A team led by researchers from Germany’s Fraunhofer Institute for Chemical Technology has developed a semi-automated robotic system that could help bomb disposal teams deal with the millions of tonnes of hazardous ordnance and chemical weapons that lie on bottom of the North and Baltic seas.
The hazardous legacy of two world wars, much of this explosive cargo was sunk at sea at the end of the Second World War when fishermen were tasked by allied forces with dumping the weapons in designated areas far out at sea.
Many of these weapons were dumped outside marked munitions areas, whilst others have been displaced by strong currents and trawling activity.
As previously reported by The Engineer, this presents a major hazard at a time of almost unprecedented activity on the seabed when areas of the North Sea are home to some of the world’s biggest and most ambitious offshore energy projects.
Disposal is both hazardous and time-consuming and is typically carried out by divers from ordnance disposal teams or specialised companies, who typically relocate explosives to an area where they can be safely detonated.
Dubbed RoBEMM, the Fraunhofer-developed system, which was designed in collaboration with researchers from the University of Leipzig and a number of industrial partners, is claimed to be able to disassemble ammunition in the sea, thereby reducing the risk to divers.
“The project’s long-term goal is to render underwater ordnance harmless directly where it is found in a semi-automated process and then dispose of it in an environmentally friendly manner,” said Paul Müller from Fraunhofer ICT.
The Fraunhofer group’s key task was to develop a method to handle explosives in which every step minimises the inevitable residual risk of spontaneous explosion.
This includes ordnance handling, disassembly, destruction of explosives, and residue treatment. Desensitising explosives with water and subsequent fragmentation is a crucial operation. The metal cases are subsequently rinsed and the explosives thermally treated, leaving only scrap metal to be brought ashore.
Even after more than 70 years, the weapons found on the seabed are still dangerous: the explosives can still detonate, and the remnant substances are highly toxic. Indeed, researchers at Fraunhofer ICT have determined that the impact sensitivity of explosives may even increase over time. What’s more, many munitions produced towards the end of the war were poorly made and are therefore particularly volatile and unpredictable.
Initial tests of the bomb disposal robot are due to begin soon.