Physics Forums

Physics Forums (http://www.physicsforums.com/index.php)
-   General Discussion (http://www.physicsforums.com/forumdisplay.php?f=14)
-   -   oil,nuclear power (http://www.physicsforums.com/showthread.php?t=214558)

hagopbul Feb11-08 08:19 AM

oil,nuclear power
 
oil have give us so much pain and blood .

it gives us problems in middle east,and with environment, opec, ...etc

so why we don't shift to the nuclear power just that simple (and for the nuclear wast if we have we can send it to the space)

so why not....

George Jones Feb11-08 08:35 AM

Quote:

Quote by hagopbul (Post 1605118)
oil have give us so much pain and blood .

it gives us problems in middle east,and with environment, opec, ...etc

so why we don't shift to the nuclear power just that simple (and for the nuclear wast if we have we can send it to the space)

so why not....

Last Thursday, I went to a talk by a founding member of Greenpeace (and former president of Greenpeace Canada for nine years) who now promotes this.

hagopbul Feb11-08 09:04 AM

ok when?
after 10000000000 year...

vanesch Feb11-08 09:16 AM

Quote:

Quote by hagopbul (Post 1605152)
ok when?
after 10000000000 year...

It's the usual misunderstanding about nuclear waste.

Nuclear waste has 3 components:

- immediately most active and "final" ashes: the fission products: decay time of the order of 300-500 years

- small quantities of unwanted "minor actinides" which could be eliminated in future combustion cycles: decay time of the order of 10 000 years

- plutonium: actual "generated fuel" that is sometimes just left in the waste:
decay time of the order of 100 000 years. In countries with a fuel cycle, this is already extracted (to make MOX).

With decay time, I mean here: the time needed to be of the same (low) activity level as the original raw uranium ore that came out of the mine.

So the strictly necessary and uncompressible decay time to "background" is only of the order of a few centuries.

And now, think about this: how long does it take heavy metals in chemical waste to decay ?

Astronuc Feb11-08 09:18 AM

There is a gradual renewal of interest in nuclear energy. Clearly there needs to be an alternative to the current reliance on fossil fuels. But there are also significant technical, envirnomental and economic issues involved. Switching to nuclear is not so simple and straightforward.

Keep in mind that as the demand for nuclear energy increases, it's cost will increase as well. It takes about 5-6 years to build a single nuclear plant, and in most countries, there is a shortage of qualified trades people who are needed to build the plants.


Disposal of nuclear waste in space is not an option. It cost about $10,000/kg to put something in orbit, and more if one wants to send it far away. That's not certainly not economical with respect to nuclear waste. Then there are the safety aspects.


Nuclear energy also does not address the current transporation infrastructure which is based upon personal mobility, vis-a-vis automobiles - and buses, trucks and aircraft. A large proportion of oil-based fuel is used in transportation. Trains can use electrical power, but only a small fraction of mileage is electrified.

hagopbul Feb11-08 10:04 AM

it is always about the money right

Astronuc Feb11-08 10:55 AM

Quote:

Quote by hagopbul (Post 1605205)
it is always about the money right

Um - yep. Eventually it comes down to a rather simple economic proposition - at least in the industrialized modern age. Of course, one could be a nomadic hunterer-gatherer.

f95toli Feb11-08 12:32 PM

Another problem with fission is that there is a limited amount of uranium available. Apparantly the prices are already going up. Now, we are not likely to run out any time soon (the estimates seem to range betwen 50-100 years) and presumably new deposits will be found, but that does not change the fact that fission -like oil- is only a temporary solution to the worlds energy problems.

Moreover, there is no way to completely separate civilian and military use of fission; if we want to world to use more nuclear power we will have to accept that ALL (or at least most) countries will need to have nuclear power plants of their own and quite a few will have to build enrichment facilites that can -in principle- also can be used to make weapon-grade uranium. Another problem is of course that even a civilian power plant can be quite dangerous if it ends up being located in the middle of a civil war, someone is bound to figure out that a nuclear meltdown is quite an efficient method of killing a lot of people and force any surviors to leave the area.

