We now know why TEPCO says “more” than 1000 millisieverts/hr, rather than the actual number, for that pool of water in unit 2’s turbine bldg.

The guy who went in to measure didn’t expect such a high reading, so the dosimeter he took with him maxed out (evidently at 1000). He could have kept resetting (per unit time less than an hr), thus doing multiple sampling, but he figured he ought to bail rather than stay long enough to do that.

Smart move on his part, as the Japanese are claiming the LD50 number is a total of 3000 millisieverts in a single dose, which he might have received if he had stayed.