Nuclear Power: My pet issue - Page 6

B-rett · #51 (**permalink**) 08-17-2008, 10:35 PM

Quote:

Originally Posted by Guy Fawkes

Fusion? I bet not in my lifetime. I mean to produce sustained energy for the public.

Actually we have experimental fusion reactors in some of our labs today. And major fission reactors are not far off from be able to sustain fusion reactions. And the United States, the EU, Russia, China and Japan have proposed building a full scale reactor in France to further study energy output.

Check it out here:
http://science.howstuffworks.com/fusion-reactor.htm
http://www.iter.org/

lardbeetle · #52 (**permalink**) 08-18-2008, 12:02 AM

Quote:

Originally Posted by bugalugs

Try thinking of the energy used in the mining, processing, enriching, transportation and decommissioning.

Exactly how is that different from the energy used in the construction of renewable energy power plants?

lardbeetle · #53 (**permalink**) 08-18-2008, 12:19 AM

Quote:

Originally Posted by bugalugs

Geothermal or solar thermal

I'd like to see a cost per megawatt analysis comparing a modern nuclear reactor such as the ones built in France with either of those technologies, and an idea of how much space it would take up in order to power an industrialized nation like the United States or Japan completely off of solar thermal.

Quote:

We can safely store it for tens of thousands of years can we? Are you sure. I am an engineer. I know very well waste like this can be managed safely for a considerable amount of time. But anyone thinking that they they can confidently develop an engineering solution for this waste beyond a hundred of so years is kidding themselves. The risk of failure may be very, very low - but the time frame we are talking is very, very long and the consequences of failure very severe. Sticking toxic waste it in a hole in the ground where there isn't water runoff and leaving it there and crossing our fingers that geological and climatological factors are not going to change significantly of the the next hundred thousand years or so is not a good option. Best management option is - do not create the waste in the first place

I agree, but we create waste with everything we do. I'm sure the guys developing the containment systems at Yucca Mountain have thought of how to create a containment system for solid waste that will last tens of thousands of years.

Quote:

Then educate me. Where are these breeder reactors running on spent nuclear fuel? Why is the USA building a big-arsed radioactive waste dump at Yucca Mountain if all this waste is potentially fuel?

Politics prevent the United States from building breeder reactors or reprocessing spent fuel.

Quote:

I am not doubting your calculations. But why are you only looking at the output of the reactor?
What about the radioactive and other toxic waste left behind after mining?
The waste from the fossil fuels used to do the mining
The waste from the fossil fuels used to crush and process the ore
The waste from the fossil fuels used to enrich the ore into a fuel
and finally the waste from decommissioning the reactor at the end of its life.

The fossil fuels could be replaced with alternative power sources. Mining anything takes energy - solar thermal plants use a lot of mirrors if I recall correctly, and you might as well consider the amount of fossil fuels used in mining those resources and assembling them on-site.

If I recall correctly, I heard a mention of reusing low-level radioactive waste in the containment structures of nuclear reactors.

All mining leaves waste behind, uranium mining is no different. Just because the waste is slightly more radioactive than the surrounding area does not mean it is incredibly dangerous - did those materials not come directly from the earth anyways?

Quote:

Will you fit all that under your office desk? I don't think so.

Of course an operating nuclear plant produces "clean" energy during it's operating phase. It is the waste and energy that comes in the mining, processing, enrichment and decommissioning phases that is the problem. You addressed none of this in your opening post.

Every power plant produces waste and energy in the construction and mining of the fuel. It is far less than is produced by the other viable, high-density alternatives such as coal and oil production, however.

Quote:

And your patronising tone is no better.

My point is stop trotting out the same old nonsense painting people who see nuclear energy as being a poor alternative as being some sort of stupid hippys. Nuclear energy is a poor alternative because it is expensive, finite and polluting. It has nothing to do with any unfounded fears.

From your post, you try to pretend that this uranium fuel just appears magically from somewhere as a wonderful non-polluting godsend to all of us! That is garbage. Look at the whole lifecycle of nuclear energy.

Don't put words in my mouth. Nuclear fuel does not magically appear, but neither do the materials used to construct the massive solar power plants that you envision. How many square miles of solar power arrays does it take to equal the average output of one nuclear plant? How much chemicals go into the batteries to even out the output so that we can use it at night?

Nuclear power is very low-pollution power, even factoring in the costs of mining - there are relatively few uranium mines in the world, and when compared to other sorts of mining, nuclear power's contribution to the waste seems insignificant.

