REMOTE NDE TECHNOLOGY FOR INACCESSIBLE SHIPBOARD PIPING INSPECTION

摘要

Piping inside fuel and ballast tanks on US Navy ships requires periodic inspection and maintenance. However, because the cost to open and enter tanks for inspection is considerable the Navy has extended scheduled in-tank inspections by up to 12 years. This has reduced maintenance costs but has increased the risk that piping corrosion goes undetected. This has led to some unexpected piping failures and in a few cases has resulted in oil spills. To prevent these pipe failures the US Navy is evaluating technologies that can enable rapid and inexpensive periodic condition assessment of piping that is inside of fuel and ballast tanks. Pipe failures were investigated to determine the exact nature of the failures and the ship systems most affected. Then a detailed technical performance requirements list was developed on which to base a review of remote inspection equipment capability. Commercially available technologies were identified and candidates selected for laboratory evaluation. The technologies presently undergoing evaluation include those that involve the insertion of sensor(s) into the pipe from outside of the tank as well as non-invasive techniques that use externally placed sensors from outside of the tank. This paper provides an overview of the problem definition, the performance specifications and a description of some potential technology solutions. The capabilities and limitations of each of the technologies under investigation are presented along with some preliminary performance testing results.