway, just a few kilograms undergo fission before the uranium blows itself apart. [..]

Materials which can sustain a chain reaction are called fissile. The two fissile materials used in nuclear weapons are: U-235, also known as highly enriched uranium (HEU), oralloy (Oy) meaning Oak Ridge Alloy, or 25 (the last digits of the atomic number, which is 92 for uranium, and the atomic weight, here 235, respectively); and Pu-239, also known as plutonium, or 49 (from 94 and 239). [..]
Fusion is unlikely to be self-sustaining because it does not produce the heat and pressure necessary for more fusion. It produces neutrons which run away with the energy. In weapons, the most important fusion reaction is called the D-T reaction. Using the heat and pressure of fission, hydrogen-2, or deuterium (


D), fuses with hydrogen-3, or tritium (3T), to form helium-4 (4He) plus one neutron (n) and energy:

2D + 3T = 4He + n + 17.6 MeV

Notice that the total energy output, 17.6 MeV, is one tenth of that with fission, but the ingredients are only one-fiftieth as massive, so the energy output per unit mass is greater. However, in this fusion reaction 80% of the energy, or 14 MeV, is in the motion of the neutron which, having no electric charge and being almost as massive as the hydrogen nuclei that created it, can escape the scene without leaving its energy behind to help sustain the reaction – or to generate x-rays for blast and fire.

Img: URL:

The only practical way to capture most of the fusion energy is to trap the neutrons inside a massive bottle of heavy material such as lead, uranium, or plutonium. If the 14 MeV neutron is captured by uranium (either type: 235 or 238) or plutonium, the result is fission and the release of 180 MeV of fission energy, multiplying the energy output tenfold.

Fission is thus necessary to start fusion, helps to sustain fusion, and captures and multiplies the energy released in fusion neutrons. [..]

Tritium production

A third important nuclear reaction is the one that creates tritium, essential to the type of fusion used in weapons and, incidentally, the most expensive ingredient in any nuclear weapon. Tritium, or hydrogen-3, is made by bombarding lithium-6 ( 6Li) with a neutron (n) to produce helium-4 ( 4He) plus tritium ( 3T) and energy:

6Li + n = 4He + 3T + 5 MeV

A nuclear reactor is necessary to provide the neutrons. The industrial-scale conversion of lithium-6 to tritium is very similar to the conversion of uranium-238 into plutonium-239. [..]

However, an exploding nuclear bomb is a nuclear reactor. The above reaction can take place simultaneously throughout the secondary of a two-stage thermonuclear weapon, producing tritium in place as the device explodes.

Of the three basic types of nuclear weapon, the first, pure fission, uses the first of the three nuclear reactions above. The second, fusion-boosted fission, uses the first two. The third, two-stage thermonuclear, uses all three.

Bunker busters URL: Caption: Photo courtesy Air Force GBU-28 Bunker Buster

Description: URL: Caption: Photo courtesy Air Force F-111 & GBU-28 “Bunker Buster”


Description: URL: Caption: The finished bomb, known as the GBU-28 or the BLU-113, is 19 feet (5.8 meters) long, 14.5 inches (36.8 cm) in diameter and weighs 4,400 pounds (1,996 kg).

Img: URL: Caption:
Photos courtesy U.S. Department of Defense
An F-117 Nighthawk engages its target and drops a bunker buster during a testing mission at Hill Air Force Base, Utah. URL: Caption:
Photos courtesy U.S. Department of Defense
An F-117 Nighthawk engages its target and drops a bunker buster during a testing mission at Hill Air Force Base, Utah. URL: Caption: Photo courtesy U.S. Department of Defense
An F-15E Strike Eagle pilot and a weapons system officer inspect a GBU-28 laser-guided bomb. URL: Caption: Photo courtesy U.S. Department of Defense
Air-to-air view of GBU-28 hard target bomb on an F-15E Eagle

IMG: URL: Caption: graphic source: 28nov04

MY COMMENT: These bombs were used to penetrate the World Trade Centers. They created the necessary entry holes for the planes. The bombs were attached to the underbelly of the planes and were fired just before the planes hit the towers. There were smart fuses to time their firing for exactly the right moment so that it would look like the planes crashed into the towers and made the entry holes. These bunker buster bombs were necessary because without them, it is highly likely that the planes would have either bounced off the perimeter walls of the towers or would have only partially penetrated the towers. Likewise, the Pentagon plane also carried this bunker buster bomb. This accounts for its very neat entry into the Pentagon.

The bunker buster bombs probably contained depleted uranium. This accounts for the white flash that came from the flames and sparks of melting metal seen in pictures. This is incorrectly attributed to thermite. Depleted uranium burns in a similar way to magnesium giving off an intense white flash.

In pictures taken of the World Trade Center planes, there is a bulging in the underbelly that looks like the outline of a missile.

