June 1, 1998
ISIS has no evidence that Pakistan has produced enough plutonium for even one nuclear weapon, although a newly commissioned plutonium production reactor may, within a few years, produce significant quantities of plutonium.
In the 1970s, Pakistan tried to acquire the ability to separate large quantities of plutonium from irradiated fuel under the cover of pursuing civil nuclear technologies. The plutonium would likely have been produced in Pakistan's power reactor. This effort was thwarted by Western suppliers, who realized Pakistan's true purpose. Before this assistance was discontinued and international safeguards strengthened on Pakistan's power reactor program, however, Pakistan managed to build a small plutonium separation laboratory, called New Labs. Estimates of the amount of plutonium separated at New Labs are below the amount needed to build a plutonium-based nuclear weapon. The estimate is based on Pakistan's shortage of unsafeguarded irradiated fuel and the relatively small capacity of New Labs.
In April 1998, Pakistan announced that it had commissioned an unsafeguarded, 50 to 70 megawatt (MW) nuclear reactor. The reactor, fueled with natural uranium and moderated by heavy water, was constructed with Chinese assistance. However, it is unknown from public sources when this reactor may achieve full power, although the experience of similar countries suggests that full-power operation could be within a few years. This date could be reached more quickly if Pakistan decides that producing plutonium is an national priority.
In any case, assuming that the roughly 50 MW reactor operates at full power an average of 60 to 80 percent of the year, Pakistan would be able to produce 10 to 15 kg of weapon-grade plutonium per year. After separation from the irradiated fuel, in New Labs or elsewhere, the plutonium could be made into bomb components. Because these various steps take time, it is highly unlikely that the devices tested by Pakistan could have used plutonium from this reactor.