Is Rocketing Nuclear Waste into the Sun a Viable Solution?

[Azael]

Hence the motivation for my arguments above. Take away the intimate access of Khan or those like him to advanced Western enrichment technology and you have a strong argument that today there would still be no Pakistani bomb, similarly no N. Korean bomb, similarly the Iranian program would be set back or non existent.

Do you have any reason to assume they would not take the plutonium route to bombs instead if Khan hadnt spread enrichment technology? North koreas bomb was suposedly a plutonium bomb(hence why it fizzled). North koreas magnox reactors are fueled by natural uranium, they did pursue enrichment technology but it doesn't seem like it has played any major part in the weapons program.

Assuming that getting rid of enrichment technology would stop proliferation seems a bit naive and like vanesch pointed out, gas centrifuges and gas diffusion isn't the only ways to enrichment. Some of the uranium for the little boy was produced in caultrons and Iraq was planning on erichening uranium with caultrons.

Considering how accelerator technology is advancing its not entirely unrealistic that spallation sources can in the future be used to produce extremely pure Pu-239 or u-233 for that matter, yet another way to get ahold of weapons grade material that is totaly disconnected from civilian nuclear power.

It all comes down to one thing, a sufficiently determined nation can always find some way to produce weapons grade material. Looks like every nation so far that has tried to get nuclear weapons has succeded.

I also believe the concern is more along the lines of a slow leak that simply allows the CO2 to re-agitate the AGW problem sequestration was supposed to prevent. The other issue is cost. So those are the three cons of sequestration: small explosive leak dangers, slow leaks, and cost. Its not comparable in any way to nuclear catastrophes.

Not even the worst case scenario for a nuclear waste repository failure is much to worry about considering the chemical properties of the actinides. Not much if any will move from the repository even if the canisters fail and leak.

 

[engineroom]

One thing with N proliferation (power or weapons) is that country A might have a nice (read western friendly) stable government today so they are "permitted" to build these facilities however what happens in the future if there was a coup?

I'm not as worried about Iran having N power or even N weapons as I am with the fact that Israel does. I think a small mircle that during the first gulf war when Saddam was launching Skuds at Israel that Israel didn't launch a Nuke back.

Any way back to the original post; The only way to have safe storage of N waste is not bury and forget. Ongoing monitoring of the containment is required. When necessary the containment will need replaced and the N waste repacked. However as the N waste gets older the containment does not need to be as severe but you are talking centries rather than decades I beleive. This is a very long time scale problem. The long term hope is that an affordable technology will be devolped for the safe distruction of the N waste

 

[vanesch]

So ship all the lasers you want, no one in Iran is going to start separating enough isotopes to make weapons with the current state of the art.

That's not what this report says:
http://www.iranwatch.org/privateviews/First Watch/perspex-fwi-Laser.pdf

Visibly shipping powerful copper vapor lasers or NdYag lasers is all they need...

EDIT: also, remember that one single centrifuge or diffusion unit can also only produce "milligrams" of highly enriched material. The point is: once you know how to produce "milligrams" with a bit more than a table top setup, it is no difficulty to produce kilograms when money and ressources are affected. Iran *already* obtained milligrams of enriched uranium with LIS.

The reasons why the AVLIS program was canceled after billions of $ of investment, and at a few hundred million $ of commercial realisation, remain a mystery - I even wonder if they weren't motivated to drop it, exactly because of proliferation issues. But the planned AVLIS plant needed to separate hundreds of tons of uranium at commercially competitive rates. This is a different requirement than to make a few kilogram of material with "unlimited" ressources and no commercial pressure for a weapons program.

 

[vanesch]

No plans I know of propose placing all of world wide sequestered CO2 in one hole.

Nor is one going to put all of the worlds nuclear waste in one hole... But that doesn't increase safety. Instead of having probability p of having a catastrophe with N victims, you now have probability m x p of having a catastrophe of N/ m victims, although that last N/m is not even sure. The average number of victims over long times remains the same, so the associated risk is the same, whether you put everything in one place, or distributed over different places, as long as the number of victims is proportional with the quantity stored. But this last thing is mostly not the case. Usually, the number of victims doesn't rise linearly with the quantity stored. In that case, spreading the waste over different repositories (be it CO2 or nuclear waste) will actually increase the risk.

As I said above, the idea is to reinsert at the well head, so chemically you simply put back in one mole of CO2 for every mole of CH4 taken out, so 10^4 - 10^5(?) kg per well per year.

So this is distributed then over 10^7-10^8 wellheads ? (in order to put away the few billion ton CO2 we have to put away a year globally)

There's a some danger there but I believe you are way off on the scale. I also believe the concern is more along the lines of a slow leak that simply allows the CO2 to re-agitate the AGW problem sequestration was supposed to prevent.

Sure, that's one thing. But concerning nuclear waste, would you be satisfied with the phrase "there is some danger there but I believe you are way off on the scale" ?

What tells you that you can be absolutely sure that 1 million years from now, the stored gas is not going to be released suddenly, when a future civilisation will drill large holes into it ?
(this is the kind of questions that one asks for nuclear waste repositories).

The other issue is cost. So those are the three cons of sequestration: small explosive leak dangers, slow leaks, and cost. Its not comparable in any way to nuclear catastrophes. And I would have to check my geochemistry, but I'm guessing CO2 left underground for 10ky is very much not going to be in the same form as when originally placed there, waiting for a bone head on a back hoe (BHOBH) to blow the cap.

10000 years from now, the nuclear waste is essentially gone - at least its radio-toxicity. The CO2 will still be there, although a part of it might be absorbed by ground water, in which case it becomes carbonic acid, which can dissolve some rock formations (and hence "blow the cap"). After all, that was the idea! If it wouldn't be there anymore, where would it be ? The methane that was there, remained there for millions of years. If the CO2 interacts with the rocky material, that means that it transforms it chemically, and that would mean that it changes the repository. The other thing it can do, is dissolve in ground water, which is not immediately an advantage, because that means it can migrate, accumulate somewhere else, get released...

I only wanted to point out that one holds nuclear stuff, for an irrational reason, to totally different standards as other kinds of materials. One requires a much higher safety proposal (in projected number of victims) than one requires for other technologies, and one uses worst-case scenarios as "proof" against nuclear activities, while one uses "common knowledge" for other activities.

The probability for massive CO2 release by a repository is probably very low. But so is the probability for a massive release by a nuclear reactor or for a waste repository (even much more so, given its finite lifetime). The number of victims in both cases is comparable (so it is not true that the "nuclear catastrophe" would be worse than the CO2 catastrophe - we've been over this already several times, but even a terrible accident like Chernobyl is not any worse than any average industrial catastrophe or even routine activity: 60 direct dead, probably some 10000 victims of polution over the 50 years after it - compare that to the YEARLY 24000 victims in the US alone by coal fired plants).

The kind of risk assessment for nuclear somehow must have a thousand to a million fold higher quality than for other activities, at equal danger (number of victims). Why is this ?

 

[vanesch]

I'm not as worried about Iran having N power or even N weapons as I am with the fact that Israel does. I think a small mircle that during the first gulf war when Saddam was launching Skuds at Israel that Israel didn't launch a Nuke back.

A country having nukes will, IMO, never use them, because of fear of retaliation. The "need for a nuke" is based upon 2 other reasons: self-protection (especially from an enemy having nukes), and "international weight".

