Explosives that won’t detonate unless activated with an inert fluid

This technology has the potential to make the transport and storage of explosive materials safer.

A high-speed camera  frame of a detonation wave propagating through a liquid-filled, 3D-printed high-explosive lattice. The lattice was “switched on” when it was filled with water.  | Photo Credit: Physical Review Letters

The volatility of certain high explosives presents a potential hazard. Impact, heat, or friction can produce an unplanned explosion with high explosive materials. For example, the 2020 incident of accidental detonation of stored ammonium nitrate in Beirut, Lebanon, killed more than 200 people, including workers and nearby residents. Equivalent to an earthquake, the explosion levelled the port district and was felt across the country and the region. While unusually large, the event was not unprecedented; 500 unplanned explosions occurred at munitions plants from 1979 to 2013, according to an estimate.

A team of Los Alamos National Laboratory scientists has developed a way to create “switchable” high explosives that will not detonate unless activated by being filled with an inert fluid, such as water. They fabricated high-explosive charges with a lattice structure that by themselves cannot sustain detonation. They found that an unfilled charge’s Gurney energy—the propulsion resulting from an expansion of gaseous products in an explosive—was 98 per cent lower than that of an equivalent water-filled charge. Their findings were published in a recent issue of Physical Review Letters.

“We’ve designed a high explosive system that won’t work when it’s not supposed to, like during transport and storage, but can quickly be made ready when required,” said Alexander Mueller, principal investigator for the project.

The team also found that replacing water with higher density fluids increased propulsion by up to 8.5 per cent and decreased detonation velocity by 13.4 per cent. The results point to the technology’s possible tenability for a variety of industrial purposes.