The Japanese government [has] declared that the Fukushima Daiichi nuclear plant had reached a stable state known as cold shutdown." But the formal status change at the plant, experts cautioned, means only that its problems have become less dire; they have not disappeared. The plant still leaks radiation into the sea. Its makeshift cooling system is vulnerable to earthquakes. And the cleanup work remains dangerous, with many flooded and debris-strewn areas of the reactor buildings difficult even for robots to access. In normal circumstances, a reactor in cold shutdown mode is entirely stable, its fuel intact, with no chance of a chain reaction. To achieve its version of a cold shutdown at Fukushima Daiichi, ... Japan had to loosen the definition. Fukushima now meets the government's requirements because temperatures at the bottom of the three damaged reactor pressure vessels have dropped below 100 degrees Celsius (212 degrees Fahrenheit). Airborne leaks into the environment have also been almost halted. The declaration poses new questions for many of the 80,000 people who fled towns around the plant ... since the government had made the cold shutdown a precondition for even considering reopening parts of the no-go zone to residents. Many areas within the no-entry zone - a 12-mile radius around the plant - will be uninhabitable for decades, maybe longer.