The News That Matters about the Nuclear Industry

Global stability is undermined by US nuclear force modernization

missiles s korea museumFlag-USAHow US nuclear force modernization is undermining strategic stability: The burst-height compensating super-fuze,  Bulletin of the Atomic Scientists Hans M. Kristensen ,  Matthew McKinzie , Theodore A. Postol , 1 Mar 17 The US nuclear forces modernization program has been portrayed to the public as an effort to ensure the reliability and safety of warheads in the US nuclear arsenal, rather than to enhance their military capabilities. In reality, however, that program has implemented revolutionary new technologies that will vastly increase the targeting capability of the US ballistic missile arsenal. This increase in capability is astonishing—boosting the overall killing power of existing US ballistic missile forces by a factor of roughly three—and it creates exactly what one would expect to see, if a nuclear-armed state were planning to have the capacity to fight and win a nuclear war by disarming enemies with a surprise first strike.

Because of improvements in the killing power of US submarine-launched ballistic missiles, those submarines now patrol with more than three times the number of warheads needed to destroy the entire fleet of Russian land-based missiles in their silos. US submarine-based missiles can carry multiple warheads, so hundreds of others, now in storage, could be added to the submarine-based missile force, making it all the more lethal.

The revolutionary increase in the lethality of submarine-borne US nuclear forces comes from a “super-fuze” device that since 2009 has been incorporated into the Navy’s W76-1/Mk4A warhead as part of a decade-long life-extension program.

We estimate that all warheads deployed on US ballistic missile submarines now have this fuzing capability. Because the innovations in the super-fuze appear, to the non-technical eye, to be minor, policymakers outside of the US government (and probably inside the government as well) have completely missed its revolutionary impact on military capabilities and its important implications for global security.

Before the invention of this new fuzing mechanism, even the most accurate ballistic missile warheads might not detonate close enough to targets hardened against nuclear attack to destroy them. But the new super-fuze is designed to destroy fixed targets by detonating above and around a target in a much more effective way. Warheads that would otherwise overfly a target and land too far away will now, because of the new fuzing system, detonate above the target.

The result of this fuzing scheme is a significant increase in the probability that a warhead will explode close enough to destroy the target even though the accuracy of the missile-warhead system has itself not improved.

As a consequence, the US submarine force today is much more capable than it was previously against hardened targets such as Russian ICBM silos. A decade ago, only about 20 percent of US submarine warheads had hard-target kill capability; today they all do. (See Figure 1.)

This vast increase in US nuclear targeting capability, which has largely been concealed from the general public, has serious implications for strategic stability and perceptions of US nuclear strategy and intentions.

Russian planners will almost surely see the advance in fuzing capability as empowering an increasingly feasible US preemptive nuclear strike capability—a capability that would require Russia to undertake countermeasures that would further increase the already dangerously high readiness of Russian nuclear forces. Tense nuclear postures based on worst-case planning assumptions already pose the possibility of a nuclear response to false warning of attack. The new kill capability created by super-fuzing increases the tension and the risk that US or Russian nuclear forces will be used in response to early warning of an attack—even when an attack has not occurred.

The increased capability of the US submarine force will likely be seen as even more threatening because Russia does not have a functioning space-based infrared early warning system but relies primarily on ground-based early warning radars to detect a US missile attack. Since these radars cannot see over the horizon, Russia has less than half as much early-warning time as the United States. (The United States has about 30 minutes, Russia 15 minutes or less.)

The inability of Russia to globally monitor missile launches from space means that Russian military and political leaders would have no “situational awareness” to help them assess whether an early-warning radar indication of a surprise attack is real or the result of a technical error.

The combination of this lack of Russian situational awareness, dangerously short warning times, high-readiness alert postures, and the increasing US strike capacity has created a deeply destabilizing and dangerous strategic nuclear situation.

When viewed in the alarming context of deteriorating political relations between Russia and the West, and the threats and counter-threats that are now becoming the norm for both sides in this evolving standoff, it may well be that the danger of an accident leading to nuclear war is as high now as it was in periods of peak crisis during the Cold War.

How the new accuracy-enhancing fuze works. The significant increase in the ability of the W76-1/Mk4A warhead to destroy hardened targets—including Russian silo-based ICBMs—derives from a simple physical fact: Explosions that occur near and above the ground over a target can be lethal to it. This above-target area is known as a “lethal volume”; the detonation of a warhead of appropriate yield in this volume will result in the destruction of the target……..

The history of the US super-fuze program. The super-fuze is officially known as the arming, fuzing and firing (AF&F) system. It consists of a fuze, an arming subsystem (which includes the radar), a firing subsystem, and a thermal battery that powers the system. The AF&F is located in the tip of the cone-shaped reentry body above the nuclear explosive package itself. The AF&F developed for the new W76-1/Mk4A is known as MC4700 and forms part of the W76 life-extension program intended to extend the service life of the W76—the most numerous warhead in the US stockpile—out to the time period 2040-2050………

The implications. The newly created capability to destroy Russian silo-based nuclear forces with 100-kt W76-1/Mk4A warheads—the most numerous in the US stockpile—vastly expands the nuclear warfighting capabilities of US nuclear forces. Since only part of the W76 force would be needed to eliminate Russia’s silo-based ICBMs, the United States will be left with an enormous number of higher-yield warheads that would then be available to be reprogrammed for other missions……….

