French nuclear regulator ASN has been investigating the reactor – the third to be built at the power plant – after weak spots were detected in its lid and base in 2015.
The weaknesses were caused by an anomaly in carbon concentrations in its steel cover.
Excess carbon can make steel fragile and more likely to fracture when exposed to movement or sudden changes in temperature.
According to French newspaper Le Figaro, a preliminary report by ASN has concluded that the reactor meets safety requirements.
Reuters news agency has reported that EDF has declined to comment and ASN said a provisional ruling would be formally issued in the summer, before a final decision is issued in September.
The third reactor had expected to be operational by 2012, but has suffered numerous setbacks and is now hugely over-budget.
If given approval, the reactor could become operational next year.
