Or, why don't I know of any good weblogs run by nuclear engineers?
Hiroko Tabuchi and Matthew Wald write:
Risk of Meltdown Spreads at Japanese Plant: TOKYO — The risk of a meltdown spread to a third reactor at a stricken nuclear power plant in Japan on Monday as its cooling systems failed, exposing its fuel rods, only hours after a second explosion at a separate reactor blew the roof off a containment building.... Operators fear that if they cannot establish control, despite increasingly desperate measures to do so, the reactors could experience full meltdowns, which could release catastrophic amounts of radiation. The two reactors where the explosions occurred are both presumed to have already suffered partial meltdowns — a dangerous situation that, if unchecked, could lead to full meltdowns....
Mr. Edano said cooling systems at a third reactor at the Fukushima Daiichi plant had failed. The water level inside the reactor fell, exposing the fuel rods at its core for more than two hours despite efforts to pump seawater into the reactor, he said. Exposure of the rods means they heat up, melting their outer casing and raising the risk of a meltdown. At first, water was successfully injected into the reactor and the rods were again submerged. But new problems resulted in the rods being exposed again. A vent that had been letting out steam from the reactor closed, leading to pent-up pressure inside the containment vessel and hampering water from being injected. Water levels then fell rapidly, leaving the fuel rods again exposed, Tokyo Electric officials said at a news conference early Tuesday.
The jury-rigged fire hose pumps being used by the workers have added to the crisis by hindering efforts to keep reactors adequately cooled...
And at this point I have to say that Tabuchi and Wald do not seem, to me, to know what is going on. You want to keep the fuel rods submerged in order to keep them cooled so they don't melt. Pumping water into the reactor keeps the fuel rods submerged and keeps them cool. Jury-rigged fire-hose pumps that pump water into the reactor help keep the reactor adequately cooled: they don't hinder it.
They go on:
Difficulties in gauging exactly how much water remains in the containment vessel, as well as what exactly is occurring at the heart of the reactor, have also added to problems.... Hidehiko Nishiyama... said plant workers had renewed efforts to flood the reactor with seawater, and readings suggested that water again covered the fuel rods. Workers were also battling rising pressure within the reactor, Mr. Nishiyama said. They have opened vents in the reactor’s containment vessel, which houses the fuel rods, a measure that could release small amounts of radiation....
On Monday morning, Tokyo Electric, which runs both plants, said it had restored the cooling systems at two of three reactors experiencing problems at Daini. That would leave a total of four reactors at the two plants with pumping difficulties...
Reading between the lines (although it would be nice to know):
- They lost the pumps--overwhelmed with seawater from the tsunami
- They lost the power grid--washed away with seawater from the tsunami
- They lost the generators--overwhelmed with seawater from the tsunami
- They have brought in firehoses to connect the ocean to the reactors
- They have brought in extra diesel-fueled pumps
- They are pumping seawater into the reactor
- The seawater is turning into steam and pressure is building up.
- Some of the seawater is going into a higher-energy state by dissociating into hydrogen and oxygen gas--and then at some point all at once all the hydrogen and oxygen gas will revert to the lower energy state and go BOOM...