Non-Destructive Testing at the Lignite-Fired Power Plant in Neurath
When you think of a lignite-fired power plant, the energy transition isn’t necessarily the first thing that comes to mind. But renewable energy isn’t available around the clock. During periods of low wind and sunlight, conventional power plants therefore step in to flexibly meet electricity demand. This is also the case for RWE’s Neurath lignite-fired power plant in the Rhineland mining region.
The first power plant unit at the Neurath site, near the major cities of Düsseldorf and Cologne, went online in 1972. As part of the phase-out of coal by 2030, only the two largest and most modern power plant units are now in operation at the site—units F and G, built in 2012, each with a net capacity of 1,100 megawatts.
Overview of the Neurath lignite-fired power plant,
Source: RWE.
Our assignment at the Neurath power plant: Quality at a height of 162 meters
To ensure reliable operation and flexible use as the backbone of the energy transition in the coming years, the walls of the boiler in power plant unit G are currently being relined. Our colleagues are on site year-round to monitor and inspect the new weld seams.
The boiler inside the unit reaches a height of approximately 162 meters. The tube walls are being replaced in the range from about 122 to 132 meters. To keep downtime as short as possible, welding, monitoring, and testing are carried out around the clock. Specifically, this involves approximately 1,700 welds. Every single weld is critical to safety, as it must later withstand high thermal and mechanical stresses.
Inspections are conducted inside the boiler at a height of over 100 meters. Source: TÜV AUSTRIA Deutschland GmbH.
Non-Destructive Testing for Greater Safety
Various non-destructive testing (NDT) methods are used. These include X-ray testing, also known as radiographic testing, which can reveal internal defects in welds. For weld inspection, established NDT methods include X-ray testing (RT), ultrasonic testing, visual inspection, dye penetrant testing, and magnetic particle testing.
In addition, we perform surface crack inspections, such as dye penetrant testing, also known as PT testing. This method reveals surface defects such as fine cracks, pores, or weld defects. The penetrant utilizes capillary action: it penetrates defects open to the surface, is then removed from the surface, and made visible again using a developer. This combination is particularly crucial for new welds in order to identify internal irregularities and external defects.
Boiler Wall Under Pressure
Once the welding and inspection work is complete, another crucial step follows: the pressure test. During this test, water is pressurized into the system, and the pressure is increased to approximately 340 bar. The pressure must not drop during the specified holding time. Only after this test has been successfully passed can the system be put back into operation.
Pressure tests are fundamentally used to verify the pressure resistance and leak-tightness of pressure-bearing system components. They are conducted using documented test procedures and calibrated measuring equipment.
Good to know: TÜV AUSTRIA was founded in Vienna in 1872 as an independent Austrian mutual steam boiler inspection and insurance company (DUVG). Boiler pressure tests are therefore part of our DNA.
We ensure safety, availability, and trust
This work demonstrates what the TIC business is fundamentally about: safety, availability, and trust. Our inspections do not cause any damage, but they reveal what remains hidden to the naked eye. They help identify risks early on, ensure the quality of new welded joints, and enable the safe continued operation of technical systems.
Even against the backdrop of the planned phase-out of coal, the operational safety of existing facilities remains critical. That’s why every inspected weld counts. Non-destructive testing means responsibility—especially where pressure, temperature, and material limits converge.
A big thank you to all our colleagues on site, especially Sven Rygol-Bündgens, Thomas Esser, and Olaf Wolschke, who make this work possible while working in shifts, at great heights, and under challenging conditions. This is precisely where the importance of experience, qualifications, and precision in non-destructive testing becomes evident.
For questions about the project:
Sven Rygol-Bündgens, Site Manager
TÜV AUSTRIA Deutschland GmbH
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