Retrotechtacular: Better Living Through Nuclear Chemistry

March 8, 2025 by Dan Maloney 11 Comments

The late 1950s were such an optimistic time in America. World War II had been over for less than a decade, the economy boomed thanks to pent-up demand after years of privation, and everyone was having babies — so many babies. The sky was the limit, especially with new technologies that promised a future filled with miracles, including abundant nuclear power that would be “too cheap to meter.”

It didn’t quite turn out that way, of course, but the whole “Atoms for Peace” thing did provide the foundation for a lot of innovations that we still benefit from to this day. This 1958 film on “The Armour Research Reactor” details the construction and operation of the world’s first privately owned research reactor. Built at the Illinois Institute of Technology by Atomics International, the reactor was a 50,000-watt aqueous-homogenous design using a solution of uranyl sulfate in distilled water as its fuel. The core is tiny, about a foot in diameter, and assembled by hand right in front of the camera. The stainless steel sphere is filled with 90 feet (27 meters) of stainless tubing to circulate cooling water through the core. Machined graphite reflector blocks surrounded the core and its fuel overflow tank (!) before the reactor was installed in “biological shielding” made from super-dense iron ore concrete with walls 5 feet (1.5 m) thick — just a few of the many advanced safety precautions taken “to ensure completely safe operation in densely populated areas.”

While the reactor design is interesting enough, the control panels and instrumentation are what really caught our eye. The Fallout vibe is strong, including the fact that the controls are all right in the room with the reactor. This allows technicians equipped with their Cutie Pie meters to insert samples into irradiation tubes, some of which penetrate directly into the heart of the core, where neutron flux is highest. Experiments included the creation of radioactive organic compounds for polymer research, radiation hardening of those new-fangled transistors, and manufacturing radionuclides for the diagnosis and treatment of diseases.

This mid-century technological gem might look a little sketchy to modern eyes, but the Armour Research Reactor had a long career. It was in operation until 1967 and decommissioned in 1972, and similar reactors were installed in universities and private facilities all over the world. Most of them are gone now, though, with only five aqueous-homogenous reactors left operating today.

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Integrated Micro Lab Keeps Track Of Ammonia In The Blood

February 17, 2025 by Dan Maloney 6 Comments

We’ve all got our health-related crosses to bear, and even if you’re currently healthy, it’s only a matter of time before entropy catches up to you. For [Markus Bindhammer], it caught up to him in a big way: liver disease, specifically cirrhosis. The disease has a lot of consequences, none of which are pleasant, like abnormally high ammonia concentration in the blood. So naturally, [Markus] built an ammonia analyzer to monitor his blood.

Measuring the amount of ammonia in blood isn’t as straightforward as you think. Yes, there are a few cheap MEMS-based sensors, but they tend to be good only for qualitative measurements, and other solid-state sensors that are more quantitative tend to be pretty expensive since they’re mostly intended for industrial applications. [Marb]’s approach is based on the so-called Berthelot method, which uses a two-part reagent. In the presence of ammonia (or more precisely, ammonium ions), the reagent generates a dark blue-green species that absorbs light strongly at 660 nm. Measuring the absorbance at that wavelength gives an approximation of the ammonia concentration.

[Marb]’s implementation of this process uses a two-stage reactor. The first stage heats and stirs the sample in a glass tube using a simple cartridge heater from a 3D printer head and a stirrer made from a stepper motor with a magnetic arm. Heating the sample volatilizes any ammonia in it, which mixes with room air pumped into the chamber by a small compressor. The ammonia-laden air moves to the second chamber containing the Berthelot reagent, stirred by another stepper-powered stir plate. A glass frit diffuses the gas into the reagent, and a 660-nm laser and photodiode detect any color change. The video below shows the design and construction of the micro lab along with some test runs.

We wish [Markus] well in his journey, of course, especially since he’s been an active part of our community for years. His chemistry-related projects run the gamut from a homebrew gas chromatograph to chemical flip flops, with a lot more to boot.

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Big Chemistry: Catalysts

January 28, 2025 by Dan Maloney 19 Comments

I was fascinated by the idea of jet packs when I was a kid. They were sci-fi magic, and the idea that you could strap into an oversized backpack wrapped in tinfoil and fly around was very enticing. Better still was when I learned that these things weren’t powered by complicated rockets but by plain hydrogen peroxide, which violently decomposes into water and oxygen when it comes in contact with a metal like silver or platinum. Of course I ran right to the medicine cabinet to fetch a bottle of peroxide to drip on a spoon from my mother’s good silverware set. Needless to say, I was sorely disappointed by the results.

My little impromptu experiment went wrong in many ways, not least because the old bottle of peroxide I used probably had little of the reactive compound left in it. Given enough time, the decomposition of peroxide will happen all by itself. To be useful in a jet pack, this reaction has to proceed much, much faster, which was what the silver was for. The silver (or rather, a coating of samarium nitrate on the silver) acted as a catalyst that vastly increased the rate of peroxide decomposition, enough to produce jets of steam and oxygen with enough thrust to propel the wearer into the air. Using 90% pure peroxide would have helped too.

