a friend of mine works on Nuclear plants. I asked him about the Fukushima disaster.
Here is his response (two different responses, but you'll get the gist.
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As for Japan, well, you know my distrust and disdain for the traditional media...so I tried not to listen. Too many people talking about stuff they don't know about or think they do, or thought they did. Also, it makes catchier headlines to overreact, hype, and spread fear.
When the quake hit the reactors scrammed...automatically...as designed. At that moment, the fissioning process stops and then the concern is controlling residual heat until it dissipates. The plant lost all outside electricity when the transmission lines were swept away by the tsunami, and they can't make any on their own...their reactor has shut down.
So they use the back-up generators to run the coolant pumps, until they quit from water in the fuel. So they go to battery back-up until they're used up. Now they have NO power. This is all in the first 12 or so hours.....lot's of stuff going on.
As for a meltdown (China Syndrome) happening....I don't think so. The fissioning process had been stopped, there's simply not enough heat to melt through the RPV (Reactor Pressure Vessel). However, there is a tremendous amout of steam pressure remaining.
From what I've read, the explosions occurred in the containment building...which is esssentially a metal barn. Meant to keep weather out, but nothing in. It has nothing to do with primary nor secondary containment of the reactor.
When somebody compares the Japan situation to Chernobyl or Three Mile Island I turn away.
First of all, Chernobyl had NO containment...just a graphite cooled reactor. (bad design, but cheap). The reactor exploded, the graphite caught fire, and sent highly radioactive material in the air. The reasons for the explosion are many...much too involved for here. Further reading is suggested.
As for TMI, it was under full power for many hours with reduced water inventory, and the fuel did melt down. However, it was all contained inside the RPV and containment structures....as designed. Only a very little gas was vented.
So in answer to your question....how much should we believe?
I'm not sure how much or what you have heard....but I'd say overall very little.
The main question that we don't have an answer to, yet...and won't for awhile...did the containment structures survive the initial quake?
What has happened in Japan is a tragedy, but the real tragedy is in the loss of human life and a society....not a nuke plant.
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Until they give quantities or the details of their findings, I am a little suspect.
Here's why...
The average person receives between 360 and 630mr (millirem) per year from normal background radiation. (depends on who you read). So that equates to 1 to 2 mr a day.
The other day when I linked that picture of a core and fuel bundle, I had just spent 20 hours over the course of 2 days working right over the core. On one of our 'jumps', I picked up 22 mr. Not a lot, but you could truthfully write a headline that screams "Nuke worker picks up 10 to 20 times normal radiation", investigation continues.
So until they publish quantifiable amounts or what they were measuring, you really don't know what they're comparing.
Up until a couple of years ago...5 Rem or R (5,000 millirem) was the annual limit for a nuke worker. You could have 4.99R on December 31st and then on January 1st your count for the year would reset.
Most of the industry has recently changed to a 2R (2,000 millirem) yearly limit. My company has a 2R rolling limit. Meaning in that any 12 months...that is your limit.
These are ultra conservative amounts. It takes 50R (50,000 millirem) before any kind of visible change to blood cells. So we are working under a 4% threshold.
The work I was doing recently was very low dose. I have been on jobs doing RPV head inspections that were in areas known as "Locked High Rad Areas". Yes, they are locked with key.
Anyhow, say our dose limit for that one 'jump' was 800mr with a maximum dose rate of 1R (1,000 millirem) per hour.
And...let's say I picked up my 800mr limit. You could write another headline that screamed "Nuke worker picks up 80 times normal radiation", investigation continues.
So...until you see amounts listed, who knows what they're trying to say.
From what I've read, the most exposure that anybody has received is 10R...a crane operator.
To put that in perspective....ever had a whole body CT scan?
You then received 1.5 to 10R (1,500 to 10,000 millirem) dose from such a scan.
Okay....that was for dose, or the amount of energy received.
Now there is also contamination.
Any amount of radioactive material where it is not wanted is contamination. So, if some material is found anywhere where it is not wanted the headline can truthfully scream "****(pick any number) times higher than normal detected."
Truthfully? Yes
Does it mean anything? Maybe.
Is this situation serious. YES!!
The fact that they're venting is not good, but is it the end of mankind as some would have you to believe? I don't think so.
There is opportunity in every situation...I'll be heading West with my newly processed iodine pills, shortly. I don't have any kelp, but do have piles of buffalo chips.[/sarcasm]
