University Of Utah’s TRIGA Research Reactor Set To Produce Electricity

Research reactors come in many forms and sizes, with the TRIGA class being commonly found at universities. The TRIGA reactor at the University of Utah was installed in 1975, and for the past half century the thermal energy it produced was bled off into cooling systems. Now for a world’s first, the reactor will be used to generate electricity instead.

A TRIGA reactor core, with the blue glow from Cherenkov radiation. (Source: DoE, Wikimedia)
A TRIGA reactor core, with the blue glow from Cherenkov radiation. (Source: DoE, Wikimedia)

What makes the TRIGA design so practical for small research reactors is its inherent safety due to the use of uranium zirconium hydride (UZrH) fuel, which imposes a strong negative thermal coefficient on the reactivity. Along with no need for any kind of containment, these pool-type, water-cooled reactors thus allow for a pretty good at the literal internals of the reactor core.

Their thermal power outputs range from 0.1 – 16 MWth, with the University of Utah reactor generating on the low end of the scale here, at 50 kWth. This energy will be partially used by a generator that has been developed by Elemental Nuclear, a startup company who looks to be trying to commercialize TRIGA fuel for microreactors with sodium coolant.

The installation at this TRIGA reactor should thus be seen as a proof-of-concept for Elemental Nuclear’s generator design, which uses a closed Brayton cycle with helium gas to generate an output of about 2-3 kWe from the ~13 kW generated by the turbine. This generated power will – of course – be used to power some racks with GPUs for ‘AI’ tasks. If successful, it could show the way for TRIGA-based microreactors to power datacenters.


Top image: the TRIGA reactor during a tour. (Credit: University of Utah)

This Az-El Mount Is Worth Following

Communication with satellites often involves the use of high-gain directional antennas coupled with careful positioning to find and track the target. With a geostationary satellite the mount is either fixed or a single-axis polar mount, but when the craft is moving in a different orbit it becomes more of a challenge to stay locked on. An azimuth-elevation mount is needed to cover the whole sky, and [Ham Radio Passion] has one as a work in progress. It’s 3D printed and looks straightforward, making it a project to watch.

An az-el mount has two parts, the first being a turntable to set the azimuth, and the second being a horizontal rotating axis to set the elevation. He’s mounting the antenna to a piece of aluminium extrusion and driving it through a set of 3D printed gears driven from a 360 degree servo with a worm drive. He explains why the servo makes more sense to him here.

The result is not yet a finished project, but it shows enough promise to make it worth keeping an eye on. It’s by no means big enough for a huge antenna array, but we can imagine antennas for higher frequencies would be well within its capabilities. Meanwhile it’s certainly not the first az-el mount we’ve seen.

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How To Better Enjoy VR On Linux

Linux folks are used to having to roll many of their own solutions, and better Linux desktop usability is a goal of the WayVR project, which aims to provide desktop control and app launching from within a VR session.

VR applications can already stream from Linux to standalone headsets with projects like WiVRn, but what WayVR does is let one launch programs and access desktop screens within VR. Put another way, instead of the headset being limited to acting as a pseudo-monitor that only receives the output of an already-running VR application, the headset and controllers can now be used to interact with one’s computer as if one were physically sitting at it. Controls and user interface are highly flexible and help users to do anything they need — including clicking, typing, and launching applications. It’s a considerable step forward for convenience and general usability.

Naturally, when it comes to using a computer from within VR there is plenty of unexplored territory regarding user interfaces. It’s fertile ground for experimentation in everything from DIY headsets to ways to input text without a keyboard, so if you enjoy working on the frontiers of such things, it’s a good scene to dive into.

Learn Programming Without A Computer

Presumably aimed at children, NHK World’s Texico program teaches the main ideas about programming without actually using a computer. Instead, it uses items like a toy train, playing cards, and other gadgets to teach concepts such as analysis, combination, simulation, abstraction, and more.

There are ten episodes in English and French. Some of them are more about critical thinking, which, admittedly, is important for solving problems in general with or without a computer. For example, a “magic” trick relies on the observation that tearing a sheet of paper into nine rectangular pieces will mean each piece has at least one perfectly straight edge except for the center piece.

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A 1947 Radio Gets A Face Lift

We’ve all done it. We spy an old radio at a garage sale or resale shop. We know someone should bring it back to life, but it looks like a project, so we pass it by. Not [Ken] from [Ken’s Shop]. He found an Arvin 664A AM radio from 1947 in what appears to be a home-built cabinet and decided to bring it back to life.

From what we could find, the original case was a white plastic, not the wood box it is in today. So the first challenge was simply getting inside to see what was going on. Continue reading “A 1947 Radio Gets A Face Lift”

Direct FDM Printing With Granules

The idea of FDM 3D printing using granules rather than filament is an appealing one: rather than having to wrangle spools of filament that need to adhere to strict dimensions and cannot be too flexible, you can instead just keep topping up a big hopper with fresh granules. This is what [HomoFaciens] has been tinkering with for a while now, with their Direct Granules Extruder V7.0 showing significant improvements.

There’s also an accompanying article, with details of previous granule extruder attempts detailed on the same site. Many of the improvements here focus on making sure the granules melt properly before they reach the end of the extruder, with the auger screw helping to push things along. While this seems straightforward, there are many details to get right, with the previous v6.2 version having issues like the hot plastic backing up into the cold section and clogging things up.

For the test bench a Prusa Mk4 FDM printer is used, with the standard extruder swapped for the experimental extruder. On the extruder the cold, top part is water cooled to ensure it stays cold, with each turn of the wood-screw-turned-auger providing the right extrusion speed. As can be seen with the print tests, the results look pretty good despite the extruder not having been tuned yet.

If you want to give it a shot yourself, the article page provides files for download.

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Taking Polyphony To A New Level

There are all manner of musical synthesis techniques, from the early electromechanical instruments through analogue tape systhesis, the all-electronic waveform synthesisers of the 1960s onwards, and Yamaha’s FM systhesis of the 1980s, to name but a few. One of the attributes of such a machine lies in how many voices it has, or in simple terms, how many notes it can play simultaneously. Electronic complexity limited those early synths, but what happens on an FPGA where vast numbers of circuits can be made with little extra cost? [Tsuneo.Ohnaka] is pushing the envelope a little, by cramming 10240 individually controllable oscillators onto a Terasic DE10-nano FPGA board.

While this thing can in theory generate 10240 different notes at once, in practice that doesn’t mean it has 10240 voices. Instead he calls it a spectrum engine, in that with such a large number of oscillators all with individually controllable frequency, phase, and amplitude, he’s made the part of all those Fourier transform maths where all the different frequencies are combined, in hardware. It’s as though you had a sound card which wasn’t based around a DAC fed with samples, instead all those spectrum points you’d derive from a Fourier transform. Because it’s a massive parallel array of real oscillators it all happens concurrently, instantaneously in real time, and is not held back by the processing constraints of a microprocessor. Think of it as something akin to a software defined radio transmitter, but for the world of audio synthesis.

In that light, it can emulate all those other forms of audio synthesis driven by software, but without the software overhead of generating the waveforms. It’s certainly a different approach to generating audio from a computer, and he’s posted a cacophonic demo video below of it as an 80-voice polyphonic synthesiser. We like it.

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