UPDATE: Japan PM – “Very High” risk of further radiation release
Utility pulling non-essential personel out. Remaining residents out to 30 kilometers being told to stay inside, and
“shelter in place”, according to CNN.
This explosion, reported to have occurred at 6:14 a.m., happened in the “pressure suppression room” in the cooling area of the reactor and inflicted some degree of damage on the pool of water used to cool the reactor, officials of Tokyo Electric Power said. But they did not say whether or not the incident had impacted the integrity of the steel containment structure that shields the nuclear fuel.
Radiation levels around plant spiked after the explosion to 8,217 microsieverts an hour from 1,941 about 40 minutes earlier, the company said. Some emergency workers there were evacuated, though the levels would have to rise far higher to pose an immediate threat to health, officials said.
Any damage to the steel containment vessel of a nuclear reactor is considered critical because it raises the prospect of an uncontrolled release of radioactive material and full meltdown of the nuclear fuel inside. To date, even during the four-day crisis in Japan that amounts to the worst nuclear accident since Chernobyl, workers had managed to avoid a breach of a containment vessel and had limited releases of radioactive steam to relatively low levels.
Rachel Madow’s program tonight (monday) had the most lucid explanation of what is going on that I have yet heard on mainstream media. The most recent update is that there is still question about the integrity of the primary containment vessel on the Unit number 2 reactor. This explosion, while apparently not as spectacular and visible as the first two, may have actually caused the kind of damage that has been feared.
A guest on Maddow, Nuclear Engineer Dave Lochbaum of the Union of Concerned Scientists indicated that recent reports mentioned decreasing pressure in the containment vessel, which might indicate a loss of integrity somewhere in the containment vessel or the maze of plumbing that cools the system.
Just how many blasts were there? Is this the third explosion at one location? Or the second at one plant?
On Saturday morning (in the US), unit one blew up it’s housing.
On late sunday, early monday morning (US), unit 3 blew up.
Now, monday night, March 14, we have a third explosion at unit 2, which seems to have been an explosion inside the containment somewhere.
There are several signs that the system may have lost integrity, including untraceable losses of pressure and water from the system.
The official line seems to have changed from “we’re just doing a precautionary evacuation” to something a shade darker.
So this means 5 explosion at Japanese nuclear plants.