"[W]ith Pakistan's help, the North Koreans had 'chopped many years off' the development process" of an enriched- uranium bomb.... Pakistan helped North Korea conduct a series of 'cold tests,' simulated nuclear explosions, using natural uranium, which are necessary to determine whether a nuclear device will detonate properly."
http://www.newyorker.com/fact/content/?030127fa_fact
--tim francis-wright "He can't make ends meet--probably too many economists in the government" -- The Doctor, The Sunmakers.