The danger of a country giving nukes to a terrorist group is also not to be over-estimated: they will still be responsible for it. So I think the real danger of someone using nukes is pretty small, and will yield in expected yearly number of victims over a century, probably much less than the number of victims we already have from cars and coal-fired powerplants (1.2 million and 500 000 per year, which means about 170 million over a century).

EDIT: that doesn't mean that one shouldn't fight proliferation by all means. But the main way of avoiding proliferation is by international and political pressure: to make the balance of a country flip over to the side where NOT making a nuke is more interesting than making a nuke.

This deviates from nuclear engineering, and goes into political science, but why does Iran want a nuke ? Why did Pakistan want a nuke ? Why does N. Korea want a nuke ? Why did Israel build a nuke ? Mainly for self-protection - and also for regional domination.
Pakistan needed a nuke because its ennemi, India, had made some. Iran needed a nuke to protect itself first from Iraq, and later from a similar invasion as Iraq suffered. It would also help Iran to become a major regional power. N. Korea's dictator needs a nuke to stabilise itself, to get rid from Chinese influence. Israel needed nukes because it is bathing in a region of hostility. In all these cases, nukes are nothing else but some ultimate "nation guarantee". If Iraq would have had nukes, I think the US wouldn't have invaded it.
As to "rogue states", I have a hard time imagining roguer states than the USSR under Stalin, or China under Mao. They had tons of very heavy nukes. Nothing happened.

So in as much as it is a good thing to try to convince nations not to build nukes, one mustn't over-dramatize it either.

I remain convinced that any reasonably develloped country with enough financial means can, if it wants to, build a nuke in the coming decades. Maybe it won't be able to hide its intentions.

Any way back to the original post; The only way to have safe storage of N waste is not bury and forget. Ongoing monitoring of the containment is required.

I don't know where you get that claim from. It would actually be riskier to leave access to the canisters, than to close the access geologically. It will take more than a thousand years (and probably much more so) for the canisters to leak. With reprocessed and vitrified waste, moreover the glass has to dissolve. Really, what can physically be released from a repository is a very very small pollution, mostly hundreds of times below the background radiation. The ultimate containment are not the canisters, but rather the geology. That's a "very big canister".

 

[russ_watters]

You're doing a great job, vanesch, but to amplify one thing:

I only wanted to point out that one holds nuclear stuff, for an irrational reason, to totally different standards as other kinds of materials. One requires a much higher safety proposal (in projected number of victims) than one requires for other technologies, and one uses worst-case scenarios as "proof" against nuclear activities, while one uses "common knowledge" for other activities.

You say "worst-case" for nuclear activities only because there is no stronger word to describe the scenarios posed by "environmentalists". In reality, they are far beyond "worst-case", crossing over into science fiction/fantasy. People believe a China Syndrome or even a Chernobyl represents a "worst-case" scenario for an American reactor, but they don't. Those scenarios are simply not possible. The closest we get to reality for a really bad accident requires something like a meteorite vaporizing a plant (nevermind that an meteorite is just as likely to kill 10,000 people directly by vaporizing a city skyscraper as it is to kill 10,000 people from cancer by vaporizing a nuclear plant).

So while people use a relatively reasonable risk/reward assessment for other activities (coal power kills 20,000 Americans a year, but on the plus side, it enriches the lives of everyone else), they use utterly ficticious scenarios as the standards for nuclear power (such as the Yucca mountains' rediculous 1,000,000 year standard).

 

[mheslep]

...Not even the worst case scenario for a nuclear waste repository failure is much to worry about considering the chemical properties of the actinides. Not much if any will move from the repository even if the canisters fail and leak.

Yes waste is another topic and at least once it gets inside Yucca Id not be that concerned about it.

 

[mheslep]

A country having nukes will, IMO, never use them, because of fear of retaliation. The "need for a nuke" is based upon 2 other reasons: self-protection (especially from an enemy having nukes), and "international weight".

The danger of a country giving nukes to a terrorist group is also not to be over-estimated: they will still be responsible for it. So I think the real danger of someone using nukes is pretty small,

I don't know that and think neither do you. These are handwaving arguments; let's get back to some sources.

Islamic calculus on retaliation:

"Ruling Iranian cleric Ayatollah Ali Akbar Hashemi-Rafsanjani declared Friday that the Muslim world could survive a nuclear exchange with Israel - while accomplishing the goal of obliterating the Jewish state.

[The] application of an atomic bomb would not leave anything in Israel - but the same thing would just produce damages in the Muslim world," Hashemi-Rafsanjani said, in quotes picked up by the Iran Press Service.

BTW the Israelis know he's right about the damage to Israel. Israel is only 10mi wide at one point.

and will yield in expected yearly number of victims over a century, probably much less than the number of victims we already have from cars and coal-fired powerplants (1.2 million and 500 000 per year, which means about 170 million over a century).

A bit a of strawman. I don't say that nuclear power is not important, cars aren't helped by nuclear, and I don't say that coal as used is without harm. I'm saying that the dangers from proliferation are being underplayed, not over dramatized, and that therefore renewables and cleaner fossile (gasification/sequestration) is to be preferred over nuclear if / when it is technically possible, even at some finite cost premium.

As for the scope of the threat: I don't believe a nuclear detonation in a developed country otherwise at peace will be limited to blast and fallout victims. Here's some better hand waving: the world as we know it today will stop. People are concerned today about starvation in the thousands caused by elevated corn prices due to economic shifts, and about maybe 3 ft of sea level rise in the next century. Try a nuclear attack. In today's environmental context the attacked city is abandoned and not rebuilt like Hiro/Nagi for 50-100 years if ever. Intl. trade will halt while awaiting retaliation. If it is the US that's hit, US foreign food aid stops. If Three Mi. Island and Chernobyl stopped new plants, imagine what a hostile detonation will do to the industry.

Why does N. Korea want a nuke ? ... Mainly for self-protection - and also for regional domination.

It is because Kim Ill-Song is an unstable megalomaniac and building himself a weapon gets worldwide attention, esp. that of the US.

As to "rogue states", I have a hard time imagining roguer states than the USSR under Stalin, or China under Mao. They had tons of very heavy nukes. Nothing happened.

It is fair to say that fear of retaliation could be partially credited for preventing nuclear war in the 20th century, and perhaps the prevention of another world war. Its not fair to say that this was anything else other than an extremely risky, even a 'MAD' game to play. The US and USSR came very, very close to blowing themselves up in the Cuban Missile crisis. Observing this history and concluding simply the risk is small because 'nothing happened' is dangerous, but unfortunately seems to be part of human nature. See for example RP Feynman on NASA management leading to the Challenger disaster: "http://history.nasa.gov/rogersrep/v2appf.htm" ."

I remain convinced that any reasonably developed country with enough financial means can, if it wants to, build a nuke in the coming decades. Maybe it won't be able to hide its intentions.

The major points of my argument:
- the multidisciplinary and systems engineering required for weapons size enrichment is extremely difficult and expensive. The knowledge required is likewise not simple, it is vast and complex and thus be can restricted with effort.
- it is therefore within the power of developed democratic nations to make the weapons acquisition by rogues 10x, 100x, maybe 1000x harder by a) yes, the use of the NPT and export restrictions, and also by b) phasing out nuclear if and when renewables and clean fossil make it possible.

EDIT: that doesn't mean that one shouldn't fight proliferation by all means. But the main way of avoiding proliferation is by international and political pressure: to make the balance of a country flip over to the side where NOT making a nuke is more interesting than making a nuke

I moved this comment to the bottom so we end in some agreement. Nuclear power is important, it has more than one advantage over fossil fuels. It also brings with it several dangers. IMO, via proliferation, N. power is linked unfortunately to N. weapons.

