Is there a new nuclear option that Permaculture can endorse?

Eric,

Yeah, I have no faith in “renewables” like solar PV and wind farms in terms of continuing current lifestyles and industrial operations. Just not enough EROEI compared to petroleum products. When I say conservation, just want to clarify that I mean actually using less energy and not just powering current US American lifestyles with solar PV or whatever. I personally would rather live low-tech and use homescale energy generation or just do without certain stuff, but for those less willing/able to do without certain comforts, I think large scale commercial renewables have a place as a stopgap measure, although I think solar PV in particular is not especially sustainable or renewable in reality (if we look at inputs). Even if it were more affordable to the consumer. Alas.

Eric, how long ago did you get that solar quote, At today's prices, most systems amortize pretty quickly.

Jennifer, the cost of these reactors and whether they will pay back is not likely to be an issue, the problem is the length of the investment period before the return on capital is there. These projects are relatively long term, especially in the US which is why many investors and researchers are fleeing to other friendlier countries where the regulatory climate is less severe, and the research can lead to licenses and new prototypes quicker.
Countries like China can move quickly and absorb the high upfront costs that will later pay back with dividends.  Politicians in this country can't afford long term projects that cost lots of money, raise taxes in the short term and get politicians fired.

As far as population 's correlation with energy, your fears may be misplaced.  Abundant, pollution free electricity may be able to reduce the demands on natural systems. Many forests are destroyed just to cook food and heat houses.  But I do agree, if you have listened to some of the claims the advocates make, they want to ride this energy well past the simple task of solving the waste issue and setting up sustainable systems, but that just means we have to infect more brains with Permaculture.  

Bob,

I base my assertion that human population growth and social complexity correlate with energy use on ecological frameworks (such as described in Catton’s book overshoot) which, to oversimplify, indicate that when resources are abundant, populations are able to increase rapidly, at which point they overshoot the carrying capacity of their environments and collapse.

Also basing it on the historical record that iindicates that human population growth really took off starting during the industrial revolution and its exploitation of high-density energy sources in the form of fossil fuels.

Haven’t read this in full, just Googled and found it and gave it a quick scan, but it looks like it discusses some of the issues I’m talking about:

https://www.resilience.org/stories/2009-04-20/peak-people-interrelationship-between-population-growth-and-energy-resources/

Someone mentioned that we all need to start with conservation, that we are currently using/demanding too much energy.
Here is a quick view on how much energy we are using per year.


https://www.lowtechmagazine.com/2018/01/how-much-energy-do-we-need.html

Back in the days before terrorism paranoia, when I was studying Engineering, we had two particularly interesting site visits as part of the curriculum: one to the only nuclear reactor in Australia, and another to a coal power station. In both instances we were close enough to physically touch the ‘furnace’.

Personally, I felt safer at the coal PS: they don’t have ‘Men In Black’ security people and technicians continually monitoring things, air-lock type blast doors, and containment buildings designed to withstand aircraft impacts and earthquakes! Seeing spent fuel rods decay Cherenkov radiation in a pool of heavy water was somewhat unnerving, particularly when we asked one of the physicists how dangerous were the rods and he responded: ‘Put it this way, if they were a metre below the surface of the tank, I wouldn’t be within a kilometre of here!’

In comparison, the coal PS had a long conveyor belt to the mine – coal would be dug up, put on the conveyor, transported to a tank where very large random sized cast iron balls would crush it to a fine powder, then it was injected into the furnace to fuel it. There are very few if any no-go areas in a coal PS when it’s switched off for maintenance, try that with any area in the nuclear fuel cycle!

Most people don’t realise that atomic/nuclear energy is one of the few technologies that was invented without a need: it’s a by-product of atomic weapons manufacturing.

Electricity production remains a pretty simple thing: a power source to heat a liquid to high temperatures that produces steam or a heat exchange to turn a turbine and create electricity. In essence, we’re still in the steam age.

The nuclear versus coal debate is always interesting. If you look at the fuel cycle and compare each, nuclear does leave behind a long list of extremely toxic elements, pollutes the ground and water table it sits on, uses more fuel (electricity, petrol, diesel) to refine, and we all know the waste issue. Every site, building, pipe and bolt used in the enrichment cycle is a future hazmat problem, it doesn’t matter whether they’re labelled low, medium or high level, it’s all very nasty stuff, and it remain nasty longer than human history has existed.

Based purely on the toxicity and longevity of waste products, including the construction materials and the earth and water table the structures sit on, I cannot morally support any type of nuclear energy.

Coincidentally, on TV last night they had a documentary on ITER ( International Thermonuclear Experimental Reactor) = fusion reactor based on a tokamak (torus shaped). It MAY go critical in 2025. The resources used to create the thing are enormous, and may prove a waste.

I always smile when the ‘coal power stations release more radioactive waste than nuclear power stations’ comments arise, no doubt originally perpetrated by the pro-nuclear lobby groups. It’s not that simple . The isotopes released from coal are the ‘less dangerous’ types e.g. the ones that produce background radiation. The man-made transuranic ones produced and used in nuclear fission are highly hazardous and, just to make things interesting, mostly decay into other isotopes throughout their long life cycle. So, an isotope may start out a bit dangerous, then decay into another isotope that is highly hazardous, taking hundreds of thousands of years to decay further to whatever.

There’s more abundant, less polluting and lower cost alternatives that don’t cast loads of excrement on future generations. I suspect the reasons for not going down those roads is greed driven.

Just 150M kilometres away we have the solar system’s largest thermonuclear reaction happening, and it’s estimated to last another four or so billion years. But, we’ve yet to take advantage of it in a meaningful manner – no doubt due to corruption and short-term money making schemes … because sunlight is free.

MSR may prove to be a way to generate short term electricity while its more important function is to clean up all the crap that was produced over the last 70+ years - much like an old garbage dump that can be tapped for its methane. But, at the end of the day it too remains a significant problem for some future generation. Hopefully we invent a ‘Mr. Fusion Home Energy Reactor’ like the one in ‘Back To The Future’, just not on a DeLorean!

