For years, some scientists and policymakers have worried that the reliability of U.S. nuclear warheads could diminish as their plutonium components age. Such concerns have led some to argue the United States should resume nuclear testing, rebuild its older warheads, or both. Most recently, plutonium aging has been used by the Bush administration to justify an ambitious new proposal for remaking the weapons complex and the nuclear arsenal.
Think again. A new set of government studies finds that the plutonium primaries, or pits, of most U.S. nuclear weapons “will have minimum lifetimes of at least 85 years,” which is about twice as long as previous official estimates. The findings have led the National Nuclear Security Agency (NNSA) to admit that “the degradation of plutonium in our nuclear weapons will not affect warhead reliability for decades.”
The plutonium research results obliterate the chief rationale for NNSA’s emerging strategy to replace at least six of the major U.S. nuclear warhead types with new warheads over the next 20 to 30 years. This approach would gradually overtake the existing Stockpile Stewardship program, which involves periodic upgrades of the conventional explosives and nonnuclear components in existing weapons, and, if necessary, remanufacture of the plutonium pits to previous design specifications. To produce new types of “replacement” warheads, the NNSA also wants to build a new, multibillion-dollar “plutonium center” to increase the current U.S. capacity to produce plutonium pits for warheads from a few dozen to 125 per year.
The new evidence that weapons plutonium lasts for a century without significant degradation makes it even clearer that United States can reliably maintain its arsenal under the 1996 Comprehensive Test Ban Treaty (CTBT). Moreover, there is no reason to spend scarce tax dollars to expand bomb production capacity, let alone try to replace thousands of well-tested warheads with new, unproven designs.
As a result, NNSA’s new plan, known as “Complex 2030,” will be even tougher to sell to skeptical lawmakers. In response, administration officials are now using other but still dubious reasons for building replacement warheads.
For instance, NNSA argues that more efficient and modern replacement warheads would be less expensive to maintain. In reality, costs will rise, not fall, for the next decade or two because NNSA will continue to spend billions to extend the life of existing warheads until such time as their replacement warheads are built.
Acting NNSA administrator, Thomas D’Agostino, has argued that some warheads in the U.S. stockpile, such as the W76 submarine-launched missile warhead, were designed to minimize size and weight and maximize yield, making them sensitive to changes and upgrades, especially to the nuclear components.
Perhaps. But the reliability of existing warheads can be maintained more easily by avoiding unnecessary alterations to the existing weapons during refurbishment. Rather than build new and robust replacement warheads, the reliability of existing warheads can also be improved by adding more boost gas to increase the explosive energy of the primary stage of the weapon well above the minimum needed to ignite the secondary, or main, stage of the warhead.
In fact, confidence in the reliability of U.S. nuclear stockpile could erode if warhead designs are changed to those not validated by past nuclear testing. Nevertheless, according to news reports, the NNSA may choose a design to replace the W76 that consists of various components that have not been previously tested together.
The new plutonium findings also warrant Senate reconsideration of the technical viability and security benefits of the signed but unratified CTBT. As former Secretary of State George Schultz, former Secretary of State Henry Kissinger, former Secretary of Defense William Perry, former Sen. Sam Nunn (D-Ga.), and others recently wrote in January in The Wall Street Journal, the time has come for “initiating a bipartisan process with the Senate…to achieve ratification of the [CTBT], taking advantage of recent technical advances, and working to secure ratification by other key states.”
Action on the CTBT is more important than ever. Leaders of many key states doubt the United States and the other nuclear-weapon powers intend to pursue their own nuclear Nonproliferation Treaty (NPT)-related disarmament obligations, which include ratification of the CTBT. That shrinking faith erodes the willingness among certain states in the non-nuclear-weapon majority to fulfill their own NPT obligations, much less to agree to strengthen the regime. U.S. leadership on the CTBT would also spur others, particularly China, to follow suit and make it more difficult for them to build new and more dangerous types of nuclear weapons.
Rather than pursue a costly and unnecessary campaign to build a new breed of nuclear weapons, the scientific evidence and international security situation calls for a reduction in the role and number of U.S. nuclear weapons, the use of existing tools to maintain those that remain, and approval of the global test ban.