Pipe Crawler Internal Piping Characterization System

Category: Characterization > Monitors > Multipurpose Detectors
Reference # : OST No 1810 , DOE/EM - 0355 Model No : PipeCrawler

Pipe Crawler was developed by Radiological Services, Inc., for use as part of a turnkey pipe inspection, decontamination and survey service. The technology consists of a wheeled robot, or mule, on which is mounted an array of thin Geiger Mueller (G-M) detectors. The crawler is manually transported through pipes using flexible fiberglass rods. If piping systems are accessible from both ends, up to 200 feet of pipe, including multiple bends can be surveyed. Crawlers have been building for pipes as small as 2 inch to as large as 18-inch internal diameter. Pipe Crawler was demonstrated in December 1996 at Argonne National Laboratory's CP-5 reactor as part of DOE's Large Scale Demonstration Program. Surveys were conducted primarily in the rod storage holes, along with portions of a pair of 12-inch vent lines servicing the reactor area. Several rod storage holes each of 5-, 6- and 12-inch diameter and 10- to 17-foot depth were surveyed, along with about 40 feet of the combined vent lines. All surveys were preceded by a recorded video inspection, but without the benefit of any pipe pre-decontamination. Dimensions of Tech Model (LxWxH):Diameter: 12 in 18 in X 36 inWeight of Tech Model (lb): 50 lb

Benefits

Covers wide range of pipe sizes, lengths, and materials Capable of making activity measurements of sufficient quality inside piping to support free-release decisions Saving of 45% of original cost estimate for the CP-5 project based on demonstrations results vs. anticipated cost of excavation and disposal Pipe Crawler covers a wide range of pipe sizes, lengths and materials Surface coverage can be adjusted to any desired level to meet release requirements Detector arrays have ample sensitivity relative to release limits Detector array calibration is straightforward using the dispersed calibration sources Maintenance of precise detector geometry during surveys assures accurate readings Calibration control charts, daily response checks, and detectors array "knockdowns" lend further confidence to the reliability of measurements Use of off-the shelf detectors and other components simplifies repairs and increases up time The system generates little or no waste

Limitations

A single crawler can survey only a narrow range of pipe diameters, typically plus or minus. 5 in. The technology is not well suited to alpha surveys, especially in large pipes, due to geometry of detectors relative to pipe surfaces Stepwise movement of crawlers is time consuming and labor intensive but yields ample delectability and readily identifies hot spots Units are currently custom made and used as part of turnkey service, hence current capacity is fairly limited; widespread implementation would probably require considerable "tooling up" of the technology It would be helpful to have software that converted readings from cpm to dpm/100 sq.cm. and plotted the results as a profile for each hole or line surveyed for comparison to the 5000 dpm/100 sq.cm. release standard Different-size units are required Cannot be used in pipes with standing water Pipes must be free of obstructions or accessible from either end of and obstruction Crawlers can become contaminated if used in untreated pipes. (However, only minor contamination of low-cost wheels occurred during the demonstration from loose corrosion in the untreated pipes) Pipes accessible from only one end present to detection of alpha contamination Video inspection revealed mismatched pipe joints presenting snag pointsr nominally different pipe sizes

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Pictures

Side view of the pipe crawler

Videos