The lies, deceit, cover-ups, habitat destruction and deaths perpetrated by the atomic/nuclear industry should be argument enough to shut them down. It’s hard to police something that has no smell, taste or feel. A major concern is the possible sideline of metallic wastes e.g. pipes, wiring, beams, plating, etc that can easily enter the resource recycling stream i.e. that kitchen sink you just purchased could be emitting gamma rays! They like to give really hazardous sites and practices innocuous, sugar-coated names e.g. Project Ploughshare, ‘Ship/Submarine Recycling Program (SRP)’, a reactor is ‘retired’ or ‘decommissioned’ (but it remains toxic), etc.

There are many issues we need to face as a species: population is the main one that will destroy us. We share this planet with other life-forms and have a moral obligation to ensure we all have space and a clean environment to live and evolve. When a virus exceeds its limit, the host is killed. Humans are quickly becoming the virus analogue, the planet doesn’t need us to survive but we need it. Population growth requires a lot of hard thinking. Producing vast amounts of electricity is like the idiotic capitalist principle that economic growth is infinite … resources are finite, go figure their logic.

It angers me a lot - we have the technology to produce things that are totally recyclable and/or biodegradable, yet continue to produce a myriad of toxic substances that are not. Using finite resources like oil, coal, uranium, whatever, to fuel our desires to operate puerile electronic gizmos, it is idiocy taken to a new level.

Nuclear power, at least in its current form, is a Dodo on life support.

In regards to Solar PV, sadly it’s STILL not for everyone and still early days. Like others have said, battery technology is way behind. A relative who is an Electrician advised me that Solar PV are only worthwhile at the moment if most electricity consumption is during daylight hours e.g. you work from home, young kids, and so on. Otherwise the expense of batteries and really low tariffs make it uneconomic in the ‘pay back’ instance = it’ll take several decades to break-even. I’m not willing to buy a big-arse Tesla Powerwall battery that costs about $AUS11,000 installed, only lasts 10-15 years, and will degrade over that time.

It would be more economic if every new house, commercial and factory building had rooftop Solar PV incorporated into a rooftop garden (edibles or not) to offset greenhouse gases and thermal issues. That should be a mandatory requirement for all new buildings and modest renovations. With the electricity grid connected, occupants could use it when required and local, community owned, storage cells would bank it for night use. A further step would include connecting the local cells to a State or Nation-wide grid, with hydro, thermal, wind, wave, etc all having inputs and providing back-ups.

I live in pessimistic hope!

F Agricola,

I am typing this from my phone so I can only respond to a short number of your thoughts.  And for the record and the sake of civility, while I cannot agree with every point you make, I strongly support your right to make them.  I cherish the free exchange of ideas we have at Permies and will do whatever I can to defend and support this ethic.

But for starters, I have to agree with you that I can’t tolerate leaving vast quantities of toxic radioactive materials that will need to be sequestered for countless generations.  At the same time, I can not ignore the incredibly low carbon emissions of nuclear, even if we are to include mining and enrichment.  The total life cycle carbon emission per kw hr of nuclear is absolutely trivial compared to coal.  And coal is hardly a clean source of energy.

You stated that the figure about coal releasing uranium was probably brought about by the nuclear industry.  In fact, it derives directly from the coal industry.  The coal industry spent a not-so-small fortune to get their contaminants exempted from regulations as uranium in coal is considered NORM or Naturally Occuring Radiological Materials.  The very same uranium involved in any way with a nuclear plant is intensely regulated—and for good reason.  What this does is create a double standard for uranium (and other contaminants).  If the uranium (the exact same uranium whether it is “burned” in a coal plant or a nuclear plant) is associated with coal, it is basically assumed to be natural and therefore harmless and ignored.  If the exact same uranium is in any way associated with a nuclear plant it is intensely regulated and at great (and justifiable) expense captured and contained/sequestered.  The net effect is that coal plants emit far higher amounts of uranium than nuclear power plants.

On a more controversial note is the body count associated with coal.  I don’t have the exact figures off the top of my head or right in front of me, but the number is surprisingly high.  There have been an inordinate number of deaths from coal induced asthma and COPD.  One striking example was London’s “killer fog” of the 1950s.  Over the course of a couple of weeks (if memory serves), the death toll reached into the thousands.

Compare that figure to nuclear (and I am talking about the present-day PWR nuclear from which I dearly want to transition away) and the death toll is under 100 for the big 3 nuclear accidents.  In increasing order of deaths, we start with Three Mile Island.  The death toll for TMI is zero.  The next most deadly civilian event (not a bomb or test event)  was Fukushima.  A single person has died from acute radiation poisoning from Fukushima, and that happened in November of 2018.  By far the most deadly nuclear accident was at  Chernobyl where the death toll I believe (feel free to fact check me here) was around 40 persons, most of whom died due to exposure from fighting the fire.

F Agricola, I am not making this statement to be argumentative, I am doing so to be clear.  You stated earlier that you cannot ethically back nuclear.  I cannot ethically back coal.  And it is coal that powers well over 50% (correction here:  I had old data.  The actual percentage of coal fired electricity is just under 30% and dropping) of American electrical generation (sorry, I don’t know what it is for Australia).  The numbers just don’t add up.  And again to be clear I am not supporting the current PWR form of nuclear that dominates the nuclear environment.  I am supporting a form of nuclear that is fundamentally different and produces a bare fraction the waste compared to current reactors and that minimal amount of waste itself can be reduced further in a fast spectrum MSR.  I know that supporting nuclear on a forum dedicated to gardening sounds preposterous on its face, but as I think about the wider ramifications of power consumption (something we all do) I am forced to ask myself why shouldn’t MSR be taken seriously for electrical generation?

Eric

Pessimistic hope, what a concept.

I did want to put a new link here to the original link I used to start the discussion, in a thread this long it is easy to overlook.  webpage

This is a quick review of the specific thorium technology, a bit of it's history, and a glance toward it's future. There are some minor discrepancies that Eric and I see, but in general it is a good start.

Throughout this thread there has been a great deal of criticism of the nuclear option in general, specific worries about side issues, but the common thread of agreement is   if it can really deliver on the promise to eliminate existing nuclear waste and trade it for a much smaller amount with a shorter term management issue that it's a possible way to go.
Reducing the mountains of long term (100,000 years+)highly dangerous radioactive waste would come with a side product, energy for decades to come, as much energy as we want and as fast as the reactors can be developed and built.

In the industry itself  energy is the primary product and consuming waste is the possible sideline of specific Molten Salt Reactors not using thorium as the primary fuel.  

