News Feasibility of Nuclear Energy with Recycling (Pu) as Energy Solution in US

[Herodotus]

Sorry, I meant 35% by 1973, about three years after our production peaked. 2/3 is an accurate figure for the United States now.
About nuclear power, 10 years ago, when oil wasn't so costly, scare tactics kept us away from nuclear power. I mean we really lack common sense. The United States doesn't even recycle our fuel because the concentrated uranium that's obtained "might" be used for bombs...

[Edit: moved from - Will lifting oil drilling bans in the U.S. lower the price of oil?
https://www.physicsforums.com/showthread.php?t=245685 ]

 

[mheslep]

...The United States doesn't even recycle our fuel because the concentrated uranium that's obtained "might" be used for bombs...

Not uranium, it is the Pu produced by the current PUREX process that is the concern.

From "The Future of Nuclear Power"

Proliferation. The current international safe-guards 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.

http://web.mit.edu/nuclearpower/pdf/nuclearpower-summary.pdf

 

[Astronuc]

Proliferation. The current international safe-guards 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.

I disagree with this statement for a number of reasons. One primary reason is that no one in their right mind would use PG-Pu for a nuclear weapon, certainly the military wouldn't. Most studies, like this one, do not elaborate on risk, specifically how one diverts the SNM. Certainly the people at BNFL and Cogema are not interested in diverting material.

Enriched U has not been used in nuclear warheads for a long time in the US. Use of WG was superceded by WG-Pu back in the 50's and 60's. I believe the WG-U systems were the first to be decommissioned, and the US DOE has been downblended/diluting Russian WG-U for several years now.

 

[mheslep]

...I disagree with this statement for a number of reasons. One primary reason is that no one in their right mind would use PG-Pu for a nuclear weapon, certainly the military wouldn't. Most studies, like this one, do not elaborate on risk, specifically how one diverts the SNM. Certainly the people at BNFL and Cogema are not interested in diverting material...

The MIT statement is appropriately tailored: "expanded nuclear deployment contemplated in the global growth scenario". Areva et al is not the problem. Blessing a nuclear process for world wide deployment is.

 

[mheslep]

I disagree with this statement for a number of reasons. One primary reason is that no one in their right mind would use PG-Pu for a nuclear weapon,

Can you elaborate, given this statement in Chapter 1 under NONPROLIFERATION:

Three issues are of particular concern: existing stocks of separated plutonium
around the world that are directly usable for weapons...

http://web.mit.edu/nuclearpower/pdf/nuclearpower-ch1-3.pdf
and later in Chap 4, page 33:

...separated plutonium inventory required for option two is 167 metric tons. A nuclear weapon of significant yield can comfortably be made with less than 10kg of Pu, so this amount represents the potential for thousands of nuclear weapons...

I don't think you mean all the authors are not of right mind:

PROFESSOR STEPHEN ANSOLABEHERE
Department of Political Science, MIT
PROFESSOR JOHN DEUTCH — CO CHAIR
Department of Chemistry, MIT
PROFESSOR EMERITUS MICHAEL DRISCOLL
Department of Nuclear Engineering, MIT
PROFESSOR PAUL E. GRAY
Department of Electrical Engineering and Computer Science
PROFESSOR JOHN P. HOLDREN
Professor of Environmental Science and Public Policy
Department of Earth and Planetary Sciences, Harvard University.
PROFESSOR PAUL L. JOSKOW
Department of Economics and Sloan School of Management, MIT
Director, Center for Energy and Environmental Policy Research
PROFESSOR RICHARD K. LESTER
Department of Nuclear Engineering, MIT
PROFESSOR ERNEST J. MONIZ — CO CHAIR
Department of Physics, MIT
Director of Energy Studies, Laboratory for Energy and the Environment
PROFESSOR NEIL E. TODREAS
Department of Nuclear Engineering, MIT
Professor of Mechanical Engineering
Department of Mechanical Engineering, MIT
ERIC S. BECKJORD
Executive Director

...Most studies, like this one, do not elaborate on risk, specifically how one diverts the SNM...

Certainly any material has some non zero chance of being illegally diverted, that chance growing the more abundant and widespread the material.