Just before one of the planes hits the tower, there is a bright orange fireball at its nose-end just as it is about to make contact with the tower. This is the fireball of the bunker buster exploding as it hits the perimeter wall of the tower. The missile could be fired in a very precise manner because it was equipped with a smart fuse.

Hard Target Smart Fuse (HTSF)

The Hard Target Smart Fuze enables precision bombs with penetrating warheads to detonate at a desired point inside buried or reinforced concrete targets such as underground bunkers and command centers. Detonation occurs after a sensor tells the fuse that the weapon has passed through a pre-programmed number of hard layers or voids in the target.

One of the newest weapons in the Air Force’s arsenal of hard target penetrating bombs is the AFRL Munitions Directorate-developed Advanced Unitary Penetrator (AUP), equipped with the Hard Target Smart Fuze. [..] The HTSF, designated the FMU-157/B, is an active decision-making accelerometer-based fuzing system capable of counting layers and voids (floors), as well as calculating distance traveled. When the weapon reaches the pre-determined floor it tells the bomb to explode. The HTSF is compatible with a variety of penetrating warheads.

The Hard-Target Smart Fuze [HTSF], developed at the Wright lab, is a microcontroller-based, in line fuze designed to be physically and electrically compatible with GBU-10, GBU-15, GBU-24, GBU-27, GBU-28, AGM-130, and general purpose MK-80 series weapons. The HTSF was designed for current and future penetrator weapons to define the fuze function point as either a desired distance within a desired void or a depth of burial beneath a hard layer. It operates in one of three modes: hard-layer detection, void detection, and path-length integration. It also has an adjustable backup time delay that is set in 1-msec increments with a maximum delay of 250 msec. The HTSF uses a void sensing technique to count layers within a structure to initiate fuze function, a depth of burial mode that causes the fuze to function a preset distance after it senses a hard layer, and an integral time delay backup.

Mark 83 – strategic nuclear bomb designed to be carried by aircraft


TIFF from: Img: Caption:


  • Yield: Low Kt to 1.2 Kt
  • Fusing: Retarded Airburst, and Contact Laydown.
  • Number Produced: 650
  • Weight: 2,400 lbs.
  • Dimensions: 18″ x 145″

The Mark 83 is the current high-yield strategic TN bomb. 650 were produced between June, 1983 and 1991. In 1997, all were in service.

The B61 (Mark-61) bomb URL: Caption: B61 about to be loaded

The B61, which exists in several mods, is actually a family of weapons based on a single basic weapon and physics package design. The physics package of the B61 has been adapted to yield several other warheads – the W-80, W-81 (now retired and dismantled), W-84 (now retired and in the inactive stockpile), and the W-85 (which was retired, and then readapted to yield another B61 variant). See W-80 page for pictures of the actual warhead.

Two stage radiation implosion weapon.

Light weight, intermediate yield bomb with variable yield options (“dial-a-yield” or DAY), and flexible fuzing and delivery options. Designed for high-speed external carriage and low altitude delivery. Modular weapon system design.

Contains two neutron generators (supplied by General Electric).

Spin stabilized by rocket. 24 ft. Nylon/Kevlar-29 ribbon parachute ejected by gas generator. Allows rapid deceleration from supersonic velocity (only 2 seconds required to decelerate to 35 mph). Tested at up to Mach 1.2.

The lowest yield option for the B61 (the same for all tactical mods) is 300 tons which probably represents the basic unboosted yield of the fission primary. URL:

The B61 has four major sections:

  • Nose Subassembly: contains a dual-channel radar airburst fuze and two piezoelectric crystal impact fuzes, and shock mitigating material for laydown delivery.
  • Center Warhead Subassembly: “hard case” containing the actual thermonuclear warhead, sealed and desiccated with polyurethane spacers to support warhead and provide shock isolation. Also contains thermal batteries, safeties, and firing circuits.
  • Rear Subassembly: Preflight arming controls, fuzing option switches, safe separation setting dials, and spin rockets for free fall weapon stabilization.
  • Tail Subassembly: consists of bomb fins, afterbody structure, parachute with associated deployment and release mechanisms. Complete parachute assembly weighs 115 lb. URL: Caption: B61 bomb in various stages of assembly. The nuclear component is the smaller silver cylinder behind the nose cone.

Primary consists of beryllium reflected plutonium (the derivative W80-0 contains supergrade plutonium)

  • Deuterium-tritium boosted
  • Primary also contains aluminum and uranium
  • Contains oralloy (highly enriched uranium), either in primary or as secondary tampe
  • Lithium-6 (95% enrichment) deuteride fusion fuel URL: Caption: Internal nuclear components of the B61 bomb.

