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former IAEA Director-General

News Analysis: What Is a “New” Nuclear Weapon?
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Tom Z. Collina

During the 2008 presidential campaign, Democratic candidate Sen. Barack Obama (Ill.) told Arms Control Today, “I will not authorize the development of new nuclear weapons.” In its first months, the new administration stated on its Web site that it “will stop the development of new nuclear weapons.” Now, as the administration wraps up its Nuclear Posture Review (NPR) and presents its fiscal year 2011 budget request to Congress, some important details are emerging about what President Obama’s pledge really means and how the administration defines a “new” nuclear weapon.

The Obama administration has been debating over the past year how far the Department of Energy’s National Nuclear Security Administration (NNSA), which oversees the U.S. nuclear weapons complex, should be allowed to go when it rebuilds nuclear warheads that have reached the end of their shelf life. (See ACT, November 2009.) The options include rebuilding some or all the parts but staying within the confines of the original warhead design (“refurbishment”), mixing and matching well-tested nuclear components of different warheads (“reuse”), and manufacturing new, untested nuclear components of new design to replace existing ones (“replacement”).

Gen. Kevin P. Chilton, head of U.S. Strategic Command, testified before the House Armed Services Committee March 16 that the NPR “is examining the appropriate policy guidance for considering future choices between refurbishment, reuse, and replacement.” Now planned for release in April after numerous delays, the NPR is also expected to resolve the related question of how the administration defines a “new” nuclear weapon. For example, does a “refurbished” warhead of old design but newly made parts count as “new”? Can a warhead of new design that performs an old mission count as “old”?

According to an administration source, the NPR will likely reflect the definition of “new” currently used by Congress. As part of the fiscal year 2003 National Defense Authorization Act (Section 3143), Congress defined a “new nuclear weapon” as one that “contains a pit or canned subassembly” not in the stockpile or in production as of 2002. A pit is the plutonium component in a warhead’s primary stage, and a canned subassembly (CSA) is the uranium and lithium-deuteride component in the secondary stage. Together, these parts are known as the warhead’s “nuclear explosive package.”

Although it does not explicitly say so, the congressional definition would allow the refurbishing of warheads within the confines of existing designs, as is now being done by the NNSA’s Life Extension Program (LEP). The 2003 defense authorization act and subsequent legislation explicitly endorsed such life extension efforts, but the definition does appear to prohibit the introduction of new “replacement” pits and CSA designs into the stockpile after 2002. This is analogous to allowing a mechanic to rebuild a car’s engine to existing design but prohibiting its replacement with a newer, possibly more powerful design.

The administration appears to be following this definition in its fiscal year 2011 budget request for the NNSA. For example, the administration is requesting $252 million in fiscal year 2011 for a life extension study for the B61 aircraft-delivered gravity bomb. According to the budget request, this funding would enable the NNSA to “extend the life of the nuclear explosive package which may include an extension of the B61 nuclear primary’s life (reusing the existing B61 nuclear pit), potential implementation of multipoint safety, and reuse or remanufacture of the canned subassembly (CSA) and for a complete life extension of the B61 -3, -4, -7, and -10, if directed by the Nuclear Weapons Council.”

In the case of the B61 LEP, the most extensive planned so far, both the primary and the secondary may be refurbished, but neither would be redesigned. If the primary is rebuilt, the existing pit would be reused intact, and for the secondary, the CSA would be reused or remanufactured to original design. These activities would be consistent with the congressional definition because the design of the nuclear explosive package would remain unchanged.

How the administration defines a “new” nuclear weapon is important because new warhead designs have been proposed to increase the reliability of the stockpile and to make warheads even more secure against possible terrorist acquisition. Serious consideration of new warhead designs to increase reliability was essentially put to rest by the September 2009 JASON report of senior scientists, which found that the lifetimes of existing warheads could be extended indefinitely through refurbishment with no loss of confidence in the stockpile. (See ACT, December 2009.) Sen. Byron Dorgan (D-N.D.), chairman of the Senate Appropriations subcommittee that controls NNSA funding, said at a March 10 hearing that he agrees with the JASON conclusion that “these nuclear weapons will be reliable well out into the future.”

Terrorist-Proof Warheads?

The JASON report left open the question of the need for new warhead designs to address physical security, finding that “[f]urther scientific research and engineering development is required.” Chilton testified March 16 that JASON concluded “only reuse or replacement options allow for the inclusion of intrinsic surety features that would be the last line of defense against unauthorized use.”

However, one member of JASON, physicist Richard Garwin, gave a Jan. 28 briefing on Capitol Hill where he said that “ideal security implies that a nuclear weapon could be captured by a knowledgeable group and, somehow, could never be made to provide a nuclear yield.” He continued, “[O]ne hypothetical possibility, for instance, would be for the security package intentionally to detonate the high explosive at a single point (which for all U.S. nuclear weapons is now guaranteed to provide no significant nuclear yield) so as to disperse the plutonium, substituting a massive radiological mess for the possibility of a later terrorist nuclear explosion.” Garwin concluded that “usually, less extreme security options are chosen.” U.S. nuclear warheads are deemed to be “one-point safe” if the detonation of the high explosive at one point (by a stray bullet, for example), as opposed to a multipoint detonation, does not result in significant nuclear yield.

Intrinsic security modifications like those he described would require new warheads to be designed and new nuclear components to be produced, Garwin said. He said that, for a stockpile of 5,000 deployed and reserve warheads, replacement would take at least 50 years because the maximum rate planned for pit production at Los Alamos National Laboratory in New Mexico is about 100 per year. According to Garwin, “What can be said about weapon security is that the most secure design imaginable…would not soon solve or even reduce our security problems.”

No New Military Missions

The administration’s apparent ban on new warhead designs appears to extend to providing nuclear warheads with new military capabilities, such as higher yields. “I need no new [nuclear] military capabilities today,” Chilton said at the March 16 hearing. Undersecretary of State for Arms Control and International Security Ellen O. Tauscher said Feb. 17 at a conference on nuclear deterrence that the United States is “not in the business of seeking new nuclear capabilities. They are not needed to preserve a strong, credible deterrent.”

Another issue is how the administration defines a “nuclear weapon” in the context of its no-new-nuclear-weapons pledge. For example, the Air Force plans to begin work in fiscal year 2011 on a new, nuclear-capable long-range cruise missile, according to Department of Defense budget documents. The new missile would replace the current B-52 bomber-delivered air-launched cruise missile (ALCM) that is now in service but slated for retirement by 2030. ALCMs are armed with W80-1 nuclear warheads. Would the new missile count as a new nuclear weapon?

According to an administration source, Obama’s reference to “nuclear weapons” was specific to nuclear warheads, not delivery systems such as missiles and airplanes. Indeed, in addition to the new cruise missile, the administration is moving ahead with a variety of nuclear-capable delivery systems, such as the F-35 Joint Strike Fighter, a replacement for the Ohio-class nuclear-armed submarine, and the modernization of existing strategic ballistic missiles such as the land-based Minuteman III and submarine-based Trident II.

 

 

Posted: March 31, 2010