Kurdt Feb11-08 12:53 PM

With fast reactors and reprocessed fuel we could have several thousand years.

russ_watters Feb11-08 04:47 PM

Quote:

Quote by hagopbul (Post 1605205)
it is always about the money right

Sort of. Right now the economics are driven by the politics and in the US, anyway, the politics are not favorable. In France, the politics are favorable, so they use nuclear power almost exclusively. Put quite simply, the hippies killed nuclear power in the US in the '60s and '70s, to the severe detrement of our country. Flower power will not drive a turbine. But the economics is what is now bringing it back. Electricity is getting expensive as oil prices rise. Other countries are seeing a resurgence of the dangerous attitudes that killed nuclear power in the US. Germany, for example, is setting itself up for an economic disaster right now with it's "environmental" policy for alternate energy, which does not include nuclear power.

That huge drawback of nuclear power, the waste containment issue, was also invented by "environmentalists". It simply doesn't exist. For the short-mid term (the next hundred years or so), on-site storage plus reprocessing makes the Yucca mountain project irrelevant. For the longer term, well, if you reprocess the fuel, there is little that needs to go anywhere except a nice, safe, landfill. Anything worse can be stored in a mountan, but it only needs to be secure for a hundred years at a time. The 10,000 year lifespan engineering criteria of the Yucca project is just crack smoking, pure and simple. You cannot design a structure for that kind of longevity, even if you had to, and in this case, you don't. If our civilization deteriorates enough that we can't maintain the facility or create a new one a hundred years from now, the need for it to be secure goes away as well.

So no, on this issue, the politics is driving the money more than anything else.

russ_watters Feb11-08 04:52 PM

Quote:

Quote by f95toli (Post 1605328)
Another problem with fission is that there is a limited amount of uranium available. Apparantly the prices are already going up. Now, we are not likely to run out any time soon (the estimates seem to range betwen 50-100 years) and presumably new deposits will be found, but that does not change the fact that fission -like oil- is only a temporary solution to the worlds energy problems.

To expand on Kurd's statement, the 50-100 years estimate comes from so-called environmentalists who have so far succeeded in keeping reprocessing illegal in the US. Imagine - "environmentalists" who are against recycling!

I'm a little on the distrustful side, so when I see people doing such irrational things, I think that unless they are incredibly naive, there must be another motive at work. Ostensibly, though, reprocessing was outlawed (by presidential order) for nuclear proliferation reasons.

f95toli Feb11-08 06:16 PM

True, with reproccssing it would last much longer.
However, as far as I understand the problem with reprocessing is that it requires more or less the same type of plants as are used for enrichment (it is basically isotope separation) which just brings us back to my main point about the security issues (I am not usally paranoid, but having a lot of enriched uranium floating around makes me nervious, even if it is only reactor-grade).

I am not a big fan of nuclear power, in my view it is too dangerous and too difficult to control. Imagine a world where all the exisiting fossil fuel power plants were replaced by fission reactors; from a CO2 point-of-view it would be a good thing; but the drawback is that there would be a LOT of fission reactors around; many of them in poor countries and quite a few in places that are politically unstable. Remember that the worlds energy consumption is rapidly going up.

I wouldn't really have a problem with fission as a short term solution (i.e. replacing the current generation of reactors in countries that already have nuclear power) if it wasn't for the fact that it is likely to kill off all funding to research into viable -but in the short term very expensive- alternatives such as fusion. I don't really have much faith in the political system when it comes to research funding, the only way to make sure the neccesary funds become available is if the general public and industry start fearing that we will run out of energy; only then will there be enough pressure on the politicians to invest the hundreds of billions of dollars that will be needed.

mgb_phys Feb11-08 06:34 PM

Quote:

Quote by f95toli (Post 1605737)
However, as far as I understand the problem with reprocessing is that it requires more or less the same type of plants as are used for enrichment (it is basically isotope separation)

Nope it's basically chemical - you remove the waste products that you don't want, you aren't trying to extract pure U235. The technology to enrich U has nothing to do with reactors it's more precison machining.

Quote:

which just brings us back to my main point about the security issues (I am not usally paranoid, but having a lot of enriched uranium floating around makes me nervious, even if it is only reactor-grade).
Reactor fuel is a pretty useless starting point for a weapon. The same non-proliferation treaty that we keep going on about says that we (nice safe countries with nuclear weapons) are supposed to provide the uranium for them in return for them not trying to play with the stuff themselves.

Quote:

but the drawback is that there would be a LOT of fission reactors around; many of them in poor countries and quite a few in places that are politically unstable. Remember that the worlds energy consumption is rapidly going up.
We don't seem to mind have high pressure gas pipelines or Methyl-cyanide plants in poor countries - presuably because an accident only effects the locals.

