During a major overhaul of Doel 3 in 2012, parts of the reactor vessel were inspected with a new ultrasonic device that delivers better results. The inspection led to the discovery of hydrogen flakes in the reactor vessel of Doel 3 and later also in the reactor vessel of Tihange 2. This discovery started an extensive investigation, for which experts from Electrabel, Laborelec and Tractebel Engineering worked with renowned organisations both from Belgium and abroad. After tens of thousands of hours of investigation, they decided that the hydrogen flakes have been present ever since the construction of the vessels, that they have not developed since and that they have no impact on the strength of the vessel. Doel 3 and Tihange 2 resumed operation. Electrabel still periodically inspects the reactor vessels to monitor the hydrogen flakes, under supervision of the Federal Agency for Nuclear Control.
The concrete projects in Doel 3, 4 and Tihange 2 and 3 also show that Electrabel leaves nothing to chance. In 2017, the concrete surfaces of the walls and ceiling on the upper floor of an auxiliary building in the non-nuclear part of the Doel 3 plant were discovered to be damaged. The power station was shut down for investigation. The concrete was found to be affected by the hot vapor that is released through steam outlet valves on the upper floor of this building every time when the power plant is shut down. Electrabel immediately took remedial actions at all units that were affected by this issue.