Dropping a nuclear warhead may not seem like a particularly bright idea, but earlier this year Sandia National Laboratories did just that. As part of the US government’s Life Extension Program (LEP) for its nuclear arsenal, the inert W88 ALT 370 warhead was dropped from a crane in New Mexico onto a slab of concrete to test the updated design’s safety.

The United States hasn't fielded a new nuclear weapon since 1988 and its deterrent arsenal is the oldest in the world. In order to ensure that the current inventory of warheads remain safe and effective for another 20 to 30 years, the National Nuclear Security Administration is carrying out a program of inspecting, refurbishing, and updating the stockpile. As part of this effort, Sandia carried out a series of tests this year on the W88’s radar arming and fusing system, as well as drop tests to simulate a loading accident involving the warhead.

The purpose of the tests was to determine how well the modifications to the warhead work, as well as gathering data for computer modeling for further updates and simulations of various accident scenarios. In the first test, the Critical Radar Arming and Fuzing Test (CRAFT), an unarmed W88 was launched in June by a Trident II missile from an Ohio-class nuclear submarine with the goal of seeing how the radar operated at hypersonic re-entry speeds, which generate ionized plasma that can interfere with radar.

The second test was conducted in July at Sandia’s 85-foot Drop Tower Facility. Its purpose was to see if the warhead could remain safe after a fall similar to one that might occur during a loading or shipping accident. In real life, there would be no chance of a nuclear explosion, and the warhead would not be expected to function afterward, but there is concern that radioactive or toxic materials might be exposed should the warhead’s casing crack.

Sandia says that this is the first drop test conducted on a W88 warhead since 1988. The shock and vibration data will be used to update its design specifications for later modifications and to simulate other accidents that might occur, but have not been tested in real life.

The W88 is one of the United State’s primary nuclear weapons. With a yield of 475 kilotons, it’s designed to be small enough for as many as 14 to be fitted in a MIRV configuration atop a Trident II missile, though only eight are carried on each launcher under the terms of the Strategic Offensive Reductions Treaty.

Sandia and its partners are currently evaluating the results from both sets of tests, though the company says that the radar functioned as expected.

Source: Sandia