The B61 (Mk-61) Bomb

Weight 695-716 lbs
Length (body) 10 ft 10.75 in (130.75 in)
Length (incl. fins) 11 ft 9.5 in (141.5 in)
Body Diameter 13.4 in
Tail Fin Span 22.5 in
Number In Service 600 (tactical), 750 (strategic)
Available Yields (Kt) 0.3 / 1.5 / 60 / 170
Type Tactical
Available Yields (Kt) 0.3 / 1.5 / 10 / 45
Type Tactical
Available Yields (Kt) 10 / ? / 340
Type Strategic
Available Yields (Kt) 0.3 / 5 / 10 / 80
Type Tactical
Available Yields (Kt) 0.3? / ? / 340
Type Tactical/Strategic

Flash of ordnance

IMG1: IMG2: URL: Caption: The small-diameter bomb is a 250-pound class munition, providing the warfighter with a four-fold increase in weapons per aircraft station. It can penetrate more than 13 feet into a target and can be accurate from up to 70 miles away.

My comment: Look at the ordnance flash. Colors seen in this flash are white, yellow and orange. These colors reflect the high temperatures of the fireballs. The materials that burn in an explosion have high temperatures at which they vaporize. The white color is the highest temperature, next yellow, then orange and lastly red. [Include temperature chart of burning materials or steel] This flash looks like the one seen when the planes crashed into the Twin Towers and the Pentagon. On these occasions, the flashes were seen just as the planes hit or were about to hit the buildings.

Fission Weapons

Fission Weapons – from Federation of American Scientists

An ordinary “atomic” bomb of the kinds used in World War II uses the process of nuclear fission to release the binding energy in certain nuclei. The energy release is rapid and, because of the large amounts of energy locked in nuclei, violent. The principal materials used for fission weapons are U-235 and Pu-239, which are termed fissile because they can be split into two roughly equal-mass fragments when struck by a neutron of even low energies. When a large enough mass of either material is assembled, a self-sustaining chain reaction results after the first fission is produced.

The minimum mass of fissile material that can sustain a nuclear chain reaction is called a critical mass and depends on the density, shape, and type of fissile material, as well as the effectiveness of any surrounding material (called a reflector or tamper) at reflecting neutrons back into the fissioning mass. Critical masses in spherical geometry for weapon-grade materials are as follows:

Uranium-235 Plutonium-239
Bare sphere: 56 kg 11 kg
Thick Tamper: 15 kg 5 kg

The critical mass of compressed fissile material decreases as the inverse square of the density achieved. Since critical mass decreases rapidly as density increases, the implosion technique can make do with substantially less nuclear material than the gun-assembly method. The “Fat Man” atomic bomb that destroyed Nagasaki in 1945 used 6.2 kilograms of plutonium and produced an explosive yield of 21-23 kilotons [a 1987 reassessment of the Japanese bombings placed the yield at 21 Kt]. Until January 1994, the Department of Energy (DOE) estimated that 8 kilograms would typically be needed to make a small nuclear weapon. Subsequently, however, DOE reduced the estimate of the amount of plutonium needed to 4 kilograms. Some US scientists believe that 1 kilogram of plutonium will suffice.

If any more material is added to a critical mass a condition of supercriticality results. The chain reaction in a supercritical mass increases rapidly in intensity until the heat generated by the nuclear reactions causes the mass to expand so greatly that the assembly is no longer critical.

Fission weapons require a system to assemble a supercritical mass from a sub-critical mass in a very short time. Two classic assembly systems have been used, gun and implosion. In the simpler gun-type device, two subcritical masses are brought together by using a mechanism similar to an artillery gun to shoot one mass (the projectile) at the other mass (the target). The Hiroshima weapon was gun-assembled and used 235 U as a fuel. Gun-assembled weapons using highly enriched uranium are considered the easiest of all nuclear devices to construct and the most foolproof.

Implosion-Device – from Federation of American Scientists

Because of the short time interval between spontaneous neutron emissions (and, therefore, the large number of background neutrons) found in plutonium because of the decay by spontaneous fission of the isotope Pu-240, Manhattan Project scientists devised the implosion method of assembly in which high explosives are arranged to form an imploding shock wave which compresses the fissile material to supercriticality.

The core of fissile material that is formed into a super-critical mass by chemical high explosives (HE) or propellants. When the high explosive is detonated, an inwardly directed implosion wave is produced. This wave compresses the sphere of fissionable material. The decrease in surface to volume ratio of this compressed mass plus its increased density is then such as to make the mass supercritical. The HE is exploded by detonators timed electronically by a fuzing system, which may use altitude sensors or other means of control.

The nuclear chain-reaction is normally started by an initiator that injects a burst of neutrons into the fissile core at an appropriate moment. The timing of the initiation of the chain reaction is important and must be carefully designed for the weapon to have a predictable yield. A neutron generator emits a burst of neutrons to initiate the chain reaction at the proper moment —- near the point of maximum compression in an implosion design or of full assembly in the gun-barrel design.

