But California got both. It's pretty grim reading.Originally Posted by Demigrog
Bad Post-Doc
But California got both. It's pretty grim reading.
_____________________________________________
Gillian
"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"
"You can't erase icing."
"I can't believe it doesn't work! I found it on the internet, man!"
Order of Kilopi
There have been a couple of things going on in the developed world over the past couple of decades with reguards to electricity generation. The first is deregulation/privatisation. The results of this have been very mixed as if it is done done badly it can result in inefficiency and high costs for consumers as electricity supply is a natural monopoly and when done badly it can result in very high prices for consumers as customers have no easy way to get an alternative supply of electricity if the power company owns both the generating capacity and the grid that is connected to their house or business. Another trend, which has been mixed in with deregulation and privatization, is a shift towards more market based selling of electricity. In Australia this has generally been achieved by splitting electical supply into suppliers that generate electricity and distributers that sell it to people over the grid. This helps prevent monopoly, although the Australian system does have it's drawbacks. A couple of years ago distributers in South Australia had to briefly pay about $4 US a kilowatt-hour because the largest power plant decided to hold back supply to force up prices. (Something comparable happened on a huge scale in California.) Market based electricity markets work against nuclear power as nuclear plants have extremely long pay back periods and competitors pushing down prices introduces risk and can result in massive losses for the reactor owners.
Order of Kilopi
Ronald, how does the start-up cost of a dam compare to that of a nuclear plant? Are big ones in the same ball park? Or not even close?
Established Member
Looks like the saucer aliens shafted the earth rubes for a fusion power plant.
I wonder what the aliens got in return?
Or is it politicals a different species.
Order of Kilopi
That depends on a lot. Usually the sites that are cheapest to dam in a country are used first and the price increases for less suitable sites and in addition to electrical generation there are also the benefits of water storage and flood control as well. Also, hydroelectricity has advantages over nuclear power in its very low operating costs and because it can adjust its output to be load following while nuclear power is base load. But generally hydroelectric schemes that have been built are lower in start-up cost than nuclear power. Potential hydroelectric power sites that remain in Australia would be cheaper to construct than nuclear power, however new and existing hydroelectric schemes in temperate Australia are at risk from climate change which is drying up much of the continent.Ronald, how does the start-up cost of a dam compare to that of a nuclear plant? Are big ones in the same ball park? Or not even close?
The three gorges dam in China will have a cost of around $30 billion US when complete and will have an average output of about 11.4 gigawats. This is less than half the start up cost of the new nuclear reactors of French design that are going to be built in China, although older model reactors under construction in China may be cheaper. Hoover dam cost about $736 million in today's money and has an average output of nearly .46 gigawatts. That's less than a third the start up cost of new nuclear power in the US. Of course, when Hoover dam was built nuclear power was not an option.
Order of Kilopi
Thanks Ronald. I'm still trudging through everything. There's quite a lot.
Member
Apparently these guys can do nuclear fusion for $50 million Canadian... and the Canadian government has said it will match private financing under certain conditions..
http://www.generalfusion.com/
I mean, if ITER is billions and the NIF was billions.. 50 million is pretty cheap for a fusion experiment.. I think it would be worth it even if it was just a shot in the dark.. 50 million is nothing in terms of what has already been spent on fusion technology.. After converting to US dollars the cost is probably significantly below 50 million.. in any case.. I hope you guys go to the site and check it out..
Fusion Power is the holy grail of green technology and it would solve the energy crisis as we know it provided it could be made commercially viable..
something tells me the oil cartels and the media are going to try to push this entire project into the Pacific Ocean before anyone notices it...
Order of Kilopi
Worth a shot.
And I presume you mean the oil majors? The oil cartel, OPEC, is a bunch of countries. If someone gets fusion to work, and it truly is a game changer, and if the oil majors are still around, I'd expect one of them to buy the method. Er...that's what I'd do anyway.
Member
Yeah.. I do mean the oil majors.. there is also the distinct possibility that the military will be interested in this technology. Military involvement is sometimes nice because the military often have a lot of funding. But sometimes things go crazy and everything ends up being top secret and then scientists start disappearing or blowing up in their cars (I'm told this is what happend with some of the scientists working on Jerry Bull's super gun project for launching projectiles into space via a super long gun)..
but in the grand scheme of things and relative to what has been spent so far 50 million is nothing.
