Scientists See Stockpile Lasting for Decades
Weighing in on a long-simmering debate within the
The study could affect the ongoing Nuclear Posture Review (NPR), which is expected to address whether the
“The JASON study offers yet more evidence that the
However, in a statement e-mailed to Arms Control Today, Rep. Michael Turner (R-Ohio) said, “Setting aside the political pros and cons of CTBT ratification, on [a] technical basis alone the JASON report does not instill confidence that the nuclear security enterprise is in a position to provide long-term sustainment of our nuclear stockpile in a CTBT regime.”
JASON, which had access to classified nuclear weapons design information, reviewed the National Nuclear Security Administration’s (NNSA) Life Extension Program (LEP) at the request of the House Armed Services Strategic Forces Subcommittee, which released the summary Nov. 19. JASON conducted a similar review of the Reliable Replacement Warhead (RRW) program in 2007.
The goal of the LEP is to extend the service lives of existing, well-tested nuclear warhead designs, a process known as refurbishment, without nuclear testing. Congress asked JASON to compare the LEP approach to the RRW program, which calls for “replacing” existing warhead designs with new, untested ones to address concerns that the reliability of today’s warheads could decline as they age. (See ACT, November 2009.)
So far, the LEP has not changed nuclear primaries, which contain plutonium cores, or “pits.” JASON, the NNSA, and Lawrence Livermore and
The most prominent advocate of “replacement” warheads has been Secretary of Defense Robert Gates, who in September told the Air Force Association that, “in one or two cases,” the
The JASON study, however, found no basis for concerns that warhead aging and efforts to address it reduce reliability. The panel found “no evidence that accumulation of changes incurred from aging and LEPs have increased risk to certification of today’s deployed nuclear warheads” and that current
“We welcome the release of the JASON scientific advisory panel’s review of warhead Life Extension Programs,” Strategic Forces Subcommittee Chairman James R. Langevin (D-R.I.) and Turner, the panel’s ranking member, said in a joint statement. “We believe their recommendations provide a sound technical basis to inform subsequent
While minimizing concerns about the reliability of life-extended warheads, the JASON report highlights surety as another potential rationale for replacing existing warheads. Gates and others point out that current warheads do not have the latest surety systems, a term that encompasses safety, security, and “use control,” which refers to technologies to prevent the use of lost or stolen weapons. That discussion goes back to 1992, when President George H.W. Bush signed into law a congressionally mandated moratorium on nuclear tests and, at the same time, authorized additional tests for safety and security purposes. Those tests were never conducted because the Air Force and Navy determined that the marginal improvements were not worth the budgetary cost of deploying the new systems.
Events since then may have changed some attitudes. The Sept. 11 terrorist attacks and the Aug. 30, 2007, incident in which the Air Force lost track of six nuclear cruise missiles have focused attention on the vulnerability of nuclear weapons to theft and on improved security and use control. According to congressional staffers, the
JASON did not take a stand on the need for surety improvements. Instead it found that “[f]urther scientific research and engineering development is required,” the summary said. The panel noted that implementation of “intrinsic” surety features, i.e., those inside the nuclear explosive package, would require “reuse or replacement” options. In other words, such changes could not be made through typical refurbishment of existing designs but would have to “reuse” surplus nuclear parts or designs that have already been tested with modern surety features (as the W87 warhead’s design has). Information about security or use control features that would require new “replacement” designs is highly classified.
The panel found that the surety of nuclear weapons carried by strategic bombers could be upgraded using reuse options. That may be a reference to a safety feature known as fire-resistant pits, which are intended to prevent the dispersal of plutonium during an aircraft fire. That feature is used in the most recently developed weapons, including the W87 warhead and the B83 strategic bomb. The panel also noted that upgrading intrinsic surety features in the entire stockpile would “require more than a decade to complete,” which was described as an understatement by one source familiar with the study. As a result, the panel recommended that the potential benefits of surety technologies be assessed “in the context of the nuclear weapons enterprise as a system, including technologies that can be employed in the near term.”
Because changes to warheads utilizing reuse or replacement options may take the weapons beyond previous test experience, “[c]ertification of certain reuse or replacement options would require improved understanding of boost,” the panel said. Boosting, the practice of increasing the yield of a warhead’s primary stage with tritium gas, is one of the most challenging aspects of nuclear weapons physics to simulate in the laboratory.
According to the summary, the report also concluded that the NNSA surveillance program, which is responsible for finding age-related problems with the stockpile and therefore essential to stockpile stewardship, is “becoming inadequate” and that nuclear weapons expertise is “threatened by lack of program stability, perceived lack of mission importance, and degradation of the work environment.” In response, administration officials say that the fiscal year 2011 proposed budget, to be submitted to Congress in February, will include increased spending on NNSA stockpile maintenance activities.
In his e-mail, Turner said the JASON report “raises serious concerns” about the adequacy of the surveillance program and “maintenance of critical expertise and capabilities.”
NNSA spokesman Damien LaVera said in a Nov. 19 written statement that “[t]he JASON’s review confirms the challenges associated with adding performance margin and incorporating modern safety and security features into aging weapons systems, acknowledges the need to preserve our workforce, and reaffirms our long held belief that the strength of the science, technology and engineering at the laboratories and plants is the key to our success.”
LaVera added that “certain findings in the unclassified Executive Summary convey a different perspective on key findings when viewed without the context of the full classified report.” According to congressional staff, the NNSA was referring to possible problems with the stockpile that may be discovered once the surveillance program is improved, otherwise known as “unknown unknowns.”
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