W89

It entered Phase 2A technical definition and cost study in November 1986. It entered Phase 3 development engineering and was assigned the numerical designation W89 in January 1988. The W89 design was a 13.3-inch (33.8 cm) diameter by 40.8-inch (103.6 cm) long weapon, with a weight of 324 pounds (147 kg) and yield according to unofficial information of 200 kilotons. The design was canceled in September 1991 along with the SRAM II missile, prior to production of any units, though some test devices may have been manufactured. According to one source, the plutonium cores (technically known as pits) of the W89 warheads were planned to be reused from existing W68 warhead pits, which were surplus at the time. Lawrence Livermore engineers have hinted in prior press reports that the Reliable Replacement Warhead design that they were preparing might be based on the W89 warhead design. On March 2, 2007, the NNSA announced that the Lawrence Livermore National Laboratory RRW design had been selected for the initial RRW production version. One of the selection reasons given was that the LLNL proposed design was more closely tied to historical underground tested warhead designs.