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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Ask Hackaday: What’s Your Worst Repair Win?

January 9, 2023 by Dan Maloney 191 Comments

Like many of you, I’ve become the designated “fix-it” person for my family and friends. While it can be a lot of work — I just finished an oil change that required me to lay in a cold, wet driveway and I can’t mention in polite company the substances I was bathed in while fixing a clogged pipe last week — I generally relish my role. I enjoy solving problems, I love working with my hands and my head, and who doesn’t like saving money and time?

But for me, the best part of being the fix-it guy is the satisfaction that comes from doing something others can’t do. I find this especially true with automotive repairs, which conventional wisdom says is strictly the province of factory-trained experts. A little bit of a hero complex, perhaps? Absolutely! After all, I don’t get paid for my repairs, so I’ve got to get a little something for the effort.

This is why a recent pair of unrelated fixes left me feeling thoroughly unsatisfied. Neither of these jobs was a clear win, at least in terms of getting the rush of being able to do something that nobody else could. At best, these were qualified wins, which both still left me feeling a little defeated. And that got me thinking that I’m probably not the only one who has had marginal repair wins like these.

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Excuse Me, Your Tie Is Unzipped

January 5, 2023 by Al Williams 102 Comments

If you ask your typical handyperson what’s the one thing you need to fix most things, the answer might very well be duct tape. But second place — and first place in some circles — would have to be zip ties. These little wonders are everywhere if you look for them. But they are a relatively recent invention and haven’t always had the form they have today.

The original zip tie wasn’t called a zip tie or even a cable tie. In 1958 they were called Ty-Raps and produced by a company called Thomas and Betts. Originally meant to improve aircraft wiring harnesses, they found their way into various electronic equipment and packaging uses. But they’ve also become helpful in very unusual places too. A policeman trying to round up rioters would have problems carrying more than a few conventional handcuffs. But flexible cuffs based on zip ties are lightweight and easy to carry. Colon surgeons sometimes use a modified form of zip tie during procedures.

History

Maurus Logan worked for the Thomas and Betts company. In 1956, he was touring an aircraft manufacturing plant. Observing a wiring harness being put together on a nail board, similar to how car harnesses are made, he noted that the cables were bundled with waxed twine or nylon cord. A technician had to tie knots in the cord, sometimes cutting their fingers and often developing calluses. In addition, the twine was prone to fungal growth, requiring special treatment.

Logan kept turning the problem over in his mind and tried various approaches. By 1958, he had a patent for the Ty-Rap. The tie was lightweight, easy to install, easy to remove, and inexpensive.

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All About USB-C: Resistors And Emarkers

January 4, 2023 by Arya Voronova 16 Comments

If you’ve been following along our USB-C saga, you know that the CC wire in the USB-C cables is used for communications and polarity detection. However, what’s not as widely known is that there are two protocols used in USB-C for communications – an analog one and a digital one. Today, let’s look at the analog signalling used in USB-C – in part, learn more about the fabled 5.1 kΩ resistors and how they work. We’ll also learn about emarkers and the mysterious entity that is VCONN!

USB-C power supply expects to sense a certain value pulldown on the CC line before it provides 5 V on VBUS, and any higher voltages have to be negotiated digitally. The PSU, be it your laptop’s port or a charger, can detect the pulldown (known as Rd) because it keeps a pullup (known as Rp) on the CC line – it then checks if a voltage divider has formed on CC, and whether the resulting voltage is within acceptable range.

If you plug a device that doesn’t make a pulldown accessible through the CC wire in the cable, your device will never get power from a USB-C port, and would only work with a USB-A to USB-C cable. Even the smarter devices that can talk the digital part of USB-C are expected to have pulldowns, it’s just that those pulldowns are internal to the USB-C communication IC used. A USB-C port that wants to receive power needs to have a pulldown.

This part is well-known by now, but we’ve seen lack-of-resistor failures in cheap devices aplenty, and the colloquial advice is “add 5.1 kΩ resistors”. You might be afraid to think it’s so simple, but you’d be surprised. Continue reading “All About USB-C: Resistors And Emarkers” →

2022: As The Hardware World Turns

January 3, 2023 by Tom Nardi 30 Comments

Well folks, we made it through another one. While it would be a stretch to call 2022 a good year for those of us in the hacking and making community, the light at the end of the tunnel does seem decidedly brighter now than it did this time 365 days ago. It might even be safe to show some legitimate optimism for the year ahead, but then again I was counting on my Tesla stocks to be a long-term investment, so what the hell do I know about predicting the future.

Eh, my kids probably weren’t going to college anyway.

Thankfully hindsight always affords us a bit of wisdom, deservedly or otherwise. Now that 2022 is officially in the rearview mirror, it’s a good time to look back on the highs (and lows) of the last twelve months. Good or bad, these are the stories that will stick out in our collective minds when we think back on this period of our lives.

Oh sure, some might wish they could take the Men in Black route and forget these last few years ever happened, but it doesn’t work that way. In fact, given the tumultuous times we’re currently living in, it seems more likely than not that at some point we’ll find ourselves having to explain the whole thing to some future generation as they stare up at us wide-eyed around a roaring fire. Though with the way this timeline is going, the source of said fire might be the smoldering remains of an overturned urban assault robot that you just destroyed.

So while it’s still fresh in our minds, and before 2023 has a chance to impose any new disasters on us, let’s take a trip back through some of the biggest stories and themes of the last year.

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BBC World Service Turns 90

December 22, 2022 by Al Williams 23 Comments

If you’ve ever owned a shortwave radio, you’ve probably listened at least a little to the BBC World Service. After all, they are a major broadcasting force, and with the British Empire or the Commonwealth spanning the globe, they probably had a transmitter close to your backyard. Recently, the BBC had a documentary about their early years of shortwave broadcasting. It is amazing both because it started so simply and when you think how far communications have progressed in just a scant 100 years.

Today, the BBC World Service broadcasts in over 40 languages distributing content via radio, TV, satellite, and the Internet. Hard to imagine it started with four people who were authorized to spend 10 pounds a week.

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Big Chemistry: Liquefied Natural Gas

December 21, 2022 by Dan Maloney 44 Comments

The topic of energy has been top-of-mind for us since the first of our ancestors came down out of the trees looking for something to eat that wouldn’t eat them. But in a world where the neverending struggle for energy has been abstracted away to the flick of a finger on a light switch or thermostat, thanks to geopolitical forces many of us are now facing the wrath of winter with a completely different outlook on what it takes to stay warm.

The problem isn’t necessarily that we don’t have enough energy, it’s more that what we have is neither evenly distributed nor easily obtained. Moving energy from where it’s produced to where it’s needed is rarely a simple matter, and often poses significant and interesting engineering challenges. This is especially true for sources of energy that don’t pack a lot of punch into a small space, like natural gas. Getting it across a continent is challenging enough; getting it across an ocean is another thing altogether, and that’s where liquefied natural gas, or LNG, comes into the picture.

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