THE US Senate was not justified in rejecting the Comprehensive Nuclear Test Ban Treaty in 1999, according to the US National Academy of Sciences, which has analysed the reasons the Senate cited for the rejection.
The treaty bans all tests of nuclear explosives, but opponents in the US government claimed it would prevent the country from safely maintaining its nuclear stockpile. They also said it would be impossible to monitor compliance, and that cheating would endanger US security. But a study published last week by the NAS refutes all three objections, and concludes that the US would be safer with the treaty than without.
Critics of the treaty have long complained that it would be impossible to detect covert explosions. But the panel behind the report, headed by Harvard professor of environmental policy John Holdren, says that any tests small enough to slip under the detection threshold would be of little use to a country that didn’t already have nuclear weapons.
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“We judge that an underground nuclear explosion cannot be confidently hidden if its yield is larger than 1 or 2 kilotons,” the panel concluded. By contrast, the crude fission weapons that destroyed Hiroshima and Nagasaki yielded 10 to 20 kilotons. To hide small explosions, countries would need to conduct their tests in an “insulating” cavity or simultaneously detonate large amounts of conventional explosives nearby. Explosions in water, open air or solid rock would be easier to spot. Countries such as Russia and China might be able to conceal smaller tests, but states lacking nuclear expertise would have a hard time designing low-yield tests or learning much from them.
Worries that US nuclear stockpiles will degrade over time unless tests continue are also unfounded, says the NAS. “The United States has the technical capability to maintain confidence in the safety and reliability of its existing nuclear weapon stockpile” without further nuclear tests, the panel concluded. Most of the hundreds of nuclear tests the US has performed over the years have been part of weapons development or have tested newly produced models. Only two have been to test older, stockpiled weapons.
However, the report is unlikely to make a big political impact, because it was commissioned in 2000 by the previous Democrat administration. The treaty was rejected by a Republican Senate, and although the Senate is now Democrat-controlled, the Republican Bush administration has said it will not submit the treaty to the Senate for ratification.
The US has not conducted a test since 1992, and the Bush administration has not announced plans to resume testing. But that could change with pressure to develop new “bunker-busting” nuclear warheads (91av, 7 October 2000, p 6). Verifying any new designs would probably involve nuclear tests. While the report addressed the reasons given by Senate for rejecting the treaty, it did not consider the issues of military strategy or the desire to test new weapons.