Is My Idea Valid? Nuclear Fusion Power

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Teen4Ideas
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So as we all know (or at least I assume) Global Warming is real and happening, I am a teen, 17, and not trying to get answers for homework or anything like that.

I just want to know, is it possible to create fusion using the temperature found at active Geo-thermal sites to reach the temp needed for nuclear fusion, combined with proton-proton fusion process(or Similar) to create a viable fusion reactor?

I know the temp needed for fusion is 400 degrees Celsius, such a temp is found at actives sites from what I've read, and I've read that the Tokamak Nuclear Test Reactor has achieved both the density and temp need for fusion but is unable to do both at the same time, would this fix this problem? And is this too wordy? Is this a dumb idea?
 

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you are correct let me check back to revise my figures
 
You know the first time I saw the figures it seemed to make sense, seriously it did, and now I feel kind of silly, I must have miscalculated somewhere and added a zero or something similar...darn...
 
if its not possible to reach the temp needed for fusion, then perhaps I can figure a way to reach the pressure needed
 
I don't think that's what happened. I was looking at some charts on Wikipedia and they implied the same thing until I read the legend and its said measurement in millions of degrees.

Its always good to keep track of where you gather your info for times like this.

Don't feel foolish either, you need to make mistakes and do dumb things to appreciate the true experience of being right.
 
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Okay, where mind I find resources to help me with this stuff, it would be pretty cool to solve energy problems and eliminate need for fossil fuels use
 
where might I find*
 
"Its always good to keep track of where you gather your info for times like this.

Don't feel foolish either, you need to make mistakes and do dumb things to appreciate the true experience of being right."

Thanks, I got most of my info here:
http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fusion.html#c1
I believe this is reputable?
 
Teen4Ideas said:
Okay, where mind I find resources to help me with this stuff, it would be pretty cool to solve energy problems and eliminate need for fossil fuels use

There are plenty of places online, such as wikipedia, hyperphysics, etc. Just watch out for those sites that claim to have invented some device to generate power that's cheaper, easier, or safer than current technology, but that its being repressed or covered up by mainstream science/government/whoever. Also, if it sounds too good to be true, it probably isn't true. There is a LOT of misinformation out there.
 
You won't be able to achieve fusion with typical stuff found in hardware stores and assembled in your garage.
You'd need to build an apparatus capable of producing temperatures and pressures similar to those in the core of the Sun,
(and having a way to contain it)
Working fusion reactor designs do exist, but they require more energy to get them started than the energy they produce.
The latest attempt to produce a fusion reactor which could be economically feasible is this:
http://en.wikipedia.org/wiki/ITER

That is an international collaboration currently estimated to amount to a cost of €16billion, and it won't be ready even for trial testing until at least 2019.
 
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Reaching 400°C is very easy, by the way. Every wood fire achieves that, steel production routinely uses temperatures above 1000°C. There is no need to use geothermal energy for those low temperatures.

Actually, reaching the necessary temperature is not the main issue for fusion. It has been achieved - getting fusion reactions can be done with existing machines. Keeping the plasma confined well and long enough to get more energy out than you put in is the hard part.
 
I accidentally misquoted the degrees needed, its not 400 degrees Celsius, its 15-40 million degrees, I am aware of the sites that are test reactors, as well as various ways to contain the energy, magnetic, etc... I was pointing out how one test reactor, mentioned above, managed to get very close to Lawson criterion, I thought if the temp problem was solved with no artificial help, then focus could shift to solving density problem, instead of trying to do both, I did not get the figures right. I apologize.
 
Would heavy water, which contains tritium, be a viable substitute for breeding tritium from lithium? And could a laser combined with magnetic containment-using heavy water be better than lithium, I can't find which one slows neutrons more, heavy water or lithium, I would think heavy water would be better, as it could serve a similar function as if it were in a fission reaction. Or am I completely off track?
 
What makes a d-t reaction better than a d-d reaction cycle? I would be most appreciative if anyone could suggest a resource with these figures and arguments...
 
Teen4Ideas said:
What makes a d-t reaction better than a d-d reaction cycle? I would be most appreciative if anyone could suggest a resource with these figures and arguments...

