Fairewinds Chief Engineer, Arnie Gundersen, analyzes new video from the Fukushima Daiichi Plant. Gundersen determines that the fuel rack in reactor building 4 is exposed to air.
Arnie Gundersen: Hi, I’m Arnie Gundersen from Fairewinds Associates. It’s Thursday, March 31st. You’ve probably noticed that this is the second update of the day. Normally I update you every other day, however some disturbing video has shown up on Ustream that I wanted to talk to you about.
First off, a little bit about my background. I used to be an executive in the nuclear industry, and one of the divisions I ran built nuclear fuel racks for boiling water reactors, so nuclear fuel racks are something I that know a little bit about.
Nuclear fuel racks look like this. This is [a video of] square cans at the bottom of what is essentially a swimming pool. Each can is designed to handle one nuclear fuel bundle. That’s the glowing thing you see sliding into the can. The wrapper around those cans has boron in it, and that’s designed to prevent a nuclear chain reaction from occurring in the pool. You don’t want a chain reaction to occur in the pool; that should occur in the reactor.
What happened at Fukushima was, when the whole site lost power, at Fukushima [Unit] 4, there was no reactor operating. All the fuel had been removed and was in the fuel pool. Normally, the pools are cooled; however, they lost power, so there was no longer any cooling. It appears that the pools boiled dry. The roof blew off the building. That indicates that hydrogen was built up from something called a zircoloid-water reaction that had to occur at temperatures over twenty-two hundred degrees [Celsius] (2200 degrees C). After that, the Fukushima staff has been attempting to pour water into that reactor. You can see in this picture that, up the side of the building is a hydraulic device, it’s actually designed for pumping concrete, that is pumping water up and over the roof and pouring water into the nuclear fuel pool.
This picture is undated, but when it was taken, it clearly shows that there is no water in the pool. If you look, there’s a green, a long, green device. That’s the refueling bridge. Normally that glides along on rails above the pool, and the pool is that crystal-clear water that you’re used to seeing. Well, after the explosion it has collapsed and is lying in the pool. Between seconds thirty-three and thirty-seven on this video you can see little boxes. The little boxes are just to the left of that green bridge. The boxes are in air. Those boxes are the top of nuclear fuel racks. They’re supposed to be under thirty feet of water. They’re not.
What that means to me is a couple things. First off, the top of the nuclear fuel is exposed. Perhaps all the nuclear fuel is exposed, but certainly the top is. You can see steam coming up, but not from the top of the fuel. [From] down further in the cavity there is steam coming up. So, the water that they’re spraying in is hitting the nuclear fuel and creating steam, but it’s not filling that swimming pool. The water has two purposes: cooling, but also shielding. That means the fuel is unshielded. That [unshielded fuel] emits gamma rays, and the gamma rays go up into the sky, bounce off of air molecules through something called “sky shine,” and rain back down on the site as a background radiation that’s much higher than normal. That makes work on the site really difficult, and it makes work on that refueling pool almost lethal.
The other thing it means to me is that the nuclear fuel itself is extraordinarily hot, and the plutonium inside can become volatile. I spoke yesterday, in the [I mean] earlier update [today], about cerium being discovered offsite and plutonium being discovered, and the fact that the nuclear fuel pool does not have water in it, to me, indicates that it might be a clean path for those heavy elements to be escaping from the building and being discovered offsite. I would recommend, based on this, that the evacuation zone should be pushed back further because of these heavy elements being released, as well as the cesium that was also in those racks. It does have some serious consequences. As this situation develops, and perhaps, more clear pictures are available, I will update you again.