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U.S. Department of Energy
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Development of an inspection vehicle for the detection of stress corrosion cracking in natural gas pipelines. Final report

Technical Report ·
OSTI ID:10169099
; ;  [1]
  1. Pope (C.W.) and Associates, Georgetown, NSW (Australia)
C. W. Pope and Associates have developed a system to detect stress corrosion cracking (SCC) exceeding 20% wall thickness in natural gas pipelines. This development constituted a research agreement with the Pipeline Research Committee (PRC) of the American Gas Association (AGA). The research program consisted of a set of development milestones followed by three sets of field trials of increasing complexity and environmental harshness. The Newcastle Field Trials, the Australian Field Trials and the US Field Trials are detailed in this report. The system allows the direct comparison between two different detection technologies being piezoelectric technology and electromagnetic acoustic transducer (EMAT) technology. The system is capable of continuous sampling runs of up to 4.8km (3 miles). The system consists of a self contained, battery powered vehicle controlled by on board computers linked with a set of user interface computers via a radio telemetry link. The vehicle is programmed to move through unpressurized pipe to report areas of ultrasonic activity corresponding to SCC in the bottom section of the pipe. The system performed reliably in the harsh desert environment over the three week period in Arizona that exceeded 43{degrees}C (11O{degrees}F) daily. Fine dust present in the field also added to the demands on equipment and personnel. Following these trials the two test lines were dug up, coating removed and examined by magnetic particle inspection (MPI) for verification. Selected lengths were transported to El Paso upon request for later follow up. This report reviews the two detection technologies. The EMAT detection technology proved successful in detecting intergranular SCC while the piezoelectric wheel probe technology proved disappointing in real pipe conditions. This report makes reference to results of the El Paso pipeline digups and lists design concepts for future development of the system in the detection of SCC in pipelines.
Research Organization:
American Gas Association, Inc., Arlington, VA (United States). Pipeline Research Committee; Pope (C.W.) and Associates, Georgetown, NSW (Australia)
Sponsoring Organization:
American Gas Association, Inc., Arlington, VA (United States)
OSTI ID:
10169099
Report Number(s):
AGA--94015618; ON: UN94015618; CNN: Project PR-198-9108
Country of Publication:
United States
Language:
English