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China's Yanlong: a small nuclear reactor strictly for district heating
- moneytide1 9y agoSeems more efficient to bypass steam as a transfer medium. Just like in "The Martian".
- lexxed 9y agoA small nuclear reactor in a swimming pool.. what could go wrong..
- DennisP 9y agoNot much. This is actually a common reactor type, and you don't have to worry about things like cooling pumps going bad or high-pressure pipe breaks. > The water acts as neutron moderator, cooling agent and radiation shield. The layer of water directly above the reactor core shields the radiation so completely that operators may work above the reactor safely. This design has two major advantages: the reactor is easily accessible and the whole primary cooling system, i.e. the pool water, is under normal pressure. This avoids the high temperatures and great pressures of nuclear power plants. Pool reactors are used as a source of neutrons and for training, and in rare instances for processing heat but not for electrical generation....Most research reactors are of the pool type. https://en.wikipedia.org/wiki/Pool-type_reactor https://en.wikipedia.org/wiki/Pool-type_reactor
- kldavis4 9y agoNC State University has a pool reactor on the main campus used in their nuclear reactor curriculum: https://en.wikipedia.org/wiki/North_Carolina_State_University_reactor_program https://en.wikipedia.org/wiki/North_Carolina_State_Universit...
- plandis 9y agoThat’s cool! Thanks for sharing
- vorotato 9y agoI think this comment shouldn't be downvoted because it's a common misunderstanding rooted in how unintuitive it is that water is so good at blocking radiation.
- Symmetry 9y agoXKCD had a really great illustration of that. https://what-if.xkcd.com/29/ https://what-if.xkcd.com/29/
- foxyv 9y agoI love this! > But just to be sure, I got in touch with a friend of mine who works at a research reactor, and asked him what he thought would happen to you if you tried to swim in their radiation containment pool. “In our reactor?” He thought about it for a moment. “You’d die pretty quickly, before reaching the water, from gunshot wounds.”
- deadmetheny 9y agoA lot less than you think. These are the reactors normally used for research and they are rather safe, as pretty much all modern reactors are.
- sdfasfdsaf 9y agoA lot less than in a submarine or electrical reactor. Heck McMaster U has a swimming pool sized 5 MW. There's no pressure vessel and a massive thermal inertia. Not child's play, but very safe. The big issue is the waste.
- sandworm101 9y ago>> around the same volume as an Olympic swimming pool. >> with each 400-megawatt unit capable of warming 200,000 urban households. >> with temperatures not exceeding 100 degrees Celsius, Think about that for a minute. If the water isn't going to exceed 100c but the reactor is still going to pump out 400-megawatts, it isn't going to be a calm pool. They are going to have to pump insane amounts of water in and out of this pool if they want to keep things under 100c. That's fine. Just don't pretend this is going to hum along quietly like a research reactor. And don't tell me thing will remain at 100c should that flow of water be interrupted. Any non-boiling, low-pressure, reactor is going to need exponentially more cooling (by volume) than an equivalent traditional reactor. Let us hope they keep a lake nearby as backup.
- adrianN 9y agoIt is possible to regulate the output of a nuclear reactor. In case the pool boils off in some freak accident, the chain reaction also stops, because water is acting as a neutron moderator in these designs. So you only have to ensure that the residual heat from normal decay doesn't melt the reactor. That doesn't sound too hard.
- Symmetry 9y agoIsn't the residual heat from normal decay something like 10% of the reactor output? When you split Uranium you get a lot of byproducts with short half-lives that continue decaying away even when Uranium chain reaction stops. So you've still got 40 MW to deal with, at least until those short-half-lived byproducts finish decaying.
- adrianN 9y ago5% for the first few seconds: http://www.euronuclear.org/info/encyclopedia/r/residual-heat.htm http://www.euronuclear.org/info/encyclopedia/r/residual-heat... but your point of course still stands. It's certainly not trivial to build passive-safe reactors, but it's also not impossible.
- vilhelm_s 9y ago
- xbmcuser 9y agoStuff like this makes me feel western countries really underestimate Chinese tech chops. They are able to force stuff on the people that most countries have to cajole and negotiate with their citizens. I get cognitive dissonance from the fact that China is doing it's best to decrease coal usage where as US is tried to increase coal usage.
- jonwachob91 9y ago>> Stuff like this makes me feel western countries really underestimate Chinese tech chops. The west largely underestimates Chinese tech chops b/c they steal so much of our IP... Their ability is evident in the number of Ph.D's they turn out, so why don't they invest in developing their own technology instead of stealing everyone else's? "Catching up" is not an acceptable answer with how much intellectual firepower they have.