Order of Kilopi
It looks interesting. It would be nice if somebody managed an approach that was more practical for eventual development to commercial fusion reactors.
If fusion is "green," so is conventional nuclear. Fusion would have some of the same issues as nuclear fission, like radioactive waste and possible use in weapons production. I'd be happy to see practical fusion, but I expect that the same people that oppose conventional nuclear would also oppose fusion. Personally, for now, I'd like to see more research on advanced fission reactor (Gen IV) designs, and more commercial use of current reactors. We know conventional nuclear works.Fusion Power is the holy grail of green technology and it would solve the energy crisis as we know it provided it could be made commercially viable..
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
Order of Kilopi
Right. I'll believe it when I see it. Their website says they're working towards commercial technology - they don't have it yet.
Established Member
Well, their general approach is Magnetized Target Fusion, which is legitimate enough. General Fusion has an interesting design; they use a spinning liquid metal/lithium mixture to capture neutrons, and basically can pump the mixture out of the reactor to heat exchangers. Because the mixture is spinning, they create a vortex in the center where the reaction can take place without coming in contact with metal (the quenching problem). The lithium also protects the reactor structure from neutron embrittlement, and tritium can be extracted from it to produce more fuel. The inertial compression is done via large mechanical pistons arranged in a sphere around the fuel, which fire together to create a compression wave and initiate fusion. Pulse time would be about 1 second, which keeps the magnetic confinement relatively simple.
Until they try to build one, I doubt they'll know the full list of engineering problems they are going to face. Keeping the pistons in sync might be hard, and there are a lot of high temperature moving parts involved in the liquid lead-lithium vortex. Maintaining the vortex accurately enough to avoid fuel-metal contact might be tough. Unexpected energy losses in general might doom the approach.
They do have big cost advantages over pure magnetic and pure inertial designs, but that won't matter if they never achieve ignition.
Member
I'm not sure about this. I know that while a fission reactor can melt down a fusion reactor apparently cannot melt down. I have in fact been told that the conditions under which fusion occurs are so precise that if the conditions are not met, the fusion reaction simply stops working altogether (hence the current problems with maintaining a fusion reaction for more than a few seconds etc. in the first place). Contrast this with fission reactors which are essentially designed to prevent the thermodynamically favorable chain fission reaction seen in nuclear bombs. It seems--from the meltdown perspective--that fusion is far safer than fission.
In addition the waste produced by a fusion reactor is apparently a small fraction of the waste produced via fission. Also, the fusion waste products are apparently easy to recycle.
Also, since fusion is more efficient at converting mass into energy, the number of fusion plants which need to be built should be less than the number of fission plants. Therefore from a land-use perspective fusion is also superior (incidentally massive land-use is also a huge drawback for wind and solar technologies).
I agree though that the dangers of nuclear fission are way over-hyped and I would have no problem living next to a fission power plant. The Chernobyl incident has certainly given fission a bad name even though the Chernobyl reactor was based on a 1930's reactor model design and appears to have been sabotaged. I guess Chernobyl proved that if scientists want to they can induce a melt down in a fission plant. I think current reactors such as CANDU have triple redundancy systems which prevent operator error by shutting the system down in the event of a possible meltdown sequence. Turning off a fission plant and turning it back on is apparently very expensive.. but is obviously better than a meltdown.
On the other hand just look at what France has done with nuclear fission. I think it's fantastic. The high air quality there no doubt has a lot to do with the fact that 75% of the nations power comes from nuclear fission. The French economy will really benefit in the coming years because: a) it can export its nuclear technologies to other countries and b) it can sell its excess electricity to England and Germany. It's interesting that ITER ended up being build in Cadarache France. I think that there is a strong political will in France to be at the forefront of all nuclear technology.
Order of Kilopi
Let's be clear on this point: the fission chain reaction in a fission reactor also shuts down quite easily and instantaneously. It is the decay heat that challenges the safety systems to prevent fuel melting.
