Advanced inspection
Inspection of nuclear components by non destructive testing (NDT) presents many challenges. Direct access is often difficult if not impossible because of the radiation hazard. NDT has to detect, size and record defects of concern with reliability, accuracy and repeatability.
TWI is helping the nuclear industry to meet these challenges.
- Automated and robotic techniques such as Teletest ® can reach inaccessible regions and reduce operator dose.
- Ultrasonic time of flight diffraction and PSCAN are accurate sizing techniques where scans can be recorded for later comparisons to see if defects have grown.
- Specialist procedures such as phased array are being developed and tested for new applications.
| Mock-up of a nuclear steam generator |
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TWI's NDT experts have nuclear industry experience and can provide advice on most ultrasonic, electromagnetic and radiographic methods. TWI was recently asked to develop a technique to inspect the inner wall of a double walled containment. However, not all problems require a high-tech solution as a recent project to plan the inspection of a large number of nuclear waste storage cylinders showed - it was found that prioritisation by design could reduce the amount of work.
The demonstration of inspection reliability through inspection qualification and performance demonstration has its roots in nuclear safety. The European methodology for inspection qualification is now a standard way of providing the necessary confidence. TWI has experience in all parts of the process:
- preparing and assessing technical justification
- setting and invigilating NDT performance trials
- membership and chairmanship of inspection qualification bodies.
NDT performance trials require test specimens containing realistic defects. There is a range of techniques available at TWI for producing suitable defects of a given morphology and size. Test specimens have been manufactured for many laboratory and performance trials including some of the large test pieces used for the qualification of the inspection of the Sizewell B pressurised water reactor, and more recently, for submarine nuclear plant.
Contact us at:
power@twi.co.uk