Nuclear power

[eledille]

Thanks for your careful post, eledille.

Thank you for the kind words, I enjoy the discussion. I love it when people are willing to look at the numbers. Now let's see if I can convince you with this monster post

To start with the scenario "Germany is an island, missing 20TWh within 2 weeks". ... should France or Norway stop trading electric power with us ...

This scenario does not depend on unwillingness to export power by the neighboring countries. We are trying to eliminate coal, nuclear and NG completely, Germany's neighbors are doing the same, indeed, they are being forced to do so by the EU. Even France is building windmills. The situation in which all of Europe is covered by clouds and lacking wind is not uncommon. Solar doesn't contribute much during winter anyway, so a lull is very challenging in itself. In these scenarios, the neighboring countries will be struggling to cope with their own massive losses of unreliable renewable power.

Norway might contribute a little due to our gigantic hydro reservoirs, but the problem is the enormous power required. We have lots of stored energy, but only a little bit more generator capacity than we need. Total capacity is about 30 GW, and we need about 25 of those ourselves. Increasing power delivery would be enormously costly and very controversial due to environmental concerns - fish does not like rivers that are a raging torrent one day and a trickle the next, and the insect larvae on the bottom of the lakes die when they're suddenly 10 meters above the water. Norway will not volunteer to become an environmental disaster area, and if anyone tried then you can count on chain gangs and sabotage. The government has met massive problems trying to build a transmission line which is essential to secure supply to Bergen. A forest of power lines for the benefit of Germany is out of the question, and even a tripled export capacity would be a drop in the ocean when all of Europe needs power at once.

Germany will have to fend for itself.

Today's installed capacity is 25GW. Typical efficiency is 60% so we need to feed them with 33TWh of natural gas during that two dark winter weeks. The German natural gas network features 47 storage units, holding a total of 24b cubic meters today. 1m³ NG = 10kWh so total stored energy is 240TWh, well in excess of that required 33TWh.

Good, so NG can fill in, but you need to more than double installed capacity to back up those two weeks. Who will pay for the standby capacity? CCNG costs about 1 billion euro per GW, so you need about 35 billion, not counting running expenses (maintenance, minimum staff). Two weeks of operation per year is not going to pay for the investment. Surely, the unreliable sources will have to pay for their own backup, how does this affect the cost of wind power?

A 6MW demonstration plant for methane synthesis from surplus electrical power goes online in 2013. Planned efficiency is 60%. If we assume that during 50 week's time, these plants operate for 20% of the time (when surplus power is generated) to cover these 2 dark weeks per year, the required synthesis generation capacity is 33TWh in 10 weeks, equaling 20GW natural gas output and 33GW electrical power input. A whopping 5500 plants will do the job. :scared:

There is no way that they can have 60% round-trip efficiency. I bet that's just methane generation efficiency, and if so, it's extremely good, electrolysis is usually said to be about 50% efficient, and these guys add another complex step and increase efficiency to 60%. They're trying to sell the concept, so I'm tempted to think they're exaggerating, but let's use their figure anyway. This means that you need to input 33 TWh to get 20 TWh of methane. But you need 33 TWh of methane to get the 20 TWh of electricity, so electrical input will have to be 55 TWh. You need nine thousand two hundred of those plants. Oh, wait - I forgot transmission losses. Multiply by 1.07. Assume they're about as costly as CCNG plants - add another 40 billion plus running costs.

Methaniation requires an input of massive amounts of CO[sub]2[/sub]. You need one molecule of CO[sub]2[/sub] per molecule of methane. This carbon must be captured from either the atmosphere or a biomass plant equipped with a CCS system to be carbon neutral. Is there enough biomass in Germany to provide all that CO[sub]2[/sub]? Biomass for this purpose would also compete with both solar panels and biofuel for the aviation industry. Or you might add CCS to the CCNGs themselves, and feed their own CO[sub]2[/sub] back to the methaniation plants. All of these alternatives are also shockingly expensive. Add another ... 20 billion? Plus a CO[sub]2[/sub] distribution system, I have no idea what that might cost.

Further, there is an energy cost to capturing all that CO[sub]2[/sub] that you did not count. This is likely to be about 25%. Now we're up to 80 TWh input to the storage system. But there are no guarantees that there will not be two episodes like this per year. One might want to have some extra methane capacity on hand and the windmills to power it.