A surrounding tamper may help keep the nuclear material assembled for a longer time before it blows itself apart, thus increasing the yield. The tamper often doubles as a neutron reflector.

Implosion systems can be built using either Pu-239 or U-235 but the gun assembly only works for uranium. Implosion weapons are more difficult to build than gun weapons, but they are also more efficient, requiring less SNM and producing larger yields. Iraq attempted to build an implosion bomb using U-235. In contrast, North Korea chose to use 239 Pu produced in a nuclear reactor.

other mass (the target). The Hiroshima weapon was gun-assembled and used 235 U as a fuel. Gun-assembled weapons using highly enriched uranium are considered the easiest of all nuclear devices to construct and the most foolproof.

Fusion Weapons – From Federation of American Scientists

A more powerful but more complex weapon uses the fusion of heavy isotopes of hydrogen, deuterium, and tritium to release large numbers of neutrons when the fusile (sometimes termed “fusionable”) material is compressed by the energy released by a fission device called a primary. Fusion (or ‘‘thermonuclear’ weapons derive a significant amount of their total energy from fusion reactions. The intense temperatures and pressures generated by a fission explosion overcome the strong electrical repulsion that would otherwise keep the positively charged nuclei of the fusion fuel from reacting. The fusion part of the weapon is called a secondary.In general, the x-rays from a fission primary heat and compress material surrounding a secondary fusion stage.

It is inconvenient to carry deuterium and tritium as gases in a thermonuclear weapon, and certainly impractical to carry them as liquefied gases, which requires high pressures and cryogenic temperatures. Instead, one can make a “dry” device in which 6Li is combined with deuterium to form the compound 6Li D (lithium-6 deuteride). Neutrons from a fission “primary” device bombard the 6 Li in the compound, liberating tritium, which quickly fuses with the nearby deuterium. The a particles, being electrically charged and at high temperatures, contribute directly to forming the nuclear fireball. The neutrons can bombard additional 6Li nuclei or cause the remaining uranium and plutonium in the weapon to undergo fission. This two-stage thermonuclear weapon has explosive yields far greater than can be achieved with one point safe designs of pure fission weapons, and thermonuclear fusion stages can be ignited in sequence to deliver any desired yield. Such bombs, in theory, can be designed with arbitrarily large yields: the Soviet Union once tested a device with a yield of about 59 megatons.

In a relatively crude sense, 6 Li can be thought of as consisting of an alpha particle ( 4He) and a deuteron ( 2H) bound together. When bombarded by neutrons, 6 Li disintegrates into a triton ( 3 H) and an alpha:

6 Li + Neutron = 3 H + 3 He + Energy.

This is the key to its importance in nuclear weapons physics. The nuclear fusion reaction which ignites most readily is

2 H + 3 H = 4 He + n + 17.6 MeV,

or, phrased in other terms, deuterium plus tritium produces 4He plus a neutron plus 17.6 MeV of free energy:

D + T = 4 He + n + 17.6 MeV.

Lithium-7 also contributes to the production of tritium in a thermonuclear secondary, albeit at a lower rate than 6Li. The fusion reactions derived from tritium produced from 7 Li contributed many unexpected neutrons (and hence far more energy release than planned) to the final stage of the infamous 1953 Castle/BRAVO atmospheric test, nearly doubling its expected yield.

Underground Nuclear Weapons Testing – From FAS (illustrate with your own diagrams of WTC) – THESE ARE THE STEPS THE PERPS TOOK TO DEMOLISH THE WTC TWIN TOWERS)

The following description of a vertical drill-hole test breaks down the operation into seven individual steps:

Step1. Site Selection and Drilling.

There are two subsets of site selection as it applies to nuclear tests, namely: selection of an existing drill hole for a specific event, and selection of a new drill site from the Nuclear Test Zone for a specific event because the stockpile does not contain a suitable site. The goal of siting is to optimize the various parameters so that operational feasibility and successful containment of yields of interest to device designers can be attained at a suitably low cost.

Many factors are considered. Some of these are: (1) scheduling of field resources; (2) event schedules; (3) shock sensitivity of a given experiment and possible interactions with other experiments; (4) depth range required for a suitable device emplacement; (5) geologic structure; (6) geologic material properties; (7) depth of standing water; (8) potential drilling problems; (9) adjacent expended sites, craters, chimneys, subsurface collapses; (10) adjacent open emplacement holes or unplugged post-shot or exploratory holes; and (11) non-test program constraints such as groundwater concerns, roads, and power lines (Olsen, 1993).

