Comment by mm0lqf

theres the well known inherent problem with the graphite at UK AGR reactors which could be very bad (can crack or misshape in such a way that the control rods or fuel rods cant be moved), not to mention the boiler cracking at the weldseams, they only mitigated this at some sites because they all are slightly different in design, they basically ignored it in the ones which didnt yet have it for decades ,the regulator ended up finding exactly that lessons learnt on older reactors were not being applied to newer ones which had the same problems inherent to them