Now we're approaching the real cost of unreliable energy. I'm counting at least 115 billion euro - in addition to the cost of the unreliable renewable generation capacity itself.

This back-of-envelope calculation neglects any possibilities of further efficiency increases, better power demand management, or vehicle-to-grid services.

These are mature technologies, there are no revolutionary efficiency increases to be had. Power demand management might help a little bit, but don't expect much, BMW will be less than impressed if you tell them that they have to stop their factories for a week. V2G might actually help by a noticeable amount, but this time, the problem is energy capacity. You need two or three weeks of backup, not two days.

The price of the backup system alone will pay for 40-50 GW of modern reactors, which would provide 70 to 85% of Germany's power. Together with the renewables already installed, demand management and V2G, this might actually do the trick.

I don't care how Germany rids itself of carbon, and coal in particular, it's just that I can't see how it can be done without nuclear. There isn't enough money.

I encourage you to take another long, hard look at the Integral Fast Reactor and try to identify its weaknesses. I can't find a single flaw, except for the word "nuclear". That is a significant disadvantage, however.

It's an extremely elegant solution, everything has been thought of, no loose ends are left dangling. I would recommend buying "Plentiful Energy". It's a bit repetitive and somewhat dry, but it does examine the design in great detail, and was written by those who know it best. You'll get through it in a week. You can find most of the material by starting at this post at the bravenewclimate blog and following the links, if you don't want to pay those Argonne pro-nuke technofixers for their book (tongue-in-cheek).

We need to start building solutions now, we can't wait for the IFR. So take a look at AP1000 and ESBWR and try to find their weaknesses too, under the assumption that we will be deploying IFRs en masse in ten to fifteen years. If you would try your best to shoot down that plan, then I would be happy to try to defend it :biggrin:

Take all the time you want responding, I can't keep this pace up anyway. :scared:

*edit*

Changed from "renewable" to "unreliable renewable". There are multiple types of reliable, renewable power, e.g. hydro, osmotic and tidal power. I'm all for those, they have no hidden costs. Solar energy in the deserts of northern Africa might also possibly qualify as reliable, I'm not sure.

 

[Bipo]

Here you can see the energy mix of Spain and how the wind power gives us lots of zero-carbon, zero-radioactivity, free GWh:

IMHO Wind, solar, hydro... That's the future, not the nuclear way

P.S: The darker green strip above the eolic one shows solar + industrial cogeneration.

 

[eledille]

Bipo: Nice charts. I have no doubts whatsoever that wind and solar can generate lots of kWhs. The problem is that you can't control when. You can't take the wind to court and order it to blow.

You can choose between a carbon neutral reliable backup for the unreliable sources, or you can choose unreliable power and accept that Spain comes to a grinding halt for weeks at a time. How long can you be without power before the food in your fridge spoils?

Do you have a solution to the problem we were discussing?

Robert.Boston: Wave might contribute, but not by much. Britain is very well endowed with wave power - it's ideally positioned right in the path of the waves of the Atlantic. Still, MacKay estimates the upper bound to be 4 kWh/day/person. That's about 2-3% of the needed amount. Tide is good stuff though, particularly because it's reliable. MacKay's estimates for Britain are here, he gets a maximum of about 8% of UK consumption. Britain is exceptionally well endowed with tidal power. We still need to find a way to store 80% of UK consumption for two or three weeks.

 

[RDoc]

While I'm a strong supporter of nuclear power, I do think that the current pressurized water technology is operationally unstable, far too prone to catastrophic failure, requires unmanageable construction projects, and produces far too much waste which is politically undisposable. IMHO we really need a different technology, one possibility being modular molten salt thorium reactors.

The main problem with nuclear power going anywhere, as I see it, is the entire nuclear industry's culture which results in huge, complex, wildly expensive projects. Perhaps the industry needs someone like Elon Musk who forces a completely different attitude to reactor design and construction as he's done for rockets with SpaceX. Failing that, I don't think nuclear has a future for both economic and political reasons.

Unfortunately, I doubt that the alternative is renewables due to unsuitability for base load use and cost. Natural gas looks to me like the likely world's energy source for some time to come, first from fracking, then as that runs out from methane hydrates. That of course leads to runaway global warming.