 

[Azael]

The major points of my argument:
- the multidisciplinary and systems engineering required for weapons size enrichment is extremely difficult and expensive. The knowledge required is likewise not simple, it is vast and complex and thus be can restricted with effort.
- it is therefore within the power of developed democratic nations to make the weapons acquisition by rogues 10x, 100x, maybe 1000x harder by a) yes, the use of the NPT and export restrictions, and also by b) phasing out nuclear if and when renewables and clean fossil make it possible.

Im beginning to feel horribly repetitive. But let's sum up what I have been saying.

There are two paths to nuclear weapons.

1. Very difficult uranium enrichment resulting in material that is easy to make weapons off.

2. Very easy plutonium production resulting in material that is hard to make into a working weapon.

You are focusing completely on 1 and totally ignoring 2 even though India took this path, North Korea tried and sweden was planning on it. If every nation on Earth stopped using light water reactors and erinchment plants path two would still be there wide open for anyone that wants a weapon without needing to smuggle any sensitive technology.

Now can you make a convincing argument that path 2 is inherently orders of magnitude more difficult than path 1? If not then putting a stop to comercial enrichment technology will have zero or extremely small effect on proliferation, it will only change the path taken or encourage countries to find other ways to enrichen uranium. Like iraq and the caultrons.

Also keep in mind that there are plenty of ways to have nuclear power without any need for uranium enrichment(CANDU, fast breeders, thermal thorium breeders), your argument is really against LWR and enrichment, not against nuclear power.

 

[baywax]

Im beginning to feel horribly repetitive. But let's sum up what I have been saying.

There are two paths to nuclear weapons.

1. Very difficult uranium enrichment resulting in material that is easy to make weapons off.

2. Very easy plutonium production resulting in material that is hard to make into a working weapon.

You are focusing completely on 1 and totally ignoring 2 even though India took this path, North Korea tried and sweden was planning on it. If every nation on Earth stopped using light water reactors and erinchment plants path two would still be there wide open for anyone that wants a weapon without needing to smuggle any sensitive technology.

Now can you make a convincing argument that path 2 is inherently orders of magnitude more difficult than path 1? If not then putting a stop to comercial enrichment technology will have zero or extremely small effect on proliferation, it will only change the path taken or encourage countries to find other ways to enrichen uranium. Like iraq and the caultrons.

Also keep in mind that there are plenty of ways to have nuclear power without any need for uranium enrichment(CANDU, fast breeders, thermal thorium breeders), your argument is really against LWR and enrichment, not against nuclear power.

It got a little more difficult to build a nuke or power a nuclear plant today. The Government of British Columbia, friends with Arnold Terminator of California, placed an outright ban on Uranium exploration and extraction in the Canadian province.

http://www.reportonbusiness.com/servlet/story/RTGAM.20080501.wbrethour0502/BNStory/robColumnsBlogs/home

Edit: PS... I don't know if this is purely politically motivated or if there is sound science behind not wanting to stir up the abundant uranium deposits that are found in the province's agricultural and watershed regions.

 

[Andrew Mason]

However as the N waste gets older the containment does not need to be as severe but you are talking centries rather than decades I beleive. This is a very long time scale problem. The long term hope is that an affordable technology will be devolped for the safe distruction of the N waste

The only technology that could conceivably destroy radioactive waste would be a time machine.

AM

 

[mheslep]

Im beginning to feel horribly repetitive. But let's sum up what I have been saying.

There are two paths to nuclear weapons.

1. Very difficult uranium enrichment resulting in material that is easy to make weapons off.

2. Very easy plutonium production resulting in material that is hard to make into a working weapon.

You are focusing completely on 1 and totally ignoring 2

Thats correct for the moment, one conversation at a time. I know a lot less about Plutonium and about the only thing I know about Pu implosion is that I've read and scene lectures saying its very difficult to do. I am not able to gauge what difficult is. I know Pu can be made from Magnox reactors using natural Uranium, the designs for which were inexplicably unclassified by the UK and then reportedly used by N. Korea.

even though India took this path, North Korea tried and sweden was planning on it. If every nation on Earth stopped using light water reactors and erinchment plants path two would still be there wide open for anyone that wants a weapon without needing to smuggle any sensitive technology.

NK appears to be an example of how the PU path ~fails; Sweden is a responsible democracy that's going to abide by the NPT so I have no problem w/ them. I am not familiar w/ the history of India's Pu bomb. I'm curious how indigenous their bomb was or did they also have AQ Khan _like_ external help. India was also a fairly large and technically advanced country at the time which it comes by in part because its a stable democracy. My priority is to prevent smaller rogue states from getting access to the tech to build a bomb. That is, let's prevent the small groups of thugs who haven't bothered to build a country from going nuclear - like a Mugabe in Zimbawe in 20 yrs, Burma, Cuba, and N. Korea (from having an easier path).

Now can you make a convincing argument that path 2 is inherently orders of magnitude more difficult than path 1? If not then putting a stop to commercial enrichment technology will have zero or extremely small effect on proliferation, it will only change the path taken or encourage countries to find other ways to enrich uranium. Like iraq and the caultrons.

I've seen pictures of one of the Iraqi caultrons. If they're anywhere as incapable and problematic as the ones Berkely / Livermore intended to use during WWII then a caultron would be a great time waster for thugs w/ nuclear ambitions. They're horribly inefficient.

Also keep in mind that there are plenty of ways to have nuclear power without any need for uranium enrichment(CANDU, fast breeders, thermal thorium breeders), your argument is really against LWR and enrichment, not against nuclear power.

If there really is no weapons path from any those three technologies then yes I'm on board. Are they economically viable for power?

 

[mheslep]

That's not what this report says:
http://www.iranwatch.org/privateviews/First Watch/perspex-fwi-Laser.pdf

?? I believe it does. There's nothing in there that says the Iraqis ever generated anything other than milligrams, as I said, and its not clear they even did that.

Visibly shipping powerful copper vapor lasers or NdYag lasers is all they need...

No its not all they need. Many other disciplines are needed in cooperation; the Iran Watch piece mentions several - electron guns, vacuum chambers - and not just as piece parts they have to be integrated in with the system. Then those lasers have to be tuned to 1 part in 10^5 at least. Then that is going to vary w/ even the slightest change in temperature of the lasing material. Then you have criticality issues to deal with as you try to scale up and replicate w/ a pile of U here, another over there. Oak Ridge went through all of this and were on track for a while to kill everybody there until Los Alamos advised them otherwise.

EDIT: also, remember that one single centrifuge or diffusion unit can also only produce "milligrams" of highly enriched material. The point is: once you know how to produce "milligrams" with a bit more than a table top setup, it is no difficulty to produce kilograms when money and ressources are affected.

In no way is LIS a yet a desktop operation. And as a general concept its simply wrong to say small scale production operations can be scaled up with difficulty or at all. There are numerous examples of where scale ups are not just hard but impossible w/ the same physics used to manufacture at small scale. Semiconductors is a good example. One can not build a working 2007 40nm CPU with say 1990 40um technology - there are electrical signal and power issues they even infinite money and resources would not overcome. In the case of gas centrifuges, scaling them up certainly doesn't qualify as 'no difficulty' for some of the above reasons and as evidence by the Oak Ridge story; it too can be impossible without application of other technology.

Iran *already* obtained milligrams of enriched uranium with LIS.

Perhaps they did, its not clear if IAEA says they could have made or they actually did.

