Tomorrow it will be two weeks since I left Tokyo with my family. Every day we scan the news for clues for when it may be safe to return, but it’s not easy.
Achim Steiner, the executive director of the United Nations Environmental Program (UNEP) questioned why “clear, precise information” on the nuclear situation in Japan was so difficult to come by.
The IAEA advised the Japanse government to check the need for evacuation in Iitate village, some 40 km from Fukushima because levels of I-131 were too high. It was the environmental organisation Greenpeace and not the Japanese government that had first collected data there.
Radiation in seawater near the plant exceeds legal limits by 4385 times, the highest level ever. Ditches filled with radioactive water are within 10 cm of overflowing and sandbags and cement are being used to prevent them spilling.
Water injection into the partially uncooled overheated reactor cores has been cut back for fear of radiactive water leaking back out and obstructing efforts to restart electric cooling pumps. Some of the water inside the plant is radiating 1000 millisieverts per hour, exposing the workers to the recent raised maximum annual dose for nuclear emergencies (250 mSv) within only 15 minutes (or within 6 minutes before the raise).
Only the spent fuel pool at unit #1 has a concrete pump attached for topping up cooling water. Other pumps of the same type are to be flown in from Germany now. No spent fuel pool water temperatures are available for unit 1, 3 and 4 (which hold 292, 514 and 1331 fuel assemblies) because of “measuring instrument malfunction”. Only the temperature for the pool in #2 (with 587 assemblies) is known. Seawater was still being used for topping up pools, which means salt will accumulate when the water boils or evaporates
Fukushima holds 1780 tons of nuclear fuel, versus 180 tons in Chernobyl. The majority of that fuel is held in spent fuel pools which are outside the containment building. The pool in unit #4 holds the largest number and also the most radioactive of the spent fuel assemblies. Unit #4 shares its control room with unit #3, which looks the most damaged in aerial shots. Unit #4 itself has holes 8m by 8m in size in its wall.
The containment building at unit #2 is at or near atmospheric pressure (0.11 MPa absolute), indicating a crack or open valve. At least a portion of the fuel rods probably already melted through the pressure vessel onto the concrete floor of the containment.