You offer several points here, but I dispute that Chernobyl was sabotaged. That accident was caused by a combination of stupidity, arrogance and a flawed design.
As to CANDU reactors - all western nuclear plants have multiple redundancy in their engineered safety systems.
As to the French nuclear program, I agree they have a working system, and great political will to sustain it. Don't know about the rest. Their technology is about the same as the US and Japan.
Member
It's possible that Chernobyl was not sabotaged (it appears that there may have been a conspiracy theory leaked about it having been sabotaged..so it's probably a good idea to challenge the idea.)
Regarding safety of fusion versus fission, I found this on Wikipedia (please let me know what your opinion is on this):
original Wikipedia article:The likelihood of small industrial accidents including the local release of radioactivity and injury to staff cannot be estimated yet. Nevertheless the likelihood of a catastrophic accident in a fusion reactor resulting in major release of radioactivity to the environment or injury to non-staff, is estimated to be much smaller than that in a fission reactor. The primary reason is that the fission products in a fission reactor continue to generate heat through beta-decay for several hours or even days after reactor shut-down, meaning that a meltdown is possible even after the reactor has been stopped. In contrast, fusion requires precisely controlled conditions of temperature, pressure and magnetic field parameters in order to generate net energy. If the reactor were damaged, these parameters would be disrupted and the heat generation in the reactor would rapidly cease.
There is also no risk of a runaway reaction in a fusion reactor, since the plasma is normally burnt at optimal conditions, and any significant change will render it unable to produce excess heat. In fusion reactors the reaction process is so delicate that this level of safety is inherent; no elaborate fail-safe mechanism is required. Although the plasma in a fusion power plant will have a volume of 1000 cubic meters or more, the density of the plasma is extremely low, and the total amount of fusion fuel in the vessel is very small, typically a few grams. If the fuel supply is closed, the reaction stops within seconds. In comparison, a fission reactor is typically loaded with enough fuel for one or several years, and no additional fuel is necessary to keep the reaction going.
http://en.wikipedia.org/wiki/Fusion_power
I'm always pretty skeptical about Wikipedia.. but this particular quote seems to be suggesting that 'runaway reactions' are possible in fission, but not likely in fusion. (It does seem to confirm the idea that decay heat is the culprit though..)
Order of Kilopi
This is a sensationalist mischaracterization of the way fission reactions behave. The chain reaction leading to a nuclear explosion seen in nuclear bombs is not thermodynamically favorable. It is in fact impossible to achieve. The idea that fission reactors can undergo nuclear detonations is pure Hollywood. Even the most dangerous reactors were only in danger of producing excessive output power, causing them to reach temperatures sufficient to melt the core, an event that could lead to steam explosions and fires. There are now numerous designs that are inherently unable to reach such levels, making it impossible to melt the core with its own heat. I strongly suggest you do some actual research on the subject before claiming knowledge of it.
Member
Not thermodynamically favorable.. ok.... but..
you say it is impossible to achieve right after you say it is seen in nuclear bombs.... this seems contradictory.. could you elaborate a bit on this please?
thanks.
Member
here is one of the original articles which misled me: http://science.jrank.org/pages/4754/...trol-rods.html
I remember reading somewhere else too that the control rods were used to prevent 'runaway' reactions and explosions..
but thanks for the corrections.. I appreciate it.... it's hard to know what to believe on the internet.. maybe I should just stick with textbooks..sigh..
Order of Kilopi
Impossible in a reactor. Bombs require very specific isotopes and are nothing at all like reactors in design. For a nuclear detonation, you need U-235 or Pu-239, obtained by painstaking enrichment of natural uranium (which is almost entirely U-238) or extraction of the plutonium from partially burnt nuclear fuel. Reactors use fuel with a large amount of U-238, which can not sustain a chain reaction...it does not produce enough neutrons of sufficient energy to do so. Some reactors can even burn natural uranium (99+% U-238) or thorium, transmuting them into useful fuels as they burn them. These materials simply can not be made to explode in a nuclear detonation.