 

[Azael]

Thats correct for the moment, one conversation at a time. I know a lot less about Plutonium and about the only thing I know about Pu implosion is that I've read and scene lectures saying its very difficult to do. I am not able to gauge what difficult is. I know Pu can be made from Magnox reactors using natural Uranium, the designs for which were inexplicably unclassified by the UK and then reportedly used by N. Korea..

I would venture to guess that the design was declassified because its very easy to design a crude plutonium producing reactor. You won't prevent any state from producing plutonium by trying to keep reactor designs secret.

How hard it is to make a working bomb only those that design bombs probably know. But so many countries has produced working Pu bombs so its obviously not insurmountable.

NK appears to be an example of how the PU path ~fails; Sweden is a responsible democracy that's going to abide by the NPT so I have no problem w/ them. I am not familiar w/ the history of India's Pu bomb. I'm curious how indigenous their bomb was or did they also have AQ Khan _like_ external help. India was also a fairly large and technically advanced country at the time which it comes by in part because its a stable democracy. My priority is to prevent smaller rogue states from getting access to the tech to build a bomb. That is, let's prevent the small groups of thugs who haven't bothered to build a country from going nuclear - like a Mugabe in Zimbawe in 20 yrs, Burma, Cuba, and N. Korea (from having an easier path)..

I used sweden as a example of a small country that in secret was laying the groundwork for serial production of bombs without anyone knowing about it. Plenty of developing nations today probably has the same resources that sweden had in the 50's and 60's. Preventing spread of enrichment technology won't neccesarly make much of a different even for small countries that want to build weapons. Preventing spread of nuclear power won't make any difference in the ability of small countries to produce plutonium.

I've seen pictures of one of the Iraqi caultrons. If they're anywhere as incapable and problematic as the ones Berkely / Livermore intended to use during WWII then a caultron would be a great time waster for thugs w/ nuclear ambitions. They're horribly inefficient..

This is a quote from FAS(no idea how reliable it is) regarding the caultrons.
http://www.fas.org/nuke/guide/iraq/nuke/program.htm

Once the plants at Al Sharqat and Tarmiyah went into operation, Iraq would have been able to produce enough enriched uranium for one bomb a year from each plant. No industrial production had started at the two plants, but both would have been operational in 1992 or 1993.

If there really is no weapons path from any those three technologies then yes I'm on board.

There are always ways to make weapons. You could use any reactor to produce plutonium for weapons. But it would be extremely inefficient and illogical if someone wants weapons grade plutonium to build a expensive and complex power producing reactor when a primitive and cheap reactor can do the job just aswell.

 

[vanesch]

The major points of my argument:
- the multidisciplinary and systems engineering required for weapons size enrichment is extremely difficult and expensive. The knowledge required is likewise not simple, it is vast and complex and thus be can restricted with effort.
- it is therefore within the power of developed democratic nations to make the weapons acquisition by rogues 10x, 100x, maybe 1000x harder by a) yes, the use of the NPT and export restrictions, and also by b) phasing out nuclear if and when renewables and clean fossil make it possible.

I agree that making nuclear weapons is a complicated engineering problem. That's why I think that it is highly unlikely that a terrorist group "makes a nuke in their basement". However, I'm totally convinced that a country with financial means, and with a certain level of development (universities, research labs...) can do it entirely by itself. Western countries don't have the monopoly on inventing nuclear technology. The biggest secret was whether it could be done, but THAT knowledge is out. Most of the basic knowledge is public domain, or is at least "not contained" anymore.
True, a lot of technical details ARE still hidden. But you seem to forget that nuclear weapons were invented in the 40-ies (true, by brilliant people, but who established most of the basic knowledge). Technology, in general, has gone way up since then. We now have laptop computers that have a million fold the capacity of what was available back then.
So the few missing engineering details can be re-invented. This will take time, and this will take an effort, but it can be done. Maybe it will take 20 years of research efforts to re-establish something that is classified. But it can be found back - or the problem can be solved differently. Again, with enough ressources and enough determination, any reasonably develloped country can build a nuke. Independent of whether others use power plants.

What I do grant you is that such research would be more visible when there would be a world-wide ban on any nuclear activity (not just power plants, but also research reactors etc...). Because then ANY nuclear research activity would be suspicious, while now, a country could try to cover up its secret research by civil nuclear research activities. It is about the only reason for which nuclear power phasing out would "help".

However, look at Israel. They don't have nuclear power. They nevertheless developed nukes.

So, it is not clear to me that even if other countries phased out nuclear power, and nuclear technology all together (and how many decades will that take ?), in how much we diminish the probability that some "rogue states" with enough means and determination will succeed in making themselves a few nukes.

Also, by the time that one could hope that renewables ever take over (my guess is that this is more than a century away from us) as mass electricity production, about every country will have nukes, or will have decided not to want them, but it won't be a technological hurdle.

All this means that we would be foregoing to an entire technology, with all its advantages, worldwide, just to eventually (and I'm not convinced of it, but let's take it on) slightly diminish the probability of someone, somewhere, making a weapon, but not eliminating that possibility at all. Is that really such a good deal ?

 

[vanesch]

Islamic calculus on retaliation:
BTW the Israelis know he's right about the damage to Israel. Israel is only 10mi wide at one point.

That's what I mean: a regional nuclear conflict in the ME has an expectation of the number of victims in the same order of the number of victims we accept over a century for car driving and coal fired power plants.

A bit a of strawman. I don't say that nuclear power is not important, cars aren't helped by nuclear, and I don't say that coal as used is without harm.

I think you missed the point I tried to make. I wasn't saying that nuclear power is going to avoid those 170 million victims in the 21st century (which are SURE victims of car traffic and coal fired power plants), I was pointing out that even a regional nuclear exchange in the 21st century would not be a worse kind of catastrophe than the kind of victim levels that society apparently accepts for its living confort.

If apparently we accept, without blinking, to kill 170 million people in the coming century, just for the confort of displacing ourselves and our goods, and for the confort of having electricity, then such numbers are "acceptable risks". Well, a regional nuclear exchange is not of a bigger magnitude, so it can be negociated to be an "acceptable risk" too, if it comes with comparable advantages. If that advantage is "power too cheap to meter" and maybe avoiding a catastrophic climate change at the end of that century, knowing that this only contributes a very little to the probability of our conflict happening or not, then that's an acceptable deal.

I'm saying that the dangers from proliferation are being underplayed, not over dramatized, and that therefore renewables and cleaner fossile (gasification/sequestration) is to be preferred over nuclear if / when it is technically possible, even at some finite cost premium.

I would also prefer renewables, if they could do it. I even would prefer "magic stone" that generates electricity: you put a magic stone on your power meter in the basement, and electricity comes out. Point is, it is entirely unthinkable to generate 80% of worlds electricity needs with these technologies for the next 50 years. And by then, the proliferation issue will not be there anymore, as everybody who wants nukes, will have them.

As for the scope of the threat: I don't believe a nuclear detonation in a developed country otherwise at peace will be limited to blast and fallout victims. Here's some better hand waving: the world as we know it today will stop. People are concerned today about starvation in the thousands caused by elevated corn prices due to economic shifts, and about maybe 3 ft of sea level rise in the next century. Try a nuclear attack. In today's environmental context the attacked city is abandoned and not rebuilt like Hiro/Nagi for 50-100 years if ever. Intl. trade will halt while awaiting retaliation. If it is the US that's hit, US foreign food aid stops. If Three Mi. Island and Chernobyl stopped new plants, imagine what a hostile detonation will do to the industry.

