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Small Modular Nuclear Reactors Overcome Existing Barriers to Nuclear
- Animats 10y agoThis is strange. There is no "containment vessel". That's the reactor pressure vessel. Usually, there's an outer containment vessel as well. Chernobyl didn't have one at all, which is why that was such a disaster. Fukishima's reactors had ones that were too small and didn't have enough expansion volume to diffuse the pressure after loss of coolant. There's a design assumption here that there will never be a meltdown.
- AlgorithmicTime 10y agoIt shows an inner "reactor vessel" which looks to be the pressure vessel, and an outer "containment vessel."
- ParrotyError 10y agoA containment vessel at Chernobyl would have been useless. The Chernobyl disaster was a combination of poor reactor design leading to dangerous reactor physics, poor safety systems, poorly-trained staff, and an dangerous and unnecessary "experiment" being performed on the reactor (i.e. operating it in a dangerous regime). No containment building could have been strong enough to contain the explosion. The RBMK is a particularly bad design of reactor.
- pdkl95 10y ago> dangerous and unnecessary "experiment" We always hear about how they were running the reactor in a dangerous mode to run the experiment, but the nature of that experiment is rarely mentioned. The experiment itself is the craziest part! The experiment was a test of a new cooling system feature. The RBMK's suicidally stupid design had a positive void coefficient of reactivity[1]. Coolant voids increased reactor activity. The operators new this; they had backup diesel pumps that would take over from the electric pumps if power wasn't available. They also knew that it would take some time[2] for the backup pumps to reach full speed, which was not fast enough. So someone had the "clever" idea to modify the electric pumps so they would continue to spin freely when they lost power, so their remaining kinetic energy could continue pumping coolant at a rapidly falling rate. The hope was that there would be sufficient kinetic energy to keep the reactors from voiding. The experiment was basically a bad hack to work around several serious design problems. The experiment shouldn't have existed. Everything about the coolant situation should have been a reason to decommission the reactor. The experiment itself is evidence that someone knew about the positive void coefficient problem, or they wouldn't have tried such a crazy workaround. Yes, a lot of the staff was poorly trained, but someone knowledgeable about reactors decided they couldn't afford even a few seconds[2] without coolant. [1] https://en.wikipedia.org/wiki/Void_coefficient https://en.wikipedia.org/wiki/Void_coefficient [2] like 50 seconds? if I remember correctly?
- Aelinsaar 10y agoA positive void coefficient doesn't have to be suicidal or stupid, it just was in that design. See: CANDU
- witty_username 10y agoCANDU has a very small positive void coefficient.
- Aelinsaar 10y agoI didn't say anything about a large void coefficient, and I pointed to CANDU as an example of a reasonable beta, responsibly managed.
- yaakov34 10y ago> had a positive void coefficient of reactivity Had and still does. There are 11 RBMK blocks still operating.
- unique_parrot2 10y agoThat's great. You know how expensive it is to get rid of radiactive material. It this comes true the big power plants can just dump the waste into the river and say "It wasn't me". I would not want to live next to such a thing.
- i_feel_great 10y agohttps://en.wikipedia.org/wiki/Deep_geological_repository https://en.wikipedia.org/wiki/Deep_geological_repository
- einrealist 10y agoAnd? There is no repository in the world available, that is either guaranteed to be secure for thousands of years of accepted by the population. Also putting it in the earth has one huge disadvantage: You cannot get it back if something goes wrong. I can recommend this documentation about the waste disposal problem http://www.imdb.com/title/tt2979302/ http://www.imdb.com/title/tt2979302/
- tremon 10y agoThere is no repository in the world available, that is either guaranteed to be secure for thousands of years of accepted by the population. But we would have no need for "thousands of years" if the development of nuclear reactors is allowed to advance. Fast breeder reactors can use our current "waste" as fuel, leaving only stable and short-halflife isotopes as waste.
- kuschku 10y agoLet’s look at the German Asse II and Schacht Konrad. We deposited lots of nuclear waste, and years later discovered it was leaking into the tap water. Now we have to dig it all back up.
- marak830 10y agoMaybe someone here can inform me, howuch does the waste weigh? Would it be viable to launch it into space then send it on a course to the sun?
- shaqbert 10y agoThis is not really about micro reactors, but about making the monolith power plant more like a microservice modular thing. So that you can potentially prevent decomissioning after 40 to 60 years and keep it operating much longer. The downside of nuclear power still remains though: - still high upfront costs (maybe lower that monolith plants, but still freaking high) - poisonous and radioactive fission products that are hard to deal with - perverse incentives between economic efficiency and safety (did I mention that a couple of those babies [1] here would have prevented the fukushima disaster) [1]: http://us.areva.com/EN/home-1495/new-challenges-proven-solutions-mitigation-passive-autocatalytic-recombiner-par.html http://us.areva.com/EN/home-1495/new-challenges-proven-solut...
- Aelinsaar 10y agoTo be fair, the byproducts are not something we're unaware of how to manage, we're just socially and politically unwilling to do it. Likewise, we know how to design and maintain much safer and more efficient reactors than anything we currently have running, but we lack the social and political will to make the change. Besides, we like to pretend that burning coal isn't killing millions of us around the world, decade in, decade out. Focusing on the real human cost of when nuclear goes wrong, vs. when coal goes right makes it an easy choice.
- jon_richards 10y agoPer kilowatt, nuclear energy is by far the safest. People fall off wind and solar installations all the time. Hydro fails catastrophically.
- mkesper 10y agoHow can you say that without being cynic when it made big parts of Japan uninhabitable for centuries if not thousands of years?
- theamk 10y agoDo you have quantitative information about that? I was always wondering how big is Fukushima's nuclear incident zone (in km^2) today. How much bigger is it compared to coal waste ponds / landfills, or hydroelectric dam which provides the same amount of power?
- tremon 10y agoThe article doesn't seem to mention what type of reactor this is. Are these still gen-III boiling water reactors, or is this a gen-IV type reactor?
- tehwalrus 10y agoThe design illustrates fuel rods; so not a thorium reactor (if that's what you mean by Gen4).
- whiskers08xmt 10y agoDoesn't some gen-IV designs boil water too?
- shaqbert 10y agoNobody designs new boiling water reactors these days. Reactors efficiency increase with temperature, that is why pressurized water is the name of the game - as it can have a much higher boiling point. The higher temperature = better reasoning is also the reason why there is such a hype train going for reactor designs based on molten salts. Needless to say a higher temperature also puts more strain on any material and makes safe operation generally harder.
- wolfram74 10y agoOne of the things that I don't get is that there a lot of cool fission designs that are arguably only hampered by the state of the art in molten-salt plumbing, but the only fusion design with mainstream support requires molten lithium plumbing for breeding tritium and heat exchange, along with a few other things that are still a touch experimental. Hash out the molten salt plumbing for the fission reactors since it appears strictly a subset of the fusion problems.
- shaqbert 10y agoNo, its not a subset of fusion problems. Very different problems: Molten salt fission problem = dealing with vast quantities of a highly chemically active salt touching our plumbing directly over 40 to 60 years. Fusion problem = containment of a small quantity by a magnetic field.
- cowardlydragon 10y agoLFTR should be implemented like this: modules that can be decommissioned on a scheduled basis so that the transmuted parts of the container can be recycled/extracted.