Reactor temperatures in Dai-ichi as of 5/4

Looking at the latest plant parameter data, all reactor 3 temps apart from suppression chamber are continuing to climb. Reactors 1 and 2 are also hot from a historical perspective. This is probably why the rate of water injection is higher at this particular unit vs the other two, and at last check stands at 9 cubic meters/hr. It seems like they are trying hard to bring the temperature down at this particular unit, and this may provide an explanation for all that steam release observed on the live cam last night and earlier this morning.

Workers are getting set to stabilize unit 1, and as part of this process, "the building must be vented of radioactive air to allow operators to approach the reactor".  The CSM highlights some concerns with the operation:

"But important questions remain about how safe the cold shutdown process will be. To bring down the temperature in Unit 1, the company plans to inject water into the primary containment structure – a large, light-bulb-shaped container that surrounds the inner reactor vessel that holds the uranium fuel core.

Will the primary containment structure be able to hold the many tons of water that will fill it – or will it leak or split because it is damaged? Will a new quake or aftershock damage a containment structure that is far heavier because it is full of water?

"They're basically getting ready to run a big experiment," says Edwin Lyman, a nuclear reactor expert with the Union of Concerned Scientists, a nuclear industry watchdog group that is closely monitoring the situation in Japan. "It sounds like they're assuming that the structural issues [with the primary containment structure] aren't that serious – and there's debate over that."

Even so, filling up the containment structure "seems like a reasonable thing to do if they can't cover the cores in any other way," Dr. Lyman adds. "They're just stuck with doing whatever is going to work. The problem is, they're learning by experimentation – not by some well-thought through contingency plan."

Nothing else for us to do but hope for the best and trust that these guys know what they are doing.  All justifiable criticisms aside, we should feel fortunate that the Japanese are quite transparent with info and forthcoming enough to provide the public with detailed data, which probably wouldn't be the case if it happened in certain other countries (like China).