That's because of over-scared people from a little bit of radiation. Indeed, one can't stop uninformed or ill-informed people make wrong choices. Like the 30 km zone around Chernobyl, where the radiation levels are lower than many other places in the world.
People are not dropping dead in Hiroshima today, are they ?

 

[vanesch]

Im beginning to feel horribly repetitive. But let's sum up what I have been saying.

There are two paths to nuclear weapons.

1. Very difficult uranium enrichment resulting in material that is easy to make weapons off.

2. Very easy plutonium production resulting in material that is hard to make into a working weapon.

There is even a third way, and I'm surprised nobody (except India?) ever took it, as far as I know:
very easy U-233 production from thorium in a graphite reactor.

U-233 has the double advantage of an easy bomb (gun-type) and easy separation from thorium (chemistry).

 

[vanesch]

Edit: PS... I don't know if this is purely politically motivated or if there is sound science behind not wanting to stir up the abundant uranium deposits that are found in the province's agricultural and watershed regions.

It is mainly BS. A coal-fired power plant sends several tons of uranium in the environment every year. There are even people who think of using coal burning as a form of uranium mining. The fly ash of a coal-fired plant is almost "good ore"...
So if there is a coal-fired plant in the neighbourhood, the "uranium (and mercury, and ...) is already stirred up".

http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html

That said, every mining activity has its environmental problems, and it depends on the type of mining that is projected.

 

[Azael]

There is even a third way, and I'm surprised nobody (except India?) ever took it, as far as I know:
very easy U-233 production from thorium in a graphite reactor.

U-233 has the double advantage of an easy bomb (gun-type) and easy separation from thorium (chemistry).

Its probably because its almost impossible to produce u-233 without u-232 contamination and u-232 has a very nasty gamma daughter in its decay chain.
http://www.princeton.edu/~globsec/publications/pdf/9_1kang.pdf

Didnt the US blow up a few u-233 bombs though?

 

[mheslep]

... Point is, it is entirely unthinkable to generate 80% of worlds electricity needs with these technologies for the next 50 years. ...

Just caught this on 2nd pass. I disagree that its entirely unthinkable. Even with wind power alone its very conceivable: 1.5MW turbine farms now give us 10MW/km^2. US electric capacity is ~1000GW, so 10^5 km^2 (25M acres). That compares to about 20M acres currently in use for US corn ethanol (a mistake).

 

[Azael]

But you need atleast 3000GW installed wind capacity(assuming a optimistic 30+% capacity factor) to supply on avarage 1000GW. Thats not even touching the intermittency issue which would require another 1000GW of reliable non wind capacity that can easily load follow.

So we are rather looking at 100M+ acres of wind farms since they all can't be in optimal locations + the entire current american capacity running on idle to load follow. Thats 2 million wind turbines, you would have to install 800 each week for 50 years to achieve that ignoring lifetime.

As for nuclear it would require 660 EPR size reactors to supply 1000GW or 13-15 built each year for 50 years, the world as a whole started up on avarage 24 reactors/year during the period 1980-1987(peak was 33 started in 1984) so its achivable.

Both scenarios are unrealistic of course, but I find the second far more plausible than the first economicaly.

 

[mheslep]

But you need atleast 3000GW installed wind capacity(assuming a optimistic 30+% capacity factor) to supply on avarage 1000GW.

You're right, I was mistakenly using nameplate instead of capacity.

Thats not even touching the intermittency issue which would require another 1000GW of reliable non wind capacity that can easily load follow.

That is already installed to some degree by way of existing heat cycle power plants. The 3000GW at 30% capacity will of course have peaks, and wind electric peaks can be used to make H2 or some other hydrocarbon to store energy to be later burned in heat cycle plants, or drive existing pump storage (26GW PS installed in the US).

So we are rather looking at 100M+ acres of wind farms

It is still 25M/0.3 = 75M acres for the average power of 3000GW. During the peaks wind would store energy as above.

since they all can't be in optimal locations + the entire current american capacity running on idle to load follow.

The millions of corn ethanol acres (as an example) are already well spread out, most of it in the wind belt.

Thats 2 million wind turbines, you would have to install 800 each week for 50 years to achieve that ignoring lifetime.

Thats underestimating mass production a bit. Given that a single car company like Fiat can easily make 750 cars per day, that in WWII the US made 10,000 ton ships in 40 days at the rate of one per day, then I believe you could up that 800/week by 10X with some effort and do it in 5 years. Certainly 10 years.

Oh, there's already 100GW of hydro+renewables installed in the US so just 900 to go.

 

[mheslep]

Wind also installs at ~$1.7/W. Nuclear has to fight the hippies to get that cost down now, and would have to keep work hard to keep it there w/ a big mining load and a big waste load.

 

[Azael]

Well there is a big difference betwen building a 1,5MW wind power plant and a car, plenty of on site construction needs to be done. But I don't doubt it would be possible if america decided to do it. But the needed rate of constructing new nuclear power has been demonstrated so there is no doubt that it is achivable.

But I don't think neither germany nor denmark has achieved capacity factors close to 30%(might be wrong) so its a bit to optimistic IMO to assume 75M acres or is enough.

The main problem with wind vs nuclear is that wind require a lot more construction material etc, total amount of mined materials for wind is far higher than nuclear. Vattenfall has some interesting statistics
http://www.vattenfall.se/www/vf_se/vf_se/Gemeinsame_Inhalte/DOCUMENT/196015vatt/815691omxv/819778milj/P0282332.pdf
(The high copper consumption for nuclear is because the swedish waste disposal method relies on copper cannisters).

There is also the economic problems, it costs more to produce electricity with wind. A recent report by a swedish research institue shows the following results excluding all taxes and subsidies for new generation capacity(can be found http://www.elforsk.se/rapporter/ShowReport.aspx?DocId=613&Index=D%3a%5cINETPUB%5celforsk4kr9h8d%5cRapporter%5cpdf%5cindex&HitCount=1&hits=aeb2+." but its on swedish)

Wind on land 7.9 cents/kWh
Wind in sea 13,8 cents/kWh
Nuclear 4,5 cents/kWh
Coal with carbon capture 12,1 cent/kWh

The load following will also contribute more to CO2 emissions than a nuclear scenario would since many fossil fuel plants would need to be running continously.

I think as much wind should be built as is feasible and economic. But I doubt we will ever se more than 30% of electricity from wind in any country anywhere. Denmark gets around 20% of electricity from wind, but they could not do it if they didnt import plenty of electricity from sweden, norway and germany.

I have higher hopes for wave power, they don't ruin the view as much either. http://www.el.angstrom.uu.se/forskningsprojekt/Islandsberg_E.html

The entire waste problem can be handled quite easily if the ban on reprocessing is just lifted. Seems like that is anticipated
http://www.knoxnews.com/news/2008/may/06/tva-design-concept-plan-nuclear-waste-reprocessing/

 

[mheslep]

Denmark/Germany - It doesn't surprise me that they're delivering lower than 30% capacity since Denmark in particular deployed very early on the wind technology vs time curve - back when the standard unit was 0.2MW, lower height with more variable wind, etc., which earned the Danes some criticism for hype chasing by other Danes. -Just an observation; I havn't looked into it.

Nuclear Cost:
I like the http://web.mit.edu/nuclearpower/" with a cost of $14B + $3B transmission, or ~$7/W; no chance of $0.06/kw-hr power coming from Levi at that cost.

