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Breeder reactors: Difference between revisions
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(Created page with "Uranium occurs in nature as a mix of isotopes: uranium-235 (0.7%) and uranium-238 (99.3%). This proportion does not vary within the Earth's crust. * Today's nuclear reactors <small>(not breeder reactors)</small> can only get their energy from uranium-235 (U235). {{x|Technically the nuclear reactions are a bit more complex than that, but still limited by the scarcity of U235.}} * Breeder reactors can also get energy from the more abundant uranium-238 (U238). Breeder...") |
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Nuclear fission '''breeder reactors''' are a possible alternative to [[conventional nuclear power]]. They could overcome some of its main problems. | |||
{{considerations}} __NOTOC__ | |||
==Status quo== | |||
{{sum|Not in use}} | |||
The only breeder reactors that exist are experimental/research-based, not providing electricity on a commercial scale. <!-- TALK: could we replace the word "commercial" with something more universal w.r.t. both capitalism and communism? --> | |||
==Fuel supply== | |||
{{sum|Abundant|good}} | |||
Breeder reactors | Breeder reactors can obtain [[energy]] from [[thorium-232]] and [[uranium-238]], which are far more abundant on Earth than the uranium-235 used in [[conventional nuclear reactors]]. | ||
This means that fuel scarcity would no-longer be a reason why nuclear power can't scale up and replace [[fossil fuels]]. Breeder reactor fuels, while not ''renewable'', have mineral reserves are far greater than coal, oil and gas combined (in terms of [[energy]]). | |||
<!-- TODO: add calculations --> | |||
== | ==Breeder rate== | ||
{{sum|Probably a major limitation}} | |||
Uranium-238 & thorium-232 are not directly ''fissionable'' {{light|(unlike uranium-235)}}, but they are ''fertile'' which means they can be "bred" to become fissionable materials. This where the term "breeder reactor" comes from. | |||
For this process to work, breeder reactors still need to start with ''some'' fissile material, but they produce ''more'' of it than what they started with. A breeder reactor's ''doubling-time'' is a useful way to measure this: how long it takes for the reactor to produce twice as much fissile material as it started with. Breeder reactors ''so far'' have a doubling-time of over 100 years, unfortunately. | |||
<ref>Example quoted from [https://energyeducation.ca/encyclopedia/Breeder_reactor energyeducation.ca]:<br /><q>Thorium hasn't been used in large scale reactors, however some reactors have used it successfully in the past. A light water breeder reactor in Shippingport, Pa. USA operated for 5 years, and by the end of its operation it had 1.4% more fissile fuel than it began with.</q><br /><br />This cites another source:<br /><small>World Nuclear Association. (June 19 2015). Thorium [Online], Available: http://www.world-nuclear.org/info/Current-and-Future-Generation/Thorium/#b</small></ref> | |||
Scientists are trying to get this down to 10 years (no guarantees). Even in such a case, it would probably still take decades to breed enough fuel to meet global energy demands {{light|(unless uranium/thorium mining could somehow be done at an extremely fast rate?{{rn}})}}. | |||
Because of this, maybe we can't count on breeder reactors to solve [[climate change]] soon enough. We'll probably still need [[wind]] and [[solar]]. | |||
==Risk of weapons proliferation== | |||
{{sum|Major risk in some cases|bad}} | |||
[[Uranium-238]] breeder reactors are '''high''' risk. | |||
{{minor|The uranium-238 is bred to become plutonium-239, which is considered "easy" to make nuclear bombs with.}} | |||
[[Thorium-232]] breeder reactors are '''lower''' risk. | |||
{{minor|The thorium-232 is bred to become uranium-233, which is considered far more difficult for making nuclear bombs.}} | |||
If breeder reactors are to become a mainstream source of energy, they have to be designed extremely securely{{en}} to prevent the possibility of anyone maliciously siphoning off some of the fissionable materials. {{rn}} | |||
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TALK: is it true that the nature of breeder reactors makes it harder to notice such "siphoning off"? if so, what could be done about it? | |||
--> | |||
==Nuclear waste== | |||
{{sum|Almost none|good}} | |||
Breeder reactors produce less than 1/1000th as much nuclear waste as conventional nuclear power{{x|Conventional nuclear power is wasteful because uranium occurs naturally as just 0.7% uranium-235; the rest is uranium-238 which goes to waste. Breeder reactors don't have this problem.}} (for the same amount of energy). | |||
==External links== | ==External links== | ||
* [https://energyeducation.ca/encyclopedia/Breeder_reactor Breeder reactor - Energy Education] - another wiki which elaborates more on the technical details | * [https://energyeducation.ca/encyclopedia/Breeder_reactor Breeder reactor - Energy Education] - another wiki which elaborates more on the technical details | ||
* http://www.world-nuclear.org/info/Current-and-Future-Generation/Fast-Neutron-Reactors/ | * [http://www.world-nuclear.org/info/Current-and-Future-Generation/Fast-Neutron-Reactors/ Fast Neutron Reactors] | ||
* [http://hyperphysics.phy-astr.gsu.edu/hbase/NucEne/fasbre.html Fast breeder reactors] | * [http://hyperphysics.phy-astr.gsu.edu/hbase/NucEne/fasbre.html Fast breeder reactors] | ||
====Some reactor types that might show potential==== | |||
* [https://en.wikipedia.org/wiki/Traveling_wave_reactor Traveling wave reactor] | |||
* [https://www.iaea.org/topics/molten-salt-reactors Molten salt reactor] (Thorium) | |||
* [https://www.sciencedirect.com/topics/earth-and-planetary-sciences/liquid-metal-fast-breeder-reactor Liquid metal fast breeder reactors (LMFBR)] (Uranium-238) | |||
* [https://www.gen-4.org/gif/jcms/c_42151/supercritical-water-cooled-reactor-scwr Supercritical-Water-Cooled Reactor (SCWR)] | |||
==References== | |||
<references /> | |||
[[Category:Energy sources]] | |||