3
Current Nuclear Arsenals
The United States has dismantled thousands of weapons following the end of the Cold War, but we still maintain a massive nuclear arsenal. To get an idea of just how many weapons we have, consider the following: The U.S. Air Force conducts periodic exercises on our fleet of B52 bombers to assure that they are ready for a nuclear strike. Aircraft are assembled at Barksdale Air Force Base in Louisiana and crews practice mounting bombs and missiles, maneuvering the planes into takeoff position, and other aspects of nuclear war. All this must be accomplished within a set period of time to assure that, should this capability ever be needed, it will be ready.
I observed one such exercise while I was a member of United States Strategic Command’s Strategic Advisory Group, a body that advises the commander on various issues. In blustery, cool weather we watched enlisted men mount a brace of cruise missiles on the wing of a bomber and talked to the crew about their simulated mission. Later, we were driven along the flight line of aircraft that, parked wingtip to wingtip, stretched for more than a mile, a display of strategic might visible from Russian spy satellites. We passed plane after plane after plane, each capable of carrying many strategic nuclear bombs or nuclear-tipped cruise missiles. One could hardly imagine a more vivid demonstration that nuclear weapons are still very much a part of the defense equation. Match this with hundreds of land-based intercontinental ballistic missiles and their submarine equivalents, and one can understand that the American nuclear deterrent is potent indeed.
Many different concepts for nuclear explosives have been proposed and tested, but most modern strategic weapons are based on a two-stage design consisting of a primary and a secondary, as shown schematically below. The primary stage contains high explosive and plutonium and is similar in principle to the implosion bomb dropped on Nagasaki, although much smaller and lighter. However, the main purpose of the primary in a modern weapon is to generate enough energy to implode the secondary stage, which actually produces most of the yield. The secondary is what makes a two-stage weapon a “hydrogen bomb,” since it usually involves the fusion of isotopes of hydrogen in its operation. Smaller weapons might contain only a primary stage, dispensing with the secondary altogether.
Whereas the implosion bomb developed during the Manhattan Project weighed more than four tons and was nearly five feet in diameter, a modern primary weighs less than a few hundred pounds and is usually less than two feet in diameter. Hundreds of nuclear tests were required to refine the design to this level since, as with all highly optimized systems, there is a risk of failure when one cuts margins too thin. Every effort has been made to make the primary both reliable and safe—it must have a near perfect probability of working when needed and a probability of less than one in a million of accidentally exploding in the most severe accident. Some weapons employ “insensitive high explosive” (IHE) that is less susceptible to detonation should the weapon be subjected to fire (e.g., in an aircraft crash) or shock (e.g., bullets or fragments from anti-aircraft missiles).
Primitive nuclear weapons designs sometimes separate the plutonium from the rest of the weapon until just before use, an added safety feature when the amount of fissionable material is so great that an accidental nuclear detonation could occur in an accident. Security features have been built into modern weapons that make it impossible for an unauthorized person to detonate them.
To a first approximation, the larger the secondary, the more yield it will produce. Various types of advanced secondary designs have been investigated for special applications, but the degree of complexity associated with such advanced designs puts them beyond the reach of most entry-level nuclear powers and certainly beyond the range of proliferants who have never tested a nuclear explosive.
The primary and secondary are mounted in a case, which contains the energy generated by the primary long enough for the secondary to implode and produce its yield. Cases are typically made of heavy metals.
Security restrictions make detailed information on nuclear weapons hard to come by. While all the acknowledged nuclear weapons states have published some account of their forces, close inspection often reveals little detail beyond the fact that different types of weapons exist. The official government position is one of purposeful ambiguity, a refusal to officially confirm or deny what is otherwise generally known. The number of each type of weapon in the American arsenal is classified, as is its yield and geographic location. Several publications have attempted to collect basic data about nuclear weapons, but classification rules prohibit me from commenting on the accuracy of any of these estimates.
