"These (only) Go To 100 "
At the end of August/Beginning of September several reports came out that radiation level at a few of the numerous vats of stored radioactive water "spiked" from 100 to 1800 millisieverts/hour. However, as this detailed article describes, the levels did not increase:
In fact these were at 1800 millisieverts/hour for an unknown amount of time. The reason for the 100 millisievert reading is that the detectors used only go to 100! That's one sure way to ensure that you won't get any high radiation readings. Why in the world even use a detector that can't detect truly dangerous levels of radiation?
While 300 tons of water leaked from a storage tank into the Pacific a few weeks ago, this leak did not drain any of the tanks appreciably. That's good, but its also bad in that it means that just a few drops of leakage can cause a potentially deadly radiation level. 1.8 Seiverts/hour is enough to cause vomiting in 30 minutes, and in three hours give you more radiation that Harry Daughlian received in 1945 when he was killed testing an atomic bomb.
A while back I suggested sardonically that Japan could host a radioactive Olympics, when the press reported they now have over 100 Olympic swimming pools full of contaminated water. Now it looks like Japan is seriously hoping to host the Olympics in Tokyo, within 200 miles of Fukushima. They recently committed half a billion dollars to allay worries that the area may not be environmentally safe to host. Its nice to know that Japan's Abe government takes nuclear safety seriously...at least when putting in an Olympic bid.
The real problem (at least one of them) is that the melted down reactors are now a permanent source of contamination to an underwater river of groundwater. Some 400 tons per day are pumped out of the reactor building to stem the flow. As this diagram in the BBC article above makes clear...
...the only possible solutions are to isolate the reactor from the groundwater, or to divert the river. Its not surprising that the underground steel dam TEPCO hoped would stop the flow has not worked. Meanwhile as much of the water as possible must be put into tanks, and a growing army of people are now required just to monitor the tanks for leaks.
One can only imagine what would happen if these hundreds of tanks were subjected to, eg. another earthquake, a powerful tornado such as those that struck Koshigaya, north of Tokyo yesterday (injuring dozens), or heaven forbid, a crazy nut with a machine gun.