Mururoa may not be leaking now, yet even the French admit the radioactive waste stored under their feet will eventually escape. But they say it won't be for thousands, perhaps 10,000 years. But there's good evidence it will happen much more quickly than that. Professor Peter Davies visited Mururoa in the early 80s. He studied just how porous the atoll's base is.
Some parts are far leakier than others.
Well the worst case scenario is related to something happening associated with the test and that's almost instantaneous. And accidents have happened. In July 1979, a 120 kiloton bomb got stuck halfway down the shaft, at 400 metres. They exploded it anyway, and because tests were then on the rim of the atoll, part of the southern side collapsed in an underwater landslide. The French have admitted to some million cubic meters of rock having come away from the side of the atoll.