Edit: Scenario for this report grows from current worldwide 325GWe to a theoretical 1500GWe in ~2051. Accordingly separated Pu grows from the current 6.3MT per year to 167MT of Pu, spread worldwide, in 2051. Tables 4.1, 4.2 in Chapter 4.

 

[mheslep]

Astronuc:
I speculate that this Note 5 on high burnup designs in Chapter 7 is related to your objection to the possibility of using separated Pu:

5. As the burnup increases, the proportion of plutonium-239 in the plutonium declines, while the proportion of Pu-238 increases. For example, an increase in the burnup of PWR fuel from 33 MWD/kg to 100 MWD/kg would result in a decline in the Pu-239 content from 65% to 53%,while the Pu-238 content would increase from 1% to about 7%. (Zhiwen Xu, Ph.D. dissertation, Department of Nuclear Engineering,M.I.T., 2003). Pu-238 is a particularly undesirable isotope in nuclear explosives because of its relatively high emission rate of spontaneous fission neutrons and decay heat. According to some specialists, a Pu- 238 content above about 6% would make plutonium essentially unusable for weapons purposes. The denaturing effect of Pu-238 would be limited to a couple of centuries, however, because of its relatively short (87-year) half-life.

It is not clear to me what ratio of weaponizeable Pu-239 is produced in day one of the current PUREX /MOX cycles.

 

[mgb_phys]

It is not clear to me why a country would avoid nuclear power because of a possibility that terrorists could make a fission weapon form reactor waste - and at the same time allow LPG tankers into harbours in the middle of major cities and have high pressure gasoline pipelines running under populated areas.

 

[Astronuc]

Astronuc:
I speculate that this Note 5 on high burnup designs in Chapter 7 is related to your objection to the possibility of using separated Pu:

5. As the burnup increases, the proportion of plutonium-239 in the plutonium declines, while the proportion of Pu-238 increases. For example, an increase in the burnup of PWR fuel from 33 MWD/kg to 100 MWD/kg would result in a decline in the Pu-239 content from 65% to 53%,while the Pu-238 content would increase from 1% to about 7%. (Zhiwen Xu, Ph.D. dissertation, Department of Nuclear Engineering,M.I.T., 2003). Pu-238 is a particularly undesirable isotope in nuclear explosives because of its relatively high emission rate of spontaneous fission neutrons and decay heat. According to some specialists, a Pu- 238 content above about 6% would make plutonium essentially unusable for weapons purposes. The denaturing effect of Pu-238 would be limited to a couple of centuries, however, because of its relatively short (87-year) half-life.

That's part of the reason. We push fuel to rod average burnups > 50 GWd/tU and the rim region (periphery of the ceramic pellet) will have local burnups of 100-150 GWd/tU.

The Pu isotopic vector for RG-Pu is very different from WG-Pu. I'm not saying that one couldn't do it. Rather no one who wants a reliable weapon with a high yield and relatively long storage life would use RG-Pu. The radiation from Pu-238, Pu-241 and Am-241 would have a deleterious effect on the electronics and triggering system. But then again, terrorists and dudes like Saddam Hussein are not in their right minds.

I know one the authors of the MIT report, and I'll have to ask him about the report the next time I see him. I am sure the authors from the Nuclear Engineering department are providing the technical information for a problem that is largely about policy and political matters. They are certainly not advocating using RG-Pu for weapons, only that it is a concern that others might.

 

[mheslep]

It is not clear to me why a country would avoid nuclear power because of a possibility that terrorists could make a fission weapon form reactor waste - and at the same time allow LPG tankers into harbours in the middle of major cities and have high pressure gasoline pipelines running under populated areas.

Because 1) the power of the nuclear weapon is ~one million times greater and 2) LPG / Gas explosions don't produce long lasting after effects from fall-out radiation? One can start rebuilding the moment the fire is out from a hydrocarbon explosion. Any modern city that suffers a single, isolated, nuclear attack is done. All the survivors will simply leave.

 

[mgb_phys]

So because the attack on 9/11 was less energetic than an atom bomb it had no terrorist value?
And http://en.wikipedia.org/wiki/Halifax_Explosion in Seattle/Newark/San Fransisco wouldn't be a problem?

