LZH develops underwater laser method to defuse explosive ordnance in the sea

09 Mar 2022

Project UNLOWDET develops Laser-induced Low-Order Detonation to safely remove stray ordnance.

Together with project partners, researchers at Laser Center Hannover, Germany (LZH) are developing a process to defuse world war ammunition under water using a laser. Their goal: to affect the ecosystem as little as possible while saving time and costs.

In the North and Baltic Sea, an estimated approximately 1.6 million tons of war ammunition lie on the seabed. But the danger of their unforeseen detonation is not the only problem. Over time, the water causes the steel shell of the explosive ordnance to corrode, releasing the explosives into the sea – with significant environmental consequences for humans, animals and the entire ecosystem.

Removing explosive ordnance, however, is a challenge: blasting underwater is not only dangerous, it also creates significant pressure waves and affects the sea dwellers that live there. Furthermore, unreacted, environmentally harmful explosives can spread in the sea after detonation.

In the project UNLOWDET, scientists of the LZH are working on a solution together with the companies Laser on Demand and Eggers Kampfmittelbergung. Together they are researching how to defuse explosive ordnance underwater remotely controlled by a laser. Thereby, the impact of the blasting on the environment will be reduced.

Laser-induced detonation

For this, the project partners are following the approach of a so-called “Low-Order Detonation”, in which, in contrast to a “High-Order Detonation”, only a small part of the explosive is reacted.

In the first step, a laser beam is used to make a defined cut in the explosive ordnance, thus weakening the shell. In the second step, a Low-Order Detonation is then to be triggered with the laser beam, so that the detonator is removed and the ignition chain is interrupted. Since the system technology is to be positioned at the explosive ordnance with a diving robot, the process can be controlled from a safe distance.

This method makes the process of defusing not only safer but also significantly more efficient: For example, the time-consuming and cost-intensive application of bubble curtains, which are usually used for noise protection during blasting, can be dispensed with. At the same time, the risk of unreacted explosives spreading in the sea after detonation is minimized.

UNLOWDET making it quieter!

In the project UNLOWDET, the partners are developing a process for laser-induced underwater Low-Order Detonation for the efficient defusing of explosive ordnance in the sea. In addition to the LZH, Eggers Kampfmittelbergung, and Laser On Demand GmbH are involved.

LZH and partners previously developed a new method for defusing unexploded ordnance on land based on laser technology in the project DEFLAG (pictured, right).

Associated partners advising the project are the Hamburg Fire Department, the Lower Saxony State Office for Geoinformation and Land Surveying, the Bremen Police, the Schleswig-Holstein State Criminal Police Office, the State Office for Central Police Tasks and Technology, the GEOMAR Centre for Ocean Research Kiel and the Lower Saxony Ministry for the Environment, Energy, Building and Climate Protection.

The joint research project is funded by the German Federal Ministry for Economic Affairs and Climate Action under the funding code 03SX550B by the project coordinator Jülich.