 

[Johan]

While I'm a strong supporter of nuclear power, I do think that the current pressurized water technology is operationally unstable, far too prone to catastrophic failure, requires unmanageable construction projects, and produces far too much waste which is politically undisposable. IMHO we really need a different technology, one possibility being modular molten salt thorium reactors.

The main problem with nuclear power going anywhere, as I see it, is the entire nuclear industry's culture which results in huge, complex, wildly expensive projects. Perhaps the industry needs someone like Elon Musk who forces a completely different attitude to reactor design and construction as he's done for rockets with SpaceX. Failing that, I don't think nuclear has a future for both economic and political reasons.

Unfortunately, I doubt that the alternative is renewables due to unsuitability for base load use and cost. Natural gas looks to me like the likely world's energy source for some time to come, first from fracking, then as that runs out from methane hydrates. That of course leads to runaway global warming.

IFRs operate at normal pressure. The cooling/heat transfer is done via liquid sodium (at near atmospheric pressure). The only thing that's pressurized water is the steam turbine, but that's hardly dangerous?

Clarification/Elaboration:

Modern (gen. III/IV) IFR (Integral Fast Reactors) operate as described above. Since they operate with a different fuel mix than older generation reactors they cannot go in to "runaway" meltdown mode, even if the circulation of cooling is interrupted (in their case liquid sodium). With an old generation reactor it would be disastrous if the water pumps stopped, that why they often have three or four redundant pumping/cooling systems and also why they are so expensive to build.

In a modern reactor there is one closed loop of liquid sodium which in turns heats another closed loop of liquid sodium which in turn heats the water to vapor which drives the turbine. The water/stem-turbine component can be in another structure some way from the actual reactor core, though I don't think you would want to complicate the design like this? IFR's are extremely safe. We should convert to only building them, and we should change out coal burners in existing coal plants to IFR design reactor, while keeping the same turbines. An IFR requires very little input of fuel once it is started, and it only requires non-enriched uranium which isn't even dangerous to handle. The waste is minimal compared to old. gen. nuclear plants and is only radioactive for 200-300 years.

 

[Bipo]

Bipo: Nice charts. I have no doubts whatsoever that wind and solar can generate lots of kWhs. The problem is that you can't control when. You can't take the wind to court and order it to blow.

You can choose between a carbon neutral reliable backup for the unreliable sources, or you can choose unreliable power and accept that Spain comes to a grinding halt for weeks at a time. How long can you be without power before the food in your fridge spoils?

Do you have a solution to the problem we were discussing?

Here in Spain we use the natural gas combined-cycle turbines to get enough power when the wind doesn't blows. In fact, the peak power of the grid at the worst day is about 42 GW, but we have 100 GW of installed power. Spain exports electricity 24/7, to Portugal, to Morocco and even to France sometimes. There is not blackouts (the last that I remember here was several years ago, after a lightning, and only last a couple of hours), so our grid is extremely reliable. We have built lots of 400 kW long distance connections so we are ready to generate and delivery electricity across the whole country.

To answer your question: IMHO the backup power for renewable energy should be natural gas until we develop more hydroelectric accumulators and, eventually, static batteries deployed all over the country (maybe inside each house), and managed by the grid operator. That will allow the grid to store electricity when it's generated but cannot be spent. Of course the electric car should allow us to store electricity during the night, when there is a great excess of production available. Smart grids are the answer.

 

[eledille]

While I'm a strong supporter of nuclear power, I do think that the current pressurized water technology is operationally unstable, far too prone to catastrophic failure, requires unmanageable construction projects, and produces far too much waste which is politically undisposable. IMHO we really need a different technology, one possibility being modular molten salt thorium reactors.

LFTRs are a promising idea, I agree. Their primary advantage over the IFR is that they run hotter, which means that higher efficiency is attainable. An LFTR can drive a gas turbine instead of a steam turbine, which bumps efficiency up from the mid thirties to the low forties. Their primary drawback is that they are much, much less tested and researched. They probably need 20 years of development before they can be commercialized, while the IFR can be built right now. In fact, the British are currently considering GEH's offer to build two of them at Sellafield to destroy surplus plutonium.

The IFR is proven, commercial designs are ready, and it is at least as safe as the LFTR. But the IFR can do some things that an LFTR can't, for example burn spent nuclear fuel and depleted uranium. Also, the IFR can breed fuel for traditional reactors. This will become important if uranium becomes scarce.

