uired to reach the boosted yield.However, boosting adds its own problems to nuclear weapon design and maintenance because hydrogen reacts chemically with plutonium and uranium, and the artificial isotope of hydrogen (tritium) has a half-life of 12.3 years, so that the tritium supply must be renewed on a scale of several years. Although the remaining tritium can be recycled, boosting imposes the requirement for continued production of tritium if nuclear weapon numbers do not fall with time faster than the decay rate of tritium.In 1952, the United States demonstrated with its 10-megaton yield “MIKE” test the concept introduced in early 1951 by Edward Teller and Stanislaw Ulam, by which the energy from a “primary” nuclear explosion, emerging as thermal X-rays, is used to assemble a “secondary” charge containing thermonuclear fuel. Initially, the secondary contained liquid deuterium, which required refrigeration and was unwieldy. The secondary was soon replaced with solid thermonuclear fuel, using deuterium that was solidified by chemical binding to the naturally occurring lighter isotope of lithium, which captures neutrons in the process and yields tritium to burn with deuterium. --R.L.G....
