04/09/2010 - 10:59

Nuclear exchange: RRW for CTBT?

Yousaf Butt

Yousaf Butt

Butt is a research professor and scientist-in-residence at the James Martin Center for Nonproliferation...

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Two weeks ago, on the very day that the breakthrough in the new START arms control negotiations was announced, Ohio Republican Rep. Michael Turner posted to his website three letters from the directors of the country's nuclear weapon laboratories expressing doubts in the viability of the programs that maintain U.S. warheads. While none of the letters directly advocated for designing and developing new warheads, the timing of Turner's message was unmistakable: We would be better off making new--supposedly more reliable--nuclear weapons, if we're trending toward a smaller arsenal. In fact, veteran New York Times reporter William Broad wrote that the lab directors' letters "implicitly endorsed the idea of creating an expensive new generation of more reliable nuclear warheads," à la the so-called Reliable Replacement Warhead (RRW) Program.

Reviving RRW seemingly would be impossible as Congress has twice zeroed out the program's funding, and the newly released Nuclear Posture Review (NPR) promises that the "United States will not develop new nuclear warheads." But since the Obama administration wants to eventually submit the Comprehensive Test Ban Treaty (CTBT) to the Senate for ratification--a move that requires the cooperation of at least eight Senate Republicans--the pro-RRW lobby now has a significant bargaining chip in its effort to raise the program from the grave.

Nor is the NPR's promise of not creating new warheads as stringent as it first appears. By definition, the NPR's term of validity is 5-10 years and the pro-RRW lobby can easily argue that it's planning for the future. Further, the NPR allows for three options in warhead modernization: refurbish, reuse, and replace. The latter option would be consistent with RRW since according to the NPR the replacement design needs only to be "based on previously tested designs." (The first RRW, WR1, is loosely based upon the two-stage, boosted SKUA-9 design that was tested several times in the 1970s.)

Generally speaking, Democrats favor the CTBT and dislike RRW; conversely, most Republicans favor RRW and dislike the CTBT. So the grand bargain might be CTBT ratification for RRW funding. But any such quid pro quo would be dangerous both to the credibility of U.S. nuclear forces and Washington's nonproliferation efforts. Untested new weapons could hardly be considered a better deterrent than the tested weapons in the U.S. arsenal; on the other hand, were the new weapons to be tested, it would be harder to dissuade other countries from also testing. Therefore, the "RRW for CTBT" bargain should be strenuously resisted.

The basic link between RRW and CTBT was spelled out during the Bush administration's waning days. At that time, the Defense and Energy Departments issued a joint report, "National Security and Nuclear Weapons in the 21st Century," that placed a high priority on RRW, more or less threatening to restart nuclear testing unless Washington adopted it. "Without nuclear testing, at some time in the future the United States may be unable to confirm the effect of the accumulation of changes to tested warhead configurations," it warned. Defense and Energy were basically engaging in blackmail: Buy RRW or the CTBT cannot be ratified because the legacy warheads may need to be tested in the future.

But this reasoning completely ignores the findings of a peer-reviewed National Academy of Sciences (NAS) study that included three nuclear weapon laboratory directors on its panel. The NAS study concluded that the United States "has the technical capabilities to maintain confidence in the safety and reliability of its existing nuclear-weapon stockpile under [a test-ban treaty], provided that adequate resources are made available to the [Energy Department's] nuclear weapons complex and are properly focused on this task." Indeed, the recent large increase in NNSA funding has provided more than adequate resources to ensure that the arsenal doesn't atrophy.

While the NAS study admitted that age-related defects (mostly of non-nuclear components) can be expected, it went on to say that nuclear test explosions "are not needed to discover these problems and . . . not likely to be needed to address them." Rather, the study proposed a thorough stockpile surveillance program, remanufacturing some components to original specifications, minimizing changes to existing warheads, and non-explosive testing and repair of non-nuclear components.

Even though the RRW might be based on previously tested designs, the inherent risk of making entirely new weapons is greater than the risk of continually and carefully refurbishing the well-tested legacy weapons. As Richard Garwin, the longtime defense consultant who helped design the first hydrogen bomb, explained, "The stockpile weapons, as gradually modified, are closer to the test pedigree than is either of the RRW designs to a nuclear test explosion." (The two RRW designs he refers to are those that were proposed by the Lawrence Livermore and Los Alamos National Laboratories.)

Robert Peurifoy, the former vice president of technical support at Sandia National Laboratories also has weighed in on the topic: "The present nuclear weapon stockpile contains eight or so nuclear weapon types. . . . These weapons have benefited from a test base of perhaps 1,000 yield tests conducted during the 40 or so years when nuclear testing was allowed. Is [the Defense Department] really willing to replace tested devices with untested devices?"

Here's another way of thinking about it: Would RRW supporters rather fly on a brand-new airliner that had never had a single test flight--even though its physics and aerodynamics may be perfectly well understood and its engineers have "certified" it--or on a well-tested "legacy" 747 that had been continually upgraded? For their own safety, one would hope they would choose the well-tested 747. So it's puzzling why RRW advocates believe that untested new weapons would work better at deterring our enemies than our already well-tested weapons we have.

If anything, untested new weapons would be a less credible deterrent in the eyes of potential adversaries, an idea I explained at length in the Bulletin about 16 months ago. The salient point being that the actual numerical reliability of a warhead--whether it's 70 percent, 90 percent, or 98 percent--matters little in the ways of deterrence, where the critical factor is perception of retaliatory destruction. And as far as such perceptions go, an untested stockpile will always be marginally less credible than a tested stockpile in the eyes of potential adversaries. Our current warheads are approximately 98-percent reliable, with high confidence, which exceeds the reliability of their delivery vehicles. Plus, recall that even an "unreliable" warhead might still completely destroy a city, as the government considers a warhead with an expected yield of 90 percent or less of its design yield as unreliable.

Further, while nuclear weapon laboratory scientists might be willing to certify a new untested weapon based on its theoretically greater performance margin (as compared to the legacy weapons), it's inconceivable that military officials would accept an arsenal of untested weapons under their command. This isn't a hypothesis: A similar scenario has already played out in France. Under President Francois Mitterrand, the French accepted untested new nuclear warheads into their submarine-based stockpile based on the results of sophisticated computer simulations. But when Jacques Chirac became president, France conducted a handful of nuclear explosions--just to make sure that the weapons actually worked. The same thing will undoubtedly happen with RRW if it goes forward. And if the proposed RRWs are eventually tested, it will be more difficult to stop other, possibly adversarial, nations from doing the same.

But back to RRW in the context of CTBT: The blue-ribbon NAS panel that was specifically tasked with examining the health of the U.S. arsenal in terms of CTBT ratification concluded that we can maintain confidence in the safety and reliability of our tested stockpile under a test ban. Moreover, in a detailed report, former Chairman of the Joint Chiefs of Staff John Shalikashvili painstakingly laid out the pros and cons of CTBT ratification for the country. His net assessment was that the CTBT "is a very important part of global nonproliferation efforts and is compatible with keeping a safe, reliable U.S. nuclear deterrent."

I, too, believe that U.S. interests, and those of our friends and allies, will be served by CTBT ratification and entry into force--without resorting to untested warheads that would undermine the credibility of our nuclear stockpile. However, if RRW supporters are still committed to holding the ratification of CTBT hostage to RRW funding, then, in my view, it would make sense to build the absolute minimum number of the new warheads to placate them. In the long run, ratification of the CTBT is more important.