A global nuclear disaster potentially worse than Chernobyl may be under way in Japan as hundreds of tonnes of highly radioactive spent nuclear fuel are open to the sky, and may be on fire and emitting radioactive particles into the atmosphere. Many countries have advised their citizens in Japan to leave the country. "This is uncharted territory. There is a 50-percent chance they could lose all six reactors and their storage pools," said Jan Beyea, a nuclear physicist with a New Jersey consulting firm called Consulting in the Public Interest. "I'm surprised the situation hasn't gotten worse faster... But without...