Nuke plants simply do not require that much fuel, because they use a much more efficient power source than chemical reactors, especially if we used breeder reactors and waste reprocessing to decrease our demand to roughly 2% of the current level.

Guy Fawkes · #54 (**permalink**) 08-18-2008, 12:49 AM

Quote:

Originally Posted by B-rett

Actually we have experimental fusion reactors in some of our labs today. And major fission reactors are not far off from be able to sustain fusion reactions. And the United States, the EU, Russia, China and Japan have proposed building a full scale reactor in France to further study energy output.

Check it out here:
http://science.howstuffworks.com/fusion-reactor.htm
http://www.iter.org/

I know what we have and what it will take to run a sustained fusion process fro energy. I think I selected my words correctly on this one. But thanks for posting your information so others might feel compelled to educate themselves.

enochthered · #55 (**permalink**) 08-21-2008, 07:03 PM

Quote:

Originally Posted by justabubba

it is the disposal of nuclear wastes and the extremely long half lives that gets in the way, in my opinion. also, it is not so much what remains of the spent fuel rods after reprocessing but what becomes of the obsolete nuclear facilities once they have served their design life
any thoughts on that?

Decommissioning a nuclear power reactor is not a big deal. OK, some people claim it's expensive - how expensive is it, really?

Let's suppose, for arguments sake, that it costs half a billion dollars - an enormously inflated figure - to decommission a nuclear power reactor, and completely restore to greenfield conditions, or whatever.

A typical modern nuclear power reactor generates, say, 1100 MW, with a 95% capacity factor, for a lifetime 50 years. 500 million dollars divided by (1100 MW * 90 percent * 50 years) is 0.12 cents per kWh. So, it's really not expensive at all - just add 0.12 cents to the cost of a kilowatt-hour - it's peanuts!

Quote:

Originally Posted by justabubba

by comparing the resident radioactivity of a nuclear facility with that of your watch i think you are failing to address the concerns about high level radioactive wastes. they must be dealt with. if they are being administered in an environmentally appropriate manner than that should be communicated. if we are not there, then we need to know at what time we will be to alleviate concerns that after building new facilities we will still have toxic waste which requires disposal and no provisions have been made to illustrate my concern,

Radioactive waste, and used nuclear fuel, can be dealt with adequately and safely. What this entails is the efficient use of the nuclear fuel, including sensible, non-wasteful re-use of any uranium, plutonium and other actinides in the fuel, and then possibly separation of valuable radionuclide fission products, like the platinoid metals and other nuclides that have valuable technological, scientific or medical applications, followed by vitrification and packaging of any fission product waste that is left over, and disposal in a deep geological repository, via something like Sweden's KBS-3 process.

To demonstrate the safe and successful transport of radioactive waste, and its final disposal in a permanent geological repository, look at the Waste Isolation Pilot Plant (WIPP) in New Mexico.

Whilst the idea of a deep geological repository - like Yucca Mountain - is completely sound, I agree that the current idea in the US, of taking whole, unprocessed LWR fuel assemblies and sticking them in Yucca Mountain, is terribly inefficient and wasteful, and shouldn't be done.

Quote:

Originally Posted by bugalugs

There are major hazards involved with using nuclear power, but yes, they can be managed. The question is - why bother? Nuclear energy is expensive and inefficient. Why waste even more money and energy on managing the risks. Just use a better energy source.

The earth is experiencing significant impact from the waste produced by using fossil fuels. Why do you want to replace this with a far more toxic waste?

Hazards of nuclear power? Except for the Soviet Union's folly, leading to the Chernobyl accident, nuclear power plants have never hurt anybody. Have a look at all the people killed every year by coal accidents, gas accidents and even wind farm accidents - and then look at nuclear power, which doesn't injure anybody. The actual risk is purely imagined.

Nuclear energy is inefficient? Care to elaborate on what that means?

Nuclear energy is expensive? Can we really, honestly generate energy cheaper using solar thermal, or geothermal, or wind or something?

Recently, as you'll no doubt be aware, construction of solar thermal power plants in Australia has just been proposed by one group - where the plants will cost one billion dollars, to generate only 250 MW, with a capacity factor of about 30%.

That's an absurdly high construction cost - it's the equivalent of 13-14 billion dollars for the construction cost of a single nuclear power reactor, in terms of the equivalent amount of energy output, and it's about four times what modern LWR nuclear power plant costs to construct.