 

[Herodotus]

Not uranium, it is the Pu produced by the current PUREX process that is the concern.

From "The Future of Nuclear Power"

http://web.mit.edu/nuclearpower/pdf/nuclearpower-summary.pdf

I was talking about the United States fuel supply...
Instead of fear of nuclear proliferation, we could persuade the countries that do use plutonium to use pyrometallurgical methods instead of PUREX. That way, the resulting products won't be of weapons grade quality. Either way though, terrorists don't actually need a working bomb. A "fizzle" from a nuclear bomb would be more than sufficient as a terrorist weapon.

 

[mheslep]

So because the attack on 9/11 was less energetic than an atom bomb it had no terrorist value?
And http://en.wikipedia.org/wiki/Halifax_Explosion in Seattle/Newark/San Fransisco wouldn't be a problem?

Those are strawman as I think you know; that 9/11 has impact is not at issue. You proposed that a nuclear attack is in impact to a chemical explosion. I answered why I believe it is not.

 

[WarPhalange]

And he's saying "Just because it's not as powerful, means we can ignore it?"

 

[vanesch]

Because 1) the power of the nuclear weapon is ~one million times greater and 2) LPG / Gas explosions don't produce long lasting after effects from fall-out radiation? One can start rebuilding the moment the fire is out from a hydrocarbon explosion. Any modern city that suffers a single, isolated, nuclear attack is done. All the survivors will simply leave.

Hiroshima is still on the map... But of course people have much more irrational fears than back then. I guess you're right.

We've been already through this discussion, but I think one should make a big distinction between a *country* trying to make a bomb, and a *terrorist group*. I don't think that a terrorist group can put up its own little Purex process in the basement, together with the pyroprocessing needed to get metallic plutonium. A country can of course.
So "terrorist danger" (let us remind ourselves that we are talking about a hypothetical danger here, which has never manifested itself in reality: so we might be chasing ghosts) is only with separated, pure, plutonium. This can be avoided by changing the processes, and in fact, even in current reprocessing, the plutonium oxide is remixed with uranium oxide again to form MOX. With MOX, the Purex separation has to be done all over again. So the danger is just between the PUREX output, and the MOX blending.

Next, imagine that a terrorist group got hold of some plutonium (reactor grade). They now still have to make the implosion device and the initiator. That is not impossible, true, but it is quite a challenge in any case. Finally, reactor grade plutonium requires, for the same yield, more precise implosion and initiation than weapon-grade plutonium, and finally, reactor grade plutonium has a higher power dissipation, which makes it hot if you confine it within an implosion device (which can damage the explosives if not assembled just before delivery).

But finally, it is not clear whether there's any motivation for a terrorist group to make a nuclear hit. It would remove all sympathy for their cause. It would trigger a terrible reaction. Nations even somewhat sympathetic to their cause would have to distantiate from them out of fear of retaliation. No, I repeat, no nation would ever be so stupid as to get involved in helping terrorists build a nuke as that would easily be seen as then having done the strike themselves and expose them to retaliation.

So let's have the discussion again after there have been a certain number of nuclear terrorist attacks. We will then know much better what we are talking about.

 

[vanesch]

Because 1) the power of the nuclear weapon is ~one million times greater

A terrorist weapon would - at least in the beginning - not have a higher yield than the typical first generation bomb: 15-20 kT and probably less. I guess that after they've gained some experience, they might go to higher yields with more sophisticated designs.
The potential energy in an LNG tanker is much higher! But of course it wouldn't be as much an explosion, rather than a big fire, which reduces significantly the blast effects.

 

[vanesch]

I was talking about the United States fuel supply...
Instead of fear of nuclear proliferation, we could persuade the countries that do use plutonium to use pyrometallurgical methods instead of PUREX. That way, the resulting products won't be of weapons grade quality. Either way though, terrorists don't actually need a working bomb. A "fizzle" from a nuclear bomb would be more than sufficient as a terrorist weapon.

And how do we call that ? Carter-II ?

You have to understand that other nations will not necessarily follow the US desires. That was the case already back then.