Wind Cost:
UK BWEA report, 2005, with 2003 costs.
http://www.bwea.com/pdf/briefings/target-2005-small.pdf
Average onshore: $0.06 / kw-hr
Average offshore: $0.11 / kw-hr

US Dept. of Energy Cost report, 2006:
http://www1.eere.energy.gov/windandhydro/pdfs/41435.pdf, page 10.
-Busbar price
-Reduced by/inludes the available US tax breaks - the federal 'PTC' which is $0.015 / kw-hr
-Reduced by/includes 'Renewable Energy Certs', RECs - unknown but only 10% of the 2006 installations got them.
Average: $0.036 / kw-hr over 5.6GW installed, one sigma range $0.023 /kw-hr to $0.049 / kw-hr
With the above caveats worse case should be $0.049+$0.015=$0.064 /kw-hr actual generation cost.

The DOE Wind studies also point out that though the 1.5MW turbines are most commonly installed, a growing chunk are 3MW, and 5MW units are available. These larger units will necessarily make more efficient use of the land. I havnt looked up the actual usage for 3 and 5.

 

[mheslep]

From MIT's 'Future of Nuclear Power':
http://web.mit.edu/nuclearpower/img/summary.gif

Proliferation Summary

Proliferation. The current international safeguards regime is inadequate to meet the security challenges of the expanded nuclear\ deployment contemplated in the global growth scenario. The reprocessing system now used in Europe, Japan, and Russia that involves separation and recycling of plutonium presents unwarranted proliferation risks.

Under unresolved problems:

Proliferation: nuclear power entails potential security risks, notably the possible misuse of commercial or associated nuclear facilities and operations to acquire technology or materials as a precursor to the acquisition of a nuclear weapons capability. Fuel cycles that involve the chemical reprocessing of spent fuel to separate weapons-usable plutonium and uranium enrichment technologies are of special concern, especially as nuclear power spreads around the world;

Statement:

Nuclear power should not expand unless the risk of proliferation from operation of the commercial nuclear fuel cycle is made acceptably small. We believe that nuclear power can expand as envisioned in our global growth scenario with acceptable incremental proliferation risk, provided that reasonable safeguards are adopted and that deployment of reprocessing and enrichment are restricted. The international community must prevent the acquisition of weapons-usable material, either by diversion (in the case of plutonium) or by misuse of fuel cycle facilities (including related facilities, such as research reactors or hot cells). Responsible governments must control, to the extent possible, the know-how relevant to produce and process either highly enriched uranium (enrichment technology) or plutonium.

Three issues are of particular concern: existing stocks of separated plutonium around the world that are directly usable for weapons; nuclear facilities, for example in Russia, with inadequate controls; and transfer of technology, especially enrichment and reprocessing technology, that brings nations closer to a nuclear weapons capability. The proliferation risk of the global growth scenario is underlined by the likelihood that use of nuclear power would be introduced and expanded in many countries in different security circumstances. An international response is required to reduce the proliferation risk. The response should:

o re-appraise and strengthen the institutional underpinnings of the IAEA safeguards regime in the near term, including sanctions;

o guide nuclear fuel cycle development in ways that reinforce shared nonproliferation objectives.

Recommendation:

Accordingly, we recommend:

o The International Atomic Energy Agency (IAEA) should focus overwhelmingly on its safeguards function and should be given the authority to carry out inspections beyond declared facilities to suspected illicit facilities;

o Greater attention must be given to the proliferation risks at the front end of the fuel cycle from enrichment technologies;

o IAEA safeguards should move to an approach based on continuous materials protection, control and accounting using surveillance and containment systems, both in facilities and during transportation, and should implement safeguards in a risk-based framework keyed to fuel cycle activity;

o Fuel cycle analysis, research, development, and demonstration efforts must include explicit analysis of proliferation risks and measures defined to minimize proliferation risks;

o International spent fuel storage has significant nonproliferation benefits for the growth scenario and should be negotiated promptly and implemented over the next decade.

Design recommendations: some particular designs and methods as realizing the lowest proliferation risk:
-a uraniuim once-through and dispose fuel cycle vs a close-thermal or closed-fast cycle. They specifically mention the use of the PUREX/MOX closed cycle used by Europe and Japan as inferior to open cycles for non-proliferation purposes.
-gas-cooled vs LWR

 

[vanesch]

Just caught this on 2nd pass. I disagree that its entirely unthinkable. Even with wind power alone its very conceivable: 1.5MW turbine farms now give us 10MW/km^2. US electric capacity is ~1000GW, so 10^5 km^2 (25M acres). That compares to about 20M acres currently in use for US corn ethanol (a mistake).

This is the straw man argument given by a lot of anti-nuclear people: wind is better. But there is not to be chosen between wind (or solar, or whatever) and nuclear: both are possible. Wind is not hindered by nuclear, and nuclear shouldn't be hindered by wind. There are many countries NOT using nuclear power, but they have not developed wind energy (if it is so possible) into a significant fraction of their production. My opinion is: first SHOW ME that wind CAN provide a country with, say, 60% of its electricity (without cheating). If that's done, and we can evaluate this, then do this everywhere. And once half of the world turns for 50 or 60% on wind, then we can consider the option of dropping nuclear, eventually. If wind cannot do that (and until it is demonstrated, I don't believe it), then wind is all right, but no substitute for nuclear or coal or gas. It is then just a nice auxiliary minority means of generating power - against which I don't have anything, btw.
So let us give wind all of its possibilities, but let us not stop nuclear before wind has shown to be capable to do what nuclear can do. Personally, I don't believe it, but I can readily accept to be wrong on the issue.

The country that gets most out of wind, is Denmark. Denmark actually has two non-connected grids, and over the whole of Denmark, 16% is wind energy, while over the "windy" grid, it is 20%... but that grid is connected to Sweden's grid (and I think, also to Germany's grid). Sweden has no problem with the fluctuations of Denmark, because Sweden, because of its particular geography, has about 50% hydropower. So each time that the wind blows harder in Denmark, the hydropower in Sweden is diminished, and vice versa. When Denmark has no wind, then Sweden cranks up a bit more its hydropower, to compensate.
So Sweden plays Denmark's buffer. And we see here BTW that Denmark's wind turbines DON'T displace much CO2 production: what it wins, is mainly compensated by LESS hydropower in Sweden.
But to be fair, we should now look at what is Denmark's wind energy fraction, over the production of Denmark and Sweden combined, and then we get below 10%.

So the Danish experiment shows us that, combined with a very suitable wind placement, and a very suitable geography (Sweden's, with a lot of hydro), they managed to get ~10% wind energy installed.

Also, realize that the Danes are extremely well placed for wind energy. Their offshore farms are on the better places in the world, with a high wind offer, that is rather steady. On land, this is much worse.

The Germans have much less than 10% wind installed. In march 2007, they decided to build 27 brown coal power plants. They have suffered a few major grid breakdowns, which some analysts pointed out to be their wind turbines - although others disagree with that. Now, in Germany, the atmosphere is pretty anti-nuclear (they want to get rid of their 36% nuclear) and the public opinion is very "green", so, if wind was such an attractive option, why do they forego this then, and build *brown coal* power plants ??

Nevertheless, wind turbines are a pain for the network management, because of their erratic character. THAT is the main reason why I think that wind cannot be, in the next decades, be the main power source of any country. Most network analysts think that a network containing much more than 20% of wind energy becomes essentially unpilotable, unless you associate with each farm, also gas turbines which compensate immediately and locally, or when you have a very big and distributed network of hydropower plants. Then you can get to higher fractions, but still less than 50%. A ratio of 1/3 of installed power, and average power, is considered a very good performance (usually only with offshore farms on a good place).