A typical one gigawatt, base-load, coal fired power station emits nine million tonnes of carbon dioxide, every year, and that's just the carbon dioxide alone, not to mention the sulfur dioxide, nitrogen oxides, mercury, arsenic, cadmium, beryllium, the dreaded radioactive thorium and uranium, polycyclic aromatic hydrocarbons, fine particulates and everything else, all of which constitutes millions and millions of tonnes of dangerous, deadly even, fossil fuel waste.

And this waste is just spewed straight out into the atmosphere - there is never any mention, at all, of how it is handled, or isolated from the environment.

And we know for a fact that this deadly fossil fuel waste kills tens of thousands of people every year. Yet, the handling of nuclear fuels, the storage and transport of used nuclear fuel, etc, has never harmed anyone!

A fairly conventional light water reactor, generating 1100 MW with a 90% capacity factor, will generate about 700 kg of fission products in a year.

Seven hundred kilograms - which is really quite a small volume - of solid fission product mixture, versus nine million tonnes of carbon dioxide, and untold thousands of tonnes of other toxic crap in the fly ash - that's the choice we're making here. In practice, it's a choice between nuclear and coal - because wind or solar thermal or whatever you're considering just can't compete with these energy systems.

Quote:

Especially waste like:
Plutonium 239, one of the most dangerous elements known to humans, is so toxic that one-millionth of a gram is carcinogenic. More than 200kg is made annually in each 1000-megawatt nuclear power plant. Plutonium is handled like iron in the body, and is therefore stored in the liver, where it causes liver cancer, and in the bone, where it can induce bone cancer and blood malignancies. On inhalation it causes lung cancer. It also crosses the placenta, where, like the drug thalidomide, it can cause severe congenital deformities. Plutonium has a predisposition for the testicle, where it can cause testicular cancer and induce genetic diseases in future generations. Plutonium lasts for 500,000 years, living on to induce cancer and genetic diseases in future generations of plants, animals and humans.
http://www.commondreams.org/views05/0415-23.htm

Helen Caldicott's scientifically ignorant, dilettantish diatribe isn't scientific, it isn't sensible, and it does not for a compelling argument make. In fact, it's an embarrassment to anybody who thinks it does.

For example, let me consider one part of that piece in detail - the idea that plutonium-239 is "one of the most dangerous elements known to humans", and it "is so toxic that one-millionth of a gram is carcinogenic". Here, I'll demonstrate where and why this rubbish isn't consistent with real, quantitative understanding of the real world.

Although the popular myth that plutonium is the most hazardous substance known to man has been refuted many times, the misconception persists that even a small amount of plutonium taken into the body will be fatal. Plutonium is hazardous, but it is not as immediately hazardous to health as many more common chemicals. This is not to say that plutonium is not a dangerous, toxic material. Chronic exposure to even small amounts should indeed be a matter of concern.

The magnitude of the ionising radiation dose, and the organs that are irradiated, depend primarily on the quantity of plutonium taken into the body and on the route by which it enters the body. In general, plutonium that is inhaled is far more hazardous than plutonium that is ingested, because it is more readily absorbed into the blood stream via the lungs than via the gastrointestinal tract.

Inhaled plutonium will deliver a radiation dose to the lungs; ingested plutonium will deliver a radiation dose to the walls of the GI tract. From either of these entry points, plutonium may migrate via the bloodstream to the bones and liver.

People inhaling less than acutely lethal quantities of plutonium will still have an increased probability of getting cancer, if the linear non-threshold dose-response hypothesis is assumed to be true. The lungs are exposed to alpha-particle radiation, increasing the risk of lung cancer, until the plutonium is potentially eventually carried to other organs, primarily the bones and liver, where the radiation potentially causes cellular damage and increases the likelihood of cancer at those sites.

When plutonium(IV) oxide, the form in which plutonium-239 is encountered in the vast majority of nuclear fuels used in commercial nuclear energy applications, is inhaled as a fine dust, 25% of it deposits in the lung, 38% deposits in the upper respiratory tract, and the remainder is exhaled. Within a few hours, all of that deposited in the upper respiratory tract, but only 40% of that deposited in the lung, is cleared out. The other 60% of the latter - 15% of the total inhaled - remains in the lung for a rather long time, an average of 2 years.

