What is non-destructive testing?

Seasoned engineers and nuclear industry experts need no introduction to non-destructive testing (NDT), but for those new to the this type of testing we take a look at it in more detail.

Destructive versus non-destructive testing

It goes without saying that some testing is quite literally designed to check to the point of destruction. Take crash dummies for instance, checking the safety and integrity of a baby seat when the force of a staged car accident is brought down upon it. Whilst testers hope there is no damage, during the project development stage there’s usually a lot of deliberate destruction as the design is tweaked and re-engineered.

Non-destructive testing however allows you to investigate without causing damage. Where surfaces need to be scanned to identify any potential defects or wear and tear which may not be visible by eye, a range of non-destructive testing equipment can be used.

NDT methods

Each NDT technique is designed to inspect, test and evaluate structural components and materials to detect flaws and defects. You may also see NDT referred to as non-destructive evaluation (NDE), non-destructive inspection (NDI) or non-destructive examination (NDE).

A wide range of NDT techniques are available including, but not limited to, Radiography NDT and Ultrasonic testing. Both quality control techniques are used by our teams of experienced NDT technicians.

Using Radiography NDT

In safety-critical environments such as a nuclear power station, ensuring the integrity of structural components such as pipe work is crucial for everyone’s health and wellbeing.

Radiographic testing techniques are well established within the engineering industry, and typically use x-ray, gamma radiation, phased array or isotopes such as Ytterbium 169 and Selenium 75 to create an image of the surface of an object. This image then allows the NDT technician to detect flaws and identify any remedial work required.

NRL’s Radiography team based in Egremont, Cumbria, support clients with quality control testing of welding on civil nuclear structural components such as pipework. Drawing on their expertise to carefully and precisely undertake NDT to generate data reports whilst maintaining a full audit trail.

Using Ultrasonic testing

Ultrasonic non-destructive testing, also known simply as UT, is a method of characterising the thickness or internal structure of a test piece or component using high frequency sound waves.

An extremely short electrical charge is sent to a piezoelectrical element in the probe which in turn transmits an ultrasonic pulse. The element generates an electrical signal when it receives a return ultrasonic signal. This electrical signal causes the element to oscillate giving a reading on the oscilloscope. The probe is coupled to the weld or pipe with a coupling paste so that the sound waves from the probe are transmitted into the test object, like medical ante-natal scans – to allow for vibration analysis.

A connected screen records the sound wave for the technician to review for any signals that might indicate a defect and collect data through the computerised scans. These are typically internal cracks, inclusion or voids which are not detectable from the exterior.

NRL’s Ultrasonic team are based in Portishead, Bristol, and support the UK’s nuclear new build industry through their computerised robotic inspection system, which can be used to test weld and steel pipe materials for defects.

Non-destructive testing and the civil nuclear industry

NDT services have been used extensively across the civil nuclear industry for decades. Here at NRL we first started delivering Radiography services and inspection methods in 1983, and for almost 40 decades have continued to support organisations with safety-led NDT testing methods to effectively detect defects.

Whether clients are looking to maintain existing structural components or establish qualification and testing processes for new civil nuclear infrastructure, our NRL NDT team are always on hand.

Get in touch

If you’d like support on an NDT project in the nuclear sector, contact us using the link below.

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NRL NDT | Non-Destructive Testing Services | Civil Nuclear