D-T has the lowest break-even temperature of any of the fusion reaction. It is the easiest fuel to ignite.

Some of the other fuels have advantageous features, and they are worth considering for 2nd or later generation reactors. But the first generation reactors will likely use D-T simply because it is the easiest.

Normal heavy water contains deuterium not tritium. Deuterium has a relatively low neutron capture cross-section, and it isn't efficient at producing tritium. Li is chosen as breeder material because is has a relatively high probability of absorbing neutrons and producing tritium.
 
There are a few tritium atoms in water (and heavy water can be extracted by isotope separation of hydrogen from regular water), but the amount is way too small to be useful.

Fission reactors use water as moderator - atoms that slow down neutrons without absorbing them. For fusion, you want that absorption to produce tritium, so you have completely different goals.
Tritium breeding has nothing to do with the magnetic confinement or lasers.

Teen4Ideas said:
What makes a d-t reaction better than a d-d reaction cycle?
A factor ~100 higher reaction rate.

You can find answers to most of your questions at Wikipedia.
 
Alright, so d-t reaction it is. Lasers or Ion beams kick start the reaction and magnets confine it, but wouldn't you still need a moderator to stop the reaction in an emergency? So the heavy water could serve a double purpose, neutrons from the reaction would create more fuel(tritium) albeit slowly, thus should the need arise you could stop the reaction with said water, correct? Do I make more sense now? No need for lithium breeder reactors...

Stronger magnets means more push to fuse right? And the lasers/Ion beams can create the heat aspect needed correct? I hope I make more sense now
 
Wait just thought of something...do you need equal parts tritium and deuterium or do you need more deuterium than tritium?
 
If by 'an emergency', you mean there could be containment failure, the reaction immediately ceases anyway, but I'm sure escaping plasma would do considerable damage to the very immediate area, by which i mean around .5 km perhaps.1km
Unlike a fission reactor meltdown, you would not have the problem of large amounts of heavy radioactive elements polluting the environment and widely dispersing.
 
Right, the reaction would stop immediately but all those neutrons would need to be stopped right? and as for the plasma, what material can absorb those ions or absorb most of the force in the event of an explosion?
 
Teen4Ideas said:
Alright, so d-t reaction it is. Lasers or Ion beams kick start the reaction and magnets confine it, but wouldn't you still need a moderator to stop the reaction in an emergency? So the heavy water could serve a double purpose, neutrons from the reaction would create more fuel(tritium) albeit slowly, thus should the need arise you could stop the reaction with said water, correct? Do I make more sense now? No need for lithium breeder reactors...

Stronger magnets means more push to fuse right? And the lasers/Ion beams can create the heat aspect needed correct? I hope I make more sense now
Neutrons play no role is the sustainment of a fusion reaction. You can not use a (neutron) moderator to control the fusion reaction. If you want to slow a fusion reaction you need to decrease the density and/or decrease the temperature. Both of these things happen naturally when you lose magnetic confinement. This is one of the appealing aspects to nuclear fusion. In the event of an accident, there is no risk of a sustained uncontrolled reaction.

Tritium does not appear in nature. We have to manufacture it and Deuterium simply does not have a sufficiently large cross section to breed sufficient amounts of tritium. In-order to sustain a D-T reaction we have to breed tritium as quickly as we burn it. Each D-T reaction produces 1 neutron. And then we have to use that neutron to produce 1 new tritium atom. This is a critical balance that we have to maintain. If we don't produce enough neutron, then we will quickly use up our supply of tritium. On there other hand, there are serious weapon proliferation issues if make to much tritium. Li is nice because it has the a high reaction cross-section. There are also two different isotope of Li that have different reactions that produce tritium. We can adjust the ratio of the two isotopes to control the rate of tritium production.

The fusion reaction rate increases with the pressure (density times temperature). Stronger magnets allow you to operate at higher pressure, but the strength of the magnetic field does not directly heat the plasma.

