Nuclear Power - Page 3

[twomers]

>> I recommend sarcasm tags, in that case.
Heretic!
I find it more amusing not to use them. Especially in real life (vocal inflections are like sarcasm tags).

[lasher511]

I fail to see why nuclear power is such a big problem. Sure there's the risk of a meltdown, but there is a risk with almost anything these days and it's not like they would put these plants in the middle of a city where millions of people live.

From what I've read, nuclear energy is quite potent, so maybe it's the solution to all this oil trouble.

Speaking of, it's kinda funny how people are so opposed to the methods used to provide them with something that makes them so damn comfortable, isn't it? Energy isn't cheap; you can't just pull it out your shiny metal butt.

And for those who are thinking Solar Energy, don't be too surprised if one day some genius is all over the press one day saying that all that energy we collect in solar panels can give us cancer or some crap.

Actually there is not much risk at all of a meltdown. People are scared of meltdowns thanks to shows like the simpsons.

Yes pretty much anything is a risk these days but do you really want to keep adding things to that mix and wait and see which one it actually is?

No matter what energy source we use someone will come out with some reason why we should not use it. Nuclear power will only be a part of the solution. While in some countries nuclear power would be great because of a low population on a worldwide scale you do start having problems with where to put the waste. For example to power the entire population of Australia for a year you would produce roughly 20 tons of nuclear waste. (about the size of a couch) Considering australia's massive amount of "dead land" 20tons of waste is nothing. However in order to power America for a year you would produce roughly 301 tons of nuclear waste per year. To power the population of the world for a year your looking at 6,602 tons a year. That would take a country like Australia over 300 years to produce.

[Dermot Herron]

I live in South Africa where we (probably) had a nuclear bomb in the 1980s and may have tested one on a small southern island (much disinformation). We gave all that up in 1994.

Now we have invented/developed the pebble-bed nuclear reactor where each billiard-ball-sized "pellet" of fuel is in its own ceramic container which is quite tough enough to contain the radioactive waste when the fuel is finally spent. And spent fuel is not hugely radioactive.

It is also inherently safe - by clever choice of materials as it gets hotter the nuclear reaction slows and thus a meltdown literally cannot happen. Rumor has it that the Chinese turned off all cooling into a 160MW reactor and it just sat there very hot. Extracting the fuel from such a faulty reactor wouldn't be very difficult because the un-melted "billiard-balls" can still be handled without scary danger. Terrorist action might result in lots of ceramic balls all over the place, but automatically mostly contained and distributed they are not very dangerous. And extracting anything nasty from the spent fuel is very difficult.

It makes enormous sense to build power-station in the middle of cities - all the inherent waste heat can be used to heat buildings almost for free thus making the whole system very efficient.

It appears that the pebble-bed reactor will be manufactured in kits making them very cheap and by combining several, as much power as you need can be had.

Think of hydrogen-fueled cars where the hydrogen is made by atomic energy - the blessed silence of the electric fuel-cell car! At the moment transport is one of the bigger polluters and making it fuel-cell electric merely moves the problem to power-stations. So a different power-generation is needed and the pebble-bed seems to have all the advantages.

[lasher511]

Thanks Dermot that sort of thing sounds awsome and a type of nuclear power that the entire world could use.

[jasimp]

Actually there is not much risk at all of a meltdown. People are scared of meltdowns thanks to shows like the simpsons.

Are you seriously blaming the Simpsons for causing a fear of meltdowns? If they anything they show how there are almost never meltdowns, despite the workers incompetence.

[lasher511]

Are you seriously blaming the Simpsons for causing a fear of meltdowns? If they anything they show how there are almost never meltdowns, despite the workers incompetence.

I blaing shows like the simpsons for causing the hype around meltdowns and the damage that they actually cause. You have to remeber that we are living in the age of stupidity and the majority of people will believe anything that they see or hear.

[scru]

On the Simpsons.

I know you humans are stupid, but gimme a break.

[lasher511]

On the Simpsons.

I know you humans are stupid, but gimme a break.

As much as you may not want to admit it. You tend to be a human as well. Pretending to be bender all the time only proves my point that humans would much rather believe in the reality presented by TV rather then reality itself.

[MidiMagic]

So why aren't there huge amounts of these cheaply fueled nuclear powerplants around?

Environmentalists are as afraid of radioactivity as they are of lead and mercury.

[Dermot Herron]

When I first saw the structure of the pebble-bed (PB) reactor I felt that at last this was a real solution to the basic problems of existing reactors.

(Don't forget that CANDU, the Canadian heavy water reactors which worked on the same reaction chain as the PB but with unenriched uranium) worked absolutely reliably for many years on the shores of Lake Ontario. Their reliability was their downfall - they never garnered any publicity. But it is the next-best proven reactor to PB. )

See Scientific American Jan 2002 ( http://www.sciamdigital.com) for some good articles and comparisons between different systems. Note that there are many more than South African interests in the PB reactor (of course our propaganda suggests we did it all) which is very favorable for the outcome. And there are competitor systems which also bodes well for the technology.

