目前,美国核武器中的平均用钚量正在显著上升,这是因为某些原来使用高浓铀的武器在逐渐改用钚。新设计的核武器,一般都要求直径小一些,武器用钚量的上升,正是为了满足小直径内爆装置的要求。钚的纯度对核武器的质量影响颇大。美国五十年代末和六十年代部署在欧洲的六千余枚核武器大部分是老式的战术裂变武器,武器用钚的成分是:钚-239为93%,钚-240为6%,钚-241及其它杂质为1%。美国目前正在研究一种特殊的同位素分离法——气态铜系统的激光同位素分离法,通过它可以提供超纯钚。利弗莫尔研究所准 At present, the average amount of helium used in US nuclear weapons is rising significantly. This is because some of the weapons originally using HEU gradually use helium. Newly designed nuclear weapons generally require smaller diameters. The increase in the amount of helium for weapons is precisely to meet the requirements for small-diameter implosion devices. The purity of plutonium has a great influence on the quality of nuclear weapons. Most of the more than 6,000 nuclear weapons deployed in Europe in the late 1950s and 1960s in the United States were old-fashioned tactical fission weapons. The composition of weapons used is: 钚-239 is 93%, 钚-240 is 6%, and 钚- 241 and other impurities are 1%. The United States is currently studying a special isotope separation method - laser isotope separation of gaseous copper systems, which can provide ultra pure germanium. Livermore Institute