 

[mgb_phys]

Remember that a terrorist bombers intention isn't the same as the military.
Small nail bomb in a litter bin on a London shopping street. Result, very few injuries, but a lot of press = no US tourists visit London that year = major financial losses = pressure on government to talk to terrorists.
But from a military point of view inconsequential.

 

[mheslep]

A terrorist weapon would - at least in the beginning - not have a higher yield than the typical first generation bomb: 15-20 kT and probably less. I guess that after they've gained some experience, they might go to higher yields with more sophisticated designs.
The potential energy in an LNG tanker is much higher! But of course it wouldn't be as much an explosion, rather than a big fire, which reduces significantly the blast effects.

Yes that's why I said power, not energy, stemming from the completion of a nuclear detonation in nano or microseconds vs the magnitudes slower shockwave and heat transfer used in chemical detonations. In WWII London and other cities received TNT tonnage greater than Hiroshima's and clearly nothing close to Hiroshima effects occurred.

 

[mheslep]

Hiroshima is still on the map... But of course people have much more irrational fears than back then. ...

Note I said an isolated modern attack, and I don't believe the millions following blindly following the emperor were more rational than today's folks. Hiroshima is still there IMO because 1) Japanese cities were in ruin everywhere, there wasn't any next town over immune to the war, 2) Millions of Japanese soldiers and civilians (eight IIRC?) had already died the war so the shock from 250k at Hiroshima would be weighed against that, 3) Japanese civilians likely had not even heard of radiation, or certainly had little understanding of it, 4) Hiroshima was an air burst, a modern terror bomb would likely be ground based and thus cause much more fall out.

 

[vanesch]

Note I said an isolated modern attack, and I don't believe the millions following blindly following the emperor were more rational than today's folks. Hiroshima is still there IMO because 1) Japanese cities were in ruin everywhere, there wasn't any next town over immune to the war, 2) Millions of Japanese soldiers and civilians (eight IIRC?) had already died the war so the shock from 250k at Hiroshima would be weighed against that, 3) Japanese civilians likely had not even heard of radiation, or certainly had little understanding of it, 4) Hiroshima was an air burst, a modern terror bomb would likely be ground based and thus cause much more fall out.

A ground explosion would be "dirtier", true, but it would also limit the blast to a much smaller area.

I'm not saying that a nuclear terrrorist attack wouldn't be terrible. But objectively speaking, the world wouldn't stop turning. I don't think it would make more victims than car traffic does per year. And, again, I think we should wait for some of these to happen before we can talk seriously about it. Even if there were some nuclear terrorist attacks (say, one every 3 years), I still think that my own probability of dying in a car accident would be greater than dying from a nuclear terrorist attack. So before I'd tackle nuclear terrorism, I'd have to stop driving my car.

 

[mgb_phys]

The point isn't wether nuclear weapons are messy, it's wether the possibility of terrorists making one from reator waste is a good reason not to build reactors.
It's like deciding not to build hydroelectric dams in case someone gets hold of a Lancaster bomber and a bouncing bomb - although the FCC would probably just ban old British war movies instead.

 

[mheslep]

...And, again, I think we should wait for some of these to happen before we can talk seriously about it. ...

?? You can't mean that.

 

[russ_watters]

Any modern city that suffers a single, isolated, nuclear attack is done. All the survivors will simply leave.

That isn't true. Both Hiroshima and Nagasaki are, today, thriving cities. They were never abandoned.

It would take a very large bomb to make a city uninhabitable.

You may have to cordon-off a few city blocks for an intense cleanup lasting a few years, though...kinda like ground-zero for 9/11.

 

[russ_watters]

The potential energy in an LNG tanker is much higher! But of course it wouldn't be as much an explosion, rather than a big fire, which reduces significantly the blast effects.

I wonder what the prospects would be for turning an LNG tanker into a FAE. I saw a cop show where some sort of industrial plant or train had a fire and when he was driving toward it, the cop started driving through a weird-smelling fog. It was propane. He backed away (at like 40 mph) and it exploded in an enormous fireball.

