About This Video

Fairewinds’ Chief Nuclear Engineer, Arnie Gundersen, conducts a field demonstration simulating the impact of Fukushima’s intense heat upon Zircaloy [zirconium alloy] fuel rods. Gundersen’s demonstration shows that intense heat weakens and embrittles Zircaloy changing it from a sturdy metal to a brittle oxide that is easily shattered. Images from the post accident Three Mile Island nuclear core show embrittled and broken Zircaloy fuel rods in the nuclear reactor.

Video Transcript

Arnie Gundersen: Hi, I’m Arnie Gundersen from Fairewinds Associates.  It´s Sunday, April 10th.

For a change of routine, I wanted to do a science experiment today.  Back in 1978 I was the lead nuclear engineer on a project in upstate New York, and the company I worked for at that time bought the last nuclear reactor that was ever bought during the first nuclear renaissance.  The project was later cancelled, but as part of that, one of the things the vendor [who we bought the reactor from] gave me, was a piece of a nuclear fuel rod.  This is a nuclear fuel rod.  This is zircoloid.  It’s the element that’s inside of the Fukushima reactors.  Now, [in the reactors] these are about twelve feet tall and there are thousands of them inside the Fukushima reactor.  This is a simulated pellet of uranium.  Now, it’s not the real thing; it’s plastic.  If it were the real thing, and had been operating in Fukushima, I’d be dead by now.  These pellets go into these fuel rods, and over four years create a lot of heat.  When the reactor shuts down, they remain hot.  What I wanted to do today was to show you what happened to zircoloid when it gets hot, as it happened when the water stopped in the Fukushima reactors.

Okay, we’ve got our experiment set up here, and this is what we plan to achieve.  Here’s that fuel, that I took that plastic out [of], and we’re going to heat it with a torch to simulate the heat that’s coming out of the inside.  Then we’re going to spray water on the outside, and you’ll see steam coming off, which represents the steam that’s coming out of Fukushima right now.  Now, in that steam is also hydrogen gas because the water hits the zircoloid and creates not just steam, but [also] hydrogen gas.

This is my friend Jim.   He’s a great neighbor, and he’s going to be the acetylene torch person.

Okay, the zircoloid is cherry red.  Now I’m going to spray it with water as if it were getting some water in the bottom of the reactor.

What we just did was we oxidized the zirconium.  You can see it’s a different color now.  The metal that was quite strong becomes very, very brittle, and we were just able to break pieces off the end of it.  Inside of the nuclear reactor, it ran at that temperature for seven to twelve hours.  The fuel got brittle, and all those nuclear pellets, then, were allowed to fall out.  We just created what went on inside the Fukushima reactor.  Note: those rods glowed that hot for twelve hours or more.  Now what happens is we’ve created an oxide.  This is zirc oxide now, and it’s very, very brittle.  I think you can see these sharp edges.  The fuel that was inside is now free to fall out, and onto the bed of the nuclear reactor and begin to melt through as is happening right now in Unit 2 at least, and perhaps Unit 3 as well.

Thank you for watching.  Arnie Gundersen, Fairewinds.  We’ll do another video in a couple days.

Thank you very much.