TEPCO has discovered locations on the Fukushima plant site with lethal levels of external gamma radiation. Fairewinds takes a close look at how this radiation might have been deposited and how similar radioactive material would have been released offsite.
Arnie Gundersen: Hi, I'm Arnie Gundersen from Fairewinds and it is Thursday, August 4th.
Two days ago, Tokyo Electric announced some really high radiation levels on the Fukushima site and I wanted to put that into perspective and let you know what I think is happening.
First, Tokyo Electric discovered very, very high radiation in a stack which is used to vent radiation out of the plant and up into the air. The quantity of that radiation was really, really high exposure. It was 10 Sieverts and to convert that over to rems, which I am used to, is a thousand rem. Now, what does that mean?
A thousand rem or more, because the instrument went off scale, a thousand rems, if you were there for less than half an hour, would mean death within a couple of days. Those kinds of exposures cause extensive neurological breakdowns that cannot be reversed medically. So basically, to be near that for any amount of time beyond a couple of minutes, would be a death sentence. What that means is really interesting. This site has been extensively mapped. There is a map that is current that shows many, many hot spots. This hot spot was not discovered until just a couple of days ago. Now that could mean a couple of things. It could mean really poor health physics in that this was missed for 100 days.
I do not think that is the case, but earlier site maps do not show this high concentration of radioactivity in that area. More likely is that this event happened over time, this radiation built up over time, and that is my theory about how the material was deposited. The key is that it occurred in a vent. Now that vent was venting the containment for weeks and months before the radiation was detected.
When you start your car up in the morning, you will see water dripping out of the end of the exhaust pipe. I think that is what happened at Fukushima. The hot humid gasses from inside the containment were going up this stack and where the gasses touched the outside of the stack, they were condensing. It was not just water and hot air, but it also contained lots of cesium. So the cesium and the hot water ran down the outside of the pipe and collected at the bottom. So over a period of time, that concentration got higher and higher and higher. It is likely that the first surveys missed it, because it just was not as high a radioactive source in comparison to all the other radioactive sources that were there.
But over time the concentration went up and up and up as more and more and more water containing cesium came down. It is important to remember that this lethal amount of radiation was found on site, not off site. So that is good. The other piece of that is, it was found in the stack, air was being pulled over that, and up and exhausted into the air for a long time. I think it really speaks to how much radiation was released over the last 140 days. And that this is just a small portion of what was released to the environment.
There is another competing theory: some people think it was blown into that location during the explosion in the first week.
Again, either the health physics practices of measuring that on site were really, really poor, or it was not there in the first week and has gradually built up over time.
Tokyo Electric has found high radiation in the ground in that vicinity and all around the plant.
And in fact has bulldozed some of it under, so that workers could access some of these areas. What that means is that we are going to continue to see over the next 10 years, spikes in radiation on site. First, as pieces that were bulldozed actually come to the surface in the excavations, there will continue to be these enormous radioactive sources that are in the dirt.
And second, when they get into these buildings to actually try to dismantle the plant, they are going to find even higher radiation levels than this one. Remember, at the bottom of the nuclear reactor, the nuclear core has leaked out and is now lying like a pancake on the concrete floor, working it's way down, but probably not through the concrete. That is even much more radioactive than this.
That is why it is going to take Tokyo Electric 10 or 20 years to clean up. This is not something you send somebody in with shovels to shovel the floor. This is going to have to be done robotically and it is going to take a long, long time.
I will keep you informed as more develops.
One last thing, I wanted to say that I made a mistake in the last video at the University of Vermont. It is Finland that has the waste repository. In my presentation, I said Sweden. My apologies to the Finns for mistaking your country.
Thank you very much.