Things like this are much smaller than an LNG ship:
http://www.youtube.com/watch?v=Xf3WKTwHpIU&feature=related

 

[russ_watters]

Yes that's why I said power, not energy, stemming from the completion of a nuclear detonation in nano or microseconds vs the magnitudes slower shockwave and heat transfer used in chemical detonations.

That really isn't relevant because:

In WWII London and other cities received TNT tonnage greater than Hiroshima's and clearly nothing close to Hiroshima effects occurred.

That just plain isn't true. On March 10, 1945, American bombers dropped 1.7 kilotons of firebombs on Tokyo (about 1/10th the explosive yield of the nukes used later), killing about 100,000 people - more than in either nuclear attack, and decimating the city.

If you looked at the pictures and didn't know what you were looking at, you probably wouldn't know which was which: http://en.wikipedia.org/wiki/Image:Tokyo_1945-3-10-1.jpg
http://en.wikipedia.org/wiki/Image:AtomicEffects-Hiroshima.jpg

Due to better construction, Dresden fared somewhat better, losing an estimated 20-40,000 people from twice as much ordinance over two days.

 

[russ_watters]

?? You can't mean that.

He absolutely does and I'm right there with him on that. It just seems to me that you don't understand risk analysis or perhaps are simply ignoring the concept in favor of fear-based reasoning. The level of risk is based on both:
1. The probability of the event occurring.
2. The severity of the event.

Only by combining the two can you have an assessment of the actual risk. And as he pointed out, even if you make rediculously pessimistic assumptions about both the probability and the severity, you still don't end up with a risk that is worth avoiding nuclear power over or being more afraid of than, say, driving your car.

Certainly any material has some non zero chance of being illegally diverted, that chance growing the more abundant and widespread the material.

There are lots of bad events that have a non-zero possibility of happening. That doesn't mean we should worry about all of them. If we did, we'd all spend our days locked in our hardend-concrete panic-room bunkers.

It depends on your driving habits, but the typical lifetime odds of dying in a car accident are about 1.2%. As such, the fear level and thus caution level of drivers should be extremely high.

And yet people fear nuclear weapons. Why? People understand cars. They don't feel as dangerous. Nuclear weapons are scary things. So people fear them. Irrationally.

 

[mheslep]

That isn't true. Both Hiroshima and Nagasaki are, today, thriving cities. They were never abandoned.

It would take a very large bomb to make a city uninhabitable.

And neither meet my conditions - I detailed why above. If Love Canal could be abandoned I think even the smallest nuclear detonation would without question mean the end of a modern city.

 

[mheslep]

He absolutely does and I'm right there with him on that. It just seems to me that you don't understand risk analysis. The level of risk is based on both:
1. The probability of the event occurring.
2. The severity of the event.

Only by combining the two can you have an assessment of the actual risk. And as he pointed out, even if you make rediculously pessimistic assumptions about both the probability and the severity, you still don't end up with a risk that is worth avoiding nuclear power over or being more afraid of than, say, driving your car. There are lots of bad events that have a non-zero possibility of happening. That doesn't mean we should worry about all of them. If we did, we'd all spend our days locked in our hardend-concrete panic-room bunkers.

It depends on your driving habits, but the typical lifetime odds of dying in a car accident are about 1.2%. As such, the fear level and thus caution level of drivers should be extremely high.

And yet people fear nuclear weapons. Why? People understand cars. They don't feel as dangerous. Nuclear weapons are scary things. So people fear them. Irrationally.

Doesn't appear you read all the thread. The first part of this response - that you agree with the declaration "wait for some of these [nuclear terror attacks] to happen before we can talk seriously about it is disconnected with the rest of the post. The suggestion that we can't even talk about this prior to some horrific event has nothing to do with risk analysis. And I understand it well enough, thank you, and I suspect so do the authors of the MIT report. I also know that risk are often irrationally assessed by those in the grip of 'go' fever, the Challenger accident being a prime example.

 

[mheslep]

...In WWII London and other cities received TNT tonnage greater than Hiroshima's and clearly nothing close to Hiroshima effects occurred.

...That just plain isn't true. On March 10, 1945, American bombers dropped 1.7 kilotons of firebombs on Tokyo (about 1/10th the explosive yield of the nukes used later), killing about 100,000 people - more than in either nuclear attack, and decimating the city.