Before surveying the nuclear weapons in the arsenals of the major nuclear powers, it is worth clarifying some terminology. Considerable confusion has arisen from misunderstanding the different categories of weapons, how they are counted, and even how the energy of weapons is measured.
In the United States, nuclear weapons mounted on missiles (either long-range intercontinental ballistic missiles or shorter-range cruise missiles) are called warheads and are identified with a “W” and a numerical designator, as in the W78 warhead mounted on the Minuteman III ballistic missile. Bombs, or weapons that fall from aircraft, are given a “B” designator with a number, as in the B83 strategic bomb. Warheads and bombs were numbered in the sequence of their development—a weapon number is not the year in which it was deployed. The W88 warhead for the Trident submarine-launched ballistic missile was the last nuclear weapon to enter the U.S. arsenal. Its design dates from the early 1980s. Work had started on the W89, which was intended for an anti-aircraft missile, in the late 1980s, but it was terminated when nuclear testing stopped in 1992.
Most numbers quoted for the nuclear stockpile refer only to strategic weapons—typically higher-yield (hundreds of kilotons) designs meant for long-range delivery. During the Cold War, a separate stockpile of lower-yield (tens of kilotons) tactical weapons was developed to stop attacking tank and infantry formations and to destroy ships at sea. Nuclear war planners see little distinction between tactical and strategic nuclear weapons—they view any use of a nuclear explosive as a strategic event of the first magnitude. But most arms control treaties deal only with strategic weapons, those that are carried on bombers, missiles, and submarines and hence are easy to count.
The explosive output or yield of a nuclear weapon is measured in kilotons or megatons. A kiloton of yield is the equivalent of one thousand tons of TNT, a conventional explosive. To put that in perspective, one thousand tons of TNT would be a stack of explosives the size of a small house. A megaton is equal to one million tons of TNT equivalent, more explosive power than was used in most wars. A low-yield nuclear weapon is usually meant to be one with a yield below about ten kilotons. Very low-yield weapons, sometimes called micronukes, have yields below one kiloton. Most strategic weapons have yields in the several hundred kiloton range. High yield is typically taken to mean weapons in the megaton class.
Nuclear weapons are not just beefed-up versions of nonnuclear bombs dropped in World War II, Vietnam, or Iraq—they are vastly more powerful and produce destruction on a completely different scale. The biggest piece of conventional weaponry—the Massive Ordnance Air Bomb—has only about ten tons of explosive energy. A small nuclear explosive with a yield of ten kilotons is thus one thousand times more powerful than the largest conventional bomb. But there is another important difference between conventional and nuclear weapons. Conventional explosives destroy targets by means of a blast wave, essentially a mechanical effect. Nuclear weapons produce blast waves plus intense heat and radiation in the form of x-rays, gamma rays, and neutrons. Dirt and other matter swept up in the nuclear fireball is transmuted and then deposited in the form of radioactive fallout, the effects of which may linger for years.
TO REACH TARGETS on the other side of the planet, long-range missiles fly into space before releasing their warheads. Once separated from the missile, the warheads fly on a ballistic trajectory without any internal guidance, just as a rock would fly after it is thrown. The warheads must then reenter the atmosphere like miniature spacecraft, and, like spacecraft, they must contend with the intense heat produced by atmospheric friction. Photographs of warheads taken during missile tests show their exteriors to be white-hot just before impact. Protecting sensitive equipment inside ballistic missile warheads is a major technological hurdle to any nuclear state and one that only a few have mastered.
U.S. ballistic missile warheads are all mounted in reentry bodies (navy terminology) or reentry vehicles (air force terminology), black cones about two feet in diameter at their base and about four feet long. Their black color derives from the use of carbon composite heat shield material, similar in function to what is used on the space shuttle. They typically weigh several hundred pounds.
Older Soviet weapons were mounted in blunt nose cones and were much larger and heavier than their American counterparts. Their accuracy on target was typically lower than modern, sharper angled cones, but their higher yield made up for poor delivery accuracy.
