French Regulator Clears Flamanville-3 Reactor Pressure Vessel

13 Oct (NucNet): The mechanical properties of the top and bottom heads of the Flamanville-3 EPR’s reactor pressure vessel (RPV) are adequate and the RPV can be put into service, the French nuclear regulator (ASN) has concluded. ASN said that it still requires the RPV top head, or cover, to be replaced by the end of 2024 because the feasibility of checks on it is not ensured. Commissioning of the RPV remains subject to the results of hydraulic tests on the main primary circuit, said ASN. On 29 June 2017, ASN said it had provisionally ruled that Flamanville-3 could start up as planned, but that the RPV top head would need to be replaced once a new one has been produced. Following a round of public consultations over the summer, ASN said in a statement that it had confirmed the earlier ruling that the RPV was safe. In April 2015, ASN, Areva and EDF revealed that tests had shown higher than expected carbon segregation in RPV material samples, indicating a possible manufacturing flaw and potentially affecting the vessel’s ability to withstand the propagation of cracks. The tests followed earlier chemical and mechanical examinations on forged steel parts representative of the RPV, which showed the carbon segregation phenomenon was higher than expected in a certain area. EDF said earlier this week that work on Flamanville-3 is on schedule with reactor startup scheduled for the fourth quarter of 2018. EDF confirmed total project costs at €10.5bn ($12.4bn). An estimate of the total cost in July 2011 was €8bn. EDF said system performance tests, which confirm how all the 1,600-MW EPR’s circuits are working, began in the first quarter of 2017 and will continue until the unit is started up. Workers on site are now preparing for cold testing, which will begin in December 2017.