There are mountains of thorium sitting around and rare earth mines were closed in this country because no one knew what to do with the thorium "waste" which was classified as a radioactive, although Thorium has such a long half life it is not dangerous in the same sense uranium and other current nuclear fuel elements are. But burning thorium does create a new set of waste products, not as much waste, and not as long term, but a definite management issue.

As to whether the energy itself is too much for us to handle responsibly and would it be better to leave the waste stacked beside the reactor for the next quarter of a million years, is an interesting question.

One of the issues mentioned, but mostly overlooked was that of small reactors in communities as opposed to centralized power plants. This is certainly a new possibility, with reactors mass produced in a factory, shipped to a prepared site by truck, almost as easy as installing a septic tank. Not many would object to these if they were thorium based, but what if dangerous waste needed to periodically be shipped to that local community to fuel it? do we still want  that?Are we willing to  start a new generation of waste issues, shorter term(300 years) and less of it, but independent of the waste recycling program?

Ok, enough, I have labored over this enough, it is gratifying to see the issue brought to light, so many have put the word "nuclear" into a dark corner of places they never want to go. Of course most of us will never have to make a single decision about whether this new possibility succeeds or fails, but public opinion is important at times and information in the light is better than fear in the darkness

I need to do other things now, but I will share this  pandora's promise

It is a nice movie, make some popcorn and prepare to rethink "what you know"

In my opinion, there are two historical travesties surrounding this issue.

The first is that of thorium. It was known that thorium could be used to power relatively safe nuclear power plants with a fraction of the waste; thorium could be used in retrofitted CANDU reactors today, and produce 10% of the waste. It was a non-starter because it didn't offer the option of weaponization.

The second is that, in a world being thrown into chaos by elevated atmospheric carbon levels, we have demonised a stable, safe, carbon-free power source as opposed to subjecting its development to strict oversight and forcing development into a direction that would maximise safety and cleanliness.

I forget the name, but there is an MIT-based nuclear power project that uses "spent" fuel, as in all the radioactive waste from the inefficient, incautious practices of decades past, as its power source, extracting something like all but 6% of the energy that was left in the "waste," which had had only 4-6% of its energy used initially.

I like the idea currently being developed of mini-reactors small enough to be carried on a tractor trailer, but built modularly, such that cores can be swapped out like batteries. The fact that they need to be made transportable immediately requires more safety inherent in the design.

There's also, in the vein of MSRs, the liquid fluoride thorium reactor, which I like the look of, personally, seeing as how so much thorium is produced in the mining of rare earth minerals for the production of magnets, so critical in today's electronics and electric vehicles.

Finally, I would love to see studies on the re-injection of radioactive materials into subduction zones, where they could be reincorporated into the earth itself. In the long run, doing so could effectively keep the core molten longer, which would have the added benefit of keeping us in geothermal energy and geomagnetic fields longer (something of a speculative joke; I have heard that the tapping of geothermal energy could cool the core faster, and that radioactive elements can create localised hotspots).

I think that nuclear power needs to be decoupled from it's militaristic beginnings and its dangerous power sources and designs. I think that modern examples using safer fissionable materials, like thorium, are a better option than, say, natural gas, as a long-term sustainable alternative to augment solar and wind energy capacity.

-CK

EDIT: My numbers are probably off. By all means, offer corrections. It has been a little while since I immersed myself in this stuff (the subject matter, not MSRs).

Hi Chris,  I just put up a post with a link to Pandora's promise--it is free, but you have to put up with german subtitles-- the unsubtitled movie is available for a fee.

If you are not familiar with it, it is a close examination of the environmental movement, nuclear energy-fact and fiction, and the fossil fuel industry scare tactics to try and boost it's own markets.

Bob,

I think I see pretty much eye to eye with you.  I am not certain what discrepancies we have encountered unless I slightly misstated some minor point.  Thanks for starting this thread in the first place!  This is a hugely controversial subject and as far as I can tell, there has been nothing but highly civil discourse on the topic, no doubt in large part due to your individual posts.

I think you have successfully taken nuclear energy, something relegated to dark and scary parts of our minds and brought it forth to show how useful, practical, and ultimately clean it can really be.  Congratulations on this difficult to achieve goal.

I would love to add some more technical information, but at the moment I have a handful on my plate.  Please, lets keep this discussion ongoing.  I think the future of energy will be one of mankind’s greatest challenges.

Eric

yes Eric, thanks for the thoughts, I  think a great deal of the success of this post should go to your contributions as well as the many others. It's always important to keep things in perspective, and most of the people on this site are aiming in the same direction. I wrote out a mission statement for the thread and started with a small bit of information, and then you fleshed it out probably better than I could have.

But I do agree,   any differences we may have had would have been some small detail or another, not that important though at this level of discussion.

Now if we independently decide we want to build a reactor, we may need to hash out some of the details.   I've got a few 55 gallon metal drums, do you know anybody with a welding torch?:-)
 

F Agricola,

Again, I am not trying to be argumentative, but I was hoping that you could clarify for me a statement you made.  You stated in your earlier post to me that nuclear power pollutes the ground and water table it sits on.  Are you referring to the plant itself or the mining operation to acquire uranium in the first place.  I do not believe that a nuclear plant, even a PWR in any way contaminates the ground or water table with nuclear waste.  Please correct me if I am mistaken on this, but the fuel that is brought into the power plant is done so in the form of pellets that are then loaded into the core, "burned" and eventually removed for storage.  At no point do they actually leak out and certainly do not contaminate the ground water.  Perhaps you are referring to one of the big three disasters?  In any case, a MSR is an entirely different device.  MSRs can not melt down because they are designed to operate in a liquid state to begin with.  If the reaction for some reason peaks unexpectedly, then the fuel salt expands into an area outside of the reaction chamber (usually located directly above the reaction chamber) where due to geometry, lack of moderator or both, fission is impossible.  When that happens, fission stops, and the fuel salt cools down and re-enters the reaction chamber.  Unlike water cooled reactors (PWRs), molten salts have a tremendous ability to handle a thermal excursion and have a built-in mechanism to reduce that mechanism.  If the salt is pushed out of the main chamber, there is then less fuel in the reaction chamber and the reaction slows down.  This factor alone makes meltdown virtually impossible.  In fact, it is hard to even see how a runaway reaction can take place, nor how any significant overheating can occur.  The materials that the reactor is constructed of have melting points (about 1200-1500 degrees C) well above the normal operating temperature (about 650 degrees C).  If things get really out of control, the freeze-plug at the bottom of the reaction chamber melts and the fuel salt pours into a drain tank where further nuclear reactions are physically impossible due to both geometry and lack of a moderator.  There, the heat of the molten salt is carried away passively until the salts freeze back into a solid.  A MSR has well-conceived totally passive safety features and is considered walk-away safe.

