Wikipedia:Reference desk/Archives/Science/2022 September 24

= September 24 =

Nuclear power station size
Do nuclear power stations have to be very large to be economically viable? What are "small modular reactors"? Thanks 86.189.224.108 (talk) 07:57, 24 September 2022 (UTC)


 * Small modular reactors "are nuclear fission reactors that are smaller than conventional nuclear reactors. They can be constructed in one location (typically a factory) and shipped to the site where they will operate. ... Modular reactors reduce on-site construction, increase containment efficiency, and are claimed to enhance safety." Clarityfiend (talk) 11:12, 24 September 2022 (UTC)
 * Cool. How do they compare with the reactors used in nuclear submarines? 86.189.224.108 (talk) 11:22, 24 September 2022 (UTC)
 * They're based on the same concept. "Since then, Rolls-Royce has designed reactors for seven classes of submarine and two separate land-based prototype reactors." for example (Rolls Royce brochure).--Phil Holmes (talk) 13:01, 24 September 2022 (UTC)


 * It's an old concept, and it's been widely studied; even as-of-2022, I might opine that some of the most innovative start-up companies in the energy sector are those companies specifically looking at smaller-scale nuclear reactors, and dispersing them. I won't name names, but you can search using keywords like "neighborhood nuclear" and "microreactor" and you'll quickly come across the major players - including old and new companies who think this is a good idea.
 * It's fraught with concerns; technically, we probably do have solutions to the technical challenges (though, there are a lot of details...)
 * Here's a 2019 review from the U.S. Department of Energy: The BIG Potential for Nuclear Microreactors.
 * Of course, the usual challenges exist: safety, security, efficiency, economics, ...
 * For the technical side, the DOE has this nice video: What is a Nuclear Microreactor? (2021).
 * I really try to opine a lot less, these days, but it is my opinion that this kind of development is probably the path-of-lowest-effort toward meeting human society's growing energy needs. I also respectfully acknowledge that the "path of lowest effort" hardly means "low effort."  Making these things safe and efficient is challenging - and not necessarily for the "obvious" reasons - we can probably engineer a reactor that works well, and fails safely.  But ...how do we spin up a global supply chain to disperse nuclear fuel to parts unheard, without compromising our ability to keep track of where it's going (and keeping it from going to scary, dark corners of the society we're trying to fuel)?  Yet, ... this is still the path of lowest effort: nuclear energy is the only realistic way to provide enough energy for developed societies who consume energy at the rates modern lifestyles demand.  Distributed nuclear power generation may be one way to make nuclear energy more economical, and to dilute risks (including, but not limited to, the economic risks).  We shall see. Each passing year, the average per-capita energy consumption increases on this planet - which isn't inherently a good or bad thing, but it is a thing... Meanwhile, I understand that the basics of solar radiation remain constant...
 * Nimur (talk) 16:17, 24 September 2022 (UTC)
 * Actually, solar radiation is increasing in the long term (and decreasing in the very long term ;-). But more to the point, incoming solar power is so high that from that perspective we can easily grow our energy consumption some orders of magnitude, and by then we can just as well build a Dyson swarm. --Stephan Schulz (talk) 17:34, 26 September 2022 (UTC)
 * I like the core concept of using solar power; it has a very clear appeal as it is fundamentally a way for us to tap into the primary source of energy for our planet. But I fear (!) that we do not know how to make it work at the scales demanded by industrial society.  I would love to be wrong.
 * Nimur (talk) 15:58, 27 September 2022 (UTC)
 * We also don't know how to build nuclear reactors without the risk of proliferation, or how to build nuclear reactor that don't need massive subsidies to be economical (you cannot currently insure any nuclear reactor on the free market). I think we should concentrate on the conservative, low-risk options. --Stephan Schulz (talk) 17:48, 27 September 2022 (UTC)
 * Nuclear power stations based on thermal neutrons indeed need to be large in order to work as they have to support chain reaction. In smaller reactors a significant fraction of neutron will just escape without slowing down and initiating nuclear fission. So, smaller reactor are invariably fast neutron reactors, which use highly enriched fuel. Ruslik_ Zero 20:09, 24 September 2022 (UTC)
 * Now note that many nuclear power stations have 4–6 units (reactor+turbine+generator+cooling), while coal or gas power stations tend to have just 1–2 units. There are exceptions. This also makes nuclear power stations bigger than fossil fuel power stations. I can think of some plausible reasons to do so. PiusImpavidus (talk) 12:54, 25 September 2022 (UTC)
 * I think the question was about the size of reactor itself. Ruslik_ Zero 20:08, 25 September 2022 (UTC)