I agree in principle that the LFTR and IFR are a great security improvement over pressurized reactors. On the other hand, both AP1000 and ESBWR would have handled the Fukushima scenario without problems, they don't need electricity or operator intervention to keep cool. Should the emergency coolant run out after two or three days, then all that is needed is a firehose to refill the non-pressurized tanks. ESBWR doesn't even have any coolant pumps, the core is cooled entirely by convection and the tendency of steam bubbles to rise and suck water through from below. They are a massive improvement over older designs. They do produce as much waste as gen II reactors, though, so they should in time be replaced with IFRs.

The main problem with nuclear power going anywhere, as I see it, is the entire nuclear industry's culture which results in huge, complex, wildly expensive projects. Perhaps the industry needs someone like Elon Musk who forces a completely different attitude to reactor design and construction as he's done for rockets with SpaceX. Failing that, I don't think nuclear has a future for both economic and political reasons.

But that is almost entirely the fault of the extremely tight regulations and continuous regulation changes, protests and demonstrations, and particularly the legal action by the anties.

Unfortunately, I doubt that the alternative is renewables due to unsuitability for base load use and cost. Natural gas looks to me like the likely world's energy source for some time to come, first from fracking, then as that runs out from methane hydrates. That of course leads to runaway global warming.

Well, that is what we must try to avoid, isn't it?

- - - Updated - - -

Bipo: Spain currently has approximately 30% renewable electricity. Non-fossil electricity needs to increase to very close to 100%. The question is how to do that. You might find the following articles articles interesting:

Not enough reliable wind? (environmentalresearchweb blog) - environmentalresearchweb
Geographical wind smoothing, supergrids and energy storage BraveNewClimate

 

[Bipo]

Bipo: Spain currently has approximately 30% renewable electricity. Non-fossil electricity needs to increase to very close to 100%. The question is how to do that. You might find the following articles articles interesting:

Not enough reliable wind? (environmentalresearchweb blog) - environmentalresearchweb
Geographical wind smoothing, supergrids and energy storage BraveNewClimate

Thanks a lot, very very interesting articles

 

[eledille]

Thanks a lot, very very interesting articles

The second article above pretends that there exists an intercontinental supergrid combining wind power in Australia, the US and Ireland - and still gets the same depressing results.

Another one, this is a must-read: Windbyte - Wind farms in North East England, the Scottish Borders and Lothians - Wind Power Generation

Also note that the wind critics as a general rule rely on statistics and real data, while the wind proponents are more liable to rely on handwaving.

You need to back your wind power up at least 95% with something reliable. There are places where wind power is useful, for instance in Norway. We can install as much wind power as we like, because we are already fully backed up by hydro. Whenever the wind blows, we can simply throttle hydro and save water. But as far as I know, no other nation on earth is in such a fortunate position. This is because we are essentially a mountain range colliding head-on with the the Gulf Stream, and there is a whole lot of Norway per Norwegian.

Wind should be thought of as a fuel-saver for whatever reliable power you have, and not a primary energy source in itself. The way the system is currently set up, however, wind destroys the business of the reliable power sources without providing the same essential reliability or having to pay for backup. Wind without carbon neutral backup does not enable a transition away from fossil fuels. Nuclear does.

 

[Johan]

The reality is wind, solar, waves, hydro are always going to be niche players, but in some local regions they can be major players. On a global scale the only solution will be nuclear - fission or fusion. Fusion is as of today not yet solved, so then it must be fission. It should be the new generation of fission and in the form of IFR since these will all of the current "nuclear waste" as fuel that could last literally hundreds of years - while at the same time not being prone to melt downs/disasters. The right questions have been asked already in this thread - does anyone else have a realistic answer to the global problem?

 

[Robert.Boston]

[moderator's note: posts on ocean energy have been moved to their own thread.]

 

[eledille]

Preliminary experimental results contradict the LNT model

High radiation doses show a more or less linear dose-response relationship. This is well established from studies of the survivors of the atomic bombings of Japan, among others. Their combined cancer risk increased by about one to two percent, and those exposed to a higher dose had a more or less proportionally higher chance of developing cancer. The data is also compatible with a non-linear curve, it's too noisy to say which curve fits better.

