Posted on 03/13/2011 8:58:27 AM PDT by SeekAndFind
As Japan scrambles to cope with a nuclear reactor damaged in the quake, Josh Dzieza talks to Ron Ballinger, a nuclear expert at MIT about how the plants work, worst-case scenarios, and more. Plus, full coverage of Japan's catastrophe.
Shortly after Japan was hit with the double disaster of a magnitude 8.9 earthquake and subsequent tsunami, a possible third reared its head: nuclear meltdown. The quake caused 11 of Japan's nuclear reactors to shut down automatically, including three at the Fukushima Dai-ichi power plant, 170 miles northeast of Tokyo. But the quake also cut Fukushima off from the power grid, forcing plant operators to switch to emergency diesel generators in order to continue cooling the reactor core, generators that then failed shortly after the tsunami hit. By the end of the day Friday, Prime Minister Naoto Kan had declared a “nuclear emergency,” and 200,000 people near the plant had been told to evacuate.
Then, Saturday afternoon, a building at the plant erupted in a massive explosion, apparently the result of hydrogen from the superheated fuel rods interacting with oxygen as plant operators tried to vent increasing pressure inside the reactor. Officials say the reactor wasn't damaged in the blast, and that radiation levels have actually been declining since. Nevertheless, they took the extreme step of flooding the reactor with seawater in an attempt to cool it down, and news that the cooling system for a second reactor at the same plant has begun to fail did little to calm worries of a meltdown. As Japan copes with its worst nuclear mishap at least since the leak at Tokaimura, The Daily Beast spoke with MIT Professor of Nuclear Science and Engineering Ron Ballinger about worst-case scenarios, iodine tablets, and why he thinks everything is going to be fine. Plus, complete coverage of the quake.
What's the worst-case scenario?
Well, first off, we can't have a Chernobyl-like situation. The system is designed so that as long as we keep water in there to keep it cool, nothing will happen. There are three levels of protection here. One is the fuel cladding, and if that's damaged then it releases radioactive material into the pressure system, which is a steel container. Then there's a containment vessel around that. What likely happened is that you had fuel damage, damage to the first barrier, which produced hydrogen in the primary system, and then to keep the pressure down they vented the hydrogen into the building that was destroyed.
What happens if all the water boils off?
Hypothetically, if the water all boils and evaporates, then the fuel will stay molten and eventually melt through the steel vessel. But that's already beyond a hypothetical worst-case scenario for me. The steel vessel is four inches thick, and they could always put seawater around the vessel, and that would keep it cool, so it can't melt. If you put a frying pan in water, you could put a blowtorch on the other side and it won't make any difference. Then you have the other containment vessel, with a concrete faceplate underneath that's between four and 10 feet thick. But melting through that is hypothetical beyond normal reasoning. Radiation spiked at 1,015 microsievert per hour before the explosion. Is that dangerous?
No, that's about 100 milirem. It's high, but you get about 35 milirems on a trans-Atlantic flight. And if you live in Denver, you get about 50 milirems per year. What is the dangerous level, and what happens when that level is reached?
The LD50—that is to say, the point when 50 percent of the people exposed will meet Jesus—is in the order of 250 rem, or maybe 400. A big number. Keep in mind, what they've been exposed to is 0.1 rem, and about 50 percent fatality is on the order of 400 rem. What would happen with that kind of exposure is that they would get sick. Radiation damage destroys the immune system. Most people who die of radiation sickness die of pneumonia or a cold, they die of some disease which they have but their immune system can't fight off.
Why is Japan distributing iodine tablets?
One of the isotopes of fission products, when fuel melts, is an iodine isotope, and it goes in your body through your thyroid. So if you take iodine tablets, the non-radioactive iodine goes to your thyroid, you bulk up your thyroid with iodine and it prevents absorption of the radioactive iodine.
What failsafes are there to prevent a meltdown?
A lot. First there's the SCRAM system, it automatically ejects the control rods into the core and shuts the plant down. That happened right after the earthquake. Then there's a number of core spray systems, which inject water to keep things cool. Then, if the system needs to depressurize, there's something called a suppression pool that it vents steam into. Then, when the system is depressurized there are other systems that inject water at low pressure. And then, worst comes to worst, there are pumps that can take water from the local cooling water supply, in this case the ocean, and just pump water in there. As long as there's water in there, it might be expensive for the utility to get it cleaned up, but everything is going to be fine.
If they're pumping in seawater, does that mean all the other failsafes failed?
The earthquake plus the tsunami destroyed all the power sources to run pumps and things like that. There are diesel generators on the site that are supposed to run for that purpose, but for some reason they ran for a while and then stopped, maybe because of the tsunami. Then they hauled a bunch of portable generators to run the pumps.
How good a failsafe is pumping in seawater?
The ocean's pretty big. But it's salt water, so from an operational point of view you're pretty screwed. If you get saltwater into the primary system, it's very hard to get it cleaned up. Salt water's not good for the materials, it requires pure water. So if they have to put saltwater into the primary system, it would keep it cool, but it would damage a lot of things and there will have to be extensive cleanup.