The worst danger in a nuclear reactor is meltdown, where the reactor puts out enough power to melt its own structure and fuel. This can lead to steam explosions, but can never lead to a nuclear explosion, and as the core falls apart it will eventually cease to be able to sustain a reaction. Some more modern reactor designs are designed to melt down safely if all other protective systems fail, dividing and containing the molten material to halt the reaction, others simply can not melt down, no matter what happens.
http://en.wikipedia.org/wiki/Passive_nuclear_safety
http://en.wikipedia.org/wiki/Generation_III_reactor
Order of Kilopi
Maybe he's Sithum is thinking of a nuclear excursion/criticality accident.
http://en.wikipedia.org/wiki/Criticality_accident
Et tu BAUT? Quantum mutatus ab illo.
Order of Kilopi
The physical geometry of a reactor also bars a nuclear detonation. Even in naval reactors, which are enriched to 93% U-235 (or were, in my day), it is impossible to achieve.
Order of Kilopi
Well, that doesn't really fit with the talk of reactors exploding if it weren't for the control rods. And that page he linked does specifically claim the reactor could explode...perhaps the original author was referring to steam explosions and the page was a victim of excessive simplification.
A good point...to make such a reactor explode (in a nuclear detonation, that is, not a simple steam explosion such as what happened at Chernobyl) would require disassembling the reactor and fabricating precision bomb components from the materials. I did mention the fact that bombs were completely different in design, but focused on the materials being incapable of producing a detonation because it seemed quite sufficient and I was unaware reactors using highly enriched fuel were still in use...it makes sense that they'd still be used where compactness is an issue, though.
Fusion plants thermally producing power would have similar hazards, as well as new ones. While they would immediately stop producing power when shut down, they are also likely to involve large superconducting coils full of cryogenic coolant. As the recent accident at the LHC shows, such coils are not free of problems...they can "quench", losing their superconductivity and dumping their stored energy in an instant as heat, leading to rapid vaporization of coolant. This could cause damage to the reactor and the surrounding building and possibly lead to release of radioactive materials produced by neutron radiation from the fusion reaction. Any fires that start should be thoroughly extinguished by the blast of boiling helium, though...
It's certainly still worthwhile, fusion does have some advantages, and learning to harness it seems likely to lead to side benefits of the technology developed. It's just not as utterly superior an approach as was suggested.
Member
Let me know how this sounds:
The advantages, so far, for fusion over fission:
1) reduction in mining activity (therefore less waste at the fuel acquisition step).
2) far higher energy yield per kilogram of fuel versus fission (less fuel required in the first place for a given amount of energy production..)
3) cleaner waste products (shorter half-lives, easier disposal/recycling etc).
4) Fuel seems to be far more abundant (therefore fusion will likely be a better long term solution for power generation)
5) safer operations according to some sources (see below).
6) more research potential?
Advantages for fission over fusion:
1) existing technology (therefore less expensive in short term).
2) has been tested and refined (reliability will be higher in short term as an adequate power source).
3) can use fuel from warheads to power fission reactors (can use to reduce nuclear war head stockpiles from the cold war era etc.,).
4) modular designs (such as pebble bed) available meaning that some plants can be expanded as energy demand increases (will this eventually be possible with fusion as well though?).
----
ref1: http://www.tenafly.k12.nj.us/~shilfs...s__fussion.htm
ref2: http://www.princeton.edu/~chm333/200...vs_fission.htm
Order of Kilopi
While certainly true, how meaningful is this? It's mostly of interest for spacecraft, which have to carry their fuel with them wherever they go...and the mass of the fusion reactor system may well outweigh the reduction in fuel mass.
Actually, D-T fusion reactors use lithium to breed more tritium fuel...and lithium is in similarly short supply. We won't burn through it quickly, but we won't quickly burn through the world's uranium and thorium either. And deuterium does take a fair bit of work to extract from natural water.
Remember, we've got so much depleted uranium lying around from the weapons programs that we use it in bullets...and while it's useless for nuclear weapons, it can be burned in reactors. There's enormous quantities of uranium still un-mined, and there's far larger thorium reserves. We're not going to run out of fission fuels for a long time.