Quote:

I wouldn't really have a problem with fission as a short term solution (i.e. replacing the current generation of reactors in countries that already have nuclear power)
So India, Pakistan, South Africa, Brazil are allowed them but Switzerland, Holland, Germany, Sweden aren't.
The only country I can think of that built nuclear power plants primarily for power rather than weapons research is Canada.

Quote:

if it wasn't for the fact that it is likely to kill off all funding to research into viable -but in the short term very expensive- alternatives such as fusion.
Fusion + short term + viable - aren't often used in the same sentance.

f95toli Feb11-08 06:58 PM

Quote:

Quote by mgb_phys (Post 1605762)
Nope it's basically chemical - you remove the waste products that you don't want, you aren't trying to extract pure U235. The technology to enrich U has nothing to do with reactors it's more precison machining.

I admitt I don't know much about the technology, but isn't the technology (which as you say is mainly chemical) monitored precisely because it CAN be used to extract Pu from fuel coming from commercial reactors?

Quote:

Reactor fuel is a pretty useless starting point for a weapon. The same non-proliferation treaty that we keep going on about says that we (nice safe countries with nuclear weapons) are supposed to provide the uranium for them in return for them not trying to play with the stuff themselves.
Well, I think we can safely forget about providing uranium for others. I would be VERY suprised if a majority of countries in the world would accept having to get all their fuel from a minority that was sitting on all the facilties for making reactor-grade uranium. Look at the current situation with Iran, whether or not they want to enrich uranium for military use is irrelevant; the point is that they can -with some justification- claim that it is in their national interest not having to rely on someone else for their uranium even if it is for civilian reactors.

Quote:

We don't seem to mind have high pressure gas pipelines or Methyl-cyanide plants in poor countries - presuably because an accident only effects the locals.

You got a point. But you are also right that it only affect the local population, a nuclear meltdown in a badly maintained power plant will affect a large area. I grew up on the east coast of Sweden and we were quite badly affected by the Chernobyl disaster (bad luck with the wind). The hunters in the are were I am from still have test the meat from time to time. And as you know Sweden is quite far from Chernobyl



Quote:

Fusion + short term + viable - aren't often used in the same sentance.
[/Quote]

Short term is something like 50 years in this case.
I was at a superconductivity conference recently and went to one of the talks about the magnet system in ITER. One of the older speakers had been working on the magnet design for over 20 years and since the project is now done (the design has been finalized) he had recently started working on the next generation (DEMO).
In his talk he pointed out that a large portion of the people in the audience would be dead before DEMO goes online (even in the best case scenario); and even the youngest people in the room (PhD students) would be close to retirement.

K.J.Healey Feb11-08 07:19 PM

How many reactors would have to be built to replace 100% of our (USA's) consumption of oil as a power source (non auto)?
lets say with 1998 numbers:
Oil Only 36 quadrillion BTU's consumed (1 year)
A nuclear PWR plant can output at 1500MWe, which leads to a calculation of about 803 PWR plants to replace Oil alone (Not counting natural gas and coal).

Is 803 a big number? Well its about double what the WORLD has in operation at this moment.

I could only imagine how much our demands would increase during the lengthy production of these plants. But then again maybe power plants in the future will be able to output more.

mgb_phys Feb11-08 07:27 PM

Quote:

Quote by f95toli (Post 1605809)
I admitt I don't know much about the technology, but isn't the technology (which as you say is mainly chemical) monitored precisely because it CAN be used to extract Pu from fuel coming from commercial reactors?

The technology to reprocess spent fuel into MOX is the same as to extract Pu from reactors. This is the only way to get Pu, although you generally use a different reactor design if your aim is Pu rather than power - you can see this is the design of most 'civil' reactors from the 40s/50s!
The technology to enrich U235 doesn't require you to have a reactor - just very good precision machinery for centrifuges or a lot of copper for race tracks.


Quote:

Well, I think we can safely forget about providing uranium for others. I would be VERY suprised if a majority of countries in the world would accept having to get all their fuel from a minority that was sitting on all the facilties for making reactor-grade uranium.
We are quite happy to get our oil/gas from countries we don't exactly trust!
The UK is building a new fleet of Trident missile subs against our tradiational cold war enemy - who will also supply 80% of our natural gas.

Quote:

I grew up on the east coast of Sweden and we were quite badly affected by the Chernobyl disaster (bad luck with the wind). The hunters in the are were I am from still have test the meat from time to time. And as you know Sweden is quite far from Chernobyl
But the UK or Norway building a few dozen coal fired power stations would effect you a lot more - I don't think the lakes and forests in Sweden have recovered from the UK's acid rain yet.