For an example, the MSRE did have an issue during its operation where a moderating rod got dropped and stuck in the core.  The temperature rose beyond the design limits.  The salt expanded out of the core, limiting the mass in the core which then reduced the thermal and nuclear output of the reactor.  The rod was eventually fished out of the core with a very long-handled tool.  The reactor was never in any danger of any type of physical damage.  This is in stark contrast of what happens when a PWR loses its coolant.

I strayed a bit in my post, but my point remains, even in the PWRs that I want to have decommissioned, the radioactive materials stay in the core until they are removed for long term storage.  They do not enter the ground or ground-water.  As I stated earlier, I grew up not far from a PWR and regularly went canoeing on the lake and streams that provided coolant to the reactor.  This was a most welcome bit of natural "wilderness" in the middle of the Central Illinois prairie now turned into corn forests.  Wilderness basically does not exist in Central Illinois except for a pocket here and there.  The waterways around the local nuclear plant were one of these few, precious patches of "wilderness" and were not contaminated or radioactive.  I thoroughly enjoyed them and have wonderful childhood memories of canoeing up a creek that looked like pristine nature (though of course it was surrounded by corn fields--I am sure that the pesticides on those corn fields did more damage than any of the fuel at the power plant).

F Agricola, I can't help but to ramble on this issue, but maybe you could explain to me more clearly what you meant by contaminating the ground and water around the reactor.  I did not experience this phenomena, and as I understand, it basically does not happen, but if I am wrong, perhaps you can show me why I am wrong.  As always, I do not want to be needlessly critical or uncivil in our discussion, but I have had a radically different experience from the scenario you described.  Perhaps we are both right and just can't see why at this moment.

Please keep me informed and please fact-check me if you feel I have gotten something wrong.  I am a fallible human and I will not be offended if you find something on which I was unclear, perceived out of context, or was just plain wrong.

Eric

Yep Bob, lets get out the 55 gallon barrels, head to Home Depot for some parts, get out the welding torches and build ourselves a backyard nuclear reactor!  Or maybe not quite yet.

I too am really pleased that our thoughts have dovetailed so nicely with one another, and I am thrilled that a topic with the potential for a high degree of invective has been incredibly polite.  I really want to keep this thread alive as I think it is an important topic, inherently controversial yet the discussion has been remarkably level-headed.  I was thinking about comparing the physics of the PWR to the MSR to show how & why the PWR produces so much more waste and has the potential for meltdown while the MSR produces a tiny amount of waste with basically no ability from first principles to have a meltdown, but being a Monday, I am afraid that I have a full plate today and don't have as much time to dedicate to my guilty pleasure of discussing nuclear physics.

I promise to keep my end of this thread going, but congratulations Bob on starting a great thread.  45 replies in 24 hours is pretty impressive!

Eric

Why the PWR makes so much waste part 1.

OK, I think I have enough time here to explain how a PWR works and why it produces so much waste.

So a PWR is a sort of bad set of compromises that were made due to the understanding we had from operating the very first nuclear reactor in Chicago known as the Chicago Pile #1.  This was strictly a proof of principle reactor and was developed simply to see if it was possible to control the rate of nuclear fission.  It was not designed to produce usable power of any type.  Being a proof of principle design, the materials were all used in the form they exist in at room temperatures--that is to say everything was a solid.  That first "reactor" (it was so rudimentary that it is almost hard to call it a reactor, but it did demonstrate that nuclear fission could be controlled), based entirely on solid fuel gave the early nuclear proto-industry the basic corpus of knowledge to build and operate and control a nuclear reaction and turn the nuclear power eventually into electrical power by heating water to steam first (Someone, I can't remember who, made the comment that in a sense we are still in the steam age.  That statement is dead-on correct and I congratulate you for your insight).

So theoretically, converting the CP1 design into an electrical generating design kept as many design principles the same as possible, and this started with the fuel.  In a PWR. the fuel is not exactly uranium, but a little pellet of uranium oxide ceramic half the size of a stick of chapstick or so.  The center of this pellet is intentionally left hollow to allow for heating, swelling and the release of gasses to stay contained (first level of containment).  The pellet is surrounded by zirconium which has a high melting point, is neutron transparent, is pretty strong and also contains any release of fission products (FP) (also, the second form of containment).

The pellets are arranged into rods which are arranged into bundles which is then arranged into a core.  At this point, we have a bunch of uranium oxide coated with zirconium and the central void is filled with helium (which is both chemically and neutronically inert.  All those pellets stacked together in the core will not do a thing until they get moderated, or rather their neutrons get moderated.  These pellets do give off sporadic neutrons, but they move so fast that they simply cannot bond with other nuclei and cause another reaction.  Occasionally one or two do collide and cause fission, but not nearly enough to cause a chain reaction, so without a neutron moderator (which is a nuclear accelerator--think of making a fire with plenty of fuel but no oxygen), no chain reaction will take place.  This is where water comes into play.  Small, lightweight nuclei tend to moderate fast neutrons fairly well (the helium just does not have enough in that tiny space in the middle of the pellet, but theoretically, helium could work under certain conditions) and the hydrogen in water is a pretty awesome neutron moderator.  As the core is then flooded with high purity water, the stray neutrons being given off strike the hydrogen attached to the water and slow down--a LOT.  Eventually they slow down enough that they can bond on to a neighboring uranium 235 nuclei quite well, cause it to become unstable and fission, releasing radiation (that promptly turns to heat), and more neutrons to go and pay the favor forward to still more u235 nuclei.  And a chain reaction is born.  

Water has several things going for it as a nuclear moderator.  Firstly, it does its job pretty well.  Secondly, it is not too bad a coolant, being rather conductive of heat and having an extremely high specific heat capacity (meaning it can carry a lot of heat per unit mass--in fact it is one of the very best substances known for this quality).  And if for some reason if the water were to suddenly disappear, then the reaction would come to a screeching halt (with one important hitch to get to in a minute) as not only the coolant but the moderator as well would be gone.

