rational defense

The Comprehensive Nuclear-Test-Ban Treaty prohibits all nuclear explosions for any purpose. Signed in 1996, the treaty has yet to be ratified by all parties and thus has not yet taken effect. Yet despite a handful of test by India and Pakistan in 1998 and a single ‘test’ in 2006 by North Korea[1], the ban has been observed in practice, over time establishing a taboo on further testing.

Obviously, even a signed treaty fully in force will not guarantee that even a signatory might not one day feel the need to test or use a nuclear weapon. RD is hardly professing a deep faith in the inviolability of written agreements when it comes to geopolitical struggles. But the more established that the ban becomes, the higher the cost of breaking it becomes. It does not actually prohibit anyone from anything, but it does change the calculus for testing and thus reduces its likelihood to some degree.

RD has argued that as long as this prohibition is observed, that it has profound implications for worldwide nuclear weapons development. In short, even crude nuclear devices are extremely complex mechanisms. Modern two-stage thermonuclear weapons are an intricate synthesis of a series of advanced technologies. Though obviously quite classified, current American warheads are widely thought to be two-stage thermonuclear designs, the newest with a non-spherical primary shaped like an egg. Translation: two distinct, but carefully timed nuclear chain reactions that must be precisely timed to a fraction of a fraction of a second. The non-spherical detail is important because it makes the already enormously complex implosion design even more intricate and complicated. Also hardened to endure not only the acceleration of launch, the cold vacuum of space and the immense heat of reentry but also electromagnetic interference, these warheads are then crammed into a steeply conical reentry vehicle composed of advanced composites to endure the heat of friction during reentry at extremely high speeds. These reentry vehicles are as small as six feet tall and less than two feet wide at the base. In sum, it is without exaggeration one of the most complex devices ever constructed by man.

These modern designs are the product of hundreds of nuclear tests (over a thousand in the American case) and dozens of operationally-fielded warheads over the course of nearly half a century. That testing is of paramount importance to the design of such a complex weapon. Though the U.S. National Labs now extensively use complex computer modeling, these models are informed by the data obtained through decades of testing.

In short, the testing freeze has the effect of severely curtailing the pace of global nuclear weapons development. Without testing, it is difficult for a country to make more than conservative evolutionary alterations to its existing, proven warhead architecture. Anything beyond conservative and evolutionary alteration would make certification without testing something of a gamble. Even with such a gamble, it would be difficult for a national command authority to have a particularly high confidence in such a warhead.

As such, the practical taboo against testing that gains credence with each passing year has the effect of removing much of the dynamism out of the global nuclear balance. The frantic pace of weapons development during the Cold War was only possible because of the equally frantic pace of testing. Without that testing, countries are in practice locked into conservative and evolutionary changes to the most modern warhead designs in their arsenals that they were able to verify through testing before the ban took effect. The more ambitious their changes, the more difficult those new designs become to accurately certify and the lower confidence will be that they will actually work.

So the test ban benefits most the countries that have the most advanced weapon designs: the United Kingdom, France, Russia but especially the United States (and perhaps Israel and China). Without the opportunity to validate extensive design changes and attempts at generational leaps in warhead architecture through actual testing, such weapons are difficult to certify. Ultimately, even with the inexorable improvement in computer modeling, without a resumption of testing on a broad scale,[2] the prospect for a highly dynamic nuclear balance reminiscent of the second half of the 20th century seems increasingly remote.

–

1 Weak seismographic data from the October 9, 2006 North Korean nuclear ‘test’ suggests a yield of less than a kiloton — and perhaps as low as half a kiloton. Though some radioactive output was detected, this suggests that the device fizzled. In other words, Pyongyang has never conducted a successful nuclear test.
2 Should testing on a 20th century scale resume, of course, all bets are off.