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a glowing green sandwich covered in red sand. But seriously, this stuff is powering those voyager probes 40 years later. Which makes me ask: why do we have to s
by marshmallow_12 6y ago
a glowing green sandwich covered in red sand. But seriously, this stuff is powering those voyager probes 40 years later. Which makes me ask: why do we have to send there technologies 10 billion miles away to make them work? Why can't my fridge be powered this way?
- neolog 6y agoI'd be interested in a real answer to this if any nuclear engineers are around
- ChuckMcM 6y agoNot a nuclear engineer, but we covered this in my third semester of physics at University. The short answer is there isn't any engineering reason why you can't do this. The "real" reason is that there is liability here that nobody knows how to deal with. If the unit became damaged and its shielding failed it could sit there and kill people who came near it for years (for example). I got to talk to one of the engineers who worked on KRUSTY[1] a 10kW nuclear reactor. This combined with some batteries for peak load could run pretty much any house for a couple of decades. (they talk about several houses in the article but realistically the peak load of a single house when the oven, refrigerator/freezer compressor, and central AC are running is a bit north of 10kW. I would seriously consider a way off grid ranch house if I could have one of these to power it :-) [1] https://www.popularmechanics.com/space/moon-mars/a20127140/nasa-tests-mini-nuclear-reactors-for-moon-and-mars/ https://www.popularmechanics.com/space/moon-mars/a20127140/n...
- burnte 6y agoRTGs get hot, that's the point of them, actually. Too hot for use in a small area like your fridge. On a space probe or rover on a cold planet, the waste heat is useful in keeping things somewhat warm. On earth, not so much. RTGs are also large, too large to power a fridge given the power draw for a fridge. There were microRTGs used in some pacemakers, but the long term safety concerns were never overcome. The decay rate is high enough that you'd need to augment or refuel your house every handful of years. Halflife of 87 years, 25% energy loss in 40ish, 10% loss in just over a decade, etc. Also, they've got little plutonium pellets in them, which is both expensive and dangerous.
- oso2k 6y agoMany advocate for the use of Thorium instead.
- AnimalMuppet 6y agoWhat's powering Voyager is a plutonium pile. Pretty sure you don't want that in your fridge. 10 billion miles from me? Sure, knock yourself out. 10 feet from me? No way.
- nitrogen 6y agoAKA "Not In My Back Yard." So the question stands and extends to include this: "why not?"
- leijurv 6y agoNuclear reactors are better and have economies of scale, it doesn't make much sense to everyone have their own.
- ddingus 6y agoRisk? That is my basic opposition. Happy to be flexible on energy in almost every way. Cost, type, uptime... But error with nuclear tech tends to endure for a very long time. Fukushima will be raising ocean radiation for a long time, just one example. These are many lifetime events. Some minor, or recoverable, some profound. Given we can reasonably run the fridge on solar, and other tech, that risk does not seem to make sense to a lot of people. Doesn't to me. Now, that said I am not ideologically opposed. Other tech could very seriously improve risk profile. Maybe it becomes worth it. Then again, the fridge in my RV can run on a small flame, or a very low current source. And no moving parts! So, we could make fridges differently too. Make tradeoffs.
- antientropic 6y ago> Fukushima will be raising ocean radiation for a long time, just one example. Will it? The ocean is very, very big. Contaminated water from Fukushima is a literal drop in a bucket.
- ddingus 6y agoAlready is. Drops over say, 10 to 100k year timelines add right up. The solution to pollution is dilution. I say that in jest, because dilution involving radioactivity works on much longer timelines than many things do.
- ryandvm 6y agoAre you really asking why we can't power your fridge with plutonium?
- junon 6y agoDo you have an answer that isn't speculation or something you concluded from a breezy stroll over to Wikipedia? Stop mocking questions. It solves nothing.
- btilly 6y agoEach Mars Rover uses 5 kilograms of plutonium 238. (Plutonium 239 is the one that is used in nuclear bombs.) Per https://www.wired.com/story/nasas-mars-rover-will-be-powered-by-us-made-plutonium/ https://www.wired.com/story/nasas-mars-rover-will-be-powered... we currently have a lab dedicated to producing it, and it makes 3.5 pounds per year. Per https://www.npr.org/2011/11/08/141931325/the-plutonium-problem-who-pays-for-space-fuel https://www.npr.org/2011/11/08/141931325/the-plutonium-probl... the cost of getting the lab restarted was a bit shy of $100 million. And once running fully it costs millions of dollars to run. At those cost points it would be cheaper to deliver you a brand new fridge each month for the next 20 years than to deliver you a single fridge using plutonium to run without external electricity for the same 20 years. Not to mention that the plutonium itself is toxic.
- junon 6y agoThanks for the info, interesting. Though FWIW I was more commenting on the mocking of a legitimate question. Not everyone has the same background as everyone else. There are no stupid questions.
- ryandvm 6y agoFair enough. I probably should have dialed down the snark. I suppose if we're looking for a Randall Munroe / "What If?" style explanation of why powering consumer equipment with plutonium is a bad idea, then it was the right question to ask.
- 6y ago
- oconnor663 6y agoYou know I was about to say something about how your fridge draws so much more power than these probes, but actually I just googled it and they're pretty close. Today I learned. (I don't know how much power the probes actually use, but anyway the wattage of the RTG itself is pretty close to the steady state power consumption of a fridge.)
- shkkmo 6y agoThe 8 figure price tag for a RTG makes consumer use uneconomical.