However, at low doses and low dose rates, the effects of radiation are too small to detect. The lowest dose rate that can currently be linked to increased cancer risk is approximately 100 mSv per year. To deal with this lack of data, the linear dose-response curve established for high doses and high dose rates was simply extrapolated linearly down to zero dose. This is called the Linear No-Threshold hypothesis (LNT), and this model is what radiation protection agencies around the world use in their work.

The LNT hypothesis postulates that all ionizing radiation regardless of dose or dose rate is harmful, and this has a huge effect on the cost of nuclear power. One example is that if it turns out to be false, then the area around Fukushima should not have been evacuated, or the evacuation zone should at least have been a tiny fraction of the size it is today. Spent nuclear fuel would also have been much less of a problem.

The LNT hypothesis has long been controversial, there are very good biological reasons to assume that it's wrong. Most biological phenomena do not work this way. To exemplify what a linear no-threshold dose-response curve means, I will use a more familiar agent: Aspirin. Assuming the Aspirin dose-response curve is of the LNT variety, and we give 20 Aspirin to each of 100 persons in a single dose and find that two of them died (a very unethical experiment), then a dose of 2 Aspirin to each of 1000 persons still yields two deaths. Moreover, if we tell the 1000 persons to scrape a tiny bit of their two Aspirin onto their breakfast in such a way that the two pills are consumed evenly over a whole year, the result will still be 2 deaths in the population.

Aspirin in fact has a hormetic dose-response curve, large studies show that if a population takes 1/2 Aspirin per day, their health improves by a small but detectable amount. On the other hand, some substances show at least some similarities to LNT - there is for example no safe dose of lead.

Radiation causes cell damage in essentially the same way as a myriad other agents - by breaking random chemical bonds in the cells and their DNA. The oxygen we breathe does the same thing. To deal with this, cells are equipped with extremely efficient repair mechanisms, and if those do not work, the cell will almost always commit suicide. Those that don't may turn into cancer cells. The repair mechanisms are known to be time dependent, and multiple broken bonds at the same time are less likely to be successfully repaired than single breaks happening one or a few at a time. This points towards a non-linear curve.

There are large studies that hint at a non-linear dose-response curve in real life too - for example, aircrews are exposed to much higher levels of radiation than the rest of the population, the equivalent of more than 1000 extra chest X-rays per year. Yet they have no higher cancer rates. Tens of thousands of people exposed to hard gamma rays from US Navy reactors had lower rates of cancer than their non-nuclear counterparts doing exactly the same kind of work. These results are explained away by referring to what is known as the "Healthy worker effect": For some unknown reason, they must have been healthier than the rest of us to begin with.

Earlier LNT debunking in the monthly journal "Radiology", from 2009.

Now there are two experiments underway to test the validity of the LNT hypothesis. Since the effects of very small radiation doses above the normal background are so hard to detect, these experiments instead reduce the background radiation by a large amount. One cuts the background radiation to 1/3 of the natural level, the other removes it almost completely. If this is found to hamper cell growth, then low-dose radiation cannot possibly behave linearly.

This now seems to be the case. The data is still preliminary, but cell growth is hampered in the low-radiation environment in both experiments.

Press release from the US Department of Energy.

 

[EchoDelta]

I think the main conditional remark that "nuclear power" needs to be "done responsibly" and can be beneficial is the crux of my turnoff. IMHO very few contexts barely qualify as responsible - space exploration probably being the only one. One just needs to know how a little of how utilities and governments operate to understand there isn't any accountability towards avoidable catastrophes.

Fukushima and Chernobyl are disasters deeper than one can glimpse on the news - just the volume of earth and topsoil that will need to be removed in the latter makes it a pharaonic cleanup job. Interestingly enough, some natural species (eg mushrooms) tend to accumulate caesium so they could be ingeniously used as cleanup agents; but even so it is a major undertaking to get anywhere near to baseline.

(About me for context - 30's, started a major in particle physics in my young days, and am very glad my car won't be powered by nuclear)

While I used to think that nuclear fission could be a good transitional energy source, now I am convinced that accelerated infrastructure investment in renewables leads to a better and more resilient grid from a technical, ecological and economical perspective. (Even with its high total capital and operational expense) Whether that acceleration is enough to escape carbon, ocean acidification etc thresholds is TBD, as nobody knows where those thresholds really are anyways.)

 

[Johan]

With regards to the above (very nice) post by elefille: There is ample evidence already, more collecting, to completely refute the NLT harm model for ionizing radiation.