Water has a couple of problems as well.  Most importantly, it boils at too low a temperature to do anything useful.  The boiling temperature can be raised--drastically so, but this is accomplished by pressurizing the water--drastically so.  It is the extremely high operating pressure to keep water liquid at 300 degrees C that drives up so much of the cost and complexity of a PWR design.  And in fact, right there you have the reason for the acronym--these reactors are Pressurized Water Reactors.  A lot of expense goes into making certain that the reactor never drastically and unexpectedly depressurizes.  Also, water has a sort of frenemy issue with the zirconium coating for the uranium pellet.  Zirconium catalyzes the breakdown of water into hydrogen and oxygen at high temperatures.  That means that we have a fuel coating that is fundamentally incompatible with coolant, and this is an issue with obvious problems that have never been sufficiently addressed.  At Fukushima and Three Mile Island, we saw hydrogen gas explosions, the source of which was high temperature water reacting with the zirconium to dissociate.  These were not nuclear explosions, but they were not exactly good things either.

The Uranium pellets have their own problems.  As the U235 decays, it creates a soup of waste that comes in two forms.  The first comes from the times that a neutron collides with another Uranium nuclei and stick--for good.  This creates a range of new, heavier elements known as Trans Uranics (TU).  The most commonly known TU is Plutonium.  The other type of waste are collectively called Fission Products (FP).  Some of the TU will actually go on to produce energy of their own, so their is at least something useful that comes out of them (an estimated 1/3 of the heat of a PWR is from Plutonium breaking down).  On the other hand, some of the FPs have the tendency to absorb neutrons and hold on to them, shutting down the reactions.  Some of these are gasses like Xe135 which is a real trouble maker with a 9 hour half-life, and others are solids that stick around longer, but in any case, a new uranium pellet can only undergo a small amount of fission before the FPs, especially gasses threaten to break apart the zirconium cladding and the second layer of containment would fail (having a bunch of radioactive elements dissolved in your coolant is a bad thing too.  In any case, the uranium pellets have to be pulled out when they have gone through a mere 0.7% of their available Uranium.  meaning now they are waste that will have to be kept in dry casks outside while still containing over 99% perfectly good U235--what a terrible waste!  Sometimes these pellets have been reprocessed, meaning they are dissolved in acid, remove the fission products and reform them back into a refurbished pellet, but the process is not cheap or easy.  Most of the pellets end their lives sitting in dry storage.

I need to go soon, but to summarize Part 1:

1)  The whole reactor must be kept under extreme pressure to keep the water from boiling

2)  The water can only carry so much heat

3)  The water likes to break down into hydrogen and oxygen thanks to the heat and zirconium cladding

4)  The Uranium pellets only live a short life, after which they have to be removed

5)  Most of the waste is actually perfectly useful fuel, but the lifetime of the pellet has been reached and must be removed to prevent reactor damage

6)  Most of the waste are used pellets

I will update this later, but I need to leave for now,

Eric

Why the PWR makes so much waste part 2.

Not directly a waste issue but a weakness of the PWR in general is that when the fuel is loaded into the core and the coolant/moderator added, the reactor is loaded up for around 18 months worth of operation.  As the fuel "burns" it becomes less and less useful as a fuel to a point where the entire reactor must be shut down & cooled (a few days) and the fuel removed, each pellet x-rayed and inspected for radiological damage, old pellets moved off into storage and other partially used pellets re-arranged and new pellets added.  If this sounds expensive, difficult and time-consuming, well, it is.  A typical PWR can expect to be down for a matter of weeks for refueling at which time it is producing no electricity and earning no money.  This is a real problem.

Also, even though a fuel pellet might be through as fuel, that does not mean that fission stops completely.  Throughout its life, a uranium pellet will undergo fission (the vast majority taking place in the core) and numerous new FPs will be created, each with their own decay chain.  When people opposed to nuclear refer to a "witches brew" of chemicals, these numerous FPs are often the reason why.  There will also be a smaller handfuls of TUs being produced over the lifetime, but the point is that just because it is not fuel does not mean that it is done with fission.  This factor does really complicate long term disposal.  Worsening disposal is that the pellets are still thermally hot and must cool down without the presence of water or else the water would moderate neutrons and the reaction would start up again and the cladding might eventually fail.  Frankly, at this point, managing nuclear gets a well-deserved reputation for producing some pretty nasty things.  Even though the nuclear industry does a very good job of keeping its waste contained, I don't think anyone, myself included, wants any of these daughter products accidentally spilling out.  To the best of my knowledge, they have not, but there is a real concern that a terrorist group might get their hands on this, or that shear negligence might result in an accidental release.  With this knowledge, up till a few years ago when I discovered the MSR, I was pretty turned off by the prospect of nuclear, despite its good track record.

So why is the MSR so much better?

For these purposes, I will focus on the moderated or thermal MSR, though many principles will also apply to the FSMR.

For starters, the fuel is a liquid and this by itself has tremendous advantages.  Liquid salts have a tremendous potential to carry away heat in order to do work and generate electricity.  Molten salts have a specific heat capacity similar to water, but don't boil until they reach into the thousands of degrees.  Also, that troublemaker Xe135 simply bubbles out of the salt and goes into timeout instead of halting the reactor.  This makes running the reactor much easier.  Being designed to operate with high temperature molten salts makes a meltdown virtually impossible on first principles as the reactor vessel itself is designed to operate at beyond the maximum temperatures of the salt fuel.  

Secondly, the salt is not under extreme pressure.  In fact, the pressure of the reactor is going to be something like the pressure of your household plumbing--enough to move fluid, but not enough to burst a pipe.  This alone vastly simplifies construction and makes the plant much, much more affordable.

Third, the MSR (not the MSFR) is designed with a sort of "chemical kidney", or an online fuel purifier. The way this works is that a small amount of the molten salt fuel is pumped into the "kidney" which selectively strips out a specific FP.  By stripping out that FP, a whole, vast chain of fission products simply can't happen because their progenitor has been removed.  In fact, if we are talking about using thorium and not waste, then by purifying the fuel stream, we are then only one step away from a stable FP that can break down no further.  And what happens to that FP that was taken out?  Believe it or not, this is a medical isotope of which the world is desperately short of right now.  So by running on Thorium, we can operate the reactor at high temperature (and that gives us high thermodynamic efficiency), produce a much-needed medical isotope and be left with only the waste that is left over in the reactor vessel when it is done operating--that's it!  If you start up the reactor again, you can keep on reducing that amount further.  Or you could take it out and put it into a FSMR and reduce it further.  The usual figure I see is that a 1GW MSR plant will produce a single coffee can worth of long lived waste which will last for 300 as opposed to 10000 years.