How will we know when the crisis is over?
The fuel has to cool down to the point where the water that's cooling it is below the boiling point. Usually when they shut one of these plants down to refuel they have to open it up. It takes a couple days to get the plant shut down to the point where they can take the lid off and replace the fuel. It might be a financial disaster, but no member of the public has been hurt, and I doubt anybody will be.
-- Josh Dzieza is an editorial assistant at The Daily Beast.
Question: where does the hot seawater go once it’s been circulated through the reactor?
Well, we had a “Chernobyl-like meltdown” in Chernobyl and how many people in the US died as a result?
Along with that, what effect did dropping two atomic bombs on Japan during WWII have on the United States? None!
Ron calmly covers the facts of the situation while the eco fecal freaks go absolutely apesh!t. Did CNN have him on?/s
CNN actually had some ‘expert’ d!ckhead on yesterday, saying the control rods were made of cesium. They were so anxious to get every anti-nuke pus chancre on, that I’m sure they never bothered to check credentials.
These nuclear power plants could have been hit by an asteriod. The horror. They were a stones throw away from the epicenter of one the biggest quakes in recorded history with a subsequent massive Tsunami and survived.
The fact that everything is undercontrol is absolutely amazing.
We need to start building thousands of nuclear power plants in the U.S. The states need to give the middle finger to the federal government and start building.
We’re going to bottle it so it can we can force feed it to fear mongering morons.
Hahaha! But seriously, is it discharged as steam? Contained somewhere? Is any of it being released into the environment?
I imagine its being recirculated after cooling. Water doesn’t hold radiation very well.
No doubt the technology of today is superior to that of the reactors in trouble now and obviously this event will be a tool for further learning and possible design changes in the future. In no way should this stop us from investing in nuclear energy- though it’s highly unlikely to happen in this administration.
My concern is the lack of solid and reliable info coming from the authorities in Japan- the conflicting reports and disinformation are on a par with Katrina when, if you remember, we had cannabalism taking place in the Superdome.
It’s a tough call for governments- even fair ones- to balance the public’s need and right to know with keeping unecessary panic at bay. I’ve gone over some pretty alarming posts at FR this morning and see there’s more than a few who expect the apocolypse at any moment. It’s not rational- and is a natural result of being misinformed or underinformed.
A lot of us- including me are woefully ignorant about nuclear energy and it’s not a far jump from Chernobyl to Japan if you’re uneducated. I’m learning every day though and considering the big picture, nuclear energy is a safe and effective source.
Chernobyl is in western Russia and is not in the path of the polar jet stream which flows westward from Japan to North America.
If you look at a map of Europe after the chernobyl accident (below), you`ll see that radiation was spread over vast parts of Europe.
It`ll take years to assess what impact that had on cancer rates and other radiation related diseases.
A must-read from an MIT scientist, “Why I am not worried about Japan’s nuclear reactors.”:
http://www.freerepublic.com/focus/bloggers/2688107/posts
WEll lets hope so.
No No NO, The media is hyping something that is a none issue. The reactor building the concrete one plays no role in containment in fact it is designed to blow outward in the case of a pressure spike. Exactly what has happened. the Steel containment vessel its around the reactor pressure vessel and the suppression pool. Its nested like Russian dolls This is not a PWR reactor where the Dome is the last line of containment. In a BWR the containment and last line of defense is steel and its form fitting to the rector pressure vessel. They have flooded the RPV with seawater and probably have flooded the inside of the containment vessel too. There is no possibility of a core release as long as the RPV and/or the containment is flooded with water. They will need to release steam for the next few days as the seawater boils but the dose will be in millirads so its a none issue. This is bad from a operators point of view as using seawater is going to lead to the shutdown of these reactors indefinitely no one would recertify a RPV that has been in contact with hot radioactive seawater. these reactors will have to be scraped and new steel members cast and welded in place. It should be noted that they were designed for an 8.2 EQ and that a 8.9 is 7 times large in amplitude well above the design specs it is a testament to Japanese engineering that they held together this well. They also were never designed to take the size of the tsunami that came on shore knocking out all the back up generators. A total plant backout is the worst of the worst case scenarios if all else fails and the cores melt the containment vessel can be flooded from the outside with seawater and the 10 feet of concrete and steel will contain the corium till it solidifies. That would be the end game but still of little health concern to the general public.
Here is a rational description of the current status:
http://www.nei.org/newsandevents/information-on-the-japanese-earthquake-and-reactors-in-that-region
Thanks for that link in THIS thread, Qbert.
Thank you for some clarity.
I was up and saw it...it looked like it came from a bad movie script. So much b.s. was being spewed it was ridiculous.
Thanks. I thought I was the only one who saw it. It was so much bs.
Not only will there be no radiation here...
THE OTHER REACTORS AT THE PLANT WILL BE QUICKLY CLEANED UP AND PUT BACK ON LINE!!!!!!!!!!!!!!!
They have done an exquisite job in this horrible disaster thanks to good design, training and hard work.
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