Despite advances in the precision delivery of conventional weapons, nuclear bombs have no internal guidance—they are released by the aircraft and fall by gravity to their target. The accuracy with which they can be placed on the ground is a complex mixture of the skill of the pilot, the altitude at which the bomb is released, the prevailing winds, and the flight characteristics of the bomb. Many bombs have a parachute to slow their descent and to give the bomber time to get away from the area before detonation. Some have timers to delay their explosion still longer—a particularly important feature for pilots engaged in slow, low-altitude drops of megaton-class weapons. Modern strategic bombs measure about one to two feet in diameter and are about ten feet long. They weigh upward of several hundred pounds, much of that weight comprising the bomb casing and parachute.
To complicate things still further, nuclear weapons are also referred to by the Mark numbers associated with the delivery packages in which they are housed. For example, the W88 weapon is mounted in the Mark 5 reentry body, and the W78 weapon is mounted in the Mark 12A reentry body. Sometimes the nuclear explosive part of a weapon is referred to as the “physics package” to distinguish it from the weapon’s electronic subsystems, external housing, parachute (if any), and other associated equipment.
The nuclear weapons stockpile is divided into two parts. The active stockpile consists of those weapons that are ready for immediate use. The inactive stockpile consists of weapons kept in lower states of readiness in secure warehouses. In addition to weapons mounted on missiles and those that are ready to be loaded into bombers, the active stockpile includes units that are in the logistics tail of the supply chain, such as those that are awaiting replacement on submarines currently undergoing a refit, those that are en route to new locations, and those undergoing periodic refurbishment.
The inactive stockpile contains weapons that do not receive the same degree of attention as active bombs and warheads, but that could potentially be returned to service. Some short-lived components, such as batteries, are removed from weapons in the inactive stockpile, and they receive fewer inspections. Weapons in the inactive stockpile are not countable under arms control agreements. The purpose of the inactive stockpile is to provide backups for active weapons should a catastrophic flaw be discovered. They also enable the stockpile to be rapidly expanded should geopolitical events worsen more quickly than new weapons can be manufactured. It is possible for the number of weapons in the inactive stockpile to exceed the number of officially recognized weapons, making weapons counting a topic of some confusion even for nuclear planners.
Nuclear Weapons Systems of the United States
Only the air force and navy have nuclear weapons—neither the army nor the marines currently has custody of any nuclear explosives. Also, only the air force has both bombs and missiles—the navy has only missile warheads. The table gives a current summary of U.S. nuclear forces.
The B61 bomb was first introduced into the stockpile in 1967 and has been modified many times since. Some are intended for tactical battlefield applications and some for strategic uses. Having these choices available in a single type bomb is a considerable cost savings for the air force, since only one type of aircraft mounting is required for multiple missions. Also, training requirements are reduced as airmen are not forced to be proficient on many different weapons systems. As shown in the photograph on Chapter 3, the B61 consists of hundreds of individual parts, most of them associated with the electronics and other systems that arm and fire the weapon.
Nuclear weapons currently deployed by the United States. Here, ICBM (intercontinental ballistic missile) refers to land-based missiles and SLBM (submarine-launched ballistic missile) to submarine-based missiles.
|
WEAPON |
TYPE |
DELIVERY VEHICLE | ||
|
B61 |
Bomb |
B52 and B2 heavy bombers and several fighter bombers | ||
|
B83 |
Bomb |
B52 and B2 heavy bombers | ||
|
W76 |
SLBM Warhead |
D5 missile on Trident submarine | ||
|
W78 |
ICBM Warhead |
Minuteman III ICBM | ||
|
W80 |
Cruise Missile Warhead |
Cruise missile carried by bombers and submarines | ||
|
W87 |
ICBM Warhead |
Minuteman III ICBM | ||
|
W88 |
SLBM Warhead |
D5 missile on Trident submarine |
The majority of the bombs in the U.S. arsenal are variants of the B61 family, the most recent one being the B61 Mod 11 earth-penetrating bomb, or B61–11, which was adapted from an earlier B61 by adding a thicker case and a stronger nose cone. These changes enable it to penetrate a few yards into the ground after being dropped from an aircraft, greatly increasing the amount of energy sent into the earth to destroy deeply buried targets such as command centers or weapons storage areas. The B61–11 has the destructive power of a surface burst many times larger.
