Sunday, January 07, 2007

The insatiable need to violate past agreements, to make the world a more dangerous place

Dazed and Confused by RRW - Parts 1 and 2

If you've been following the debate over the Reliable Replacement Warhead program (RRW) – and if you haven't, you should be – there's a good chance that you're confused over how this program is supposed to go about revolutionizing the U.S. nuclear weapons stockpile. Is RRW a "program to improve the reliability [and] longevity... of existing weapons and their components"? Or is it an "enabler" for a long-term goal of building "new (or replacement) warheads"?

Trinity1.jpgIf you're confused, you're not alone. Even the Congressional Research Service dryly observed that "many find RRW to be confusing because it is a new program and descriptions of it have changed." (The CRS study linked here, by the way, is an absolute must-read for anyone who's interested in these issues.)

Just last week, Stephen I. Schwartz wrote here on Defense Tech that even as controversy still swirls over the first RRW warhead program, the labs are developing plans for as many as three other RRW warheads – and that the end-result of RRW will be not a fixed, long-lived warhead design, but rather "steady-state production of warheads for deployment."

In order to understand what RRW is, and what it might evolve into, it’s important to take a step back and look at where the U.S. stockpile is today, and how it got there. Over the next few days, I’m going to do my best to summarize the history of stockpile stewardship in the U.S. and the debates which led to the creation of RRW (which I wrote about in greater detail here). Then we can get to the meat of what RRW is all about.

Below the jump – the Cold War ends, and Stockpile Stewardship is (re)born.

During the Cold War, high turnover was the key to maintaining confidence in the reliability of the nuclear stockpile. New weapons were constantly being designed, built, tested and added to the stockpile, allowing older weapons to be retired, or relegated to reserve status; warheads rarely accumulated more than a couple of decades of shelf life, at most.

Once a production run of warheads had made it into the stockpile, odds were slim that any of the warheads in the run would be tested again. The exception to this rule were the relatively small number of so-called "stockpile confidence tests" which took place during the late 1970s, 1980s and early 1990s, and the primary stages which were occasionally taken from stockpile warheads for use in tests of new weapons concepts.

Warhead2.jpgWhile stockpiled warheads were not often put through further nuclear tests, they were routinely sampled for disassembly, thorough inspection and all sorts of non-nuclear (or above-ground) testing. This activity, known as stockpile surveillance, was intended to catch production defects and aging-related deterioration to any of the warhead's 3000 components. Most of these components are located outside of the warhead's nuclear subsystem, so their full range of functions could be tested without a nuclear test.

The knowledge base developed over forty years of stockpile surveillance (beginning with the introduction of sealed-pit designs in the late 1950s) laid the foundations for the Stockpile Stewardship Program (SSP), which was officially born in 1994.

Three events which took place at the end of the Cold War led to the creation of SSP. In 1989, the Rocky Flats site in Colorado, where all the plutonium "pits," or triggers, in the stockpile had been produced, was shut down after years of egregious health and safety violations. In 1992, shortly before its dissolution, the USSR declared a unilateral moratorium on nuclear testing. In response, Congress passed a similar testing moratorium, and the President George H. W. Bush announced an indefinite moratorium on the introduction of new weapon designs into the stockpile. The era of high stockpile turnover was over, and the Stockpile Stewardship Program was born.

The Stockpile Stewardship Program was organized by Congress from the Department of Energy's existing stewardship activities in the 1994 Defense Authorization Act. The program was part of a new policy aimed at keeping the nation's bomb-making skills and facilities in suspended animation in case a new nuclear arms race were to break out.

In keeping with this policy, resources which were cut from bomb-making and nuclear testing activities were channeled to the three activities necessary for stockpile stewardship: improving the nuclear complex's understanding of the science of warhead performance and aging (known as "stockpile science"), keeping an eye out for signs of deterioration as warheads age ("stockpile surveillance") and repairing problems which may arise ("warhead life extension").

You can find more details about these three activities in the paper I mentioned earlier (including some worrying reports about the problems SSP has had coordinating the different activities).

The goal of the life extension programs (LEP) is to add anywhere from 20 to 30 years onto the (nominal) design lifetimes of the various warhead models in the stockpile (of course, "there is no such thing as a 'design life'"...). The W87 ICBM warhead became the first warhead to complete its LEP in 2004. The B61 bomb warhead and the W76 SLBM warhead – the first warhead slated for replacement under RRW – are currently undergoing LEPs, while the W80 cruise-missile warhead’s LEP was recently canceled by the Nuclear Weapons Council in order to free up funds for RRW.