Notice that the "pebbles" have pinhead chunks of mildly enriched uranium distributed in a graphite matrix coated in carbon and silicon-carbide ceramic. And that dummy pebbles (no uranium) are distributed in the mix to dilute the power as required.

[Dermot Herron]

The other big factor in favor of the PB reactor is the exit temperature of the gas at 900C (pressurized-water reactors work at 300C) which can be used directly in many industrial processes like making hydrogen from water or other chemical reactions so saving the very inefficient (40%) generation of electricity or the very polluting coal-burning-for-heating.

A hydrogen-from-steam fuel-cell car would have approx 80+% overall system efficiency compared to today's best diesel engines with some 50% efficiency (and if you include the mining and transport and cracking of crude oil in the equation this is nearer 30%). Also the electric-car-from reactor-steam is a much simpler (albeit much more hi-tech) end-to-end process. Again one would have to figure in mining of uranium etc, but because of the high energy-density of nuclear energy generation, this would be lower than that of any other energy method.

[Lardmeister]

The other big factor in favor of the PB reactor is the exit temperature of the gas at 900C (pressurized-water reactors work at 300C) which can be used directly in many industrial processes like making hydrogen from water or other chemical reactions so saving the very inefficient (40%) generation of electricity or the very polluting coal-burning-for-heating.

A hydrogen-from-steam fuel-cell car would have approx 80+% overall system efficiency compared to today's best diesel engines with some 50% efficiency (and if you include the mining and transport and cracking of crude oil in the equation this is nearer 30%). Also the electric-car-from reactor-steam is a much simpler (albeit much more hi-tech) end-to-end process. Again one would have to figure in mining of uranium etc, but because of the high energy-density of nuclear energy generation, this would be lower than that of any other energy method.

Wow, looks like South Africa is really on the leading edge of nuclear reactor design. Impressive! The price of electricity should soon be so low that you don't need to meter it any longer. Smooth operating hydrogen cars will crowd your streets, costing only a penny a mile to operate.

[jwenting]

Are you seriously blaming the Simpsons for causing a fear of meltdowns? If they anything they show how there are almost never meltdowns, despite the workers incompetence.

The original scare comes from the "peace" movement, who equated nuclear power with nuclear weapons. They didn't want nuclear weapons because nuclear weapons prevent the establishment of the communist world government (which they equate with "peace").
It was later picked up and expanded upon by the "environmental" movement, who don't want people to have access to energy. They want humanity to go extinct, or at the very least revert to the stone age.
Having access to an energy source that's not polluting destroys their argument of "conservation" to prevent pollution, so they can't have that.

As a result of those two groups working apart together there's been more damage done to world economies and science than at any time before in the history of the planet (except maybe Pol Pot but he was strictly regional).

[jwenting]

Wow, looks like South Africa is really on the leading edge of nuclear reactor design. Impressive! The price of electricity should soon be so low that you don't need to meter it any longer. Smooth operating hydrogen cars will crowd your streets, costing only a penny a mile to operate.

South Africa has ample access to Uranium for fuel, and not much in the way of oil and natural gas.
Due to the trade embargo that lasted from the 1960s to the 1990s they were forced to look for alternatives to fossil fuels far more than anyone else, and they did.

[Dermot Herron]

The pebble-bed reactor system is a joint development between Argentina, Brazil, Canada,
France, Japan, South Africa, South Korea,
the U.K. and the U.S. I think we are doing the actual "pebbles" while others do the rest of the reactor. Presuming this all works (and the signs are good) we will all share in the benefit. And if the fuel-cell works out oil will be used for lubricating only and the roads will be quiet.

The biggest deposits of uranium in the world are in Canada. Others are in Australia and South Africa and Russia and a few elsewhere.

[jwenting]

The problem with fuel cells is hydrogen.
Explosive, bulky, expensive to produce without access to dirt cheap electricity.

In fact at the moment most hydrogen gas is produced by chemical synthesis out of natural gas (a fossil fuel), producing tons of CO2 in the process.
Yet it's lauded as being "clean" for not producing CO2 when burned :)

[bumsfeld]

I hope no one is thinking about storing hydrogen gas under high pressure in the cars of the future. Hydrogen, being the smallest molecule, has propensity to leak and even small concentrations (1 - 2%) in air are highly explosive and easily ignitable. Kaboom, there goes the neighborhood!

[jwenting]

that's bad, as there's a few percent natural hydrogen in the air already ;)

[lasher511]

I think that the concentrations would have to be higher then 1-2% to have an explosive effect. Hell all this hydrogen actually has to come from somewhere worse that can really happen is its released back into the atmosphere where it came from.

[Lardmeister]

that's bad, as there's a few percent natural hydrogen in the air already ;)

My chemistry teacher tells me that air contains 0.00005% molecular hydrogen naturally, and that 4% to 96% in air would forcefully explode if ignited.

