NPL tests new methods to dispose of unexploded ordnance on seabed

The study compared newly developed methods for ordnance disposal with existing techniques and its findings have published in Marine Pollution Bulletin.

Unexploded ordnance from World Wars One and Two, plus military exercises and tests, poses a major environmental and safety hazard to fishing vessels, maritime traffic and offshore developments such as windfarms. The current removal method - high order detonation - presents a significant risk of injury or death to marine mammals and other fauna. It also causes seabed craters.

In the first study, NPL scientists and researchers from Loughborough University, Aarhus University in Denmark and staff from Aberdeen-based environmental consultancy Hartley-Anderson, conducted a series of experiments, including a field trial in the Baltic Sea, to compare the sound produced by high order detonations with that produced by so-called deflagration.

Developed by Alford Technologies, a Chippenham-based ordnance disposal company, deflagration involves placing a small shaped explosive charge on an unexploded bomb or shell to penetrate its casing and then insert a hot gas such as plasma. This burns away the explosive inside, but at a slow rate so that it doesn’t detonate. The bomb or shell is disarmed, leaving a residue of unburned inert explosive which is then cleared away.