At present (May 2020), the two EdF reactors at the Hunterston Nuclear Station (R3 and R4) on the shore of the Firth of Clyde in Scotland have been shut for about 2 years for safety reasons – pending review by the Office for Nuclear Regulation (ONR). Both reactors are 44 years old, ie well past their original closure date of 2006. Already the ONR has extended their lifetimes – twice. They are scheduled to close permanently in 2023. EdF is pressing ONR to permit both their Hunterston reactors to restart in June 2020. The main safety issue (of several) is the extent of cracking in the graphite cores of the two reactors. For example, according to the ONR, EDF inspections in R3 have found cracks in several hundred graphite bricks and these were causing other nearby graphite bricks to crack. Inspections have showed bricks with one or two full-height cracks and additional partial-height cracks. ONR has warned of the potential for bricks to crack into three or more vertical parts and become multiply-cracked bricks which increased the risk of the nuclear fuel snagging. Brick cracking was also found to generate graphite debris which could inhibit cooling of reactor fuel. Reactor 4 is also affected but not to the same extent.
IanFairlie 10th May 2020 read more »