* ASN gives long-awaited approval for Flamanville reactor
* Clearance crucial for survival of French nuclear industry
* Reactor cover must still be replaced by 2024 (Adds ASN comment, background)
PARIS, Oct 11 (Reuters) - The vessel of the nuclear reactor that EDF is building in Flamanville is fit for service despite weak spots in its steel, regulator ASN said in a long-awaited ruling that is key to the survival of the French nuclear industry.
After investigating higher-than-expected carbon concentrations in the base and cover of the Areva-designed European Pressurized Reactor’s (EPR) containment vessel, ASN in June gave provisional clearance for the reactor, but said its cover had to be replaced by 2024 at the latest.
The cover, which is perforated by dozens of openings for control rods and instrumentation, is seen as more vulnerable to carbon concentrations - which make the steel more brittle - than the unperforated base.
Following a round of public consultations over the summer, ASN said in a statement on Wednesday that it had confirmed its June ruling.
The regulator had been widely expected to confirm its initial go-ahead as no further technical tests have taken place since June.
Disqualification of the Flamanville reactor vessel would have been disastrous for EDF a s it would have added years of delay and billions of euros of further costs, as the reactor vessel is already welded into the building and covered by thousands of tonnes of concrete.
Flamanville is already years behind schedule and its 10.5 billion euro cost is more than three times the original budget.
Disqualification would also have scuppered a planned takeover of reactor designer Areva NP by EDF and jeopardised EDF’s plans to build two similar EPR reactors in Hinkley Point, Britain.
The Flamanville reactor is expected to start up at the end of 2018 and ramp up to full power in November 2019, provided it encounters no further technical problems and it gets start-up approval from the ASN. (Reporting by Geert De Clercq; Editing by Bate Felix and David Evans)