I hope that these last two posts can show just how different the waste profile is for PWRs and MSRs.  In a PWR, we have many tons of waste that will linger for 10000 years.  A MSR will produce a couple of pounds of waste that is harmless after 300 years.  And a MSR can consume much of the waste left over from a PWR.  I know that I will never convince everyone of the merits of the MSR.  I simply hope that one can see the strengths for themselves.

I will keep this thread going.

Eric

OK Eric,
Thanks for wrecking my day. I've read up on what I've missed over the last 20 years. This is very interesting.

Bob, I watched the Pandora's Promise video. It is generally well done. One fallacy I picked up was the lady discussing waste, and how small an amount this is. That is simply the spent rods. The actual amount of contamination is vastly higher, especially decommisioning systems. This is going to be a big problem, and that stuff is not "hot" enough to have a use, even if reprocessed. It's concrete and pipes and stuff like that. That being said the question of whether this low level of radiation is important is another issue.

I am following a discussion about paper mulching, It can be found here. There is, as several people have pointed out, a psychological revulsive issue with any waste stream. They will find an objection no matter how much data you have. I cannot get people beyond that and have stopped trying. If you are trying to get people to install a Willow Feeder, you will have a huge percentage of people who just don't understand why you don't just flush it down the magic porcelain chair, because it doesn't exist after that! People don't like that I use wood chips because people shouldn't be chipping their trees. The fact that I am using a resource that would often be landfilled (the toilet of our culture) doesn't play at all. It doesn't matter the source of the chips, they are morally objectionable however they occurred. This is a natural human impulse to reduce processing requirements called a heuristic.

So there will always be people who say any radiation is bad, even though background radiation has been around since before fire was tamed, especially at altitude. The dose-response curve takes too much processing, and so it passes to the heuristic. I get a kick out of the heuristic (that I largely use) that anything naturally occurring is good. Taken too far it falls apart. There are lots of poisons, like red tide, that are naturally occurring. So periodically you have to question your heuristic, and that is a painful process, because it means you could have done harm in retrospect. The people in that documentary who had started out (and often continue to be) generally hard-core enviros all talked about their shame, which is a moral judgement, not a scientific one. To me that is interesting, I am very careful if I have a moral sensation about something scientific. That being said moral sensations tend to keep your motivation through difficulty, and it is much easier said than done!!!

Glad you liked the movie, With a topic that broad   I think that it's easy for things to slip through.  I don't remember specifically the stat you mentioned, but I do remember feeling a little uncomfortable with bits of the movie.  Still overall, the things I took away were little tidbits like the fossil fuel industry sponsoring anti nuke demonstrations, and also the fact that closing down a nuclear facility is a fast moneymaker for the owners, so they don't really fight that hard to keep them open.

I'll probably watch it again just so I can answer questions about it. There's also a discussion about the movie featuring Robert Kennedy JRRFK Jr   and Director of Pandora's Promise

Thanks  Eric for presenting the information, Someone could get a phd reading this thread.

Phil,

Sorry it took me so long to get back to your post, but I did read it and the article to which you linked.  It is a fun thought experiment, but I think the real moral of the story (and the author you cited basically says this) is the foolhardiness of following a linear argument to its extreme.  Back in the 1990’s I was told (and , I am afraid, believed) that by the year 2150 the worlds population would be a staggering 694 billion!  And all but 2 billion of these poor souls would live impoverished in 3rd world countries.  I did not make up these figures, they were based on a series of UN projections of population dynamics.

Actually I never really believed that the population could ever get this big, and the point of the UN figure was to show that either population growth would have to come about or that starvation, disease and war would reduce the population.  I tended to have more faith in the dystopian latter than the optimistic former.

It turns out I was wrong.  The 3rd world is not experiencing a tremendous growth spurt and many countries are actually reducing their population.  The projections were wrong.  Our energy growth per capita will also trail off as we won’t cover our entire planet with solar panels, nor will we all have mr. fusions in our homes and cars.  We will face limits, but we have faced limits before and will do so again.

Eric

Hi TJ,

I did take a quick look at the paper mulching post,but don't really have time  to explore it, day will be dry, bright sunshine, so maybe I should plant something, since there will be rain again this weekend.  I have a bunch of hardy orange seeds and an area where I'd like to disrupt deer traffic. But back to the topic.

In the case of burning "spent" fuel rods we are really talking about burning platinum equivalents. the rods don't come cheap, and only a small percentage is used

Now the incidental radiation associated with gloves, metal , etc is not really useful in a reactor, a little like dumping fresh table scraps on a fire.  The little left that might burn is overwhelmed by all the stuff that would put the "fire" out. (as you pointed out).

But I think with at least some of that, there is an ongoing process of monitoring and some of the cooler stuff can deactivate itself over relatively shorter periods of time.

The impression I get is that associated materials, stainless pipes etc will continue to be a shorter (relative to 3000,000 years)  liability, and I think the plan from day 1 was just to bury the plant and put a fence around it, so likely much of that will be left in place.

I'm not sure of course what the future may hold, but it would seem some of these newer smaller MSRs could be located on or near existing sites ready to be decommissioned, and sort of continue the legacy without the need to build new infrastructure around them. The generation turbinees might even be retrofitted, or at least swapped out with the newer turbines to further lessen the destructive crawl across the landscape.

I was watching an older talk by Bill Nye and he pointed out the Roman empire didn't last 800 years.

Our technology has changed so fast in the space of my lifetime, I don't think we can have an idea what might be going on in even 300 years, let alone 300,000. Maybe we will be throwing banana peels into a "mr fusion" and rocketing back to 1984

Ok,  there is an issue that all of these discussions dance around that is much misunderstood and I must comment on it.  That issue is the half-life.  Until very recently I had a totally erroneous and completely backwards way of understanding the nature of the half-life.  

