Crack Detection in Nuclear Steam Generator Tubes

The Problem:

Steam generator tubes, found in commercial nuclear power generating plants, are sometimes subject to internal cracking. Left undetected, this cracking can ultimately lead to failure – causing unexpected shutdowns, expensive repairs and loss of revenue. Inspection of these tubes, already a challenge, is further complicated by the fact that they are located in a radiation environment.

The Solution:

LTC's patented laser-scanned penetrant inspection (LSPI™) technology is ideal for crack detection in tubes. LTC has collaborated with iP-TEC AB of Sweden to integrate our LSPI™ sensor technology with their remote penetrant delivery system. The combination of LTC’s LSPI™ sensor technology with iP-TEC’s remote penetrant delivery system enables operators to generate high-resolution and quantitative inspection results from steam generator tubes. This automated fluorescent penetrant inspection system is capable of treating and scanning a tube in a matter of minutes.

LSPI™ Image of Complex Cracking in 17mm (0.669") ID Tubing

Advantages include:

Rapid and quantitative data acquisition
Documentation of inspection results
Remote / automated operation
Near real-time results
Rugged and portable system components
Digital data format
Windows™ - based software
Can be combined with other NDT technologies, such as eddy current

The integrated penetrant delivery module and LSPI™ sensor allow operators to remotely and automatically treat and scan localized areas that are suspected to have crack indications.

The image above shows an example of typical LSPI™ test results obtained from the inner surface of 0.669 inch (17 mm) ID steam generator tubes. This new method of conducting automated fluorescent penetrant inspection (FPI) allows operators to automatically treat and scan a tube in a matter of minutes. Results are provided in a our LaserViewer™ software with quantitative “C-scan” images. Operators can measure feature geometry, print out hard-copy images and archive data for future analysis and comparison.