New U.S. Nuclear Warheads? Politically and Technically, a Bad Idea

, , physicist & co-director, Global Security | September 25, 2014, 10:29 am EST
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The New York Times recently ran an excellent story on the administration’s ambitious plan for the future of the U.S. nuclear arsenal, which includes building new generations of nuclear-armed bombers, missiles, and submarines. But I want to discuss an important issue that the article didn’t mention: The United States also intends to develop and produce new types of nuclear warheads rather than simply refurbishing existing warheads as they age. There are both technical and political reasons why this is a bad idea.

New nuclear warheads may be less reliable—and lead to resumed nuclear testing

On the technical side, the military may have less confidence in the performance of these new warheads than those they replace.

B61 bombs in storage

B61 bombs in storage. (Source: US Govt.)

Until 1992, the United States conducted nuclear explosive “proof” tests to verify that its new warhead designs would work as intended. Since then, the United States has observed an international moratorium on nuclear explosive testing and in 1996 signed the Comprehensive Test Ban Treaty (CTBT) banning such tests. The CTBT is an important barrier to nuclear weapons development by more nations.

In the past two decades, the United States has not produced or deployed any new warheads. Instead it has refurbished existing warheads by replacing aging components with new ones.

But the administration now plans a change in course. It will develop new warheads by using components from existing warheads, but in combinations that have never been proof tested. Confidence in the performance of these weapons will instead be based on experimental data from other types of tests and computer simulations. This approach could raise serious questions about the reliability of the U.S. arsenal—and lead to calls for resumed nuclear explosive testing. And a future administration might decide to do just that. If the United States resumed testing, other nuclear nations would likely follow suite and the CTBT would unravel.

New nuclear warheads would undercut non-proliferation goals

On the political side, this new approach flies in the face of President Obama’s promise not to develop new types of warheads. His 2010 Nuclear Posture Review flatly states that “The United States will not develop new nuclear warheads,” noting that the United States “can ensure a safe, secure, and effective deterrent without the development of new nuclear warheads or further nuclear testing.”

Some argue that current plans do not violate this promise. They say that these new warheads are not truly new because they will use components from existing warheads, but this is semantic shenanigans. A warhead that has never existed before is new.

Why did Obama make this pledge? To demonstrate that the United States intends to make good on its commitment as a nuclear weapons state under the Nuclear Non-Proliferation Treaty (NPT) to move toward eliminating nuclear weapons, and hence strengthen the NPT regime. The 178 NPT signatories that have forsworn nuclear weapons in return for this commitment from the nuclear weapons states undoubtedly take this pledge seriously.

If the United States proceeds to build new nuclear weapons, it will undermine the NPT regime and make a mockery of the CTBT, which was intended to prevent the development of new nuclear weapons. The United States is one of the greatest beneficiaries of these treaties, which help keep other states from building nuclear weapons.

A better approach

Rather than going down this path, the United States should simply refurbish (or, in some cases, retire) existing warheads as needed, continuing past practice. This will preclude concerns about the reliability of new types of warheads, and be consistent with President Obama’s pledge not to develop new nuclear warheads.

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  • David Sterkenburg

    What a naïve article. The US already has significantly less and less capable nuclear weapons then Russia. Russia is moreover developing new nuclear missiles and warheads, including measures to make defence against such weapons practically impossible. I would say that US deterrence at this moment is already quite weak, and it will only continue to degrade if people keep arguing for unilateral reductions. There comes a point where the Russians might feel they could actually win a nuclear war with the US. And they would probably be right.

    • LisbethGronlund

      There is no way to win a nuclear war.

      • Nukethrower

        How do you know this? So you are 100 percent certain that a state will not acquiesce to an adversary’s political demands under all circumstances in all plausible military contingencies and war scenarios?

  • Always Two Sides

    So what *is* the point of the new warhead designs? There must be some argument for having them?

    • LisbethGronlund

      Good question. Probably the biggest reason the U.S. wants to design and produce new nuclear warheads is a concern that if it does not do this
      on an ongoing basis, it will lose the capability to do so. In particular, some argue that without interesting work, it will be difficult to attract highly capable people to work on nuclear weapons in the future. However, even if weapons scientists need to design new weapons to stay interested, that is not a reason to actually produce these weapons for the arsenal. Moreover, according to some experts, there is plenty of challenging work involved in refurbishing existing warheads and in further developing the complex computer codes used to model nuclear weapons.

      U.S. officials also argue that by producing new warheads the United States will maintain the industrial capability to rapidly increase its nuclear arsenal—which they say is necessary to allow the United States to eventually reduce its arsenal to lower numbers. But the goal should be to make nuclear weapons reductions as irreversible as possible, so it is not a good thing if the U.S. and other nuclear-armed nations are poised to quickly ramp up their arsenals.

      Another reason to design and build new warheads is to incorporate a particular safety feature: insensitive high explosive (IHE). The high explosive is used to start the nuclear explosion. If it detonates by accident, it will not cause a nuclear explosion, but will disperse plutonium into the environment. IHE is less likely to detonate in an accident, and hence will reduce the risk of plutonium contamination in the event of an accident.

      Of the seven types of weapons in the arsenal now, four already have this safety feature. The other three could be replaced by new warheads that incorporate IHE.

      One of the warheads that does not now have IHE is deployed on land-based missiles. However, these missiles could accommodate an existing warhead that already uses IHE, so there is no need to use a new warhead type in this case.

      The other two warheads that don’t already use IHE are deployed on submarine-based missiles. There are no existing warheads with IHE
      that are small enough to fit on these missiles, so a new warhead design would be needed to add this safety feature. However, the submarine-based missiles use a different type of propellant than land-based missiles, one that is more easily detonated. If this propellant detonated or burned in an accident, it would result in plutonium dispersal, with or without IHE. This means that IHE would not be useful once the warhead is mated to the
      missile. IHE would provide added safety during handling and transportation of
      the warhead, but its safety benefits are limited in the case of submarine-based weapons.

      On balance, we believe that the technical risks and political costs of deploying new warhead designs outweigh the limited safety benefits of adding IHE to submarine-based weapons. I have a report due out this fall that will discuss this issue in more detail, so stay tuned.