The final welding of the High Flux Reactor (HFR) in Petten, Netherlands, will be completed this week and root cause of the deformations was galvanic corrosion, according to the Nuclear Research and Consultancy Group (NRG) of the Netherlands.

The welding activities on the High Flux Reactor’s reducers have started, and three out of four corroded parts of the reducers have been welded and inspected, said NRG.

NRG has been investigating and defining the root cause of the deformations. Analyses showed that the galvanic corrosion resulted from electolytic contact between steel and aluminium, and the presence of water was the root cause of the deformations. This interaction between the steel and aluminium (galvanic corrosion) was hardly known at the time that the High Flux Reactor was designed.

“Executing this repair has been a good decision. Galvanic corrosion is a process, that will be stopped by breaking the connection between the steel and aluminium and that is exactly what we are doing now,” said Jan-Willem Rensman, material scientist of NRG.

The date of the HFR restart remains planned for the second half of August. The remaining phases of the project will be planned in detail, added NRG.