The princeton.edu link? That page ignores the fact that modern designs either "safely" melt down or don't melt down at all, that Chernobyl was a particularly unsafe design, and that neutron radiation from nuclear fusion will also produce highly radioactive waste.
Another advantage for fission would probably be compactness. It's looking like practical fusion plants will be too big for things like aircraft carriers and any but the largest spacecraft.
Order of Kilopi
I agree. Use of Chernobyl as an example of reactor hazards loses credibility. Even using TMI as an example would ignore lessons learned.
Member
Doesn't the superior mass-energy conversion efficiency of fusion likely mean that it will take less fuel to produce the same amount of energy? Wouldn't this be important when considering fuel consumption?
It seems according to this source that the amount of uranium being consumed today far outstrips its production(check out the graph--source: http://www.world-nuclear.org/info/inf23.html)
I think it may be more meaningful though to compare what the total lithium supply is versus the total uranium supply. According to the above article the total amount of uranium available from 'known recoverable sources' is 5,469,000 tonnes. Total elemental lithium supplies seem to be currently estimated at around 28.4 million tonnes (http://www.worldlithium.com/An_Abund...%20Lithium.pdf).
The other thing to consider with lithium though is that it is used in so many other applications such as electric/hybrid car batteries and hand held electronics (it is also used in medicine, but I think the amount used here is fairly negligible). Total lithium consumption per year now is apparently around 84,000 tonnes of lithium carbonate (total amount of lithium carbonate in the world according to this article is 150 million tonnes--source: http://www.energybulletin.net/node/48026). Of course consumption is increasing and will continue to increase significantly in the foreseeable future given the direction of the auto-industry and electronics in general. However it seems that there is an abundance of lithium.
Also, it would seem that there is significantly more lithium around than uranium.
Another thing I wanted to ask: what are the other ways of making tritium? Apparently tritium can also be produced by bombarding deuterium atoms with other deuterium atoms(http://www.bookrags.com/research/tritium-woc/). Would it be better to produce tritium in this way?
Order of Kilopi
By mass, sure. And that's important for spacecraft. For ground plants, the energy recovered is still so much greater than the energy consumed in moving fission fuel to the plant that the mass isn't very relevant.
Well, again, we've got massive quantities of refined uranium lying around. There's a lot of it around, so it's cheap (we use it for bullets!), so there's not much profit in mining it. Lack of production doesn't mean we're about to run out.
Certainly, but they're within an order of magnitude of each other...if one is a problem, so is the other. There's also thorium, which is accessible in quantities at least a few times greater than those of uranium. There's more than enough of both fission and fusion fuels to satisfy needs for the imaginable future. The only claims of doom I've seen have assumed idiotically inefficient once-through fuel cycles, no breeding or use of thorium, and so on, making whatever assumptions they can to make nuclear power look bad...that's not a realistic way to look at the problem.
It might be possible, but it'll probably not be worthwhile until we start running out of lithium...
Member
I would like to do a hypothetical comparison:
Part A: If we took all the feasibly fusible material on the planet (by feasible I mean material that could be feasibly mined/produced/extracted and put into a commercially viable nuclear fusion plant to generate power) and produced energy via fusion what would the total energy output be?
Part B: If we took all the feasibly fissible material on the planet (again by feasible I mean material that could feasibly be used to power a nuclear fission power plant) and produced energy via fission what would the total energy output be?
Would part A not yield way more energy than part B?
I thought that because of the superior mass-energy conversion efficiency of fusion versus fission and because of the abundance of deuterium and lithium versus uranium, the potential amount of power producible over the long term by fusion would be far more than that which could be produced via fission (would it be several orders of magnitude higher?..I don't know.).
Would this not imply that over the long term fusion may eventually be 'the way to go'?
let me know what you think,
thanks.
Order of Kilopi
As others have mentioned, just looking at the fuel aspect does not get you to a conclusion as to which technology is best. And given that fusion still has a ways to go before being a viable commercial technology and may never get there, I don't see the utility of the comparison.
Member
but what about the potential energy production aspect? Isn't being able to produce more energy over a longer period of time better? Also, think about the cool experiments you could run with that kind of energy.
Posting Permissions
Reply With Quote