As I said, I have nothing against wind energy, but when you look at its technical issues, it is difficult to conceive it to be a majority provider (and that's an understatement).

It's not the price of the wind turbine, or the place it takes up which puts the ultimate limit to wind energy: it is its erratic power. If we don't have (and we don't) compact and cheap electricity storage (apart from hydro pumping stations), and a large variable at will load (like, you said it, hydrogen production), then I don't see this change. This is why I don't think that this is going to be different in the coming decades.

 

[vanesch]

Nuclear Cost:
I like the http://web.mit.edu/nuclearpower/" with a cost of $14B + $3B transmission, or ~$7/W; no chance of $0.06/kw-hr power coming from Levi at that cost.

I don't understand that $14B. The new EPR, which is still in "pilot" stage (no mass production yet, so more expensive), is estimated to cost ~ 3.3B Euro
http://en.wikipedia.org/wiki/European_Pressurized_Reactor
(although the Finnish project will probably be more expensive, mainly for extra regulatory issues - red tape costs). It is a 1.6 GW e plant. So even with a serious cost overrun (say, 50%), and knowing it is still a pilot plant, $14B seems extremely expensive compared to this.

Wind Cost:
UK BWEA report, 2005, with 2003 costs.
http://www.bwea.com/pdf/briefings/target-2005-small.pdf
Average onshore: $0.06 / kw-hr
Average offshore: $0.11 / kw-hr

Yes, but *average* doesn't mean: "when needed" ; as such, average erratic power is less than half the price of "available".
Taking the average price equal to the total price can only be the case when wind is "within the noise margin" of power production, as it is in all countries but Denmark. So the marginal cost of wind is relatively low for the first 10-20% of installed wind power, and once it becomes an important component in the network, and starts causing problems because of the fluctuations, costs rise dramatically, because of the need of compensation.

 

[vanesch]

Design recommendations: some particular designs and methods as realizing the lowest proliferation risk:
-a uraniuim once-through and dispose fuel cycle vs a close-thermal or closed-fast cycle. They specifically mention the use of the PUREX/MOX closed cycle used by Europe and Japan as inferior to open cycles for non-proliferation purposes.
-gas-cooled vs LWR

We've been through that, and my opinion (shared by a lot of people in the nuclear world) is that, although it is true that the current *technological knowledge* of the fuel cycle is a proliferation issue, its actual application in most western countries is not.
Personally, I find the open fuel cycle a huge waste. You throw away 95% of the energy content of the material, and you have much longer-lived waste than needed.

The real solution is the use of fast breeders (or fast reactors, not necessarily breeders), and reprocessing which is less "picky" and separates the actinides from the fission products, without separating with high purity the plutonium. There's a lot of development under way, but, contrary to the PUREX process which has an industrial experience of more than 40 years, these things are pretty new, and still in the research or prototype phase.

There's a point I don't understand in the MIT recommendation. Although it is true that the PUREX process (the technological knowledge) is a proliferation issue (and then, it is not, because you can now even find it in books, I have one), the MATERIAL itself is, I would think, not so much of an issue. The plutonium that comes out of a PWR (so in the spend fuel of the open cycle) has a bad isotopic composition to make bombs out of. It is not impossible, but it is already difficult to make a plutonium bomb with "good" plutonium (Pu-239), but it is still much more difficult to make a plutonium bomb with reactor plutonium. The probability to have a fizzle is bigger, and in any case the yield is very low (it will be a low-power bomb of at most a few kT). Now, MOX fuel is again an U-Pu mixture, so if you make immediately MOX fuel of the separated plutonium, you have not much more of a bomb material than in an open fuel cycle. In fact, making MOX fuel and putting it again in a reactor makes it hopelessly useless as a bomb material, so in fact one of the reasons to use MOX fuel is to diminish the presence of "bombable" plutonium.

In other words, the usability of MOX fuel as bomb material (before use in a reactor) is of the same order as spend fuel, and is in any case very low (you still need to separate it, and it is "bad" material of which it is difficult to make a working bomb). USED MOX fuel is hopeless bomb material. The PUREX knowledge is out, in any case. People know now how to separate Pu from U.

And, in any case, if you really want to make a bomb, and you put enough money and engineering to it, you will succeed.

 

[russ_watters]

Wind also installs at ~$1.7/W. Nuclear has to fight the hippies to get that cost down now, and would have to keep work hard to keep it there w/ a big mining load and a big waste load.

Wind is definitely a viable technology now. It isn't a single-source solutin, but it does help. But due to it's unique limitations, it can only ever be a suppliment to reliable single-source solutions like nuclear power.

 

[russ_watters]

I like the http://web.mit.edu/nuclearpower/" for my gold standard. It is not without criticism, but everyone pro and con seems to use it as a baseline for discussion.

Well, I suspect it is pretty good on the facts, it's just the opinions that are suspect. The author seems to have a pretty strong left-wing bias that reflects in his work:
http://web.mit.edu/chemistry/deutch/policy.html

Simply put, the opinion parts of his position seem based on the obsolte/incorrect hippie view of nuclear power. I must admit, I've only read his summery so far - I'll have to read more of his analysis.

 

[vanesch]

BTW, in this document http://web.mit.edu/chemistry/deutch/policy/80TheNuclearOption2006.pdf
you also find a balanced approach, with similar recommendations.

Now, personally, I would find it a huge pity to throw away all that spend fuel. That said, we can keep it in a temporary storage until people will realize (or not) that it is full of good fuel, and that we can use all that plutonium to start a fleet of breeders (50 years from now, who knows). The later the reprocessing occurs (say, 60 years from now) the easier it will be (except for the Pu-241 which will have decayed into Am-241 by then, and which is a pain).

You have to realize that in spend fuel, still 95% of the energy content is present, which is available in a fast reactor. That means that if you have been running on nuclear power for, say, 30 years, you can still extract 20 times more of it, that means, 600 years on the same material at the same power output (and still 10x more if you use all the impoverished uranium, so 6000 years), just with the spend fuel and the "waste". You don't even need mining of fresh uranium ore anymore.

Don't you think that it is totally wasteful to throw away 200 times the energy content of material you possess, just because of some idle hope that some bearded maniac will have a slightly little harder time (you think) to make a bomb ?

Also, when you have breeders, and reprocessing, you can drop not only mining, but also enrichment. So if you don't like enrichment, then you should go as fast as possible to a fleet of breeders and reprocessing.

 

[Phy6explorer]

BTW, in this document http://web.mit.edu/chemistry/deutch/policy/80TheNuclearOption2006.pdf
you also find a balanced approach, with similar recommendations.

Now, personally, I would find it a huge pity to throw away all that spend fuel. That said, we can keep it in a temporary storage until people will realize (or not) that it is full of good fuel, and that we can use all that plutonium to start a fleet of breeders (50 years from now, who knows). The later the reprocessing occurs (say, 60 years from now) the easier it will be (except for the Pu-241 which will have decayed into Am-241 by then, and which is a pain).

You have to realize that in spend fuel, still 95% of the energy content is present, which is available in a fast reactor. That means that if you have been running on nuclear power for, say, 30 years, you can still extract 20 times more of it, that means, 600 years on the same material at the same power output (and still 10x more if you use all the impoverished uranium, so 6000 years), just with the spend fuel and the "waste". You don't even need mining of fresh uranium ore anymore.

Don't you think that it is totally wasteful to throw away 200 times the energy content of material you possess, just because of some idle hope that some bearded maniac will have a slightly little harder time (you think) to make a bomb ?