In fact, our cellular systems have evolved under, and in harmony with, continous (background) radiation exposure. It turns out most organisms with DNA actually become unhealthier if background radiation is blocked for long periods of time. This is a bit in analogy to another biologic fact: mammals delivered by C-section and then raised in a completely sterile environment develop disease in their gastrointestinal tract - we are not designed to live in abscense of neither germs nor radiation. And our systems have quite some margin. Earth has been subjected to quite variyng levels of radiation during the evolution of life.

 

[eledille]

EchoDelta:

If low dose rate radiation like that found in the Fukushima and Chernobyl evacuation zones is found to be harmless, are Fukushima and Chernobyl still disasters? If so, of what magnitude compared to e.g. a plane crash?

What about reactors that don't need off-site power, backup generators, backup coolant pumps, primary coolant pump, water injectors or even operators for three days at a time, if Fukushima-style radioactive releases are harmless? Such a reactor exists (ESBWR), and that's what the data is might indicate.

Even if LNT should turn out to be correct after all, one might still ask whether a risk that is too small to detect using the best statistical methods available is worth worrying about when people routinely engage in risky activities like breathing smog, eating meat and driving cars, and the globe is heating up at a disastrous rate.

 

[EchoDelta]

EchoDelta:

If low dose rate radiation like that found in the Fukushima and Chernobyl evacuation zones is found to be harmless, are Fukushima and Chernobyl still disasters? If so, of what magnitude compared to e.g. a plane crash?

* Harmless for humans in 'state of the art for 2012' given the lack of true cohorts and inability to do real experiments seems a bit of a low safety bar to me. As Johan exemplifies, we understand very little about the subtle interplay of environment and the body & mind. I work with- and live with- doctors... they just figured out ~150 ys ago that washing hands and using antiseptics may prevent deaths. My opinion is that we still lack the tools to come to such conclusion.
* Harm is rarely related to direct exposure other than right during or after an emergency. In the long run you are looking at topsoil and farmland and water systems; each species and physical subsystem has its dynamics for different elements that accumulate or dissipate them. The example I gave above- Caesium being concentrated by mushrooms is a great example - it can be a dangerous contamination vector or a great cleanup tool, depending on your perspective. Very few people will picnic for a while on the plains of fukushima, or carry their pregnancies there, more people will eventually eat drink wear & breathe what grows out of there.
* I've been following the ESBWR work and the TWR approaches (in my layman opinion the latter seems quite interesting).Maybe too old fashioned, but I spent a summer working in a CANDU which was an interesting experience - everyone in a reactor knows every failsafe, every stable state has threats which have mitigations which in turn have threats etc. I recall the constant feeling that "For the want of a nail..."
* In addition, the supply chain for uranium is complex & dirty. Development and installation requires highly centralized control and therefore government subsidies and for a policy/monitoring/inspection apparatus.

Even if LNT should turn out to be correct after all, one might still ask whether a risk that is too small to detect using the best statistical methods available is worth worrying about when people routinely engage in risky activities like breathing smog, eating meat and driving cars, and the globe is heating up at a disastrous rate.

A big difference with eating meat and drinking coca cola is choice. It is unlikely individuals can choose not to be exposed to radiation from a reactor gone wrong that someone else installed remotely yet too close to your backyard, while they can choose to engage in some of the other risk behaviors. And especially when the approach to measurement of the risk is a matter of policy, politics and debate more than exact science.

Thinking fairly I have not seen a cradle to cradle analysis of a fission reactor of any kind vis a vis solar panels or wind; relative to kWh generated, and relative to carbon footprint or some other planetary boundary denominator, and prorating all the externalities in R&D and supply chain and disposal and safety. Would love to see a good one one if anyone has pointers. Cheers to all for the engaging discussion.

 

[Yggdrasill]

A big difference with eating meat and drinking coca cola is choice. It is unlikely individuals can choose not to be exposed to radiation from a reactor gone wrong that someone else installed remotely yet too close to your backyard, while they can choose to engage in some of the other risk behaviors. And especially when the approach to measurement of the risk is a matter of policy, politics and debate more than exact science.

People can avoid some of the other risk factors, yes, but certainly not all of them. Coal power kills around 13,000 people per year in the US alone, and I would expect NOX emissions from cars to kill a comparable number. Now, one can of course choose to live in a cabin far away from cars and coal power plants, but that is no real choice.