Say you were forced against your will to hold on to one of two balls of radioactive materials for 5 minutes.  Material 1 has a half-life of 10 seconds and material 2 has a half-life of 10 million years.  Aside from half-life, the materials are identical in every respect.  Which material would you choose?  If you chose material #2, chances are that you will walk away just fine.  If you chose material #1, you would be wrong.  You would be quite literally dead wrong.

Assuming that both materials are exactly the same in every respect aside from half-life, the materials both give off the same amount of energy each time that material fissions.  In the case of material #2, 1/2 the energy will be expended over a 10 million year timespan.  This means at any given moment, the amount of energy (read this as radiation) being given off is minimal.  In fact, U238 has a half-life of around 5 billion years which makes it harmless from a radiological standpoint (though it is still a heavy metal and can have chemical toxicity issues, but that is a different story) and U235, the nuclear fuel, has a half-life of about 700 million years which makes it pretty harmless from a radioactive standpoint.

Material #1 on the other hand is giving off half of its radiation every 10 seconds.  If we assume that both materials “start” their radioactivity the moment they hit your hand (this can’t really happen, but just to show a point, let’s pretend it can) then in the first 10 seconds you receive 50% of the radiation the material can ever give off.  In 20 seconds you get 75% the total radiation.

By the end of the 5 minutes, material #1 will have given its holder approaching 100% of its radiation.  Material #2 has radiated away almost none of its energy.  The person holding material #1 is likely dead before the end of the 5 minutes while the recipient of material #2 has received almost no radiation.

This has significant implications for disposal considerations.  The most radioactive materials are truly dangerous, but fortunately they are safe fairly soon.  The extremely long half-life material are not going to lose any meaningful radioactivity in human timescales, but they barely release any radiation.

Perhaps the most troublesome radioactive wastes are those with half-life’s in the 20-50 years timespan.  These troublemakers release meaningful radiation for a significant portion of human timescales.

I write this here because it is s common belief that since a material like material #2 (or u235, or u238) must be intensely radioactive since its radioactivity lasts for so long and a short half-life material like material #1 must be barely radioactive since its radiation will disappear in a minute or two.  But in reality, this erroneous assumption is not only wrong, but flat out backwards.  If we are to discuss radioactive decay seriously, we must do so by the proper metric.

Eric

Nice discussion. Science and tech worth thinking about.

But there is a gorilla filling the room that only one person has alluded to. Consistent, structural, system failure. Eg. the kind we see looking at the unadmitted military agenda for the development of the PWR. And real world implementation scenarios with shoddy contractors, blind legislators, venal regulators. These effects are always there and the way people seem to simply ignore that part of the equation, pretend it's a perfect world out there, bothers me exceedingly. This is a technical discussion,  one that's generally looking for the better solutions to pursue. I think that the real world path that a potentially game changing technology will traverse in this present society needs to be considered as part of the discussion of its value. We need to look at a technology's failure modes when evaluating it. And that has to include which technologies still look good after they "grow up" in the shark tank that is business development in this world. If I were a scientist or inventor, I would find this a major ethical issue.

The new nuclear options sound like they may fail more gracefully than the old. That's good. But let's keep in sight that there _will_ be failures and include these in our consideration of how we want to push forward. Like the Aussie guy says: A coal plant fiasco probably won't wipe out a region - a nuclear one might do just that. But, also, we have to consider: Staying in place may be more dangerous then embarking on "progress". Climate change looks like pretty serious business in 50-100 years.


Regards,
Rufus

Guess to figure out the economics you would have to calculate the cost of disposal in 300 years time. The right people to ask are your descendants who are going to have to do it. Seems to me to be a lot of drama for the sake of powering your toaster.
My objection to nuclear has always been an economic one. It is an uninsurable risk - the chances of a Fukushima happening are infinitesimal but when it does happen it is so expensive they have to raise Japanese taxes by 1 % . No insurance company is prepared to take that risk so it gets forced on the taxpayer. In Africa with corrupt governments I am willing to bet that no money has been saved against the possibility that our one and only reactor might go kerblooey.
In other words the political and economic robustness required to sustain nuclear energy is simply not there and will never be.  Any technology which bets against human error is bound to lose.

The replies here continue to amaze me. I've seen these discussions at higher levels of "expertise" and none of them really has all the answers for human error.and human craziness.

I mentioned the possibility that maybe just storing the waste in the safest, most secret, most remote place we can find. or putting it near a subduction zone to fuel the inner core of the earth (eventually). may be a better option than taking on the task of burning it up.

Even though we may be taking million year glances at the future, maybe there is even a process in our giant thorium nuclear reactor ball (the Earth) that automatically separates and concentrates the thorium so it can be burned.     Can't you just see your descendants in their cloud city all pissed off at us for burning so much thorium that their summer home (the earth ) has to be abandoned.

But if we're going to seriously talk about the tech and human error.

We do have the capacity to be careful. there have been governments, (even autocratic ones) that took the people's welfare seriously.  There is that last plague in Pandora's box , Hope.

So The MSR generation has the capacity to be built and mostly assembled in the factory. this reduces the need for highly skilled labor on site in the extremes of weather.

The units are small enough to be delivered on a truck, and really the primary risks would be in transport. But those risks would be more associated with localized contamination or terrorists

The design is such that if outside controls fail (or a disgruntled employee/terrorists want to blow the plant up, the worst they could do is bring in explosives, because the core itself  either over heats, melts the drain plug, and the radiation drains into a non reactive storage tank, or the heated liquid expand bubbles out a vent in the top and the reaction goes sub critical.

The idea of dictators and crazy people in unstable areas may be an issue, reactor design can not solve politics (if it could we might be a whole different world today with plenty of free energy) But the issue would have more to do with contaminating their own countries, these reactors do not make material for bombs, and they don't blow up themselves.

Rufus,

No doubt you are right that there will be accidents.  But this applies to all forms of energy and indeed to all human endeavors.  But for the moment, let’s just narrow the list to coal as coal is the main source of electrical power.

For starters, coal is a sort of slow moving disaster in and of itself.  Coal combustion, even leaving aside the the obvious CO2 emissions, releases its own witches brew of toxic chemicals.  How much NOX and SOX gets released by a coal plant each day?  Granted, they are better than in the past, but they are still not 100%.

