The reactors are located on the bank of the Scheldt, near the village of Doel in the Flemish province of East Flanders.
The life of the nuclear reactors, each with a power generation capacity of 433MW, will be extended until 2025, with an investment of €700m.
The Doel 1 reactor has been idled since February while Doel 2 is scheduled to be decommissioned in December following completion of 40 years of service.
The decision to extend the service of the two reactors comes as the country detected thousands of additional cracks in critical components of nuclear reactors Doel 3 and Tihange 2 earlier this year, reported Reuters.
The cracks were identified in the steel nuclear reactor pressure vessels of the two reactors.
The deal requires Electrabel to pay a flat nuclear tax of €200m in 2015 and €150m in 2016.
An additional €100m will be paid in 2015 and €20m in 2016 towards the settlement of an ongoing a dispute of Electrabel with the Belgian state.
Starting 2017, the payments will be around 40% of the margins earned by the company from its nuclear business.
Engie also plans to invest €600m to extend the lifespan of Tihange 1 plant.
