Reliable Replacement Warheads

November 6, 2007

in Bombs and rockets, Geek stuff, Law, Politics, Security

Old Montreal

Since July 16th, 1945 the United States has been a nuclear power. The first American thermonuclear weapon was detonated in 1952. During the span of the Cold War, tens of thousands of hydrogen bombs were assembled and mounted inside artillery shells, torpedoes, submarine launched missiles, cruise missiles, land-based ICBMs, and aircraft-mounted bombs. Now, these weapons are starting to age and a debate has emerged on what should be done with them.

Many of these weapons are highly complex. A standard submarine-based missile has a conical warhead. Inside is a uranium casing that serves to contain the original blast until a maximum amount of fission has occurred. At the bottom of that casing is a ‘pit’ of plutonium which is at a sub-critical density. Around that is a casing of brittle, toxic, neutron-reflecting beryllium. Inside it may be a cavity containing tritium and deuterium gas (in the case of a “boosted” primary). Around the beryllium outer sphere is a shell of high explosives designed to explode with fantastic precision, crush the plutonium pit to supercritical density, and initiate the fission reaction.

This whole assembly exists to initiate fusion in the ‘secondary,’ located higher in the outer uranium casing. The material that undergoes fusion – usually lithium deuteride – is wrapped around another sphere of uranium and is, in turn, wrapped in more uranium. All this is to create the largest possible yield in a relatively small and light package. The small size and conical shape allow eight or more of these devices to be placed on a single missile and then independently targeted once that missile is at the height of its ascent.

The 2008 budget allocated $6.5 billion for the maintenance of the American nuclear stockpile. That consists of 9,900 assembled warheads – 5,700 of them deployed operationally. In addition to these, about 7,000 plutonium pits are stored at the Pantex Plant in Amarillo, Texas. As the weapons age, concerns are developing about their reliability. They all contain high explosives, toxic chemicals, and corrosive agents. While it is possible to upgrade many of the non-nuclear components and replace them with more stable variants, the newly assembled bombs could not legally be tested: potentially leaving military commanders in doubt about their usability.

That is, in essence, the core of the ongoing debate about the Reliable Replacement Warhead (RRW). The program would begin by refurbishing 100 kiloton W76 warheads, which is already undergoing a less ambitious retrofitting. The hope is that the program can produce weapons with long durability and lower maintenance costs, and be able to do so without requiring full-scale tests of the devices, as were conducted in Nevada and the Marshall Islands during the Cold War. I won’t get into the details of the debate here. More than sufficient information exists online and in recent newspapers and magazines. What is less frequently considered are some of the aspects of international law relevant to nuclear weapons.

The whole program should remind people about an oft-forgotten element of the Nuclear Non-Proliferation Treaty. Everyone remembers the bit about signatories without nuclear weapons pledging not to acquire them. People forget that the treaty also obliges existing nuclear powers to reduce their arsenals as part of an overall progression towards de-nuclearization. Upgrading your nuclear arsenal to endure further decades of operational status is hardly consistent with this requirement. It also signals to other states that the United States continues to consider operationally deployed nuclear weapons an important part of their overall military strategy.

Individuals and organizations contemplating a sizable RRW program might also do well to re-read the Advisory Opinion on the Legality of the Threat or use of Nuclear Weapons set down by the International Court of Justice. While such legal considerations are relatively unlikely to affect whatever decisions are made in relation to the RRW, examining the status of the law can be a good way to reach decisions about the respective rights and obligations of states.

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{ 3 comments… read them below or add one }

. November 6, 2007 at 10:10 am

But a document newly obtained by the Washington, D.C.–based Federation of American Scientists (FAS)—founded by the creators of the original nuclear bomb in 1945 and monitoring the weapons ever since—reveals that in recent years the U.S. target list has expanded to include so-called “regional proliferators,” smaller states seeking to acquire such weapons of mass destruction.

“This is the first formal confirmation at that high level that those countries entered mainstream strategic nuclear war planning,” says Hans Kristensen, director of the Nuclear Information Project at FAS, which obtained the excerpt from a 2002 U.S. Strategic Command (U.S. STARTCOM) briefing on the new war plan to take effect in 2003. Such “broadening of nuclear targeting” is troubling, Kristensen says, “especially when diplomats claim we have decreased the role of nuclear weapons.”

Milan November 23, 2007 at 3:35 pm

Reliable evidence?

Nov 15th 2007
From The Economist print edition
America wants to ensure that its nuclear warheads would go bang rather than pop—but without letting them off to test them

“OLD soldiers never die, they just fade away. Old weapons, on the other hand, hang around stubbornly. Those of the nuclear variety left over from the cold war are causing a bit of a nuisance. Thousands of them are ageing in silos. Ensuring that they do not deteriorate and would detonate if necessary is difficult. That is because of the Comprehensive Test Ban Treaty which, as its name suggests, forbids contracted parties from letting off nuclear explosives in peacetime.

Although America has yet to ratify this treaty, its policy is to act as though it had. It stopped the tests of real warheads (such as the one illustrated above) in 1992. That means scientists wishing to find out whether a particular batch is still potent cannot just pluck a warhead at random from the stockpile and try to explode it. One way to overcome this would be to replace the warheads with newer designs that, proponents argue, would not need to be live-tested in this way. The older warheads, the most elderly of which will reach the end of their 30-year design lifespan in 2008, could then be retired without compromising the country’s nuclear shield.”

. November 23, 2009 at 9:47 am

Aging Nuclear Stockpile Good For Decades To Come

The NY Times reports that the Jason panel, an independent group of scientists advising the federal government on issues of science and technology, has concluded that the program to refurbish aging nuclear arms is sufficient to guarantee their destructiveness for decades to come, obviating a need for a costly new generation of more reliable warheads, as proposed by former President Bush. Senator Jon Kyl of Arizona and other Republicans have argued that concerns are growing over the reliability of the US’s aging nuclear stockpile, and that the possible need for new designs means the nation should retain the right to conduct underground tests of new nuclear weapons. The existing warheads were originally designed for relatively short lifetimes and frequent replacement with better models, but such modernization ended after the US quit testing nuclear arms in 1992. All weapons that remain in the arsenal must now undergo a refurbishment process, known as life extension. The Jason panel found no evidence that the accumulated changes from aging and refurbishment posed any threat to weapon destructiveness, and that the ‘lifetimes of today’s nuclear warheads could be extended for decades, with no anticipated loss of confidence.’ But the panel added that federal indifference could undermine the nuclear refurbishment program (as this report from last May illustrates). Quoting the report (PDF): ‘The study team is concerned that this expertise is threatened by lack of program stability, perceived lack of mission importance and degradation of the work environment.’”

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