When drilling is required after a test location is chosen by the sponsoring national laboratory, a drilling program outlining the requirements of the specific hole is completed. The event site is surveyed, staked, and checked for cultural and biological resources. When all environmental clearances are completed, the site is graded and leveled, and a drilling-fluid sump is constructed to contain drilling fluid and cuttings. A drill rig, usually with its own power and utilities, is moved onto the site. Water is brought in by truck, or piped in, and mixed with drilling compounds to fill the sump. The hole is then drilled using standard NTS big-hole drilling techniques. A normal hole is from 1 to 3 meters (m) (48 to 120 inches [in.]) diameter and from 213 to 762 meters (m) (600 to 2,500 feet [ft]) deep. During drilling, samples of drill cuttings are collected at 3-m (10-ft) intervals, and rock cores are taken as required. After drilling is complete,geophysical logs are run into the hole to evaluate the condition of the hole and gain a more thorough understanding of the geology. The drill site is then secured by filling the sump and installing specially designed covers over the hole.

Step 2. Event-Site Engineering and Construction.

When a hole is selected as a location for a nuclear test, the area around the hole is surveyed and staked according to the criteria set forth by the sponsoring national laboratory. The cultural and biological surveys are then rerun to determine if the status of the area has changed. The hole is also uncovered, and selected geophysical logs are refed in the hole to reconfirm its condition.

Once it is assured that the environmental clearances are complete, an area is cleared and leveled for the surface ground-zero equipment; another area close by the selected site is cleared and leveled for the recording trailer park. This is a typical earthmoving operation; native materials are used to top the pads or, if active material is unstable, decomposed granite fill is used. The on-site construction is temporary and is abandoned after the event is complete. Concrete pads are poured around the surface ground-zero to provide a stable platform for downhole operations and to provide a base for the assembly towers. Equipment is moved in to emplace the nuclear device in the hole, record the data produced, and provide radiological and seismic monitoring of the site. An extensive grounding system is used to establish baseline instrumentation grounds, which might include a pit containing salt water. The equipment to be left in position during the explosion is protected with an aluminum-foil hexcell-shaped shock-mounting material or dense foam. A circle of radiation detectors is placed back from the surface ground-zero to detect and assess any releases from the experiment. Finally, a perimeter fence is erected, and access is controlled both into and out of the event site.

Step 3. Device Delivery and Assembly.

For safety reasons, the nuclear device is delivered to the NTS unassembled. The device is assembled and inserted into a container at the Device Assembly Facility in Area 6 or in the Area 27 Assembly/Staging Facilities. The Device Assembly Facility is discussed at the end of this section. The device, now encased in the container, is delivered to the event site accompanied by armored convoy. It is then attached to the diagnostics canister in preparation for emplacement into the hole. Checks are run, and alignment is assured. Heavy security is maintained during all operations that involve the nuclear device.

Step 4. Diagnostic Assembly.

A diagnostic canister is assembled off site and transported to the test site. A typical diagnostic canister might be 2 m (8 ft) in diameter and 30 m (120 ft) long and contain all the instrumentation required to receive data at the time of the explosion (real time). The diagnostic canister might contain lead and other materials as shielding for the detectors. Upon arrival at the event site, the diagnostic canister is installed in the assembly tower to be mated with the device on site. Instrumentation cables are connected to the experiments and the recording trailer park. Slack in the cables allows the diagnostic canister to be lowered into the hole.

Step 5. Emplacement of the Experiment.

The nuclear explosive and special measurement devices are moved to the hole and lowered to the detonation position; all required diagnostic materials and instrumentation cables are also lowered into the hole at this time. Downhole operations are conducted according to a defined checklist and are monitored by independent inspectors. The whole assembly is placed on a set of fracture-safe beams that span the opening. Any auxiliary equipment is then lowered into the hole, and the area is secured. Emplacement equipment is removed from the area, and test runs are conducted on the downhole experiment.

The hole is stemmed to prevent radioactive materials from escaping during or after the experiment. Stemming materials used to backfill the hole are generally placed in alternating layers, according to the containment specification. Alternate layers of 1-centimeter (cm) (3/8–in.) pea gravel are combined with fine material to provide a barrier equal to or better than the undisturbed material. Sand, gypsum, grout, cold tar, or epoxy plugs are also placed in the hole to provide impenetrable zones. In these zones, the instrument cables are sealed to prevent a radioactive gas path to the surface. Once completed, the area is cleared of unnecessary equipment. A report is compiled for the Containment Evaluation Panel to show that the as-built condition reflects the containment design plan.

Step 6. Test Execution.

After the Containment Evaluation Panel accepts the as-built design of containment and all preliminary tests are successful, the nuclear device is ready for detonation. Security operations begin two days before the test to assure that all nonevent-related personnel are evacuated prior to the test for security and personal safety. The explosive is armed. Radiation monitors are activated, and aircraft with tracking capability circle the site in case gas and debris unexpectedly vent to the surface. Weather forecasts and fallout pattern predictions are reviewed. Then, detonation occurs.

When an underground nuclear device is detonated, the energy release almost instantaneously produces extremely high temperatures and pressure that vaporizes the nuclear device and the surrounding rock. Within a fraction of a second after detonation, a generally spherical cavity is formed at the emplacement position. As the hot gases cool, a lining of molten rock puddles at the cavity bottom.