I oversaw the engineering testing of the B61–11 and transferred it from the research and development phase at Los Alamos to service in United States Strategic Command. While the basic design of the nuclear explosive was well verified via underground nuclear tests, considerable work had to be done to verify that it could survive hitting the ground at high speed and penetrate to the required depth. Imagine dropping a highly sophisticated piece of equipment from a great height and expecting it to perform flawlessly after impact. There was considerable concern that this long, thin cylinder might break in the middle or that delicate components might be damaged by the shock of impact. More than that, we had to contend with the possibility that the weapon might land on concrete or hit a rock during its entry into the ground, and a myriad of other possibilities for which the basic B61 was never intended, all with a design that was approaching forty years old.
The other bomb in the U.S. stockpile is the B83, a megaton-class strategic bomb. Since it is a much more modern design, the B83 has a variety of features not present in the B61, making it inherently safer and more reliable. However, the increasing precision with which even unguided bombs can be delivered means that there are few targets that require such a large yield for their destruction.
The W80 warhead carried on bomber-and submarine-launched cruise missiles was designed as a standoff weapon that could be launched when a bomber was far from the dangers of Soviet air defense systems. Once released, the missile follows a preset flight plan, sometimes flying quite low to avoid detection by enemy radar. It thus combines the advantages of the bomber—the ability to cancel a mission before the weapon is dropped—and an unmanned missile that does not expose a crew to dangerous flight over enemy territory.
Photo of a B61–11 earth-penetrating weapon falling from a B2 bomber.
The air force maintains two warheads for use on intercontinental ballistic missiles: the W78 and the W87. (A third warhead, the W62, was recently withdrawn from the stockpile.) Having more than one warhead for ballistic missiles reduces the effect of a single-point failure in any class of weapon, a serious problem given the long time required (several years) to fix hundreds of units or manufacture entirely new ones. For example, if it was found that all the W78 warheads suffered from a serious problem related to their age, the W87 would still be available to maintain deterrence. The photograph on Chapter 3 illustrates a typical ICBM warhead, in this case the W78, which flies on the Minuteman III missile. The W87 looks quite similar but includes a number of modern safety features not present in the older weapon.
Bombs and warheads are only one part of a nuclear weapons system, which includes the explosive package, its delivery vehicle (bomber, missile, or submarine), and the command and control system that governs its potential use. The air force relies on two heavy bombers—the B52 and the B2—to carry its strategic bombs and air-launched cruise missiles. The B52 was originally introduced in 1954 and has undergone significant upgrades since that time, including the installation of new wings, more efficient engines, and greatly improved electronics. The air force currently plans to keep these workhorses well into the present century, making it possible for five generations of pilots to fly the same type of airplane. But age alone is not the sole criterion for reliability—the average B52 in the fleet has less flight time than the newer 757 commercial passenger airplane, which receives much more frequent use. It is quite possible for a properly maintained aircraft to keep flying safely for many decades.
The nuclear warhead carried on the ALCM.
Since a bomber must get close to a target (in the case of cruise missiles) or actually on top of it (in the case of bombs) to deliver weapons, it is especially vulnerable to fighter aircraft and anti-aircraft missiles. The B2 stealth bomber was a significant advance in large aircraft design, with numerous features that make it exceptionally difficult to detect on radar or by other means.
The air force has several kinds of fighter-type aircraft that can carry its tactical bombs. These have much shorter flying ranges than heavy bombers and were originally intended for use in a war between the Soviet Union and NATO forces in Western Europe.