Of course, it's completely nonsensical to discuss nuclear or radiological properties if we do not specifically delineate which of the nuclides of plutonium we're referring to - different nuclides of the same element have markedly different nuclear characteristics. We're considering plutonium-239 here since it's the most common plutonium nuclide, and also the main nuclide of interest as a fissile nuclide which is used to generate nuclear energy, and it's the nuclide specifically mentioned by Caldicott.

I'll wrap it up here for this post, because of the finite length limit, but I'll make another post.

Guy Fawkes · #56 (**permalink**) 08-21-2008, 07:14 PM

Quote:

Originally Posted by enochthered

Decommissioning a nuclear power reactor is not a big deal. OK, some people claim it's expensive - how expensive is it, really?

Let's suppose, for arguments sake, that it costs half a billion dollars - an enormously inflated figure - to decommission a nuclear power reactor, and completely restore to greenfield conditions, or whatever.

A typical modern nuclear power reactor generates, say, 1100 MW, with a 95% capacity factor, for a lifetime 50 years. 500 million dollars divided by (1100 MW * 90 percent * 50 years) is 0.12 cents per kWh. So, it's really not expensive at all - just add 0.12 cents to the cost of a kilowatt-hour - it's peanuts!

Radioactive waste, and used nuclear fuel, can be dealt with adequately and safely. What this entails is the efficient use of the nuclear fuel, including sensible, non-wasteful re-use of any uranium, plutonium and other actinides in the fuel, and then possibly separation of valuable radionuclide fission products, like the platinoid metals and other nuclides that have valuable technological, scientific or medical applications, followed by vitrification and packaging of any fission product waste that is left over, and disposal in a deep geological repository, via something like Sweden's KBS-3 process.

To demonstrate the safe and successful transport of radioactive waste, and its final disposal in a permanent geological repository, look at the Waste Isolation Pilot Plant (WIPP) in New Mexico.

Whilst the idea of a deep geological repository - like Yucca Mountain - is completely sound, I agree that the current idea in the US, of taking whole, unprocessed LWR fuel assemblies and sticking them in Yucca Mountain, is terribly inefficient and wasteful, and shouldn't be done.

Hazards of nuclear power? Except for the Soviet Union's folly, leading to the Chernobyl accident, nuclear power plants have never hurt anybody. Have a look at all the people killed every year by coal accidents, gas accidents and even wind farm accidents - and then look at nuclear power, which doesn't injure anybody. The actual risk is purely imagined.

Nuclear energy is inefficient? Care to elaborate on what that means?

Nuclear energy is expensive? Can we really, honestly generate energy cheaper using solar thermal, or geothermal, or wind or something?

Recently, as you'll no doubt be aware, construction of solar thermal power plants in Australia has just been proposed by one group - where the plants will cost one billion dollars, to generate only 250 MW, with a capacity factor of about 30%.

That's an absurdly high construction cost - it's the equivalent of 13-14 billion dollars for the construction cost of a single nuclear power reactor, in terms of the equivalent amount of energy output, and it's about four times what modern LWR nuclear power plant costs to construct.

A typical one gigawatt, base-load, coal fired power station emits nine million tonnes of carbon dioxide, every year, and that's just the carbon dioxide alone, not to mention the sulfur dioxide, nitrogen oxides, mercury, arsenic, cadmium, beryllium, the dreaded radioactive thorium and uranium, polycyclic aromatic hydrocarbons, fine particulates and everything else, all of which constitutes millions and millions of tonnes of dangerous, deadly even, fossil fuel waste.

And this waste is just spewed straight out into the atmosphere - there is never any mention, at all, of how it is handled, or isolated from the environment.

And we know for a fact that this deadly fossil fuel waste kills tens of thousands of people every year. Yet, the handling of nuclear fuels, the storage and transport of used nuclear fuel, etc, has never harmed anyone!

A fairly conventional light water reactor, generating 1100 MW with a 90% capacity factor, will generate about 700 kg of fission products in a year.

Seven hundred kilograms - which is really quite a small volume - of solid fission product mixture, versus nine million tonnes of carbon dioxide, and untold thousands of tonnes of other toxic crap in the fly ash - that's the choice we're making here. In practice, it's a choice between nuclear and coal - because wind or solar thermal or whatever you're considering just can't compete with these energy systems.

Helen Caldicott's scientifically ignorant, dilettantish diatribe isn't scientific, it isn't sensible, and it does not for a compelling argument make. In fact, it's an embarrassment to anybody who thinks it does.