A life extension program is a sort of 50,000-mile tune-up for a nuclear warhead: limited-lifetime components such as batteries and neutron generators are replaced, along with any other parts – "cables, elastomers, valves, pads, foam supports, telemetries, and miscellaneous parts" – which may have degraded. Most of these replacements take place outside the warhead’s nuclear explosives package, however.

While these tasks sound mundane, manufacturing the replacement components is no mean task. Manufacturing lines still exist for some components, but in other cases, lines have been dismantled, suppliers have canceled product lines or gone out of business, and health, safety and environmental regulations have grown stricter.

In these cases, a dilemma arises: should the nuclear production complex go to extreme lengths to recreate the processes needed to remanufacture these components exactly according to the original specifications? Or should they look for ways to make replacement parts that will work just as well, if not better? Since the part has to be replaced anyway, why not make maintenance easier for future generations already?

For components outside the warheads' nuclear explosives package, modifying the manufacturing specs is an attractive option, since each new component can be tested exhaustively without underground nuclear testing.

If too many of these minor changes pile up, though, a sort of "Grandfather’s axe" effect may kick in: if enough components have been modified and replaced, is the warhead design still the same one that was once tested? For this reason, the guiding philosophy has been "change-control discipline": make the fewest number of changes possible, and only after proving exhaustively that the changes will not affect warhead characteristics.

For nuclear components, the problem is more serious. While there are ways to investigate how a nuclear component will behave when detonated – computer simulations which model the component, dynamic and quasi-static experiments which measure its relevant physical properties, sub-critical experiments which assess its behavior under conditions similar to actual detonation – none of these methods has the same doubt-erasing effect as an underground nuclear test.

Any modification to proven designs for nuclear components is therefore bound to cause anxiety as long as underground nuclear testing is forbidden.

Conceptually, this is where the Reliable Replacement Warhead program (RRW) enters the picture.

While some members of the stockpile policy community argue that something like change-control discipline can be applied to nuclear components, too, others believe that if any modification is going to be made to the nuclear explosives package, a broader set of changes has to be made to the warhead design try to offset any possible drop in the performance of those modified components.

In brief, the changes being contemplated by those in the latter camp would increase the performance margins of warhead designs. The performance margin is the difference between the energy which the primary stage is expected to produce and the minimum energy needed to set off the secondary stage – essentially, the warhead's margin of error.

Since increasing the performance margin would require modifications to warhead designs that go well beyond what change-control discipline would allow, it would require an entirely new philosophy of stockpile stewardship. This philosophy is to be put into practice through a program known as Reliable Replacement Warhead.

RRW was introduced into the fiscal year 2005 Department of Energy budget by Rep. David Hobson, R-Ohio, the chairman of the House Appropriations Committee's Energy and Water Subcommittee. Hobson, a noted budget hawk, believed that the Bush Administration’s latest nuclear weapons program, the Robust Nuclear Earth Penetrator (RNEP) – or "nuclear bunker buster" – would be both costly and unnecessary, not to mention harmful to the nation’s non-proliferation posture. His committee therefore cut all funds for RNEP, and allocated the funds instead to a "program to improve the reliability [and] longevity... of existing weapons and their components" – and RRW was born.

Almost immediately, rumors began to circulate that the Department of Defense intended to use RRW as an opportunity to expand the capabilities of the U.S. nuclear arsenal – to work around the cancellation of RNEP. These rumors led Hobson, in March 2006, to complain that "sometimes within the [DOE], people hear only what they want to hear," and remind NNSA head Linton Brooks that "this is not an opportunity to run off and develop a whole bunch of new capabilities and new weapons."

Even today, though, Brooks continues to advertise RRW as an "enabler" for the transition to a "responsive infrastructure" which will one day "provide capabilities, if required, to produce weapons with different or modified military capabilities". And the official DOD website on "Stockpile Transformation" (the generic name for RRW and related plans) boasts of a goal of "develop[ing] warheads for next-generation delivery systems" – seemingly a direct contradiction of Hobson’s injunction.

This ongoing back-and-forth about RRW’s purpose inspired the Congressional Research Service’s comment, quoted in my earlier post, that "many find RRW to be confusing."In the third post, I will discuss the changes which are being made to the warheads' nuclear components, and examine the debate over whether or not those changes require a wider set of modifications to the warhead designs – and therefore RRW.

Original article postd here.

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