Ideally, solar and wind is the way to go, but it is a bit optimistic (to put it nicely) to expect solar and wind to be able to supply 100% of the electricity in the short or intermediate term. As such, nuclear is a very good option, one that should definitely be a part of the grid until such a time as one has the luxury of replacing them with solar and wind.

 

[eledille]

Cheers to all for the engaging discussion.

* Harmless for humans in 'state of the art for 2012' given the lack of true cohorts and inability to do real experiments seems a bit of a low safety bar to me. As Johan exemplifies, we understand very little about the subtle interplay of environment and the body & mind. I work with- and live with- doctors... they just figured out ~150 ys ago that washing hands and using antiseptics may prevent deaths. My opinion is that we still lack the tools to come to such conclusion.

To a certain extent, that's true. In my opinion, it's also misleading.

There is actually a massive amount of very good science on the effects of ionizing radiation. The fact is that below a certain level, the effects are too small to measure. They may be small, nonexistent or even beneficial, we just don't know which. But they can not be large.

There is no lack of good cohorts or data. There are many very well controlled and some extremely large studies - but the effects attributable to radiation are simply so much smaller than so many other things that affect cancer rates that no matter how well you control and correct, the effects of radiation cannot be detected much below a one or two percent increase in lifetime cancer risk.

We do know, however, that the long-term effects from radiation among the survivors of a plutonium bomb detonation directly above a city is on the order of a couple of percent increase in lifetime cancer risk, and that among multiple tens of thousands of navy personnel performing identical work, those exposed to gamma radiation from reactors had lower cancer rates than their unirradiated counterparts. There's a long list of similar results.

Now we also know that cells are harmed by too little radiation - at least, that's what the preliminary data says.

* Harm is rarely related to direct exposure other than right during or after an emergency.

This is not correct. One perfect example is how leaded gasoline was finally banned due to overwhelming scientific evidence of the harmful effects of chronic, low-dose lead exposure. There are many, many other examples.

In the long run you are looking at topsoil and farmland and water systems; each species and physical subsystem has its dynamics for different elements that accumulate or dissipate them. The example I gave above- Caesium being concentrated by mushrooms is a great example - it can be a dangerous contamination vector or a great cleanup tool, depending on your perspective. Very few people will picnic for a while on the plains of fukushima, or carry their pregnancies there, more people will eventually eat drink wear & breathe what grows out of there.

Norway received a relatively generous share of the fallout from Chernobyl. We still have to give raindeer and sheep uncontaminated fodder for a while before slaughtering to get the activity count below the legal limits. I personally pick and eat mushrooms and don't worry about it.

I'm much more worried about the high and rising mercury content of freshwater fish than radiation. We didn't release the mercury either, that comes from European coal fired power plants.

What really scares me, however, is climate change.

* In addition, the supply chain for uranium is complex & dirty.

I'm sorry to say this, but I'm afraid you've been lied to. This is pure propaganda with zero connection to the real world. Compared to coal, the uranium supply chain is almost as innocent as a new-born baby.

Coal mining digs up and grinds down entire mountains. Such enormous quantities are required that there will be many accidents during mining and transportation and the environmental impact is very large. The ashes contain toxic heavy metals and are hard to dispose of safely. Besides, the stuff contains so much uranium that if burned in a fast reactor, more nuclear energy can be extracted from it than you can get by burning the coal itself. Where does that uranium go? Up the smokestack and into the landfill. This together with the fact that the uranium content of coal power waste is often listed only as "trace amounts" says something about the energy density of uranium - and how dirty coal power really is.

Some facts:

Fuel consumption per gigawatt-year (tons):

Coal	3500000​
Moderated fission	160​
Fast fission	1​

The number for moderated fission is for slightly enriched fuel. 1600 tons of natural uranium is required to produce it, which leaves 1440 tons of depleted uranium. CANDU reactors don't require this enrichment. Fast reactors require higher enrichment in the initial core loading, but they can produce more fissile material than they consume during operation. A new reactor can use the fissile material from a decommisioned reactor, so this is only required for startup, while the total number of reactors is rising.

