Sunday night update: It looks like what happened to Unit #1 has now finally happened to Unit #3.
SOMA, Japan — The second hydrogen explosion in three days rocked Japan’s stricken Fukushima Dai-ichi nuclear plant Monday, sending a massive column of smoke into the air and wounding six workers. It was not immediately clear how much — if any — radiation had been released.
The explosion at the plant’s Unit 3, which authorities have been frantically trying to cool following a system failure in the wake of a massive earthquake and tsunami, triggered an order for hundreds of people to stay indoors, said Chief Cabinet Secretary Yukio Edano.
Again, this all has to do with the failure of the cooling systems, and the lack of cooling water supplies and pump power. This is still quite a ways away from a melting core, but this does mean that the situation is still serious as hell.
Sunday Evening update:
A very good source of information – read this before you pay any attention to the news media reports http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/
Sunday morning, Central Time:
Lots of updates, and trying to wade through them is lots of fun, with all that separating the excitable from the not so excitable.
Most interesting thing I’ve seen so far? The nuclear plant with the most problems at the moment was due to be decommissioned this month.
Right now, it looks like there’s 260,000 homes without power. Of course, there’s no listing of how many homes have been washed away or otherwise been damaged ala Katrina, thus not really needing power at the moment.
There’s backup power supplies that are online, and the more remote nuke plants are okay and operational, but several nuke plants not in the affected zone are offline for inspection, and for good reason.
The reactors at risk are 50 year old plants, and while generally safe from being hit by planes, apparently the cooling systems are the old style, run by pumps, and those generators went offline, got partially restored, but others went offline — or something. Modern nuke plants use a type of gravity feed for getting cooling water to the cores, so temporary power outages to the cooling system aren’t as potentially catastrophic.
The meltdowns you’re hearing of have to do with the partial uncovering of the nuclear fuel and the last gasp effort to put seawater in the cooling system. Obviously, this means 1) there’s no fresh water available to put into the cooling system, 2) seawater as a coolant is a bad idea on several levels as it increases the possibility that bad things will happen.
The good news in all this is that most likely, no matter what bad things have already happened with the various nuclear plants over there, the cores are still in the process of cooling down. Massive amounts of nuclear material shouldn’t be spewing out.
here’s a link to a primer on nuclear plants at Boing Boing
A great interview with a nuclear engineer (by his blogging daughter)
that explains things in a sensible way
As of Saturday morning:
“We’ve confirmed that the reactor container was not damaged. The explosion didn’t occur inside the reactor container. As such there was no large amount of radiation leakage outside.”
Nuclear Energy Institute
Everyone tuning into the news got to see video of the explosion at the nuclear plant, but apparently that hydrogen explosion didn’t damage anything critical at the nuclear plant in question.
At one point, part of the core was uncovered, but they used borated seawater to cover the core back up again, and it remains covered. As long as the core stays underwater, everything should eventually cool down.
Apparently, the tsunami caused the shutdown of the plants, and the backup diesel powered generators were flooded by the tsunami or otherwise damaged, because the issue was that they shut down after about an hour. The generators are used as backup, to provide power to the pumps that circulate the cooling water over the nuclear core. So, the backups got hosed, and the danger of the core overheating was real.
Since then, I believe that additional backup power supplies have arrived, and the core will remain hot but safe condition, slowly cooling down.
In other words, close, but no Chernobyl. I’m being silly here, because in truth, it turns out it wasn’t even that close. Thankfully…
Press releases from the nuclear power company as to current status: