I've been busy the past week and a half..cleaning the church, and then cooking & cleaning for the Preachers Fellowship. Much has happened, with the earthquake in Japan, the resulting tsunami, and the nuclear plants having problems. Here is an interview with MIT Professor of Nuclear Science and Engineering Ron Ballinger.
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.
End of interview.
Okay. Back to the iodine bit. People on the ditzy left coast, are panicking and buying iodide tablets, and the 'illustrious' Surgeon General said that that 'was a worthy precaution'. However, those who actually KNOW what they're talking about, say that it's completely unnecessary, and causing undue panic. I remember from my time down in Radcon (many years ago) time x distance + shielding.. or something thereabouts. By the time that anything would come this far over the ocean, it would be just so much vapour, nothing to worry about. Hubby IMed me the Tuesday morning while I was serving breakfast at the Preachers Fellowship, he said that his boss had just left for town, as the Houston media was glommed down here with the "can it happen here?" bit. I remember for fun in the office, we'd eat several bananas for lunch & then sit in front of "the pig" to see it go on :).
People don't get that we get radioactivity from *everything*. Even other people. Temperature inversions. Fruit. Sunlight. They only hear the word "radioactivity" or "nuclear" and their brain seems to switch off.
The Preachers Fellowship went great - we had brisket with fixings Monday night, and Tuesday night there was a fish fry - sea trout (deeelicious!) with hushpuppies and stuff. Lots of deviled eggs were out for that meal. I think there were even some left over, which is terribly unusual, as we usually run out of those first off.
Spring is definitely here, as the "cold" temperatures we are getting now are only down into the 50s. I put my cactus back outside, hopefully some will bloom, but the golden barrel cactus, is supposed to be 12" across before it will bloom. My hibiscus did not make it through this winter, I guess I will have to pull out the dead stuff and put in new.
Not much else going on, I'm wiped out from a week of cleaning from about 8 am through 6:30 pm, with only a stop to run to DQ for a large diet coke, no ice; or a half a subway sandwich and then back to it.
8 months ago