Waste production per gigawatt-year (tons):

Substance	Coal	Moderated fission	Fast fission
Spent nuclear fuel	0​	160​	0​
Depleted uranium	0​	1440​	0​
Fission products	0​	0​	1​
CO[sub]2[/sub]	10000000​	0​	0​
Ashes	350000​	0​	0​
SO[sub]2[/sub]	35000​	0​	0​
NO[sub]x[/sub]	25000​	0​	0​
Soot	1200​	0​	0​
VOC	550​	0​	0​
Uranium	1 to 10​	0​	0​
Arsenic	0.25​	0​	0​
Mercury	0.19​	0​	0​
Lead	0.125​	0​	0​

190 kg of mercury is a huge amount. One teaspoonful of mercury in a soluble form will pollute a 5 km[sup]2[/sup] lake.

Natural uranium is slightly toxic and weakly radioactive. It is often mined in association with other ores. In Australia, uranium appears together with copper and gold, for example.

Finally, if we started building IFRs, we would not have to mine any more uranium for the next couple of thousand years. We already have more than enough depleted uranium and spent nuclear fuel in storage. There's a lot of information about the IFR here, or you can read the book "Plentiful Energy".

A big difference with eating meat and drinking coca cola is choice. It is unlikely individuals can choose not to be exposed to radiation from a reactor gone wrong that someone else installed remotely yet too close to your backyard, while they can choose to engage in some of the other risk behaviors.

I agree that choice is important. But when it comes to electricity generation, there is no perfect choice.

When I go fishing for perch or trout with my children, I have to be careful to remind them beforehand that if we get a big fish, we have to put it back, because it's poisonous - it contains too much mercury. We can only eat the little ones nowadays. You should have seen their faces the first time I told them this - incredulity, disappointment, dismay. We don't have any coal plants and I did not invite the European power industry to dump their mercury on Norway.

We used to have beautiful summers in Oslo, with temperatures between 25 and 30 and sunny weather for weeks on end. The previous six summers have been rain, rain, rain, oh gosh it's not raining today, rain, rain. Climate change? Who knows.

By the way, I'm not trying to pretend that Norway is an innocent victim or something like that. We export coal from Svalbard and oil from the North Sea and are as guilty as sin too.

It's entirely unclear whether it's at all possible to replace fossil fuels with undispatchable renewables like wind and solar. We had an interesting argument about that in this thread just a few weeks ago.

We do know that the environmental risk of nuclear power compared to fossil fuels is very low. The risk of failure compared to undispatchable renewables is also very low.

And especially when the approach to measurement of the risk is a matter of policy, politics and debate more than exact science.

Exact science has determined that the risk from even relatively high levels of radiation is too small to detect. That does not mean that it is nonexistent or unknown, it means that it is known to be at worst very small. Science has also determined that pollution from fossil fuels is vastly more damaging to health than that from nuclear fission, and that the risk from CO2 emissions is real and potentially catastrophic. A few degrees of warming might realistically cause massive desertification of the American Midwest and the Russian steppes, for example. This is where most of the world's wheat is grown. We're currently headed towards five degrees or more.

This is the WHO/UN/IAEA report on the true scale of the Chernobyl accident.

Thinking fairly I have not seen a cradle to cradle analysis of a fission reactor of any kind vis a vis solar panels or wind; relative to kWh generated, and relative to carbon footprint or some other planetary boundary denominator, and prorating all the externalities in R&D and supply chain and disposal and safety. Would love to see a good one one if anyone has pointers.

Here is one, brand new. This is a head to head comparison of a combined wind/solar and a nuclear alternative to two Australian coal fired power plants. The report compares the following parameters: Cost, electricity production, greenhouse emission reduction, job creation, area requirements, water consumption, major construction materials consumption, network requirements and reliability.

 

[dpeilow]

The Case for Near-term Commercial Demonstration of the Integral Fast Reactor BraveNewClimate

 

[EchoDelta]

To a certain extent, that's true. In my opinion, it's also misleading.
...

Here is one, brand new. This is a head to head comparison of a combined wind/solar and a nuclear alternative to two Australian coal fired power plants. The report compares the following parameters: Cost, electricity production, greenhouse emission reduction, job creation, area requirements, water consumption, major construction materials consumption, network requirements and reliability.

Thanks for the detailed and constructive post.

The information about the uranium mining I hadn't seen before and appreciate you sharing it and the links. I generalized from personal closeness to the industry..in Latin America -still anecdotal, but 'innocent as new born baby' is an easy goal when compared to coal extraction.

Thx again for the data and links.