EDF has announced its Flamanville nuclear power plant in France will see a spending increase of €1.5 billion (£1.35bn), bringing its total construction costs up to €12.4 billion (£11.2bn).
It says this extra finance will be required to fix 66 faulty welds – among these are eight containment penetration welds the Nuclear Safety Authority (ASN) has asked EDF to repair.
The nuclear facility was originally projected to cost €3.3 billion (£3bn) and to start operations in 2012 and only last month the French energy giant said the cost of building the Hinkley Point C nuclear power plant could increase by up to £2.9 billion.
EDF hopes to use remote-operated robots to repair the welds and plans to get approval from the ASN to go ahead with the work by the end of 2020.
It says the repairs would extend the schedule for the date of fuel loading to the end of 2022.
Further work involves realigning 58 welds on the secondary system – these either suffer from quality deviations or are not in compliance with requirements defined by EDF.
The second hot functional test phase at the facility was started on 21 September 2019 and will last until the end of 2019.