The Minuteman III missile, originally deployed in 1970, is slated to carry air force warheads well into the twenty-first century. Like most long-range missiles, it has multiple stages—in this case three—that successively fall away as the missile ascends. It is powered by solid fuel, so that it can sit in a silo for years or even decades with relatively little maintenance. The Minuteman III has a range of eight thousand miles and can deliver its warheads with remarkable accuracy—after flying from the continental United States to a target on the other side of the globe, it can place its weapons within a city block.
During the Cold War, a single missile sometimes carried more than one warhead, the MIRV (multiple independently targetable reentry vehicle) concept, but under the guidelines of the Moscow Treaty of 2002, only one warhead will be mounted on a missile. This is consistent with a shift away from massive retaliation and toward the use of one or a few weapons to destroy very high-value targets in an extreme emergency. The Minuteman III is launched from hardened concrete silos located at several bases in the central part of the country.
The B2 stealth bomber is nearly invisible to enemy radar and is capable of carrying nuclear weapons.
The air force formerly maintained a fleet of Peacekeeper (or MX) missiles that, while more modern than the Minuteman III, were designed to carry more warheads than is currently required in operational plans. Also, the cost of maintaining the Peacekeeper was higher than that of the Minuteman III, so some savings were achieved by its removal.
The navy has two types of ballistic missile warheads, the W76 and the more powerful W88, both of which are mounted on the Trident D5 submarine-launched ballistic missile. Each Trident missile is capable of carrying multiple warheads and there are no plans to reduce that number to one, as in the case of air force ballistic missiles. Like the Minuteman III ICBM, the D5 missile is a three-stage, solid fuel design, although its dimensions—forty-two feet long and six and a half feet in diameter—are tightly constrained by the necessity of mounting it vertically within a submarine hull. It has a maximum range of seventy-five hundred miles, quite impressive given that it can be launched from anywhere in the world’s oceans.
The United States currently has fourteen ballistic missile submarines (naval designation SSBN), members of the Ohio class of ships named after the first of that type introduced in 1990. Only twelve of these are on active duty at any given time, the remaining two undergoing refurbishment. Each submarine carries twenty-four Trident D5 missiles, giving a single SSBN the ability to project an explosive force greater than all the weapons used in all the wars of history—they are the most destructive weapons systems ever created by humankind. Because ballistic missile submarines are nuclear-powered, they can remain submerged for months at a time and are exceptionally difficult to detect with even the most advanced sonar technology. The commander of the submarine has some freedom to set his own course while on patrol, so only a few people, all of whom are on the submarine itself, know its exact location at any given time. Sophisticated communications systems allow the ship to remain in constant contact with the United States so it is always available as part of the overall deterrent force.
USS Pennsylvania (SSBN–735) ballistic missile submarine under way.
A Trident D5 missile shortly after launch from a submerged ballistic missile submarine.
The navy maintains cruise missiles equipped with a variant of the W80 nuclear warhead, the only case where an almost identical warhead is used by the air force and the navy. These missiles can be launched from attack submarines, giving increased flexibility to the nuclear war planner.
TO FULLY UNDERSTAND how the nuclear deterrent functions, it is important to understand the command and control systems that govern weapons use. Enormous effort has been expended to ensure that U.S. nuclear weapons can be used only upon receipt of an authenticated presidential order. Codes, which are for all practical purposes unbreakable by any current or anticipated computer or mathematical technique, are carried in safes aboard submarines and bombers and kept in the control bunkers of ICBM sites. Upon receipt of a launch order, the code associated with the order is compared with the code stored in the safe—only when they agree can a launch proceed. As an additional safety precaution, modern weapons have various interlocks that are intended to prevent their detonation until a fixed sequence of events has occurred. For example, internal sensors on a weapon might verify that it has endured the acceleration of missile launch, a minimum required flight time, and the deceleration associated with reentry into the atmosphere, and that it is within a fixed set of altitudes suitable for detonation.