There are many ways to heat a plasma. Magnetically confined plasmas are typically heated using a combination of ohmic heating, neutral beam heating, and rf heating. Inertial confinement, which is a very different concept, uses lasers and ion beams.
 
rootone said:
If by 'an emergency', you mean there could be containment failure, the reaction immediately ceases anyway, but I'm sure escaping plasma would do considerable damage to the very immediate area, by which i mean around .5 km perhaps.1km
Unlike a fission reactor meltdown, you would not have the problem of large amounts of heavy radioactive elements polluting the environment and widely dispersing.

Not really. While a magnetically confined plasma is really hot, it has a really low density. The total energy stored in a magnetically confined plasma is relatively small. An uncontrolled accident will likely damage the confinement device, but it will not cause damage surrounding vicinity.

The biggest concern is that the accident will bore a hole through the confinement vessel and tritium will escape to the environment. There are a number of safety systems in place to prevent the tritium for escaping. There are also a number of regulation which limit the amount of tritium inventory in or aground the reactor.
 
I was thinking more of acoustic shockwaves than damage directly from plasma, but maybe even that would be very localised. 0.5km was I admit purely a hand-wavey guess.
 
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the_wolfman said:
If you want to slow a fusion reaction you need to decrease the density and/or decrease the temperature. Both of these things happen naturally when you lose magnetic confinement.

We have to manufacture it and Deuterium simply does not have a sufficiently large cross section to breed sufficient amounts of tritium. In-order to sustain a D-T reaction we have to breed tritium as quickly as we burn it. Each D-T reaction produces 1 neutron. And then we have to use that neutron to produce 1 new tritium atom. This is a critical balance that we have to maintain. If we don't produce enough neutron, then we will quickly use up our supply of tritium. Li is nice because it has the a high reaction cross-section. There are also two different isotope of Li that have different reactions that produce tritium.

The fusion reaction rate increases with the pressure (density times temperature). Stronger magnets allow you to operate at higher pressure, but the strength of the magnetic field does not directly heat the plasma.

There are many ways to heat a plasma. Magnetically confined plasmas are typically heated using a combination of ohmic heating, neutral beam heating, and rf heating. Inertial confinement, which is a very different concept, uses lasers and ion beams.

Note-I'm 17, just bouncing ideas, so I don't know how effective the heavy water would be at producing tritium, however, there must be concerns about producing breeder reactors... so assuming the pellet is used to start reaction why can't heavy water be used to sustain it?
What is the probability of producing tritium with heavy water vs lithium? I would think that all that plasma being contained at such high pressures would obliterate the plant and and any unabsorbed neutrons would be released.So is the tritium as pointed out above, so still my point remains, why shouldn't heavy water be used at least as a way to reduce need for lithium breeding? And why can't concepts from Inertial and Magnetic confinements be used?

http://en.wikipedia.org/wiki/Magneto-inertial_fusion I don't understand what the liner is but I assume it is like a moderator?
 
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Oh, wait now I know, you want the neutrons to heat the wall, so forget the heavy water as a moderator, but as a remedial source of tritium is it viable? and could a d-t reaction provide the necessary temp for a d-d reaction?
 
Teen4Ideas said:
Note-I'm 17, just bouncing ideas, so I don't know how effective the heavy water would be at producing tritium, however, there must be concerns about producing breeder reactors... so assuming the pellet is used to start reaction why can't heavy water be used to sustain it? What is the probability of producing tritium with heavy water vs lithium? I would think that all that plasma being contained at such high pressures would obliterate the plant and and any unabsorbed neutrons would be released and so is the tritium as pointed out above, so still my point remains, why shouldn't heavy water be used? And why can't concepts from Inertial and Magnetic confinements be used? http://en.wikipedia.org/wiki/Magneto-inertial_fusion I don't understand what the liner is but I assume it is like a moderator?

Its healthy for a 17 year to be asking questions. You have a few misconceptions as to how a fusion reactor works, and I'm trying to correct them as I see them. But please don't get the wrong impression. I like your curiosity.

Why do you think we should use heavy water in a fusion reactor. What use will it play? How does heavy water help one sustain a fusion reaction?

