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CORRECTED-EDF ready to replace Flamanville reactor cover by 2024

(In paragraph 7, replaces "before" with "at the end of")

PARIS, Oct 9 (Reuters) - French utility EDF is ready to replace the steel cover of its Flamanville 3 reactor vessel by 2024 as required by nuclear regulator ASN, despite new delays to its start-up date, an EDF official said on Wednesday.

In June 2017, the ASN ruled that EDF would be allowed to start up the long-delayed reactor in late 2018 provided it committed to replacing the flawed component by the end of 2024 at the latest because of weak spots in the steel. https://reut.rs/30WtOAZ

But since then, the start-up date has been delayed by three years because of problems with eight key weldings on pipes that penetrate the containment building.

Earlier on Wednesday EDF increased the reactor's projected cost by 1.5 billion euros to 12.4 billion euros - about four times the original estimate - and said that it now expects to load nuclear fuel into the reactor at the end of 2022.

It usually takes five to six months after fuel loading to begin commercial operations, which means the effective start-up date will probably be mid-2023. Analysts say this raises the question of whether EDF would want to start up the reactor with the flawed cover, or might possibly try to delay its replacement.

"We have arranged for the supply of a replacement cover, which will be ready by end 2024, in line with the ASN decision," EDF Senior Executive Vice-President Xavier Ursat said on a conference call with reporters and analysts.

He added that EDF is working with the ASN to see how this will be done, and that if EDF has to change the lid, it will do so at the end of the first Flamanville 3 operating cycle.

An EDF spokesman said a typical fuel operating cycle runs for 18 months, after which spent fuel is taken out of the reactor and new fuel loaded.

He added that EDF is continuing to develop new measuring technologies to test the strength of the reactor cover and that it hopes to convince the ASN that the component is fit for service.

Unlike the reactor base, the reactor cover has numerous perforations, for control rods and instrumentation. This makes it harder to test the quality of the steel.

The problem goes back to excessive carbon concentrations during manufacturing of the component, which makes the steel more brittle.

The 1600 megawatt EPR reactor - of which EDF is building two in Hinkley Point, Britain - is designed to have a 60-year lifespan.

(Reporting by Geert De Clercq and Dominique Vidalon; Editing by Kirsten Donovan)