Nuclear Weapons Systems of the Russian Federation
The Russian Federation inherited the nuclear arsenal of the Soviet Union, including all the weapons that were formerly stationed in the Ukraine, Belorussia, and Kazakhstan. Like the United States, Russia maintains a diverse set of nuclear weapons, ranging from low-yield warheads intended for use against a ground invasion to high-yield strategic weapons for use against other countries.
Russia is in the process of modernizing its nuclear forces with the deployment of the SS–27 intercontinental ballistic missile, first observed in 1994. While the plan was to deploy one regiment of SS–27s—ten missiles—per year, economic difficulties in the country have delayed that schedule so full capability is not expected before 2010. The Topol-M RS–12M1, as the SS–27 is called in Russia, is a three-stage solid propellant missile that is seventy-two feet long and six and a half feet in diameter. According to the military journal Jane’s Strategic Weapons Systems, the Topol-M has a range of sixty-five hundred miles and an estimated accuracy of eleven hundred feet. It can be launched either from underground silos or from an over-the-road transporter-erector-launcher (TEL). President Vladimir Putin announced in 2007 that the warheads on the SS–27 were capable of maneuvering around U.S. interceptor missile warheads, enabling them to penetrate our missile defense system.
Russia has a number of other nuclear-capable missiles, including the SS–25 Sickle design, which can be carried on a mobile trucklike launcher, and the SS–19 Stiletto silo-based missile. The massive SS–18 Satan missile is reported to be fitted with a multimegaton nuclear warhead, perhaps the most powerful explosive in the world—much more destructive than anything in the U.S. arsenal. At the other end of the spectrum, Russia has very capable short-range missile systems, some of which may be equipped with nuclear warheads. The purpose of these weapons is to provide a defensive capability during a period of shortfalls in Russia’s conventional forces. If one is forced to use a nuclear weapon on one’s own soil, it is wise to use the lowest yield possible.
Russia maintains a fleet of ballistic missile submarines, including the huge Typhoon submarine and the workhorse Delta class. Russia is introducing a new ballistic missile submarine, the Borey, which is intended to carry a new type of missile. The first of these new submarines was launched in 2007. Funding shortages within the Russian navy have prevented it from deploying its submarines at anywhere near the rate that it did during the Cold War, but this appears to be changing as the country stabilizes.
Finally, Russia is modernizing its strategic bomber force with improvements in the number and capabilities of its Blackjack heavy bombers. Just as the United States is maintaining our B52s, the Russians may elect to retain some of their Cold War fleet, in their case, the venerable Bear-class long-range aircraft.
Russia has a very active research and development program to improve its nuclear arsenal. It is designing new nuclear weapons for use on short-range missiles and it is conducting an extensive program of experiments at its nuclear test site at Novaya Zemlya, north of the Arctic Circle. President Putin repeatedly stated the vital role that nuclear weapons play in Russian national security and his intention to deploy new types of weapons.
Nuclear Weapons Development by Other Nations
The United States, being the first nuclear power, had to solve all the problems of atomic weapons on its own, a mammoth task involving the greatest concentration of scientific talent the world had ever seen. The Soviet Union had the advantage of U.S. data obtained by espionage, although it reproduced much of that work out of fear of being led astray by American counterintelligence. The United Kingdom worked closely with the United States during the Manhattan Project and had inside knowledge of how a weapon worked. However, British access to nuclear weapons information was suspended over espionage concerns—it was not until an agreement was signed in 1958 that cooperation was reestablished on a controlled set of topics. Hence both the Russian and British weapons programs were, in different ways, an offshoot of the American program.
France knew that nuclear weapons were possible when it set out to develop an independent nuclear deterrent. However, French scientists did not have access to data from successful nuclear powers, so they were forced to reinvent much of the technology on their own. (It was only later that the United States and the United Kingdom created carefully controlled interactions with France on nuclear matters.) France apparently went down a number of blind alleys in nuclear tests done in the Sahara Desert during the early 1960s, even though it presumably had its own espionage program aimed at America and the Soviet Union. Later experiments done at France’s nuclear test site in French Polynesia demonstrated that it has mastered the art of nuclear weapons design.
