Radioactive Storage


In order to facilitate the collection of radioactive elements without freaking out anyone in the office, I have constructed a number of enclosures for safe storage and display. (Of the elements, not the freaked out office dwellers, which there is no way to store safely).

At first I made half a dozen small lead cups, which fit inside the circular sample areas under each tile. These are used for small things, like thorium lantern mantles. I cast them in a block of plaster that had been drilled with a hole cutting saw that left a cylindrical slot perfect for casting the bottom and walls.

Next I made a leaded glass display case, "The Hot Box" to hold relatively safe, low-level samples. (See below for the story of where this marvelous glass is from.) The front swings open like a regular cabinet door: The only unusual thing really is that it's incredibly heavy, and the glass is slightly yellow. It's roughly equivalent to 1/16 inch of solid lead shielding

Then we got two somewhat more dangerous samples: Thorium metal including some relatively fine powder, and uranyl nitrate, a soluable uranium salt. These are higher in radioactivity than the other samples, but more importantly they are quite toxic from a purely chemical point of view and the thorium is potentially pyrophoric in powdered form (which means it could spontaneously catch fire, though it didn't when I poured it from one bottle to another. If a child were to get into either, it could be fairly bad. I decided that I needed to make a lockable, shielded container for them, one that would provide the necessary protection, and then go an order of magnitude or two overboard for no good reason.

"The Can" is about six inches in diameter and has approximately one and a half inch thick walls of solid lead. It weighs about 60 pounds. To secure the lid, there are two sliding locks (such as used on glass display cases) that slide onto steel straps embedded in the metal of the can. It takes two keys to open it. (How, you might ask, did I get the great mil-spec stencil lettering? I have an old stencil cutting machine from the closing out auction of the Johnson-Ross plant (perhaps most famous for fabricating the concrete batching plants used to build the Three Gorges Dam in China). It has a cast iron dial that you use to dial in the letter you want, then you pull the handle down to cut that letter out of a sheet of thin card stock you are feeding through the machine.)

In the mean time, I'd also made a pair of larger lead bowls with about half-inch walls. They have been used on and off for holding samples, but right now there are better containers for everything, so they are purely decorative.

Where did all this lead come from? And what about the leaded glass, which would cost something like $1200 new? I had the great fortune of encountering an opportunity to scavenge a large quantity of lead, and six 12x17 inch sheets of lead shielding glass, from an old hospital x-ray room. (I could have had the CAT scan machine too, decided against it.) I was taken on a tour of an abandoned hospital by a developer (who is trying to sell my company on the idea of moving to the office complex he's going to build after demolishing the hospital). Knowing that I like this kind of stuff, he pointed out the lead shielding in the x-ray room, offering that I could take as much as I wanted since the building was going to be demolished soon anyway.

The day after the tour Ed Pegg, Jim, and I went in with sledge hammers, nail pullers, lanterns, and of course permission, to see how much lead we could mine. It came in two forms, 1/8" thick sheets about 18x48 inches: Ed and Jim smashed the drywall covering them and un-nailed about 15 sheets from the wall. And 1/2" thick plates about one foot square, covered over in thin cinderblocks: I smashed out 22 of them, each weighing 36 pounds. In two hours we had collected about 1500 pounds of lead.

Almost as an afterthought, I also extracted six layers of lead glass from a large sliding lead door (which alone weighed about another 1500 pounds and which we were unable to collect). I thought the glass might come in handy for a display case of some sort, but didn't really place much significance on it.

After finishing the display case, I happened across a catalog listing for lead shielding glass, and was rather surprised to find out just exactly how much what we had collected was worth. I thought it was probably expensive glass, but I had no idea it would be $145 per square foot! The display case is a good example of something that would never have happened if not for serendipitous recycling, because there's no way I would have spent that much for new glass!

I've used about 200 pounds of the lead so far, mostly for making bowls, lumps, and cans. The sheeting was very useful for making the frame for the glass display case, and I expect to find many applications for it. The thicker plates are harder to use directly, but they are perfect for melting down into other things.

The objects are shown here on the table, but normally they are kept on side tables or the floor.

Atomic Potluck

Atomic Potluck II

Doorstock No. 1