Yes, what I said about London and other cities is true. http://news.bbc.co.uk/2/hi/uk_news/england/london/4655437.stm" alone and it was not leveled, nor did the daily life of the city grind to a halt. I'm well aware of the fire bombings of Dresden and Tokyo. I purposely left them out because they're misleading on the topic of one hit nuclear vs chemical attacks - the bombs start the fire but a great deal of the energy comes from the ignitable fuel on the ground. The only way any non-state actor is going to start a fire storm in a modern city is with a nuclear weapon. No planes into buildings or load of LNG will do it.

BTW, I am not blindly anti-nuclear - weapon or electric power.

 

[russ_watters]

And neither meet my conditions - I detailed why above. If Love Canal could be abandoned I think even the smallest nuclear detonation would without question mean the end of a modern city.

Centralia, PA has also been abandoned (due to an underground coal fire). But neither is a very large place, so it doesn't make sense to compare the abandoning of a tiny town to the abandoning of an actual city.

Your conditions are - for pretty much everythig about this subject - unreasonable.

 

[russ_watters]

Doesn't appear you read all the thread. The first part of this response - that you agree with the declaration "wait for some of these [nuclear terror attacks] to happen before we can talk seriously about it is disconnected with the rest of the post. The suggestion that we can't even talk about this prior to some horrific event has nothing to do with risk analysis.

The words were "talk seriously". It is extremely difficult to get an accurate risk assessment of an even that is exceedingly rare/unlikely. But the fact that it is exceedingly rare/unlikely means that it is also not worth wasting much effort on.

And I understand it well enough, thank you, and I suspect so do the authors of the MIT report.

Have you or they done any actual risk assessment calculations?

I also know that risk are often irrationally assessed by those in the grip of 'go' fever, the Challenger accident being a prime example.

The Challenger is an example of a management failure, but in any case, the pre-program risk assessment of the Shuttle program turned out to be pretty good. IIRC, they predicted they'd lose about 1 for every hundred launches.

 

[mheslep]

The words were "talk seriously". It is extremely difficult to get an accurate risk assessment of an even that is exceedingly rare/unlikely. But the fact that it is exceedingly rare/unlikely means that it is also not worth wasting much effort on. ...

First, that is fallacious, as I think you'll see on rereading, begging the question: "It is extremely difficult to get an accurate risk assessment of an event that is exceedingly rare/unlikely." and then go on to state it is a "fact that it is exceedingly rare/unlikely". I haven't yet seen convincing arguments about how vanishingly small or unlikely such an event is in this forum. And, please don't then take this statement to mean I believe it is likely. Second, and from your #2 above, even if the chance is vanishingly small, it is only not worth spending time on the subject if the impact of such an event is not catastrophic, and I think it would be as demonstrated above - far more than any LNG explosion or any several years of car wrecks: halt to nuclear power (a bad thing), closing of ports and borders, world wide economic impact, etc.

 

[mheslep]

... The Challenger is an example of a management failure, but in any case, the pre-program risk assessment of the Shuttle program turned out to be pretty good. IIRC, they predicted they'd lose about 1 for every hundred launches.

Well the nuclear industry has management as well. Challenger failure prediction went from 1:100 to as high as 1:100000.
Volume 2: Appendix F - Personal Observations on Reliability of Shuttle
by R. P. Feynman
http://history.nasa.gov/rogersrep/v2appf.htm

 

[vanesch]

First, that is fallacious, as I think you'll see on rereading, begging the question: "It is extremely difficult to get an accurate risk assessment of an event that is exceedingly rare/unlikely." and then go on to state it is a "fact that it is exceedingly rare/unlikely".

Well, visibly it didn't happen yet. Maybe it never will. In order to get an idea, an order of estimate, of some class of events which are so elusive that no a priori mathematical model can tell you, you need some statistics. Visibly we're not talking about a probability of more than 1 in 10 years, right ? There have now been enough "slices of 10 years" where it wasn't strictly speaking impossible to have a nuclear terrorist bomb, and we didn't have one. So claiming that we will have one every 3 years is not going to be correct. But is it one every 20 years, or one every 200 years ? Or one every 2000 years ? We'd need at least 2 or 3 events to get even an idea of that. Even one event would already exclude the "every 2000 years".