The big concern in sustaining a fusion reaction is energy confinement. A fusion reactor has to produce energy as fast as it losses energy. I don't see how heavy water can positively effect this energy balance. At fusion relevant temperature. The heavy water will ionize and breakup into deuterium and oxygen ions. The deuterium is fuel, but the oxygen plays no role is fusion. Oxygen rapidly radiates energy, cooling the plasma. Instead of injecting heavy water into a reactor, its much better to inject pure deuterium. There is no reason to inject oxygen.

The second concern is breeding tritium. But this happens outside of the plasma inside the walls of the device. There is some concern about breeding too much tritium. But honestly the bigger issue right now is not being able to breed enough tritium. Lithium has a much greater probability of producing tritium than heavy water. I don't know the number off the top of my head. If we are struggling to produce enough tritium, then using a worse tritium source is not the answer.

Magnetically confined plasmas are high temperature but very low density. The pressure of the confined plasma is small as a result of the low density. Magnetically confined plasmas operate at pressure less than atmosphere. If they lose confinement, they will not obliterate the plant. Furthermore there is a thick biological shield that surrounds the reactor, protecting the plant operators and the general public from radiation (neutrons, gammas, etc).

My above comments are specially for magnetically confined plasmas, but most of them apply equally to hybrid magneto-inertial concepts. The liner is not a moderator. It is a metallic conducting shell that "traps" the magnetic filed. Compressing the liner compresses the magnetic field, which in turn compresses the plasma.
 
Teen4Ideas said:
Lasers or Ion beams kick start the reaction
You need some heating, but no "kick start".
Teen4Ideas said:
but wouldn't you still need a moderator to stop the reaction in an emergency?
Just relax the magnetic fields, the plasma spreads out, cools and fusion will stop immediately.
Teen4Ideas said:
So the heavy water could serve a double purpose, neutrons from the reaction would create more fuel(tritium) albeit slowly
They would not produce more tritium compared to lithium. You need (on average) a bit more than one tritium produced per neutron due to losses in the system.
Teen4Ideas said:
thus should the need arise you could stop the reaction with said water, correct?
That does not make sense.

Stronger magnets mean you can reach a higher density and/or higher temperature.
The fusion reaction is 1:1, slight differences might be interesting if tritium is rare for example, but in general you want a ratio close to 1:1.

rootone said:
If by 'an emergency', you mean there could be containment failure, the reaction immediately ceases anyway, but I'm sure escaping plasma would do considerable damage to the very immediate area, by which i mean around .5 km perhaps.1km
Unlike a fission reactor meltdown, you would not have the problem of large amounts of heavy radioactive elements polluting the environment and widely dispersing.
The energy in the fusion plasma is surprisingly small - it is sufficient to melt parts of the wall, but it won't damage anything beyond that.
 
the_wolfman said:
The big concern in sustaining a fusion reaction is energy confinement. A fusion reactor has to produce energy as fast as it losses energy.
The second concern is breeding tritium. But this happens outside of the plasma inside the walls of the device. There is some concern about breeding too much tritium. But honestly the bigger issue right now is not being able to breed enough tritium.

Magnetically confined plasmas are high temperature but very low density. The pressure of the confined plasma is small as a result of the low density. Magnetically confined plasmas operate at pressure less than atmosphere. If they lose confinement, they will not obliterate the plant. Furthermore there is a thick biological shield that surrounds the reactor, protecting the plant operators and the general public from radiation (neutrons, gammas, etc).

My above comments are specially for magnetically confined plasmas, but most of them apply equally to hybrid magneto-inertial concepts. It is a metallic conducting shell that "traps" the magnetic filed. Compressing the liner compresses the magnetic field, which in turn compresses the plasma.

First of all, thank you, thank you for being patient with me and explaining this stuff to me

Now, I thought you need both high density and high temp, of course, higher pressure means higher temp(sort of) like a pressure cooker, as for a liner would iron or gold be a good example of this? And what is a biological shield? Surely we don't have a web of ivy to absorb the radiation? And I still don't understand why ion beams/lasers/xrays can't be used to heat the pellet to critical temperature and then magnetic fields to contain it...Lasers have reached the necessary temp for d-t reaction just not density