UKAEA shows X-rays could support safe, reliable fusion power

Technique detects component defects and judges lifespan

SCIENTISTS at the UK Atomic Energy Authority (UKAEA) have successfully shown that X-ray scanning can detect defects in tungsten components and accurately judge their lifespan, taking a major step in commercialising fusion power.

According to UKAEA, tungsten is the strongest of any natural metal and only diamonds can scratch its surface. It is extremely durable and can manage intense conditions, making it the perfect material to line the inside of fusion reactors, where temperatures can reach 10 times hotter than the Sun’s core (150m°C).

Despite tungsten’s durability, withstanding the intense neutron bombardment from the fusion process can eventually compromise reliability and lead to wear, especially in potential future power plants operating around the clock. The ability to detect defects in components could affect the safety and reliability of fusion power plants, and change expected lifetimes and performance. Until now, research has not presented a dependable method for detecting potential structural damage, as normal 3D X-ray scans are unable to penetrate due to tungsten’s “incredible density”.

The UKAEA team detected defects in a mock tungsten component after failure, using X-ray computed tomography (XCT) in the MeV energy range. XCT is a non-destructive technique used to visualise the interior features of solid objects, and for obtaining digital information on their 3D geometries and properties.

Imaging of the failed component revealed damage to the cooling pipe and copper interlayer within the tungsten block, as well as holes in the pipe which led to coolant loss. The scientists quantified the area of the three holes, predicting the rate of coolant loss during high heat flux testing in the HIVE facility, which caused the component to fail. HIVE (Heat by Induction to Verify Extremes) is a UKAEA-operated facility for testing advanced manufacturing.