Even after Russia’s silo-based missiles were attacked, the US nuclear firepower remaining would be staggering—and certainly of concern to Russia or any other country worried about a US first strike.

Because of the new kill capabilities of US submarine-launched ballistic missiles (SLBMs), the United States would be able to target huge portions of its nuclear force against non-hardened targets, the destruction of which would be crucial to a “successful” first strike………

The appearance created by the vast expansion of this missile defense program can and will contribute to perceptions among Russians that the United States is seeking nuclear dominance.

The Russians have most recently reacted to this ongoing program by publicly displaying and implementing a new and novel sea-based nuclear weapons delivery device as a hedge against US missile defenses.

In particular, Russia is now in the process of testing a 40-ton nuclear-powered underwater unmanned vehicle (UUV) that could robotically deliver, across thousands of kilometers, a 100-megaton nuclear warhead against the coastal cities and ports of the United States. The technical details of this bizarre system were released by Putin himself in September 2015—apparently intentionally—and testing began in December 2016. Such actions by the Russian government clearly indicate a grave concern about the unpredictable character of ongoing US missile defense programs……….

Our conclusions. Under the veil of an otherwise-legitimate warhead life-extension program, the US military has quietly engaged in a vast expansion of the killing power of the most numerous warhead in the US nuclear arsenal: the W76, deployed on the Navy’s ballistic missile submarines. This improvement in kill power means that all US sea-based warheads now have the capability to destroy hardened targets such as Russian missile silos, a capability previously reserved for only the highest-yield warheads in the US arsenal.

The capability upgrade has happened outside the attention of most government officials, who have been preoccupied with reducing nuclear warhead numbers. The result is a nuclear arsenal that is being transformed into a force that has the unambiguous characteristics of being optimized for surprise attacks against Russia and for fighting and winning nuclear wars. While the lethality and firepower of the US force has been greatly increased, the numbers of weapons in both US and Russian forces have decreased, resulting in a dramatic increase in the vulnerability of Russian nuclear forces to a US first strike. We estimate that the results of arms reductions with the increase in US nuclear capacity means that the US military can now destroy all of Russia’s ICBM silos using only about 20 percent of the warheads deployed on US land- and sea-based ballistic missiles………..

The decision by the Obama administration in 2009 to deploy the Aegis ship-based European Phased Adaptive Approach (EPAA) missile defense system has created a program under which the United States could eventually have between 500 to 700 anti-missile interceptors that could in theory be used to defend the continental United States from ships off the country’s coasts. In spite of its severe limitations, this growing defense system could appear to both Russia and China as a US attempt to reduce the consequences of a ragged Russian or Chinese retaliation to a US first strike against them.

We cannot foresee a situation in which a competent and properly informed US president would order a surprise first strike against Russia or China. But our conclusion makes the increased sea-based offensive and defensive capabilities we have described seem all the more bizarre as a strategy for reducing the chances of nuclear war with either Russia or China.

That Russian silos are more vulnerable to W76-1/Mk4A warheads will not come as an earth-shattering revelation to Russian military officials; they would have to expect that the silos would be destroyed anyway, by US land-based ICBMs. But the growing capability of the US forward-deployed sea-based nuclear missiles could raise serious questions in the minds of Russian military planners and political leadership about US intentions—especially when seen in context of growing US cyber, advanced conventional, and missile defense capabilities—almost certainly deepening mistrust and encouraging worst-case planning assumptions in Moscow.

We end this article with quotes from Vladimir Putin, talking impromptu to a group of journalists during the St. Petersburg International Economic Forum in June 2016.  His unrehearsed remarks are clear and candid predictors of how he will assess the implications of the super-fuze:

No matter what we said to our American partners [to curb the production of weaponry], they refused to cooperate with us, they rejected our offers, and continue to do their own thing.

… They rejected everything we had to offer.

… the Iranian threat does not exist, but missile defense systems are continuing to be positioned…

That means we were right when we said that they are lying to us.

Their reasons were not genuine, in reference to the “Iranian nuclear threat.”

Your people [the populations of the Western alliance] … do not feel a sense of the impending danger—this is what worries me.

A missile defense system is one element of the whole system of offensive military potential.

It works as part of a whole that includes offensive missile launchers.

One complex blocks, the other launches high precision weapons, the third blocks a potential nuclear strike, and the fourth sends out its own nuclear weapon in response.

This is all designed to be part of one system.

I don’t know how this is all going to end.

What I do know is that we will need to defend ourselves.


March 3, 2017 - Posted by | USA, weapons and war

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