- oso2k 6y agoMore than likely, 99% of that cost is the container and the apparatus to make use of its energy. [0][1] [0] https://www.thoughtco.com/what-is-most-expensive-element-606625#:~:text=It%20costs%20around%20%2448%20per,if%20you%20start%20accumulating%20it https://www.thoughtco.com/what-is-most-expensive-element-606...). [1] https://www.sciencedirect.com/topics/earth-and-planetary-sciences/thermoelectric-generator#:~:text=Diagram%20of%20Voyager%20spacecraft%20showing,the%20length%20was%2058.3%20cm https://www.sciencedirect.com/topics/earth-and-planetary-sci....
- Balgair 6y agoPlutonium-238 can only be made via Uranium-238. Per the Seaborg process, you must bombard U-238 with deuterons to get Neptunium-238, which then further decays into Pu-238. The Pu-238 then decays into U-234 with a half life of ~88 years. U-234 has a half life of ~200,000 years, btw. It is very unlikely that the production of Pu-238 would cost less to produce than the container and the apparatus that harvests the energy. Let alone the issues with the waste products of U-234 hanging about in the kitchen or basement. If you think climate change is bad as is, add in what people will do when faced with surplus uranium waste removal costs. https://en.wikipedia.org/wiki/Plutonium-238 https://en.wikipedia.org/wiki/Plutonium-238
- extrapickles 6y agoThe reason for that high of a price tag is that the engineering costs are spread over a very few units. If they made 100,000 of them, the costs would be much closer to the materials cost.
- adrianN 6y agoSo only six figures for fridge? Sounds like a good deal.
- 6y ago
- vharuck 6y agoSmoke detectors rely on a circuit powered by atomic fission ionizing the air. It isn't their power source (they still need batteries), but it is a safe way to get continuous electricity. https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/smoke-detectors.html https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/s... There's probably a way to get a little more power out of it without being too dangerous. But then we'd have ordinary citizens buying things over-the-counter that could be abused in bulk. And I don't see any hassle being worth an extra free outlet or not replacing batteries.
- souprock 6y agoWe used to power pacemakers this way. There might still be a person with plutonium inside.
- matheusmoreira 6y agoSurely it would be a horrible idea to distribute radioactive materials to the general population. https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident
- King-Aaron 6y agoAside from the high cost of a consumer grade plutonium RTG, and the size constraint issues with putting one in the base of a fridge, or the health risks with having a reactor in your house under your food, one reason might be to prevent people exploding them.
- mLuby 6y agoBack in the 60's, people thought everything would be nuclear-powered; atomic cars, planes, trains, houses, etc. But like with building-sized computers, we've chosen a different path through the tech tree. There were terrestrial exceptions though, like "the Beta-M is a radioisotope thermoelectric generator (RTG) that was used in Soviet-era lighthouses and beacons." https://en.wikipedia.org/wiki/Beta-M https://en.wikipedia.org/wiki/Beta-M But people happened across them and got radiation poisoning, so imagine that happening a lot more often if they were powering all manner of home appliance. Also a lot more dirty bombs.
- idlewords 6y agoThe Russians tried powering a bunch of remote stuff with plutonium batteries during the Soviet era. It did not end well, and cleaning those up has been an ordeal. Pu-238 was also used in pacemakers. The basic problem is just that plutonium is toxic as hell.
- sgt 6y agoNo no.. My grandfather from Irkutsk oblast had plutonium heart, and he live to long ripe age of 45! Almost unheard of in Soviet union.
- gambiting 6y agoI mean, US has been employing RTGs to power all kinds of stuff too, it's not just Russians which did. But yes, actually collecting and decommissioning them after the collapse of the Soviet Union has been an ordeal.
- bregma 6y agoMore accurately, plutonium is as toxic as lead. It's also a bit more radioactive than lead.
- baybal2 6y agoNot plutonium, strontium
- jb775 6y agoBecause if you can power a fridge this way, you can power an automobile this way. They won't let this happen. The current power structures in the world (petrodollar, etc) and world economy as a whole (massive employment within oil industry and throughout supply chains catering to oil industry) are too intertwined with the oil industry to allow any other technologies to swiftly disrupt that.
- Johnny555 6y agoWhy can't my fridge be powered this way The MMRTG is a cylinder 25" in diameter and 26" high, it's going to seriously impact space in your 'fridge. Plus it weighs nearly 100 lbs. It outputs around 100W of power, which might be enough for a small refrigerator, but it also emits around 2000W of thermal energy, so your kitchen's going to get a little warm (probably a good thing in the winter, not so much in summer). Though probably the biggest drawback is the cost -- the MMRTG costs around $100M to manufacture. The US Department of Energy makes the plutonium for it.
- TeMPOraL 6y agoAnd, if you somehow manage to procure one to power your fridge and complete all the necessary paperwork for it to be legal, you'll be on the radar of pretty much every single three and four-letter agency in your country. Not just the obvious ones (checking if you aren't selling plutonium or making a dirty bomb), but also health agencies (what if it leaks and someone eats it?), environmental agencies (what if it leaks and gets into groundwater?), child protective services (are you really storing nuclear material in reach of children?!), drug enforcement (are these parties near your "glo fridge" legal and above board?)... On the bright side, as the joke goes, being on the radar of government agencies is a good way to deter criminals from robbing your house.
- lostlogin 6y agoAccording to the below, The Perseverance could potentially give you a dose of 210 milligram in an accident. That’s not as much as I’d have thought, though would make getting the milk from the nuclear fridge a little hazardous. https://mars.nasa.gov/mars2020/spacecraft/rover/electrical-power/ https://mars.nasa.gov/mars2020/spacecraft/rover/electrical-p...
- cosmonaughty 6y agoGalen Windsor and his colleagues worked elbow deep in plutonium and uranium for years. None of them ever got sick. There are some old Galen Windsor videos on YouTube. He traveled around the country eating uranium in front of his students and audience. The EPA of his day had hissy fits. Great stuff!
- deleted 6y ago[deleted]