For example, let me consider one part of that piece in detail - the idea that plutonium-239 is "one of the most dangerous elements known to humans", and it "is so toxic that one-millionth of a gram is carcinogenic". Here, I'll demonstrate where and why this rubbish isn't consistent with real, quantitative understanding of the real world.

Although the popular myth that plutonium is the most hazardous substance known to man has been refuted many times, the misconception persists that even a small amount of plutonium taken into the body will be fatal. Plutonium is hazardous, but it is not as immediately hazardous to health as many more common chemicals. This is not to say that plutonium is not a dangerous, toxic material. Chronic exposure to even small amounts should indeed be a matter of concern.

The magnitude of the ionising radiation dose, and the organs that are irradiated, depend primarily on the quantity of plutonium taken into the body and on the route by which it enters the body. In general, plutonium that is inhaled is far more hazardous than plutonium that is ingested, because it is more readily absorbed into the blood stream via the lungs than via the gastrointestinal tract.

Inhaled plutonium will deliver a radiation dose to the lungs; ingested plutonium will deliver a radiation dose to the walls of the GI tract. From either of these entry points, plutonium may migrate via the bloodstream to the bones and liver.

People inhaling less than acutely lethal quantities of plutonium will still have an increased probability of getting cancer, if the linear non-threshold dose-response hypothesis is assumed to be true. The lungs are exposed to alpha-particle radiation, increasing the risk of lung cancer, until the plutonium is potentially eventually carried to other organs, primarily the bones and liver, where the radiation potentially causes cellular damage and increases the likelihood of cancer at those sites.

When plutonium(IV) oxide, the form in which plutonium-239 is encountered in the vast majority of nuclear fuels used in commercial nuclear energy applications, is inhaled as a fine dust, 25% of it deposits in the lung, 38% deposits in the upper respiratory tract, and the remainder is exhaled. Within a few hours, all of that deposited in the upper respiratory tract, but only 40% of that deposited in the lung, is cleared out. The other 60% of the latter - 15% of the total inhaled - remains in the lung for a rather long time, an average of 2 years.

Of course, it's completely nonsensical to discuss nuclear or radiological properties if we do not specifically delineate which of the nuclides of plutonium we're referring to - different nuclides of the same element have markedly different nuclear characteristics. We're considering plutonium-239 here since it's the most common plutonium nuclide, and also the main nuclide of interest as a fissile nuclide which is used to generate nuclear energy, and it's the nuclide specifically mentioned by Caldicott.

I'll wrap it up here for this post, because of the finite length limit, but I'll make another post.

This is worth posting again. I've grown tired of repeating myself on this subject with people other than yourself that nuclear energy is the way to go. I agree with your post and welcome to the forum.

You'll be under attack again and again so save this post as you can always repost it for the ignorant masses.

Guy Fawkes · #57 (**permalink**) 08-21-2008, 07:16 PM

So I'm not taken the wrong way, I'm for wind, solar, geothermal and other forms of CLEAN energy, I just understand the level of energy demand that none of these can deliver like nuclear can.

enochthered · #58 (**permalink**) 08-21-2008, 07:46 PM

Now, more on the plutonium. I'll put this next bit in quote - so if it doesn't look appealing to you, you can skip over it, to the conclusion - but I won't make you take my word for it, so here's the proof of the forthcoming conclusion. Nullius addictus judicare in verba magestri.

Quote:

We can straightforwardly estimate the dose equivalent to the lung tissue from one microgram of plutonium-239 oxide residing there for 2 years. With Pu-239 having a specific activity of 0.063 Ci/g, the specific activity of Plutonium-239 (IV) oxide - which I will herein denote as 239PuO2, since I don't have access to superscript or proper typesetting just for a forum post - is hence 55.6 mCi/g. Therefore, 1 microgram of 239PuO2 corresponds to an activity of 2057 Bq.

One microgram of 239PuO2 contains 3.69 nanomoles of plutonium - hence, over two years, 3.69 * 10^-9 mol * (1 - (2^(2/24110)) = 2.12 * 10^-13 mol has decayed, or 1.28 * 10^11 nuclei.

The decay energy of Pu-239 (that is, the energy of the alpha particle) is 5.245 MeV, and hence the total radiation energy deposited over two years is 5.245 MeV * 1.28 * 10^11 = 0.107 J.

The mass of the average person's lung is about 0.57 kg, and the inhaled plutonium oxide has an equal chance of being deposited into either of the two lungs. Hence, the absorbed dose is 0.107 J / (0.57 kg * 2) = 0.094 Gy.

