"However, the company operating Fukushima Daiichi has now said that, for the fuel pond at reactor 4, 'the risk of recriticality is not zero', meaning a nuclear

"However, the company operating Fukushima Daiichi has now said that, for the fuel pond at reactor 4, 'the risk of recriticality is not zero', meaning a nuclear chain reaction could restart in the rods. Quite how this has come about is unclear." Whoops, looks like you invalidated half of your article.