After a period of minutes to hours, as the gases in the cavity cool, the pressure subsides and the weight of the overburden causes the cavity roof to collapse, producing a vertical, rubble-filled column known as a rubble chimney.

The rubble chimney commonly extends to the ground surface, forming a subsidence crater. Numerous subsidence craters are present at the test site. Subsidence craters generally are bowl-shaped depressions with a diameter ranging from about 60 to 600 m (200 to 2,000 ft) and a depth ranging from a few meters up to 60 m (200 ft), depending on the depth of burial and the explosive energy yield. Some deeply buried explosions of low yield form cavities that do not collapse to the surface and, consequently, do not create subsidence craters. Past underground nuclear tests in Yucca Flat and on Pahute Mesa have fractured the ground surface above the explosions, causing displacement of the surface along preexisting faults adjacent to explosion sites.

After the test is conducted, the event site remains secure until it can be assured that the event has been contained. After a suitable time, a reentry crew is dispatched to the site. Data are retrieved, and the condition of equipment is noted. After all is assured to be secure, normal NTS operations resume. The event site is roped off, outlining an exclusion zone where there is danger of potential cratering.

Step 7. Post-shot Operations.

After the temperature of the cavity has cooled, a post-shot hole is usually drilled into the point of the explosion in order to retrieve samples of the debris. These samples are highly radioactive, but provide important information on the test. The post-shot hole is as small in diameter as possible and is drilled at an angle to allow the drill rig to be positioned safely away from surface ground-zero. After drilling and sampling operations are complete, the drill rig and tools are decontaminated. Residual radiation is cleaned up at the site, and the hole is plugged back to the surface. This generally completes the event operation, and the site is turned back to the DOE.


Plutonium manufacture and Fabrication – from Nuclear Weapon Archive

All plutonium originates in nuclear reactors and is produced by the capture of extra neutrons by uranium-238 to form U-239, which then undergoes a series of decays to form Pu-239:

U-238 + n -> U-239 -> Np-239 -> Pu-239

Some of this plutonium gets consumed by fission before it is removed from the reactor, and some of it gets transmuted to heavier isotopes of plutonium by capturing more neutrons:

Pu-239 + n -> Pu-240

The isotopic composition of plutonium is affected by how long it stays in the reactor. Short exposures produce plutonium with very little Pu-240 and with very little plutonium being consumed by fission. Long exposures produce high Pu-240 concentrations, and a substantial portion of the plutonium produced is consumed by fission.

The isotopic composition matters with regard to manufacturing weapons for two reasons.

  • First (and least important) is that Pu-240 is less fissile then Pu-239, so somewhat more plutonium is needed to make up the required amount for the weapon,
  • Second (and more important) is that Pu-240 decays through spontaneous fission, producing a substantial flux of neutrons.

In the earliest years of weapon design the emission of neutrons was a problem in making a reliable efficient weapon because of the problem of predetonation. A high neutron flux makes it difficult or impossible to compress a bomb core containing several kilograms of plutonium to supercriticality before the bomb disassembled with a greatly reduced yield. The advent of composite cores containing highly enriched U-235 and plutonium (in the late 1940s) greatly reduced this difficulty though since the option of using a relatively small amount of plutonium in a mostly uranium core became available. The later development of fusion boosted weapons (in the mid 1950s) eliminated it entirely since the fusion boosting effect ensures efficient weapons, even with low initial fission yields.

Plutonium can be obtained from special purpose plutonium production reactors, or as a by-product of commercial power or research reactors. The plutonium produced by special purpose production reactors has a relatively low Pu-240 content (20% and is called “reactor grade”.

Essentially all of the plutonium currently in weapons throughout the world was produced in special purpose plutonium production reactors. Initially each of the five declared nuclear powers began producing plutonium for weapons on a large scale many years before they developed significant numbers of commercial power reactors. Special purpose reactors were required for weapons production because there was no other sources of plutonium available.

These special purpose reactors produce “weapon grade” plutonium, as opposed to grades with higher Pu-240 concentrations, for two reasons:

1. Economics: the only reason the reactor exists is to produce plutonium. Burning plutonium up in fission, or transmuting it to less fissile Pu-240 reduces output and increases cost (up to a point, this must be balanced against the cost of processing fuel with low plutonium concentrations).

2. Handling problems: although neutron emissions do not create serious problems in weapon design, it can produce problems with weapons manufacture and handling. Neutron emissions create occupational exposures to plutonium for those assembling weapons, or handling weapons already assembled. In fact weapons that are kept in close proximity to people (like the W80-0) may even require special “supergrade” low neutron emission plutonium for this reason. URL: Caption: Plutonium processing glove boxes.

