Do I correctly recall that there were reports of having flooded the concrete containment structure around RPV #1? I recall some expressing concern that the added water could compromise the seismic integrity of the structure, (which may already be compromised, resulting in some of the leaks of radioactive sea water.) If that is so, would it not be likely that they have flooded all three concrete containment structures at least up to the level of the bottom of the RPV? And if they kept injecting water into the RPV until corium melted through the bottom, would there be a dramatic steam signature to signal that event?

"It is not necessary to have hope in order to persevere."