A technical glitch on the electrical power supply occurred during maintenance period of control system, leading to automatic shutdown of the reactor on 13 August.
A Electrabel spokeswoman said: "There was an irregularity during maintenance at the control and operating system and the reactor was shut down safely."
The Unit 1 is currently undergoing maintenance period that will last till September, while operations at the second unit were halted following detection of cracks on core tank.
In July, the Belgian Government signed an agreement with Electrabel, to extend the operational life of Doel 1 and Doel 2 nuclear reactors, until 2025.
The deal is a part of the country’s effort to replace Tihange 2 and Doel 3, which also halted operations earlier.
