That is because a highly volatile substance called zirconium was chosen back in the 1940’s and 50’s, when plans were first developed to build nuclear power plants, as the material to be used to make the rods into which radioactive fuel would be loaded.
There are 30,000 to 40,000 rods—composed of twenty tons of zirconium—in an average nuclear power plant. Many other substances were tried, particularly stainless steel, but only zirconium worked well. That’s because zirconium, it was found, allows neutrons from the fuel pellets in the rods to pass freely between the rods and thus a nuclear chain reaction to be sustained.
But there’s a huge problem with zirconium—it is highly volatile and when hot will explode spontaneously upon contact with air, water or steam.
The only other major commercial use of zirconium through the years has been in flashbulbs used in photography. A speck of it, on a flashbulb, ignites to provide a flash of light.
But in a nuclear plant, we’re not talking about specks—but tons and tons of zirconium, put together as a compound called “zircaloy” that clads tens of thousands of fuel rods.
Heat, a great deal of heat, builds up in a very short time with any interruption of coolant flow in a nuclear power plant—the problem at Fukushima after the earthquake that struck Japan.
Zirconium, with the explosive power, pound for pound, of nitroglycerine, will catch fire and explode at a temperature of 2,000 degrees Fahrenheit, well below the 5,000 degree temperature of a meltdown.
Zirconium does not explode at 2,000 oF. given that it melts at 3,400 o F ish, that would make it really rather difficult to make.
You know, let\’s stoke up the furnace, get some zirconium nice and hot and liquid so that we can pour it out into ingots and tubes n\’stuff and Ooops! no furnace left. Or building, people or plant.
It is zirconium powder which is explosive. The technical term being pyrophoric. That is, that as a fine powder it can go bang when shocked, knocked or banged.
You know, like flour can: but we don\’t then say that bread can explode.
Would it be too much to hope that a journalism professor might check the occasional source? You know, maybe even just Wikipedia?
Lordy, what a twat.