Cut and Capture System Technology for Demilitarization of Underwater Munitions
Steven Schmit | Gradient Technology
The overall objective of this project is to evaluate the use of remotely operated high-pressure waterjets to cut open hazardous unexploded ordnance (UXO) and discarded military munitions (DMM) and a capture system to capture the munition constituents of ordnance that litter the ocean floors with as little disturbance of aquatic corals and sea mammals as possible. The research combines phased tank-based and at-sea experiments to test munition accessing and content removal as an environmentally friendly alternative to blow-in-place (BIP). Data collection and analysis of qualitative munition breaching and quantitative content capture will provide validation of the process.
This demonstration takes a multi-phased approach toward substantiating the technology and in evaluating appropriate technologies for underwater demilitarization. Technology adapted from deep sea salvage operations will be used to firmly attach process equipment to the suspect munition using suction rings to form a leak-tight seal. A high-pressure abrasive entrainment waterjet will then be used to provide an access hole into the body of the munition casing. Once the access hole has been made in the munition a second high-pressure waterjet will be used to substantially wash out the internal explosive, or other filler, from the munition. The washed out munition constituents will be captured in bags for later analysis and disposal. Waterjets, operating at pressures up to 55,000 psi, are a non-traditional engineering technology that has shown great utility in land-based demilitarization and recycling of high-explosive ordnance. High-pressure waterjets have been proven to be safe for explosive ordnance recycling with an estimated two million or more successful cuts without incident during land based operations.
The novel use of high-pressure waterjets for cutting and capturing the contents of underwater explosive ordnance utilizes a remotely operated vehicle (ROV) to safely allow all control from the surface without the need for placing divers in the water and can operate continuously day and night. The process has significant environmental benefits over existing destructive technologies as there is as little collateral damage as possible to existing corals or other marine encrustations outside of the immediate device footprint. In addition, the low noise level generated by the cut and capture system presents a low risk of sonic injury to marine mammals that can be injured by existing destructive technologies.
The project intends to demonstrate the applicability of the underwater cut and capture system against inert ordnance in a test tank and in-situ in the ocean. Successful operation of the cut and capture system will be determined by the ability of the device to attach to encrusted munition shapes, cut through the casing wall, and to substantially remove and capture the munition filler.
The underwater cut and capture (C&C) system has substantial potential benefits over existing procedures. The operation of the C&C system can be performed by ROVs which remove divers from the hazards of long hours of diving as well as with working with explosive devices. The ROVs can maintain operations for over 168 hours without surfacing while divers have very limited worktime at depth. The cut and capture technology is applicable for use on demilitarizing almost all munitions underwater, as compared to traditional BIP techniques which only work with explosive munitions where the collateral damage can be tolerated. The C&C process reduces the impact on the marine flora and fauna in stark comparison to the devastation caused by BIP procedures. The impact on the marine biota, such as endangered corals and other aquatic life, will be reduced to approximately the device footprint of approximately 0.01 m2. In comparison, the detonation of even a small “bottle bomb” can destroy over 7 m2 of coral, as shown in Jennings and Polunin (1996). Coral fragments that are not directly killed by the blast may experience further post-disturbance mortality in the shifting rubble. On the other hand, the low noise level of the cut and capture water jets is not expected to have any deleterious effects on marine mammals in proximity, as compared to research which shows that an underwater BIP can deafen whales and porpoises out to many kilometers, as shown in Ketten (1995), Klima, et al., (1988), and Yelverton, et al., (1973).