The actual fabrication and processing of plutonium is done manually in glove boxes like these at Los Alamos, which means there is negligible shielding between the operator and the neutron-emitting plutonium.

The actual fabrication and processing of plutonium is done manually in glove boxes like these, which means there is negligible shielding between the operator and the neutron-emitting plutonium. If higher Pu-240 plutonium were used in weapons, then either remote control processing cells would have to be used, or the number of hours that each worker could spend at these tasks would have to be sharply reduced. Either of these would drive up the cost of weapon processing considerably. It is for this reason, as well as historical and policy reasons, that explain why reactor grade plutonium is not used in U.S. weapon. It is not due to any inherent inability to do so (contrary to some statements made by the nuclear power industry). URL: Caption: Another example of a typical plutonium processing operation.

High-Purity Plutonium Ring URL: Caption: A ring of weapons-grade 99.96% pure electrorefined plutonium, enough for one bomb core. The ring weighs 5.3 kg, is ca. 11 cm in diameter and its shape helps with criticality safety.

This ring of electrorefined plutonium metal has a purity of more than 99.96 per cent. It is typical of the rings that were prepared at Los Alamos and shipped to Rocky Flats for weapon fabrication before the latter facility was shut down, and U.S. weapon manufacture halted. The ring weighs 5.3 kilograms, enough for one bomb core, and is approximately 11 centimeters in diameter. The ring shape is important for criticality safety. There is enough plutonium in this ring to make a modern strategic nuclear weapon. URL: Caption:
Plutonium-gallium alloy ingot reclaimed from weapon pit (LLNL).

Plutonium pictures URL: Caption: Various images of plutonium metal. URL: Caption: Various images of plutonium metal. URL: Caption: Various images of plutonium metal. URL: Caption: A sample of 0.89 g of highly pure plutonium (99.99%). This sample, a standard for analysis, was
manufactured at Los Alamos, in a oxygen-free environment, and sealed under vacuum in a glass ampoule.

[image] URL: Caption:
Pu(IV) colors change with different ligands. URL: Caption: Colors of the different oxidation states of plutonium, in 1 M HClO4. URL: Caption:
A hemisphere of purified, but gallium-stabilized, delta-phase plutonium metal. URL: Caption:
Buttons of refined plutonium metal.

Uranium enrichment

Gas centrifuge process URL: Caption:
Principle of a gas centrifuge process for uranium enrichment

Process to separate isotopes in which heavy atoms are split from the lighter atoms by centrifugal forces. The separation factor depends on the mass difference of the isotopes to be separated. The process is suitable for the separation of uranium isotopes, the achievable separation factor amounts to 1.25. Uranium enrichment plants applying this process are operated in Gronau/Wesphalia (Germany) and by URENCO at Capenhurst (UK).

What’s a uranium centrifuge?

By Marshall Brain

Uran­ium is an element that is similar to iron. Like iron, you dig uranium ore out of the ground and then process it to extract the pure uranium from the ore. When you finish processing uranium ore, what you have is uranium oxide. Uranium oxide contains two types (or isotopes) of uranium: U-235 and U-238. U-235 is what you need if you want to make a bomb or fuel a nuclear power plant. But the uranium oxide from the mine is about 99 percent U-238. So you need to somehow separate the U-235 from the U-238 and increase the amount of U-235. The process of concentrating the U-235 is called enrichment, and centrifuges are a central part of the process. URL: Caption:
Photo courtesy Oak Ridge National Laboratory
Uranium centrifuge cascades

U-235 weighs slightly less than U-238. By exploiting this weight difference, you can separate the U-235 and the U-238. The first step is to react the uranium with hydrofluoric acid, an extremely powerful acid. After several steps, you create the gas uranium hexafluoride.

Now that the uranium is in a gaseous form, it is easier to work with. You can put the gas into a centrifuge and spin it up. The centrifuge creates a force thousands of times more powerful than the force of gravity. Because the U-238 atoms are slightly heavier than the U-235 atoms, they tend to move out toward the walls of the centrifuge. The U-235 atoms tend to stay more toward the center of the centrifuge.

Although it is only a slight difference in concentrations, when you extract the gas from the center of the centrifuge, it has slightly more U-235 than it did before. You place this slightly concentrated gas in another centrifuge and do the same thing. If you do this thousands of times, you can create a gas that is highly enriched in U-235. At a uranium enrichment plant, thousands of centrifuges are chained together in long cascades.

At the end of a long chain of centrifuges, you have uranium hexafluoride gas containing a high concentration of U-235 atoms.

The creation of the centrifuges is a huge technological challenge. The centrifuges must spin very quickly — in the range of 100,000 rpm. To spin this fast, the centrifuges must have:

  • very light, yet strong, rotors
  • well-balanced rotors
  • high-speed bearings, usually magnetic to reduce friction

Meeting all three of these requirements has been out of reach for most countries. The recent development of inexpensive, high-precision computer-controlled machining equipment has made things somewhat easier. This is why more countries are learning to enrich uranium in recent years.

