Japanese nuclear physicist friend wrote (today 2/16/2011) that they
keep feeding "every reactor" with pure and sea water. They also see
steam clouds ejecting from #2 and #3 reactors. But they do not worry
about a “nuclear explosion” as in Chernobyl."
"However, to confine radioactivity of stored FPs inside fuel-sheaths
(zircaloy) we need to continue cooling to minimize the release-and-
diffusion to environment. Hydrogen gas was thought to be produced by
the interaction between high-temperature zircaloy and steam. I think
the situation will get to better and safer side day by day, in gross
view."