I have been following the nuclear plant "meltdown" story from Japan trying to figure out what happened. I'm a former Naval Nuke so I know a fair bit about Nuke plants and I must say that this has been my experience so far:
I have been reading every news release on the incident since the earthquake. There has not been one single (!) report that was accurate and free of errors (and part of that problem is also a weakness in the Japanese crisis communication). By “not free of errors” I do not refer to tendentious anti-nuclear journalism – that is quite normal these days. By “not free of errors” I mean blatant errors regarding physics and natural law, as well as gross misinterpretation of facts, due to an obvious lack of fundamental and basic understanding of the way nuclear reactors are build and operated. I have read a 3 page report on CNN where every single paragraph contained an error.My take so far: Even with a catastrophic meltdown the odds of a significant release of radiation outside the plant grounds is small. Blowing off radioactive steam is not what I would consider a significant release. It would take a core breach. Plus a reactor vessel failure. AND a containment building failure to accomplish that.
This report with video of a massive steam release is pretty good.
A grim-faced Prime Minister Naoto Kan described the crisis as Japan's worst since 1945, as officials confirmed that three nuclear reactors were at risk of overheating, raising fears of an uncontrolled radiation leak.Except that there was no explosion. It was a massive steam release. And cooling the reactors by injecting sea water into them indicates a very bad situation. However if they are cooling the reactors by flowing sea water on the outside of the reactor vessel it is not so serious.
"The earthquake, tsunami and the nuclear incident have been the biggest crisis Japan has encountered in the 65 years since the end of World War II," Kan told a news conference.
"We're under scrutiny on whether we, the Japanese people, can overcome this crisis."
As he spoke, officials worked desperately to stop fuel rods in the damaged reactors from overheating. If they fail, the containers that house the core could melt, or even explode, releasing radioactive material into the atmosphere.
The most urgent crisis centers on the Fukushima Daiichi complex, where all three reactors are threatening to overheat, and where authorities say they have been forced to release radioactive steam into the air to relieve reactor pressure.
The complex, 240 km (150 miles) north of Tokyo, was rocked by an explosion on Saturday, which blew the roof off a reactor building. The government did not rule out further blasts there but said this would not necessarily damage the reactor vessels.
Authorities have poured sea water in all three of the complex's reactor to cool them down.
In any case - if at this point the reactors have not overheated to the point that the fuel rods have been breached the danger is receding as the residual heat in the plant from decaying radioactive material declines. The most critical thing right now is to get those plants on line to supply electricity to Japan. Unfortunately it will take months to check out all the plant systems and the reactor cores to make sure it is safe to restart the reactors. And that is if nothing exceptionally bad happened.
What does this tell you? It is dangerous to have only a 5% or 10% reserve margin in your electrical supply. Twenty percent is better. Of course spare capacity does not produce revenue. Which means electric rates have to go up to support plant and equipment that is relatively underused. A waste - until you need it. When you do need it - it will save lives. The question as always is how much should be spent and what should electric rates be?
And just to get on my hobby horse. Polywell Fusion. Yeah. It has been months now and there has been no news. Supposedly there will be a report done in April but I'm not actually expecting anything until September. Maybe September of next year even. I even expect the program to go dark for 5 to 7 years if they go for a working ship reactor. But it is all speculation. There is no news.
In terms of safety there are two ways (or more) to stop a Polywell from generating heat: Turn off the switch. Let air into the reactor vessel. As long as the reactor was designed to go from operating temperature to room temperature with no backup power - a fairly simple job - then no problem with loss of power accidents.
Update: 14 March 2011 0745z
The explosions recorded at the nuke plans appear to have been hydrogen explosions not venting steam.
Japan's Nuclear and Industrial Safety Agency said the blast, believed to be a hydrogen explosion, occurred at 11:01 a.m. in the No. 3 reactor of the power plant, NHK said. But radiation levels around the plant, about 170 miles north of Tokyo, remained within acceptable levels. On Saturday, a hydrogen explosion occurred in the No. 1 reactor at the same power plant.Hydrogen explosions indicate a very serious problem. There should be no hydrogen generated under normal conditions. Or abnormal conditions. The situation must be very abnormal.
The Japanese government was making efforts to allay fears of large releases of radioactive materials. ''We judge that the possibility of a large amount of radioactive materials flying off from there is low,'' Chief Cabinet Secretary Yukio Edano said at a news conference, according to the Kyodo news agency.
"We're in a key period now," nuclear expert Joe Cirincione said on "Fox News Sunday." "The next 12 to 24 hours will tell us whether the Japanese officials will be able to get control back over these reactors, or it's gone, it's lost. The pumping of the seawater into reactor number one is that last ditch effort to try to stop it before it's too late. If they can succeed, if they can hold it for the next 24 hours or, so then these reactor cores will cool down and will be implied path to containing this disaster."Nuclear expert? Hah. The reactors are under control. What is not under control is residual heat caused by fission decay products. Other than that I think it is a fair statement of the current situation.
Cross Posted at Classical Values