[lasher511]

Which means that any hydrogen taken out of the air will reduce that percent. Any leaks will likely dissipate and not cause any problems or explosions.

[GrimJack]

There is no reason why we can't ship nuclear wastes to the sun for safe destruction. Yes it will cost a lot, but probably cheaper than trying to safely store it here on earth for thousands of years.

The problem with this solution is that when you count all the energy used to build the Nuke plant, contain the contaminants, then ship them to the sun we end up with more energy going into the system than we get out. You can't just count the energy produced from the nuke plant, you must account for all the energy needed from mining the fuel, processing the fuel , moving the fuel, building the plant, building the rocket to the sun, getting the rocket to the sun.

On top of that, the cooling towers are moving heat into the atmosphere adding to global warming (though w/o all those pesky pollutants - sort of a clean way towards global warming). All these danged details keep clogging up the beauty of the free energy (in the '50s they hyped the nuke plants as so efficient that the electricity would almost be free or just pennies a KW).

Another couple of <horrid> thoughts: the burying and containment of the waste products that is supposed to last for many millenia will be handled by the lowest bidder. On the east coast (of usa), it is rumored that waste disposal is handled by 'the mob'.

[bumsfeld]

Which means that any hydrogen taken out of the air will reduce that percent. Any leaks will likely dissipate and not cause any problems or explosions.

Hydrogen is not sourced from the air, it is generated from water. It takes a large amount of energy to generate hydrogen from water. If you are good at it, you can recover about 30% of the energy spent, by using/burning the generated hydrogen back to water to drive your hydrogen car. The other 70% of the energy is lost as heat. How is that for global warming?

Sorry, I was wrong, it takes at least 4% hydrogen by volume in air to make it explosive. Very easy to obtain in a closed up garage.

[Lardmeister]

Back to the topic:
Would nuclear power be the only thing to get the hydrogen car going?

[jwenting]

Hydrogen is not sourced from the air, it is generated from water. It takes a large amount of energy to generate hydrogen from water. If you are good at it, you can recover about 30% of the energy spent, by using/burning the generated hydrogen back to water to drive your hydrogen car. The other 70% of the energy is lost as heat. How is that for global warming?

Most hydrogen is in fact extracted from natural gas (methane, ethane, etc.) through chemical processes.
End result: hydrogen, CO2, and chemical residue.
It also costs a lot of energy. Like extraction from water it probably costs more energy than the burning of the hydrogen will produce.

Another factor you didn't take into account is storage and transport of the hydrogen. That is more expensive (both in terms of money and environmental impact) than is doing the same with gasoline (though in theory if the trucks were to run on hydrogen that would be negated, if only the production of hydrogen were to cost less energy than it produces).

[codder]

any way it is very hard to get away with the wastes produc3d by nuclear power plants.if we have calculate the cost of damages cused by such hazards nuke power will never profitable.but it will be better to invest on renewable soueces to devolep better grren energy technologies...

[Dermot Herron]

There is adsorption of hydrogen onto nanotubes and other exotic materials but it isn't a completely solved problem yet. See

http://en.wikipedia.org/wiki/Hydrogen_vehicle

and

http://en.wikipedia.org/wiki/Hydrogen_storage

for a good state-of-the-art description.

Hydrogen under pressure is too low-density to be useful, and liquid hydrogen has a worse energy density by volume than petrol/gas apart from its difficulty of storage (–253 °C / -423 °F).

So there is still much development, but if one looks at America's consumption of kWh in vehicle fuel, they are going to need LOTS of generation of power in some form (which HAS to be nuclear just by numbers) to power vehicles alone in the future. This will reduce greenhouse gases hugely.

[jwenting]

the main problem with nuclear waste is regulatory. It's at the moment illegal for powerplants and storage facilities to refine and sort the waste in order to extract the vast quantities of non-dangerous materials and materials that can be reused.
If those are extracted and the rest sorted out by level of radioactivity (by halflife) things look up a lot.
Only a fraction of the waste needs to be stored at all, and the majority of that for short periods before its radiation levels are below background radiation (at which point it can be disposed of as chemical waste or used in other industries as raw material).

The main reason nuclear energy is relatively costly at this stage is also regulatory. Now, some of those regulations are necessary (safety and security), but many are way too cumbersome and expensive for no other reason than to make nuclear energy an economically unappealing alternative.

Anyone who's visited a nuclear powerplant will have seen that in operation...

[bumsfeld]

Magnesium hydride (solid) can be generated using electricity and reacts with water to make hydrogen gas in a controlled reaction. The byproduct is magnesium hydroxide (solid or sludge) that needs to be collected and recycled.

1 kg of magnesium hydride produces about 3,300 liters of hydrogen gas.

[jwenting]

so you use a relatively rare material to create hydrogen. Quite an advance over using another material that's said to be becoming rare...