Keep a lid on it

The lids of 68 nuclear reactors across the US are being checked for holes after leaking acid was found to have almost eaten through 15 centimetres of steel at the Davis-Besse reactor near Toledo in Ohio. In one part of the lid, less than a centimetre of metal remained to contain cooling water under pressure, and it had begun to balloon outwards. A leak of cooling water could cause a reactor meltdown and a massive escape of radioactivity.