Japan set to declare control over nuclear reactors

New York Times : The Japanese government announced that it has regained control of the Fukushima Daiichi nuclear plant’s reactors in what is called a “cold shutdown.” The announcement has been met with some skepticism, partly due to the fact that a cold shutdown is normally used to describe healthy reactors, to indicate that they are safe enough that their containment vessels can be opened up and their fuel rods taken out. In this situation, however, a cold shutdown means that the reactors’ temperatures can now be kept safely below the boiling point of water and that their melted cores are no longer at risk of resuming an atomic chain reaction that could allow them to heat up uncontrollably. Even that is in some dispute, as the restart of fission can’t be absolutely ruled out until the reactors can be opened and the melted fuel inside examined. The biggest risk, however, is the possibility that a strong aftershock from the 11 March earthquake could knock out Tepco’s cooling system, which was built hastily—and not to earthquake safety standards—after the accident.