"Hail Mary", "act of desperation", "very unconventional"

First it was 6,000 - then 45,000... Now about 140,000 people have been told to evacuate areas near the two Fukushima nuclear power plants following Friday's earthquake, said the UN atomic watchdog. The International Atomic Energy Agency said:

Evacuations around both affected nuclear plants have begun ... but full evacuation measures have not been completed.

Speaking to reporters Saturday afternoon, several US-based experts on nuclear power and emergency response noted that the decision to evacuate the area around the plants during a time of such dire emergency in the country is likely evidence that the government is very concerned about a potential disaster at the site. "Ordering several thousand people into motion in the immediate aftermath [of an earthquake and tsunami] is something that no government would do if could help it," said Peter Bradford, a former member of the Nuclear Regulatory Commission. He added: "That says a lot about the seriousness of the reports they were getting about the condition of the plant."

UPDATE 3:40 PM: Robert Alvarez, a senior scholar at the Institute for Policy Studies and a former senior policy advisor to the Secretary of Energy in the Clinton administration, says that the plan to use sea water to attempt to cool the reactor is an "act of desperation." "I would describe this measure as a 'Hail Mary' pass," said Alvarez. Kenneth Bergeron, a physicist who previously worked on nuclear reactor accident simulation at the Department of Energy's Sandia National Laboratories, also noted that this is a "very unconventional" method for trying to cool the reactor.

Bergeron described what's going on at the plant is known as "a station blackout"—both a loss of external power and a failure of the on-site emergency power. This kind of situation is "considered extremely unlikely," said Bergeron, though it has been a major concern for decades that something like this could happen. "We are in uncharted territory," said Bergeron.