China received material help from the Soviet Union during the 1950s, an input that was canceled just prior to providing the Chinese with the design for a simple atomic bomb. The difficult step of turning concepts into functioning machinery had to be tackled without Soviet help, as did the completion of a working design and the means to test the performance of the device. How much assistance, if any, the Chinese had in the later development of their thermonuclear arsenal is a matter of conjecture, but their remarkable rate of progress in going from a simple atomic bomb to megaton-class warheads suggests that they had some help, either through voluntary sharing or involuntary espionage.
More recent entrants to the nuclear club had two advantages. First, much information about the basic operating principles of nuclear weapons exists in the open literature. Second, the overall level of science in the world has advanced tremendously since the days of the Manhattan Project. Topics like computational hydrodynamics and opacity theory, which were invented in part to develop the implosion design during World War II, are now taught in nearly every university. Even though the application of this information to nuclear weapons is neither confirmed nor denied by the governments of nuclear powers, scientists in other countries can draw their own conclusions, and they increasingly have the tools necessary to turn theory into real weapons.
NUCLEAR FORCES OF THE UNITED KINGDOM
The British government summarized its future nuclear policy in a 2006 white paper: “We are committed to retaining the minimum nuclear deterrent capability necessary to provide effective deterrence, whilst setting an example where possible by reducing our nuclear capabilities, and working multilaterally for nuclear disarmament and to counter nuclear proliferation. We believe this is the right balance between our commitment to a world in which there is no place for nuclear weapons and our responsibilities to protect the current and future citizens of the UK.”
The nuclear forces of the United Kingdom consist of four ballistic missile submarines, each fitted with sixteen Trident D5 missiles purchased from the United States. Given the need for periodic maintenance, crew changes, and other logistical tasks, this guarantees that the UK has at least one submarine ready to launch at any given time. In an emergency, it could count on two or even three. The UK has a relatively small stockpile of warheads, numbering only about 200, and each submarine will likely carry fewer than this number while on patrol. Under their new plan, the British will reduce their stockpile to approximately 160 warheads carried on three or four new submarines. While the United Kingdom has benefited from a long collaboration with the United States in nuclear weapons technology, it maintains its own warhead design and manufacturing capability.
NUCLEAR FORCES OF FRANCE
At the dedication of the ballistic missile submarine le Terrible on March 21, 2008, President Nicolas Sarkozy announced that “our arsenal will include fewer than 300 nuclear warheads. That is half of the maximum number of warheads we had during the Cold War. In giving this information, France is completely transparent because it has no other weapons beside those in its operational stockpile.”
France has four nuclear-powered ballistic missile submarines, each carrying sixteen M45 ballistic missiles with a range of thirty-seven hundred miles. These missiles are due to be replaced starting in 2010 by the M51, a missile that will have a range of six thousand miles. Both missiles will carry the advanced TN–75 warhead, although other weapons are planned for the future. France maintains sixty ASMP air-to-surface missiles fitted with the three-hundred-kiloton TN 80/81 warhead. The French nuclear weapons program has been carefully planned to ensure operational capability for decades to come.
NUCLEAR FORCES OF CHINA
China has only a few dozen ballistic missiles capable of reaching the United States, each of which is equipped with one or more nuclear warheads in the megaton range. The relatively high yield of China’s nuclear warheads is required due to the poor accuracy of its missiles as well as the need to compensate for small numbers. To increase their survivability during times of war, Chinese missiles are launched from road-mobile TELs that can be rapidly dispatched from storage facilities. China has announced plans to modernize its nuclear forces, including land-based missiles and its own ballistic missile submarine.
NUCLEAR FORCES OF INDIA
India tested what it referred to as a peaceful nuclear explosive in 1974. Photographs suggest that the system was too bulky and heavy for deployment on aircraft and missiles. India claimed to have made significant advances in its nuclear test program of 1998, although there is some debate about the accuracy of those claims. The indigenously developed Agni missile, which has a range of twelve hundred to twenty-one hundred miles, may be fitted with a nuclear warhead, and Indian fighter-bomber aircraft could carry nuclear bombs. India is developing a ballistic missile submarine, but the government insists that this vessel is intended to carry only conventionally armed missiles and not nuclear weapons.