Now you need to turn the uranium hexafluoride gas back into uranium metal. You do this by adding calcium. The calcium reacts with the fluoride to create a salt, and the pure uranium metal is left behind. With this highly concentrated U-235 metal, you can either make a nuclear bomb or power a nuclear reactor.

Uranium pictures URL: Caption: Uranium URL: Caption: Yellowcake is a concentrated mixture of uranium oxides that is further refined to extract pure uranium. URL: Caption: Cascades of gas centrifuges are used to enrich uranium ore to concentrate its fissionable isotopes. URL: Caption: Uranium in its oxidation states III, IV, V, VI

Pichblende_border.jpg URL: Caption: Uraninite, also known as Pitchblende, is the most common ore mined to extract uranium.

Israel: Plutonium Production

The Risk Report

Volume 2 Number 4 (July-August 1996)

Israel makes plutonium for atomic bombs at Dimona, a secret nuclear complex in the Negev Desert. The French-supplied reactor there has produced plutonium free from international controls since 1963. The quality of the plutonium created by the Dimona reactor is ideal for making atomic bombs.

The size of the reactor at Dimona is listed by the International Atomic Energy Agency [IAEA] as 26 megawatts (thermal). However, experts believe it is much more powerful than that. Mordechai Vanunu, an Israeli technician who worked at Dimona for eight years, reported that the reactor had been scaled up twice before he arrived at the site in 1977. The first scale-up was from 26MWt to 70MWt; the second was to some higher level.

The first scale-up was planned when Dimona was built. Israel convinced France to make the reactor’s critical components–including its cooling circuit–three times larger than needed for a facility of its nominal size, and three times larger than originally agreed upon. This modification permitted a scale-up to 70MWt without the addition of extra cooling circuits, which would have attracted outside attention. Further evidence of a scale-up came in late 1968, when Israel diverted 200 metric tons of Belgian uranium on the high seas–a quantity considerably greater than a 26-megawatt reactor would have required. Israel probably needed the additional uranium for the first scale-up, which appears to have occurred in 1970.

Vanunu also said that Dimona had been producing 40 kilograms of plutonium per year for some time before he arrived in 1977. If the reactor at Dimona was unusually efficient (i.e., producing more than 1 gram of plutonium per megawatt day) and ran for as many as 300 days per year, the 40 kilograms could have been produced with a peak power of sightly more than 100MWt. If the reactor were less efficient, and operated for fewer days per year, the peak power would have to approach 150MWt.

Plutonium extraction

To be used in weapons, plutonium must be extracted chemically from irradiated nuclear reactor fuel. A French firm, St. Gobain Techniques, supplied Israel with a chemical extraction plant at Dimona. The plant’s first trial runs were in late 1965. By 1968, Israel had extracted enough plutonium for an atomic bomb.

The Dimona reactor, if operated continuously, could have created as much as 870 kilograms of plutonium through 1994. This figure assumes that the reactor started operating at 26MWt in 1963, was scaled up to 70MWt in 1970, and was scaled up again in 1977 to a level at which it could produce about 40kg of plutonium per year. Vanunu reported that the extraction plant where he worked produced 1.17 kilograms of plutonium per week for 34 weeks per year, a total of 40 kilograms annually. At this rate, 320 kilograms of plutonium would have been produced during the eight years Vanunu worked at Dimona. If the reactor experienced shutdowns, or was operated at a lower power, this figure could be significantly smaller.

Future plutonium production at Dimona is uncertain, primarily because of the reactor’s age. The United States has urged Israel to cap its nuclear program and cease plutonium production at Dimona, but Israel has not agreed to do so.

Size of Israel’s arsenal

The above figures for plutonium production indicate that Israel could have up to 175 bombs’ worth of plutonium in its nuclear arsenal today. This figure assumes roughly 5 kilograms of plutonium are needed per bomb, including processing losses. (Vanunu reported in 1986 that Israel was using about 4.4kg of plutonium per bomb, an amount slightly greater than the reflected fast critical mass of plutonium-239.)

It is impossible to estimate the exact size of Israel’s arsenal without knowing Dimona’s true operating history and the characteristics of Israeli nuclear weapon designs. For example, Israel has produced enriched uranium, which could be used to make additional weapons. Israel has also made a number of “boosted” weapons using tritium, also produced at Dimona. Tritium can be produced by irradiating lithium-6 targets in the Dimona reactor.

Dimona reactor:

Reactor: IRR-II
Type: Heavy water
Power: 26-megawatt (thermal) scaled up to 70MWt or more
Start-up: 1963
Safeguards: None
Plutonium created through 1994: Up to 870 kilograms

FROM: Wisconsin Project on Nuclear Arms Control Copyright © 2003 – 2011