Actually you probably also receive more radiation from UK coal power statiosn than from Chernobyl - how dangerous this is depends on the particular isotopes and where they end up, you tend to get a lot of Thorium from coal which isn't as bad as the Ceasium from Chernobyl which concentrates in biology a lot more.

Astronuc Feb11-08 08:18 PM

Quote:

Quote by K.J.Healey (Post 1605853)
How many reactors would have to be built to replace 100% of our (USA's) consumption of oil as a power source (non auto)?
lets say with 1998 numbers:
Oil Only 36 quadrillion BTU's consumed (1 year)
A nuclear PWR plant can output at 1500MWe, which leads to a calculation of about 803 PWR plants to replace Oil alone (Not counting natural gas and coal).

Is 803 a big number? Well its about double what the WORLD has in operation at this moment.

I could only imagine how much our demands would increase during the lengthy production of these plants. But then again maybe power plants in the future will be able to output more.

The 104 operating nuclear reactors in the US supply about 20% of the electricity. Several produce less than 1 GWe. Most modern nuclear plants produce ~1.1 GWe, and the newest largest ones are aimed for ~1.5-1.6 GWe. Replacing all the oil and coal plants would require about 300-400 new nuclear plants (depending on capacity), and that would leave natural gas peaking plants for reserve.

There is always reserve generation, just in case the grid or plants experience an unplanned outage or disruption.

russ_watters Feb11-08 08:33 PM

Quote:

Quote by f95toli (Post 1605737)
True, with reproccssing it would last much longer.
However, as far as I understand the problem with reprocessing is that it requires more or less the same type of plants as are used for enrichment (it is basically isotope separation) which just brings us back to my main point about the security issues (I am not usally paranoid, but having a lot of enriched uranium floating around makes me nervious, even if it is only reactor-grade).

Since we already have nuclear wepons, where is the proliferation issue.
Quote:

I am not a big fan of nuclear power, in my view it is too dangerous and too difficult to control.
Quite frankly, that's just naive. Despite what the naysayers would have you believe, the only nuclear power related accident to kill anyone was Chernobyl and more people die in coal mines every year than died as a result of Chernobyl. And that is to say nothing about the hundreds of thousands coal power has killed with pollution.

For control, which is more under control, a plume of toxic smoke dumped directly into the atmosphere or a rod of fuel that never leaves its concrete and steel bunker?
Quote:

Imagine a world where all the exisiting fossil fuel power plants were replaced by fission reactors; from a CO2 point-of-view it would be a good thing; but the drawback is that there would be a LOT of fission reactors around; many of them in poor countries and quite a few in places that are politically unstable. Remember that the worlds energy consumption is rapidly going up.
This is true, but I think you underestimate where the demand for power is. Part of what makes a country stable is also what makes a country need power. So if a country like the Sudan doesn't get a nuclear reactor, that doesn't have a major impact on the global energy outlook. Virtually all of the power is used by a handful of big countries. And since nuclear technology is expensive, there isn't much to fear about a country like the Sudan getting nuclear power - they won't because they don't have the money to.
Quote:

I wouldn't really have a problem with fission as a short term solution (i.e. replacing the current generation of reactors in countries that already have nuclear power) if it wasn't for the fact that it is likely to kill off all funding to research into viable -but in the short term very expensive- alternatives such as fusion.
Well, it would be ok with me if fission took the lions' share of the funding for a while. Research into fission was essentially halted in the 70s and 80s and as a result, the bang-for-buck potential for fission research is much higher than for fusion.
Quote:

I don't really have much faith in the political system when it comes to research funding, the only way to make sure the neccesary funds become available is if the general public and industry start fearing that we will run out of energy; only then will there be enough pressure on the politicians to invest the hundreds of billions of dollars that will be needed.
We are running out of energy and that's why nuclear power is now making a comeback. Fundamentally, the massive blackouts and rolling brownouts we've seen in the past few years are a result of insufficient generation and transmission capacity.

It is pathetic, really - part of what makes a developed country a developed country is a reliable power grid. And on that measure, we're going backwards. But it is fitting that the hippies are paying the most for their asinine beliefs, with high costs and unreliable power being the worst in the west. It warms my heart.


All times are GMT -5. The time now is 04:34 PM.

Powered by vBulletin Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
© 2014 Physics Forums