New system to speed up inspections at power plants

Citation

(1999), "New system to speed up inspections at power plants", Sensor Review, Vol. 19 No. 3. https://doi.org/10.1108/sr.1999.08719caf.007

New system to speed up inspections at power plants

New system to speed up inspections at power plants

Keywords Eddy current, Inspection

A new multifunctional inspection system which combines eddy current, remote field eddy current with magnetic flux leakage and an ultrasonic IRIS has been selected by National Power for use on the new combined cycle gas turbine (CCGT) power stations.

The TC5700, originally designed for tube inspection, also has the facility for eddy current array inspection, and is manufactured by R/D Tech of Canada and supplied by Phoenix ISL in the UK. It offers significant benefits over single technology units in terms of speed and integrity of inspections.

National Power will be using the eddy current array facility for the inspection of discs and gas turbine blades as well as other components. "The new CCGT stations incorporate new plant and materials," explains Roger Lyon, National Power's Head of Inspection Management, "therefore some of the older inspection methods may not be appropriate. In developing new techniques, the more information we can get, the greater the likelihood that we can keep plant running for longer without maintenance periods, which will inevitably result in cost savings."

The TC5700 may be configured to include any combination of EC, RFEC, MFL and UT. The combination of technologies makes it an ideal instrument for use in the wide range of applications typically encountered by NDT inspection providers. Combining two or more technologies increases inspection reliability and provides a more accurate evaluation of flaws. For instance, on carbon steel tubes, wear hidden under a support plate is very difficult to size using RFEC or MFL while a UT C-scan provides a clear and accurate measurement.

Karl Quirk, MD of Phoenix ISL, said: "This is the only product on the market which combines all these technologies in a single unit. It is a very powerful tube inspection device for the petrochemical and power industries. But the greatest demand is coming from the aerospace sector where its ability of the eddy current array to detect corrosion damage and cracking on aircraft structures at high speed represents a significant step forward in inspection capabilities."

Nonferritic condensor tubes can be inspected using the eddy current option of the TC5700, achieving multifrequency inspection speeds of 2m per second. Ferritic heat exchanger tubes may be inspected using either RFEC, MFL or IRIS.

Remote field and IRIS are both suitable techniques for inspecting boiler tubes in the generating bank. The former has significant advantages over the latter because the RFEC boiler probes can easily pass through bends with inspection speed up to 0.5m/s. IRIS would be recommended as a back-up technique for sizing defects found by RFEC.

Steel plate inspections may be carried out with multichannel UT, multichannel MFL or a combination of both, ensuring 100 per cent coverage with the most appropriate technology for the corrosion mechanism most likely to occur in a particular situation.

For further information about the TC5700, contact Phoenix on +44 (0)1925 826000 or e-mail sales@phoenixisl.co.uk.