- raguuu 9y agoBecause it's easier to 'steal'? Their laws are different so they don't see it as stealing and have no problem with it. Each country is unique and I'm happy US can't force their IP laws to everyone around the world.
- godelski 9y agoProblem is that they've already caught up. Now they are competing and passing in some areas.
- matz1 9y agoBecause its not efficient, why reinventing the wheel ?
- monocasa 9y agoYou know that exactly the same argument was made against the US, Germany, and Japan at different points in time, right?
- pwaai 9y agoIt's coined "piggyback economy" where the first move innovator ends up absorbing all the risks in developing the product and getting it to the market. The second mover then simply improves on the original product likely with ton of issues as they have to distribute their resources throughout the full journey the product makes it from the drawing board to the consumer. The market is there and the second mover is able to "catch up" when the product is as good if not better in quality which finally leads to the exit of the first innovator signaling new entrants that will put pressures on the second innovators margins.
- Retric 9y agoSeems like a much more expensive option than solar hot water heaters. It's $226.7 million for 400MW and "Each 400-MW unit can heat 200,000 homes" so ~1,133$ per home where basic models are selling in Asia for under US$250. They mention it's going to be plugged into existing heating networks, but temperature of 100C is not all that hot.
- seanmcdirmid 9y agoSolar doesn’t work that well in northern China during the winter because there is hardly any sun. Even discounting the pollution, the area would be mostly foggy and overcast, it would be like trying to use solar in Seattle. An apartment complex I lived in had solar hot water and I absolutely hated it, I could never take a “hot” shower during Beijing’s cold winter, just a luke warm one.
- vkou 9y agoFor those that don't live in Seattle, tomorrow, on Winter Solstice, the sun will not rise more then 19° above the horizon. You're not going to get much solar heating out of that... Unless you want to block your neighbor's solar heating array.
- Retric 9y agoImplementation can make a huge difference, people do install these systems in Alasca and then supplement for a few weeks in the middle of winter which is still a huge fuel savings and cost reduction. But, if your going to base this on a central location then sizing the system and maintain the desired temperature output is simplified.
- seanmcdirmid 9y agoThere isn’t much space for solar panels, so sizing is intrinsically constrained. Also, these are 32 story towers with approximately 130 units...it’s not rocket science why it doesn’t work out. They were definitely not supplementing enough.
- danohuiginn 9y agoAnd I guess you can just shut it off in summer? Nuclear normally sucks for fluctuating demand, but presumably a 6 month on/off cycle is slow enough to work.
- dsfyu404ed 9y agoYes, just insert control rods and wait for things to cool down. I assume the design is something to the tune of "put a reactor at the bottom of a water filled pit, put a big heat exchanger at the top, pump fluid through the heat exchanger and into the city's heating system and let convection do the rest" I'm sure with some creative engineering you could do some tricks with attaching something of a specific density that changes with temperature at a rate different than the cooling medium to your control rods you could have a system that self regulates based on the temperature of the water being input (control rods sink when temperature increases) so the system self regulates output.
- briffle 9y agoAny source of heat can also be used as a source for cooling. My Alma-Matter (Oregon Tech) heats and cools its entire campus with hot geothermal wells.
- dis-sys 9y agoit is just shocking that they did the trial run of the nuclear reactor in Beijing where there are over 20 million people. on the other hand, they were actually allowed to carry out such trial run close to where those most powerful live. to figure out what other crazy stuff is happening in Beijing, did a quick search and it turns out that there are dozens of experimental nuclear reactors in Beijing, with the first one built in 1964 in Beijing. Tsinghua alone operates many of them. crazy
- ptx 9y agoKTH (the Royal Institute of Technology) was running a nuclear reactor[1] in Stockholm from 1954 to 1970. So if it's crazy, it's at least not unprecedented. [1] https://en.wikipedia.org/wiki/R1_(nuclear_reactor) https://en.wikipedia.org/wiki/R1_(nuclear_reactor)
- dis-sys 9y agowith 1/10 of the population in Stockholm, the craziness is not remotely comparable.
- zengid 9y agoI wonder if this smaller reactor size would prove safer in earthquakes? There is a lot of tectonic activity in Norther China (though I'm not sure if that is where these are planned to be deployed). http://www.drgeorgepc.com/EarthquakesChina.html http://www.drgeorgepc.com/EarthquakesChina.html
- baybal2 9y agoBoth district heating and drinking water desalination plant did ran on nuclear reactors. Desal plant in Kazakhstan ran over a decade until the Aral sea moved to far away. There are few nuclear district heating plants with single loop design still running in Russia