Since only 15% of what is inhaled spends this 2 years in the lung, the absorbed dose per microgram inhaled is about 0.014 Gy. For internal alpha-particle irradiation from a nuclide such as Pu-239, the "Q" factor, or relative biological "effectivness", is 20; that is, one gray corresponds to 20 Sv, so the dose to the lung tissue is about 0.28 Sv per microgram of 239PuO2 inhaled, or 5.06 Sieverts per microcurie.

The committed effective dose equivalents from ingested or inhaled plutonium and the associated increased probabilities of cancer death have been studied extensively. A more detailed calculation than the simple calculation above gives a committed effective dose equivalent (CEDE) for inhaled PuO2 of 3.1 Sv/microcurie.

Hence, using the specific activity as above, we find that the CEDE for one microgram of inhaled 239PuO2 is: 3.1 Sv/microcurie * 1.0 * 10^-6 g * 55.6 mCi/g = 0.173 Sv.

Assuming the Linear-no-threshold hypothesis to be a workable, conservative estimate of the dangers of ionising radiation exposure, we can consider the figure, taken from ICRP 60, of 5 * 10^-2 excess fatal cancers per sievert of ionising radiation dose due to internal alpha-particle irradiation in the lungs.

Thusly, the inhalation of one microgram of Pu-239 oxide is determined to be associated with 0.0086 excess fatal cancers per person. Whilst it certainly could induce a cancer, the notion that it will is entirely false.

The actual additional risk of cancer death resulting from the inhalation of one microgram of Plutonium-239 (IV) oxide is 0.0086, or 0.86% additional risk.

For comparison, the botulinum toxin is usually regarded as truly being the most acutely lethal substance known, with a lethal dose of about 300 picograms/kg, meaning that something around one hundred grams could kill every human on the earth.

Abrin, a protein biotoxin found naturally in certain plant species, similar to the more familar phytotoxin ricin, can kill with a circulating amount of less than 3 micrograms, and the lethal dose of batrachotoxin, another naturally occuring toxin, for a 70 kilogram person, is approximately 100 micrograms. Other chemical substances including natural biotoxins such as ricin, tetrodotoxin and tetanus toxin are fatal in doses of (sometimes far) under one milligram, and others, such as the organophosphate nerve agents, or are in the range of a few milligrams.

As such, plutonium is not especially notable in terms of toxicity, even by inhalation. In addition, such chemical toxins are fatal in hours to days, whereas plutonium (and other potentially cancer-causing radionuclides) give an increased chance of illness decades in the future.

Plutonium-239 is not even an especially radioactive nuclide, at all - it's quite low in radioactivity. Radon-222, that natural stuff that percolates up from the earth into our basements, is 242 times as radioactive, gram for gram, than is plutonium. Any such radionuclide - radon, radium, polonium for example, with a shorter half-life and higher activity than plutonium-239 - is considerably more radioactive and more dangerous than plutonium, and yet these are natural nuclides that are not too uncommon in nature.

That, I think, gives you a taste for how I view these sorts of exaggerated claims from people like Helen Caldicott.

Of course, there is absolutely no way that plutonium-239 is "waste" - it's extremely useful, valuable, potent fuel.

Quote:

Could you please provide a reference to support your claim that "we could re-use 95% of that waste and put it back into the reactor" - with all due respect - I believe you are talking absolute crap.

That wasn't my claim, personally, but I'll answer you all the same.

Of these fuel assemblies, about 30% of their mass is the Zircalloy cladding and the metal hardware that actually makes up the structure of the fuel assembly, and 70% is the actual fuel itself. Of the uranium dioxide fuel, 96% of the uranium content remains as uranium - essentially all the uranium that went into the reactor is completely unchanged!

The used nuclear fuel that is pulled out of a conventional light water reactor, like the ones used for the vast majority of nuclear energy in the U.S., is 96% uranium. Yes - 96% of the content of that nuclear fuel is uranium that hasn't even reacted at all! You can see immediately why we are extremely skeptical of calling this fuel nuclear waste. 3% of that material is made up of the fission products, and a further 1% is made up of other actinide nuclides - about half of that 1% is plutonium-239.

If "nuclear waste" is such a big deal - then don't waste it!

Quote:

If you are talking about uranium based nuclear energy - there is high level nuclear waste that must be dealt with. So far - no one has developed any satisfactory management option for that.