NUCLEAR FORCES OF PAKISTAN
Immediately following the Indian nuclear tests of 1998, Pakistan tested a nuclear device with an estimated yield of about thirty-five kilotons. It was reported in the press that this was done with some assistance from China. Pakistan has several short-and intermediate-range missiles that could carry a nuclear warhead, in addition to fighter-bomber aircraft that could carry nuclear bombs. A significant challenge for Pakistan (as well as India) is the development of an effective command and control system that will preclude the unauthorized use of nuclear weapons.
NORTH KOREA
North Korea reportedly conducted a nuclear test in 2006, demonstrating at least some capability in nuclear weapons technology. While hailing its success as indigenous, press reports suggest that help might have been obtained from other countries. However, the small yield of the North Korean test suggests that all may not have gone according to plan, either due to faulty information received from others, a misunderstanding of what was provided, or difficulties in the fabrication of the device.
IRAN
Iran is pursuing the enrichment of uranium to levels higher than would be required for a nuclear energy program. There is little public information available about Iranian progress on the other phases of nuclear weapons development, especially those related to mastering the design of an implosion device or the engineering associated with turning an experimental device into a practical weapon.
OTHER NATIONS
While the Israeli government has refused to confirm or deny that it has nuclear weapons, it is widely believed to have some capability. Several other countries appear to have had, or currently have, programs aimed at developing nuclear weapons. However, aside from claims and denials, there is often little evidence to support these assertions.
Nuclear status can change with the political environment, as when the newly independent countries of the former Soviet Union elected to return all nuclear weapons on their soil to Russia. The government of South Africa decided in 1990 to destroy both its nuclear weapons and the industrial plants that produced them. Other countries, such as Switzerland and Sweden, abandoned their programs in the 1960s.
LIKE AUTOMOBILES AND airplanes, nuclear weapons differ in design according to the missions that they are intended to perform and the technological capability of their builders. Just as one chooses the vehicle according to the task—racing or hauling bricks—a nuclear state plans its nuclear forces according to the types of missions they are intended to perform. Both the United States and the Soviet Union produced miniature nuclear explosives mounted in artillery rounds, weapons that were intended to stop massive troop and tank movements on the battlefield. Nuclear-tipped torpedoes were fielded, including some that flew on short-range rockets before entering the water near their target. Weapons of greatly different yield—from tons to megatons—were developed for different types of targets, the lower-yield weapons typically intended for smaller and softer targets and the higher-yield weapons for hard targets such as underground bunkers, or large targets such as airfields or naval bases.
Testing was vital to the exploration of nuclear weapons technology. The United States and Russia each conducted about one thousand such tests over a period of more than forty years. While the two countries have comparable scientific knowledge, they followed different design philosophies in the development of their stockpiles. The Americans chose very sophisticated designs that saved on missile costs, and the Russians chose rugged construction and ease of maintenance. Despite these technical differences, each country has an assured capability to project overwhelming force anywhere in the world. The cessation of nuclear testing in 1992 has severely limited, but not totally precluded, the development of new classes of nuclear weapons. Advanced nuclear states can adapt older, already tested nuclear systems to different missions, and small modifications can be made to existing weapons without the need to test. Weapons designers still worry that an accumulation of small changes could eventually reduce confidence in the safety and performance of weapons that are not tested.
The United Kingdom, France, and China conducted far fewer nuclear tests than did the United States and Russia, so one might assume that they have a correspondingly smaller range of tested designs for possible future deployment. In the case of India and Pakistan, each of which conducted at best a few tests, one can say only that they have the ability to produce a nuclear explosion. The status of their operational nuclear capability remains in question. The same could be said of North Korea. The nuclear capability of countries that have not conducted any tests is uncertain.