Researchers at the National Institute of Standards and Technology and Colorado School of Mines have developed a prototype sensor that quickly detects very small amounts of hydrogen accumulation in coated pipeline steel. Hydrogen can cause gradual embrittlement in conventional pipelines by slowly diffusing into the metal. The new sensor could provide early warning of pipes that have accumulated excessive amounts of hydrogen and avert potentially disastrous failures of pipelines carrying hydrogen fuel.
The nondestructive, non-contact hydrogen sensor is approximately 4 square inches and is designed to be a portable sensor to make measurements on excavated or unexcavated pipeline steels. The sensor sends a current through the pipe, and measures changes in impedance as an indicator of hydrogen content within the steel and the overall steel pipe integrity. The hydrogen sensor generates alternating currents into the pipeline steel, which induces an opposing magnetic field. Any change in the hydrogen content in the steel modifies the current, resistivity, and thus the impedance. The sensor can measure hydrogen content levels in pipeline steel well below 1 part per million.