And of course it is the high-level waste that gets the most attention. The low and intermediate level waste rarely is addressed. All of the materials used in nuclear power generation, especially when decomissioning plants all require special treatment. It is manageable - but very expensive. Something the pro-nuke morons rarely bother addressing. Contaminated slag heaps and tailings dams at uranium mines? Likewise always ignored.

Refer to my above paragraphs about deep geological disposal, SKB in Sweden, Yucca Mountain, and WIPP re. disposal of radioactive waste.

Similarly, I've mentioned above about "expensive" decommissioning.

As for "tailings" at uranium mines - it's a bunch of crushed rock, natural rock that comes out of the ground. This rock has got a bit of uranium and radium in it, and other natural radionuclides in the uranium-238 decay chain. All these radionuclides are completely naturally occurring in the rock as it naturally occurs in the ground - so, just put it back in the hole in the ground.

Quote:

Yes. This is very true.

And this is the very reason that uranium based nuclear power is a poor option for the future.

Nuclear power is not prohibitively expensive, it is in fact very economically competitive, when fairly compared to the other pollution free, carbon dioxide free energy generation options in a quantitative, meaningful way, kilowatt-hour for kilowatt-hour.

Quote:

"On average, supplies of high-quality uranium ore have been steadily declining worldwide for the past 50 years, and will likely to continue to wane in the mid- to long-term...Any new uranium deposit is likely to be deeper and harder to extract, and getting uranium from lower-quality deposits involves digging up and refining more ore, according to their analysis of government and industry reports."

Don't bother invoking the Storm van Leeuwen and Smith rubbish... which anybody with absolutely any credible knowledge of nuclear energy knows is absolutely false, discredited nonsense.

Known uranium resources have increased by 17% over the last couple of years, and there is already plenty to meet future demand. Of course, the efficient use of nuclear fuel, and not taking used fuel which is 97% good uranium and plutonium and calling it "waste" helps a great deal too, as does things like doing away with the three mines policy, not to mention thorium, which is three times as abundant as uranium.

It gets "harder to extract"? So what? You still get an enormous "energy gain" or EROEI, on mined uranium, even with lower concentration ores.

Quote:

It takes a lot of energy to mine uranium ore. It takes a lot of energy to process uranium ore. It takes a lot of energy to concentrate uranium into a useable fuel.

This is all kind of true - it also takes an enormous amount of energy to manufacture highly refined silicon, and dope it, and fabricate silicon photovoltaic devices, to give you one example. It takes energy to mine coal, or to build wind turbines.

The EROEI, or the "energy gain" that you get from nuclear fuel, relative to the energy inputs to mine and mill the uranium, is enormous. The Rossing Mine in Namibia has a uranium concentration in the ore of about 350 ppm, and produced 3037 tonnes of uranium in 2004, which is sufficient for about 15 gigawatt-years of electricity with current fuel cycles and power reactor technology. The energy used to mine and mill this uranium is about 30 megawatt-years, thus corresponding to an energy gain of about 500.

justabubba · #59 (**permalink**) 08-21-2008, 08:07 PM

Quote:

Originally Posted by Guy Fawkes

This is worth posting again. I've grown tired of repeating myself on this subject with people other than yourself that nuclear energy is the way to go. I agree with your post and welcome to the forum.

You'll be under attack again and again so save this post as you can always repost it for the ignorant masses.

then post something material that supports your position. so far you have not

bugalugs · #60 (**permalink**) 08-21-2008, 08:44 PM

Welcome enochthered! Nice to see the level of debate has been raised here.

Now, let's go:

Quote:

Originally Posted by enochthered

Decommissioning a nuclear power reactor is not a big deal. OK, some people claim it's expensive - how expensive is it, really?

Let's suppose, for arguments sake, that it costs half a billion dollars - an enormously inflated figure - to decommission a nuclear power reactor, and completely restore to greenfield conditions, or whatever.

A typical modern nuclear power reactor generates, say, 1100 MW, with a 95% capacity factor, for a lifetime 50 years. 500 million dollars divided by (1100 MW * 90 percent * 50 years) is 0.12 cents per kWh. So, it's really not expensive at all - just add 0.12 cents to the cost of a kilowatt-hour - it's peanuts!

And your 500 million quote. Does that include all ongoing costs of the decommissioning? For how long will you be monitoring this site?