As it is for jet packs, so it is with industrial chemistry. Bulk chemical processes can rarely be left to their own devices, as some reactions proceed so slowly that they’d be commercially infeasible. Catalysts are the key to the chemistry we need to keep the world running, and reactors full of them are a major feature of many of the processes of Big Chemistry.

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Little Pharma On The Prairie

September 24, 2024 by Brian McEvoy 53 Comments

Let’s get the obvious out of the way first — in his DEFCON 32 presentation, [Dr. Mixæl Laufer] shared quite a bit of information on how individuals can make and distribute various controlled substances. This cuts out pharmaceutical makers, who have a history of price-gouging and discontinuing recipes that hurt their bottom line. We predict that the comment section will be incendiary, so if your best argument is, “People are going to make bad drugs, so no one should get to have this,” please disconnect your keyboard now. You would not like the responses anyway.

Let’s talk about the device instead of policy because this is an article about an incredible machine that a team of hackers made on their own time and dime. The reactor is a motorized mixing vessel made from a couple of nested Mason jars, surrounded by a water layer fed by hot and cold reservoirs and cycled with water pumps. Your ingredients come from three syringes and three stepper-motor pumps for accurate control. The brains reside inside a printable case with a touchscreen for programming, interaction, and alerts.

It costs around $300 USD to build a MicroLab, and to keep it as accessible as possible, it can be assembled without soldering. Most of the cost goes to a Raspberry Pi and three peristaltic pumps, but if you shop around for the rest of the parts, you can deflate that price tag significantly. The steps are logical, broken up like book chapters, and have many clear pictures and diagrams. If you want to get fancy, there is room to improvise and personalize. We saw many opportunities where someone could swap out components, like power supplies, for something they had lying in a bin or forego the 3D printing for laser-cut boards. The printed pump holders spell “HACK” when you disassemble them, but we would have gone with extruded aluminum to save on filament.

Several times [⁨Mixæl] brings up the point that you do not have to be a chemist to operate this any more than you have to be a mechanic to drive a car. Some of us learned about SMILES (Simplified Molecular Input Line Entry System) from this video, and with that elementary level of chemistry, we feel confident that we could follow a recipe, but maybe for something simple first. We would love to see a starter recipe that combines three sodas at precise ratios to form a color that matches a color swatch, so we know the machine is working correctly; a “calibration cocktail,” if you will.

If you want something else to tickle your chemistry itch, check out our Big Chemistry series or learn how big labs do automated chemistry.

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Repeatable “One-Click” Fusion, From Your Cellphone

July 6, 2024 by Elliot Williams 22 Comments

Sometimes you spend so much time building and operating your nuclear fusor that you neglect the creature comforts, like a simple fusion control profile or a cellphone app to remote control the whole setup. No worries, [Nate Sales] has your back with his openreactor project, your one-click fusion solution!

An inertial electrostatic confinement (IEC) fusor is perhaps the easiest type of fusion for the home gamer, but that’s not the same thing as saying that building and running one is easy. It requires high vacuum, high voltage, and the controlled introduction of deuterium into the chamber. And because it’s real-deal fusion, it’s giving off neutrons, which means that you don’t want to be standing on the wrong side of the lead shielding. This is where remote control is paramount.

While this isn’t an automation problem that many people will be having, to put it lightly, it’s awesome that [Nate] shared his solution with us all. Sure, if you’re running a different turbo pump or flow controller, you might have some hacking to do, but at least you’ve got a start. And if you’re simply curious about fusion on a hobby scale, his repo is full of interesting details, from the inside.

And while this sounds far out, fusion at home is surprisingly attainable. Heck, if a 12-year old or even a YouTuber can do it, so can you! And now the software shouldn’t stand in your way.

Thanks [Anon] for the tip!

The Intricacies Of Creating Fuel For Nuclear Reactors

January 10, 2023 by Maya Posch 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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Nuclear Reactor Eye Candy From Around The World

September 1, 2015 by George Graves 18 Comments

Everyone loves a field trip. It’s always fun to visit a manufacturing plant to see how the big-boys make all the cool toys we love. But there are a few places you might not want to go exploring, like inside a nuclear reactor.

Well fear not, now you can spend as much time as you would like with these amazing cut-away of nuclear facilities from across the globe. You can thank University of New Mexico Libraries Exhibition for hosting these photos that have been published in “Nuclear Engineering International” magazine over the years. If you happen to have a pdf allergy, you can also browse most of them on flickr here.

And if you want to see more amazing cutaways, there is this photo pool full of some 1300 other cutaway images to look at. If you know of other amazing engineering photos sets, leave us a note in the comments.