Because it makes a big difference. If it is "one every 200 years, or one every 2000 years", then it really is something one shouldn't worry too much about. Cities do get leveled "regularly" on that time scale, be it by war events, natural catastrophes, accidents, whatever. So if we are on that time scale, the size of the event doesn't even matter much. It's in the noise of what happens in any case.
If it is every 10 or 20 years, then things are different. Then they start to be an observable risk - still much smaller than most daily risks like driving a car, but it becomes something one should keep an eye on.

That doesn't mean one should be careless. All measures that do not entail large economic costs and can make it more difficult to have such a terrorist attack, are to be taken of course. That's a matter of balancing the costs and the benefits. So strict accounting of spend fuel, security at the reprocessing facilities, inspections, independent control mechanisms etc... are necessary.

That said, there's no reason that a terrorist bomb that explodes, say, in Europe, must come from material that came from a factory in Europe. (fill in "US", or whatever place).

But taking drastic measures, like banning nuclear power, or banning fuel reprocessing (and hence dividing the potential energy use of nuclear fuel by 100) for a potentiality of which there has never even been a single manifestation, sounds somewhat crazy to me. It might be like the guy who puts red poles around his house, against attacks of the giraffes. When his neighbor points out that there aren't any giraffes in the country, even less groups of giraffes that attack houses, he says that one should thank him, it's thanks to his red poles. They're more efficient than he thought!

It might be that a nuclear terrorist bomb is in fact impossible, simply because of the structure of terrorism. Maybe it is not their thing. Maybe the work and organization needed to make a nuclear weapon is incompatible with the way most organized terrorist organizations work. Maybe it doesn't fit in their politics. In that case, the effective probability of having a nuclear terrorist attack is in fact zero.

As someone pointed out, a much easier strike by a terrorist group would be blowing up a dam. It has never happened either. Happily, nobody stopped building dams in the beginning of the 20th century because of this potentiality.

 

[mheslep]

Well, visibly it didn't happen yet. Maybe it never will. In order to get an idea, an order of estimate, of some class of events which are so elusive that no a priori mathematical model can tell you, you need some statistics. Visibly we're not talking about a probability of more than 1 in 10 years, right ? There have now been enough "slices of 10 years" where it wasn't strictly speaking impossible to have a nuclear terrorist bomb, and we didn't have one. So claiming that we will have one every 3 years is not going to be correct. But is it one every 20 years, or one every 200 years ? Or one every 2000 years ? We'd need at least 2 or 3 events to get even an idea of that. Even one event would already exclude the "every 2000 years".

Agreed with all except next to last sentence "need at least 2 or 3 events". Flooding events, for instance, are forecast to 1 in 100, or 1 in 500 years for instance with little (or none?) record though of course that random variable has some distribution on the low side that can be studied.

Because it makes a big difference. If it is "one every 200 years, or one every 2000 years", then it really is something one shouldn't worry too much about. Cities do get leveled "regularly" on that time scale, be it by war events, natural catastrophes, accidents, whatever. So if we are on that time scale, the size of the event doesn't even matter much. It's in the noise of what happens in any case.
If it is every 10 or 20 years, then things are different. Then they start to be an observable risk - still much smaller than most daily risks like driving a car, but it becomes something one should keep an eye on.

That doesn't mean one should be careless. All measures that do not entail large economic costs and can make it more difficult to have such a terrorist attack, are to be taken of course. That's a matter of balancing the costs and the benefits. So strict accounting of spend fuel, security at the reprocessing facilities, inspections, independent control mechanisms etc... are necessary.

Agreed.

That said, there's no reason that a terrorist bomb that explodes, say, in Europe, must come from material that came from a factory in Europe. (fill in "US", or whatever place).

Ok, Russia.

But taking drastic measures, like banning nuclear power, or banning fuel reprocessing (and hence dividing the potential energy use of nuclear fuel by 100) for a potentiality of which there has never even been a single manifestation, sounds somewhat crazy to me.

Agreed.