From wiki:
In France, decommissioning of Brennilis Nuclear Power Plant, a fairly small 70 MW power plant, already cost 480 millions euros (20x the estimate costs) and is still pending after 20 years. Despite the huge investments in securing the dismantlement, radioactive elements such as Plutonium, Cesium-137 and Cobalt-60 leaked out into the surrounding lake
http://en.wikipedia.org/wiki/Nuclear_decommissioning

Even if your number is sound and the decommissioning is successfully achieved (nb. I have spent a lot of time travelling outback Australia inspecting mines that were supposedly "rehabilitated" - the costs go on and on and on...) - we are still talking about an excess cost that does not apply to other energy sources.

Why use a source that requires expensive decommissioning when other sources which don't require it are available?

Quote:

Originally Posted by enochthered

Radioactive waste, and used nuclear fuel, can be dealt with adequately and safely. What this entails is the efficient use of the nuclear fuel, including sensible, non-wasteful re-use of any uranium, plutonium and other actinides in the fuel, and then possibly separation of valuable radionuclide fission products, like the platinoid metals and other nuclides that have valuable technological, scientific or medical applications, followed by vitrification and packaging of any fission product waste that is left over, and disposal in a deep geological repository, via something like Sweden's KBS-3 process.

To demonstrate the safe and successful transport of radioactive waste, and its final disposal in a permanent geological repository, look at the Waste Isolation Pilot Plant (WIPP) in New Mexico.

Whilst the idea of a deep geological repository - like Yucca Mountain - is completely sound, I agree that the current idea in the US, of taking whole, unprocessed LWR fuel assemblies and sticking them in Yucca Mountain, is terribly inefficient and wasteful, and shouldn't be done.

Yes, I'm sure that radioactive waste, and used nuclear fuel, can be dealt with adequately and safely to a point. Of course, the idea that a disposal site could be engineered with a design life of thousands of years is a bit ambitious - but if we accept that there is no safety issue with the disposal of wastes, there is still the question of why bother using an energy source that requires the expensive long-term management of dangerous waste when others that don't require the expensive long-term management of dangerous waste are available.

Also, the fact that you are still describing the permanent disposal of waste shows that you are not considering this to be a sustainable technology. You are using finite resources as fuel and then having to find a disposal solution for the waste products of that fuel. It is that exact practice that got us in this mess in the first place.

Quote:

Originally Posted by enochthered

Hazards of nuclear power? Except for the Soviet Union's folly, leading to the Chernobyl accident, nuclear power plants have never hurt anybody. Have a look at all the people killed every year by coal accidents, gas accidents and even wind farm accidents - and then look at nuclear power, which doesn't injure anybody. The actual risk is purely imagined.

Yes - the risk is very small, I have no arguement - but it is not imagined. The risk cannot be engineered out completely, and though the risk is small - the potential hazard is quite significant. Again - just make a comparison to solar thermal or geothermal. The potential hazards posed by these technologies are insignificant compared to those posed by nuclear power.

So again - why bother using an energy source that poses a low risk threat of a significant hazard when others that pose a low risk threat of relatively insignificant hazards are available. And of course - the only way to keep that risk low is by spending lots of $$$$. The USA might do it. Will China? India? Indonesia?

Quote:

Originally Posted by enochthered

Nuclear energy is inefficient? Care to elaborate on what that means?

Expending a significant amount of energy to:
Excavate ore, crush ore, extract yellowcake, transport yellowcake, enrich into fuel, dispose of waste securely for long time and eventually decommission plant and dispose of waste for a long time when there are technologies available which do not require that type of energy to be expended is inefficient

Quote:

Originally Posted by enochthered

Nuclear energy is expensive? Can we really, honestly generate energy cheaper using solar thermal, or geothermal, or wind or something?

Recently, as you'll no doubt be aware, construction of solar thermal power plants in Australia has just been proposed by one group - where the plants will cost one billion dollars, to generate only 250 MW, with a capacity factor of about 30%.

That's an absurdly high construction cost - it's the equivalent of 13-14 billion dollars for the construction cost of a single nuclear power reactor, in terms of the equivalent amount of energy output, and it's about four times what modern LWR nuclear power plant costs to construct.

OK - your saying the ST plant will cost 4 times the LWR plant for the same output?

You are comparing construction cost to construction cost, yes? What happens when you add in the onging costs? The maintenence costs to maintain the high level of safety. The fuel costs (and include all fuel costs, the mining, the processing, and the eventual rehabillitation of the mine site), the security costs, the eventual decommissoining costs (half a billion was it? Peanuts? Is that todays peanuts or peanuts in 50 years time?) and the costs of removal of and storage of waste for several thousand years.

How do the costs add up now?