The W89 was an American thermonuclear warhead design intended for use on the AGM-131 SRAM II

AGM-131 SRAM II

The SRAM II was a nuclear air-to-surface missile intended as a replacement for the AGM-69 SRAM, but it was cancelled by President George H.W...

 air to ground nuclear missile.

What was to become the W89 design was awarded to the Lawrence Livermore National Laboratory

Lawrence Livermore National Laboratory

The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...

 in the mid-1980s. 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 inches (33.8 cm) diameter by 40.8 inches (103.6 cm) long weapon, with a weight of 324 pounds (147 kg) and yield of 200 kilotons.

The design was cancelled in September 1991 along with the SRAM II missile, prior to production of any units, though some test devices may have been manufactured.

Reused plutonium pits

According to one source, the plutonium cores (technically known as pits) of the W89 warheads were planned to be reused from existing W68

W68

The W68 warhead was the warhead used on the UGM-73 Poseidon SLBM missile. It was developed in the late 1960s at Lawrence Livermore National Laboratory.-Specifications:The W68 weighs...

 warhead pits, which were surplus at the time.

Reliable Replacement Warhead link

Lawrence Livermore engineers have hinted in prior press reports that the Reliable Replacement Warhead

Reliable Replacement Warhead

The Reliable Replacement Warhead was a proposed new American nuclear warhead design and bomb family that was intended to be simple, reliable and to provide a long-lasting, low maintenance future nuclear force for the United States...

 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

Lawrence Livermore National Laboratory

The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...

 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. It was described by Thomas P. D'Agostino, acting head of the National Nuclear Security Administration

National Nuclear Security Administration

The United States National Nuclear Security Administration is part of the United States Department of Energy. It works to improve national security through the military application of nuclear energy...

, as having been based on a design which was test fired in the 1980s, but never entered service.

LLNL staff have previously hinted in the press that LLNL was considering a design entry based on the tested but never deployed W89 design.
The W89 warhead had been proposed as a W88

W88

The W88 is a United States thermonuclear warhead, with an estimated yield of 475 kiloton , and is small enough to fit on MIRVed missiles. The W88 was designed at the Los Alamos National Laboratory in the 1970s. In 1999 the director of Los Alamos who had presided over its design described it as...

 warhead replacement as early as 1991. The W89 design was already equipped with all then-current safety features, including insensitive high explosives, fire-resistant pits, and advanced detonator safety systems. The W89 was also reportedly designed using recycled pits from the earlier W68

W68

The W68 warhead was the warhead used on the UGM-73 Poseidon SLBM missile. It was developed in the late 1960s at Lawrence Livermore National Laboratory.-Specifications:The W68 weighs...

 nuclear weapon program, recoated in vanadium

Vanadium

Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...

to provide the temperature resistance. The W89 warhead was test fired in the 1980s.

External links

• University of California 1989 nuclear weapons labs status report
• Allbombs.html at the Nuclear Weapon Archive at nuclearweaponarchive.org