Author Topic: Fusion (aka Tokamak) Reactor  (Read 592 times)

Offline leeor_net

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Fusion (aka Tokamak) Reactor
« on: July 17, 2016, 11:09:45 PM »
Question -- been thinking about this one and I'm not convinced that the fusion reactor power generation facility really needs to have an underground containment vessel. Seems like overkill to me -- generally speaking you'd think a facility like that would be entirely above ground.

Thoughts?

Offline lordpalandus

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Re: Fusion (aka Tokamak) Reactor
« Reply #1 on: July 19, 2016, 01:24:01 AM »
Well, it depends on the reactor type in question:

Is it a magnetically confined fusion reactor or an inertially confined fusion reactor?

Technically as Tokamak is the old name for the original magnetically confined fusion reactors, one might assume magnetic confinement, but as magnetic confinement has basically failed to produce reliable fusion for over 50+ years, one has to question if magnetic confinement can be used to provide a stable and more to the point, self-sustaining reaction.

Tokamaks, afaik, are designed much like nuclear fission reactors, with a heavy water (deuterium rich) coolant system and thus may have an underground containment vessel.

Course it all depends on whether you are going for a realistic game with realistic technology, mathematics, and physics, or if it is a fantasy game and its okay if you "fudge it on the details".

Thoughts?
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Offline leeor_net

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Re: Fusion (aka Tokamak) Reactor
« Reply #2 on: July 19, 2016, 08:46:04 AM »
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Is it a magnetically confined fusion reactor or an inertially confined fusion reactor?

No idea. This is technology supposedly 50 years or so in the future. Could be anything.

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Technically as Tokamak is the old name for the original magnetically confined fusion reactors,

Actually, Tokamak is a particular design of a toroidally shaped magnetic bottle type reactor and as I recall is a russian acronym for "toroidal chamber with magnetic coils" or "toroidal chamber with axial magnetic field".

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Tokamaks, afaik, are designed much like nuclear fission reactors, with a heavy water (deuterium rich) coolant system and thus may have an underground containment vessel.

I don't believe this is the case but I'm not a nuclear engineer so really I don't know. All the images I've ever seen of these reactors have no liquid cooling as they don't run for more than a second or two. They are, after all, just experimental reactors though ultimately there would be a need to harness the energy probably through the very typical boiling of water to create steam to turn steam turbines. /me shrugs.

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one has to question if magnetic confinement can be used to provide a stable and more to the point, self-sustaining reaction.

That's a failure of the design of the tokamak reactor in particular. Look up Stellerator reactors which are showing much more promise. At least the modern ones are.

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Course it all depends on whether you are going for a realistic game with realistic technology, mathematics, and physics, or if it is a fantasy game and its okay if you "fudge it on the details".

I guess that's the ultimate question. I think OP1 took realism too far.

Offline lordpalandus

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Re: Fusion (aka Tokamak) Reactor
« Reply #3 on: July 19, 2016, 10:36:33 AM »
Well, inertially confined reactors (ie ones that uses hundreds of lasers to heat up the fuel and contain the plasma) are appearing to be more likely feasible, that's why I mention them. I believe the first one is coming online in the USA in a couple years.

It is true it is a Russian design for a fusion reactor, but the problem is most magnetically confined reactors are based on the old Tokamak design, which has not worked yet. I'd say it has something to do with lacking sufficient free neutrons, but I'm not a nuclear physicist so I don't know if that would help or not.

Well I may be wrong about the coolant system, but it would make sense to have an underground containment vessel, in case the reactor is damaged or the reaction is unstable. It would make sense to me to have the reactor suspended over some kind of pit and drop it inside and seal off the pit in case the reactor was going critical to either minimize damage to surrounding areas or have a failsafe in place to cool off / deactivate the reactor harmlessly once inside the pit. Coolant is there to keep it running optimally in most situations; a containment vessel is there to contain a nuclear explosion or defuse the reactor when it is going out of control. So, make sense to have an underground containment vessel.

Stellarator reactors may be better, or may suffer from the same problems as other magnetic confinement options. Hard to say.

I'd say OP1 wasn't realistic actually. They tried so hard to be realistic that it became realistically unrealistic. If they wanted it to be super realistic it wouldn't have been a game as extreme realism doesn't work in a game environment. Some amount of realism works, but there is a need to have some abstraction and without it the game feels dull and boring. Well, that is, my opinion at least.
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Offline leeor_net

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Re: Fusion (aka Tokamak) Reactor
« Reply #4 on: July 19, 2016, 11:41:52 AM »
Unlike a fission reaction, I don't think there could every possibly be a runaway fusion reaction. If containment fails you get a hell of a fireball but that's effectively it. Boom, poof, facility is destroyed and reactor stops reacting. That's my understanding anyway... I could be horribly, horribly wrong though.

Offline leeor_net

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Re: Fusion (aka Tokamak) Reactor
« Reply #5 on: July 19, 2016, 11:51:55 AM »
Quote from Wikipedia:

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Runaway reactions cannot occur in a fusion reactor. The plasma is burnt at optimal conditions, and any significant change will quench the reactions. The reaction process is so delicate that this level of safety is inherent.

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In the magnetic approach, strong fields are developed in coils that are held in place mechanically by the reactor structure. Failure of this structure could release this tension and allow the magnet to "explode" outward. The severity of this event would be similar to any other industrial accident or an MRI machine quench/explosion, and could be effectively stopped with a containment building similar to those used in existing (fission) nuclear generators. The laser-driven inertial approach is generally lower-stress because of the increased size of the reaction chamber. Although failure of the reaction chamber is possible, simply stopping fuel delivery would prevent any sort of catastrophic failure.

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« Last Edit: July 19, 2016, 11:54:03 AM by leeor_net »