Also, when you have breeders, and reprocessing, you can drop not only mining, but also enrichment. So if you don't like enrichment, then you should go as fast as possible to a fleet of breeders and reprocessing.

You are completely right.That's exactly what I read about spend fuel. What about constructing factories for producing energy from spend fuel side-by-side the nuclear industries. In that way we can avoid too much transportation of the spend fuel and of course increase the amount of energy produced. But actually who said it is being thrown away?According to a UN census in 1997, in the 20 countries which account for most of the world's nuclear power generation, spent fuel storage capacity at the reactors was 148,000 tonnes, with 59% of this utilized. Away-from-reactor storage capacity was 78,000 tonnes, with 44% utilised.But the fact is that even after using up the spend fuel, that is after the reprocessing and vitrification of the 25-30 tons of spent fuel produced per year by a typical large nuclear reactor, waste is produced which amounts to about three cubic meter per year. I read that it has been accepted that this final waste will be disposed of in a deep geological repository.But my question is, what will happen to the final waste there?

 

[vanesch]

What about constructing factories for producing energy from spend fuel side-by-side the nuclear industries. In that way we can avoid too much transportation of the spend fuel and of course increase the amount of energy produced.

In fact, the US had such a pilot plant, with integrated fuel reprocessing (which was moreover much more proliferation resistent, because it didn't isolate the plutonium specifically, using pyro-processing). It was the IFR project (Integral Fast Reactor). http://en.wikipedia.org/wiki/Integral_Fast_Reactor
For totally incomprehensible reasons, this has been abandoned when it was almost finished (sounds like the Superphenix and Kalkar debacles).

But actually who said it is being thrown away?According to a UN census in 1997, in the 20 countries which account for most of the world's nuclear power generation, spent fuel storage capacity at the reactors was 148,000 tonnes, with 59% of this utilized. Away-from-reactor storage capacity was 78,000 tonnes, with 44% utilised.

Yes, temporary storage is OK with me. But when one talks about the open cycle, one means: geological (irreversible) storage for good of the fuel elements "as is".

But the fact is that even after using up the spend fuel, that is after the reprocessing and vitrification of the 25-30 tons of spent fuel produced per year by a typical large nuclear reactor, waste is produced which amounts to about three cubic meter per year. I read that it has been accepted that this final waste will be disposed of in a deep geological repository.But my question is, what will happen to the final waste there?

It will decay, and its radioactivity will decrease. The radioactive components of spend fuel are of 3 orders. You also have to know that the shorter the half life, the higher the activity, but the faster it decays, while the longer the half life, the lower the activity, but the longer it takes.

There are 3 components to the spend fuel:
- fission products: the most active, but after a few hundred years, they have decayed. It is the "essential waste" because it is the "ashes" of the fission process.
A ton of spend fuel contains about 50 kg of fission products.

- minor actinides (americium, neptunium, curium). They are undesired products produced in thermal spectrum, and they remain active for a few thousand years. They are much less active than the fission products (except for the curium, but which has a half life of 18 years, so decays quickly), but are nevertheless sufficiently active to "consider them a hasard" for several thousand years (although, as I said, much less so than the fission products).
A ton of spend fuel only contains a few kilogram of minor actinides.

- the plutonium. Similar to the minor actinides, but we have an activity for about 100 000 years. A ton of spend fuel contains about 10 kg of plutonium.

So, the fission products need to be contained for a few hundred years, the minor actinides for say 10 000 years, and the plutonium for 100 000 years. These are in fact the times it takes for the radio-toxicity to decrease to the level of natural uranium ore, at which one considers that geological presence is not much more of a problem than actual natural uranium ore.

So the problem of geological disposal is to ensure that no significant amounts of the material can get back to the biosphere and ground water before stated times.
This is partly accomplished by the human structure (canisters, fillings, ... ) and partly by the geology itself (for the longer times). The point is also that the longer one waits for a leak, the less severe are the consequences.

If we take out the plutonium (PUREX or another technique), then the last component is not part of the waste. This diminishes the necessary "containment time" from 100 000 years to 10 000 years. If we take out also the minor actinides, we arrive at a few hundred years.

The last point is important, because it is possible to design canisters that will last that long. However, it is difficult to design canisters (although the Swedish did so) that are supposed to remain intact for 10 000 years or longer.

But "taking out" is only part of the story: what do you do with it next ? With plutonium, that's easy: its a good fuel for fast reactors. So you burn it in a fast reactor. You can burn it partially in thermal reactors (MOX), but that's limited. You will always remain with a certain fraction of unusable plutonium that way.

The minor actinides are part of a discussion. You can burn them (in small amounts) in fast reactors, or you can build ADS systems which try to burn them on purpose. The discussion is whether this is worth the effort - we'll come to that.
Fast reactors don't produce minor actinides (or in very very very small quantities, that is). So this problem is purely a difficulty of thermal reactors.

Now, if you reprocess fuel, then you vitrify the essential waste (let's say, minor actinides and fission products), and these go into a stainless steel canister, which will go into a bigger "repository" canister. Around that, you put some filling material, mainly clay or concrete. Normally, that's it.

But people study what's going to happen if there is some ground water flow through the repository. The stainless steel will rust away over about 1000 years, but in doing so, it will generate iron oxide, which is a strong reducing agent. The glass will very slowly dissolve in the ground water, which will also take a few thousand years. At that point, the waste is now "free" but the fission products are gone by now. We only have the minor actinides to worry about. Turns out that minor actinides don't migrate easily through a reducing atmosphere, and the dissolved glass also forms chemical migration barriers. After that, the clay sorbs actinides very easily. So it will take several thousands of years for the actinides to even be able to migrate outside of the "human structure" in small quantities. After that, they are confronted with the actual geological barrier.

One studies several possible scenarios and tries to estimate what will be the release of radioactive material after several tens of thousands of years. By then, most has decayed to very low activity levels. From this results then the final potential "contamination" of the repository. It is usually orders of magnitude below the natural background radiation level.

EDIT:
In fact, in the case of (tiny) releases in the far future, it turns out that the culprit is mostly Sn-126, with a half life of more than 100 000 years. This is one of the few fission products which live longer than a few hundred years, are produced in very tiny quantities, and ARE able to migrate. But, as said, the doses they can deliver are orders of magnitude below background doses. The actinides never seem to be able to migrate out, as they are chemically bound so easily to the local material (clay or other).

It is this observation which makes one put a question mark on the utility of getting rid of minor actinides, as visibly it are not these which get out after a long time. With current knowledge, it wouldn't make any difference in most if not all scenarios whether or not the minor actinides were removed or not.

 

[Phy6explorer]

In fact, in the case of (tiny) releases in the far future, it turns out that the culprit is mostly Sn-126, with a half life of more than 100 000 years. This is one of the few fission products which live longer than a few hundred years, are produced in very tiny quantities, and ARE able to migrate. But, as said, the doses they can deliver are orders of magnitude below background doses. The actinides never seem to be able to migrate out, as they are chemically bound so easily to the local material (clay or other).

It is this observation which makes one put a question mark on the utility of getting rid of minor actinides, as visibly it are not these which get out after a long time. With current knowledge, it wouldn't make any difference in most if not all scenarios whether or not the minor actinides were removed or not.

I am not sure but, I think that the only way of producing lower yields of Tin-126 is using thermal reactors.But it seems that quite a few actinides are found naturally in the Earth. Then don't most actinides share some common components.Why can't they be dumped deep into the Earth, of course, in a depth which is safely above the water -table?