Day: January 10, 2023

The Intricacies Of Creating Fuel For Nuclear Reactors

January 10, 2023 by 51 Comments

All nuclear fission power reactors run on fuel containing uranium and other isotopes, but fueling a nuclear reactor is a lot more complicated than driving up to them with a dump truck filled with uranium ore and filling ‘er up. Although nuclear fission is simple enough that it can occur without human intervention as happened for example at the Oklo natural fission reactors, within a commercial reactor the goal is to create a nuclear chain reaction that targets a high burn-up (fission rate), with an as constant as possible release of energy.

Each different fission reactor design makes a number of assumptions about the fuel rods that are inserted into it. These assumptions can be about the enrichment ratio of the fissile isotopes like U-235, the density of individual fuel pellets, the spacing between the fuel rods containing these pellets, the configuration of said fuel rods along with any control, moderator and other elements. and so on.

Today’s light water reactors, heavy water reactors, fast neutron reactors, high temperature reactors and kin all have their own fuel preferences as a result, with high-assay low-enriched (HALEU) fuel being the new hot thing for new reactor designs. Let’s take a look at what goes into these fuel recipes.

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Tetris Joins Minecraft And DOOM In Running A Computer

January 10, 2023 by 6 Comments

There is a select group of computer games whose in-game logic is enough for them to simulate computers in themselves. We’ve seen it in Minecraft and DOOM, and now there’s a new player in town from a surprising quarter: Tetris.

One might wonder how the Russian falling-blocks game could do this, as unlike the previous examples it has a very small playing field. And indeed it’s not quite the Tetris you’re used to playing, but a version played over an infinite board. Then viewed as a continuous progression of the game it can be viewed as somewhat similar to the tape in a Turing machine.

The various moves and outcomes are referred to through a Tetris scripting language, so states can be represented by different sets of blocks and holes while logic elements can be be built up using the various shapes and the game logic. From those a computer can be built, represented entirely in Tetris moves and shapes. It’s a little mind-bending and we’d be lying if we said we understood every nuance of it, but seemingly it works well enough to run the game from within itself.. If it had the catchy music from the NES version, we’d declare it perfect.

Hungry for more? Here’s DOOM doing some adding, and of course Minecraft has a rich computing history.

TV personality and maker, Adam Savage, sits on a chair attached to a milk crate on wheels. It is situated inside an assortment of steel tubes forming the legs and body of a strandbeest walking machine.

Human-Powered Strandbeest

January 10, 2023 by 6 Comments

Once you’ve seen a strandbeest, it’s hard to forget the mesmerizing movement of its mechanical limbs. [Adam Savage] built a pedal-powered strandbeest in (more than) one day in full view of the public at the San Francisco Exploratorium.

One of the biggest challenges with building strandbeests is the sheer number of parts required to build a walking machine. It becomes clear rather quickly how big of an advantage the wheel is for part count on a device. Add in a few seemingly small design errors, and you might not have any forward motion at all.

[Savage]’s build takes us through all the ups and downs of this process, including lots of wrenching, welding, and more sneakers than Squitter the Spider could wear. The final product is unwieldy, impractical, and beautiful. What more could a maker ask for?

If you need more strandbeest goodness, check out this more practical strandbeest bicycle, this strandbeest Venus rover concept, or Jeremy Cook’s talk about designing strandbeest bots.

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