PM Noda Declares Cold Shutdown; Formal Stabilization Achieved

On December 16, 2011, Prime Minister Yoshihiko Noda declared 'cold shutdown' at Fukushima Daiichi, announcing that all three damaged reactor cores were now below 100°C and releasing minimal radiation. This was considered a major milestone, formally ending the acute emergency phase. Critics and nuclear experts noted that 'cold shutdown' was used loosely—the reactors were not in a truly cold shutdown state as defined for intact reactor vessels, since the fuel had largely melted through and containment was compromised. Nonetheless, the declaration allowed formal transition to decontamination and decommissioning phases.