Let’s then look at mining.  How many people die each year due to coal mine disasters?  Thorium will also have to be mined, but a LOT of thorium is already mined and is sitting in barrels as a waste product.  In fact, we can very likely get all the thorium we need by using the leftovers of other mined materials.

What do we do with coal ash once it is done?  Coal is simply not just pure carbon.  There are a lot of materials packed into the coal, including uranium.  And contrary to what was stated earlier on this thread, no, that uranium is simply not THE source of background radiation and therefore harmless.  It is uranium, and it is spread with not even an attempt at control.  The same goes for lead, mercury, and a very witches brew specific to coal.  Furthermore, some (actually a lot) of what’s left in coal ash simply will not burn and will be dumped into enourmous piles.  We saw the failure of one of these in Tennessee a few years ago when a tailings pile that had been converted into a dam suddenly gave way and flooded the downstream area with a sort of toxic wet cement.  No one planned to wipe out these homes, it was simply an accident, but one with very real consequences for anyone who lived downstream.

And what about coal mine fires.  These happen rarely, but with disturbing regularity.  These fires, once started, burn until they run out of fuel—which can take centuries!  In the process theycommonly destroy whatever town they are near as the underground fire eventually destroys the town—and anything else on the surface such as a forest.

Lastly (I could go on, but I will stop here) there is the issue of mine subsidance.  I live in coal county and there are a LOT of older, private (meaning someone just went out on his own land and started digging) mines that are not charted, registered or in any way mapped.  It is not uncommon at all for a person to find that perfect piece of land, build a house and after a couple of years have the foundation fail because an unregistered mine ran underneath the house.  The land is unbuildable and the home irreparable.

Rufus,  please understand that I am not writing this as an angry rebuke.  I am trying to put the notion of accidents in context.  At present, even the PWR industry has an admiral safety record.  I don’t really want to make that statement because I truly want to make PWRs go away, but I have to recognize facts as facts.  I truly believe that the MSRs will be orders of magnitude safer than than existing PWRs which themselves have a very impressive safety record.

All of the big 3 accidents had one factor in common—they were loss of coolant accidents.  Considering that in an MSR, the fuel is the coolant, I am hard pressed to see how one could melt down.  If they get too hot, the salt expands out of the reaction chamber and the reaction slows drastically.  If things get really out of control, the freeze plug at the bottom melts and the fuel drains out into the drain tank where fission stops and the tank passively cools.

Again, I don’t want this post to be an emotional rant—these things never end well.  But if we are to avoid every activity because we might have an accident we cannot describe, then we would never do anything.

Again, I hope to keep this channel open as a free exchange of ideas so if you disagree with me on any point, inform me and we can discuss.  I appreciate the exchange of ideas.

Eric

Rufus Laggren wrote:Climate change looks like pretty serious business in 50-100 years.

The change I see us needing, which is cheap and doable by anyone, the exact opposite of power plants of any type, is to reduce our need for energy.  This is so simple and accessible, it's something Paul talks and writes about a great deal.  So to my mind the greatest argument against any kind of nuke plant is that it is unnecessary.  Unless the plants are built expressly for the purpose of destroying nuke waste, there is simply no need to build them, in my opinion.

I agree, Eric.

People have a cognitive issue in most cases, wherein opinions are formed over time, and then sink in and are adopted as part of their psyche. They become so ingrained that changing that opinion takes real moral courage of the individual. One has to realise the possibility that not only do they not have all the facts, but that the situation they thought they understood completely was only understood on a dumbed-down non-technical level which did away with much detail that actually matters to the decision-making process.

So where it was understood that nuclear = bad because radiation, now it's much more complex (it's always been more complex, but it's hard to sell an idea that involved to the masses, and it's even harder to demonise it if the details are right there, contradicting you from your soapbox).

Many will say that if it's so complex they want nothing to do with it, and will make do with solar and wind. That's fine on a homestead; you could probably do with wood heat and candlelight or alcohol lamps. But providing power on a larger scale doesn't cleanly scale from that model; if we all heated with wood, cities would probably be largely unliveable.

I mean, imagine the woodsmoke from about 2,235,145 households in an area of 5,905.84 square kilometers. That's 1003.8 people per square kilometer. That's Toronto, by the way. I know most american cities are tiny by comparison, but still.

Just for a lark, Eric, what's the future of nuclear beyond MSRs? What does post-steam nuclear look like?

Also, how efficiently is the radiation converted to electricity via steam production? What are the conversion losses?

-CK

Periodically I love to play the devil's advocate.  I know by now, people understand that I like this design, at least the idea of it, and think it has great potential, and in this case "great" is such an understatement.the potential here is to remake society. near free, limitless energy (I looked it up, we have a thousand years supplying the world with pollution free energy(relatively) just burning the existing waste.)

But we also have a history of neglect , complacence, stupidity at times.  Advice to proceed cautiously with a material that can ruin your day for 300,000 years is well heeded.

There is really no debate here.  The only possible reply is yes, these elements are important to consider now and at every step along the way. And even more important is to design in fail safes for when the manufacture of these reactors becomes commonplace. It's pretty easy to get on this train heading for a wonderful destination, just don't forget to slow down on the curves.

That being said, I also see your point Tyler, we can get there conserving and using renewables. and the next question becomes how do we consume this nuclear waste without creating energy? I don't think it is possible at our level of technology except possibly some sort of fission- fusion cycle that breaks down the large atoms and rebuilds them using the energy from the fission.

The obvious answer becomes to substitute that energy into our existing grids,  and as I alluded to earlier that powers the world for 1000 years. From a Permaculture standpoint, using waste of one element as a resource for another really opens up a whole new perspective. We have lots of Earth shaping to do, deserts to green,...just imagine that we suddenly have a waste stream that can forge our steel, remove carbon from the atmosphere and make synthetic fuel, (The technology thought to make fuel from CO2 and water on Mars.)

And while this sort of thought experiment is fascinating, and I'd love to theorize about the possible implications a world with free energy might have on Permaculture Systems, I have to go out and enjoy this beautiful day.

Hey Chris,   Kirk Sorensen, the guy who revived the MSR technology and published the data on the internet talks about gas turbines instead of steam.. The relatively higher temps of the salt  make very high efficiency possible. I'm going to say the number 45% efficient because that's what sticks in my head, but better verify that before making any bets.

Of course the overlooked part of that is the temps are so hot, that they can be used in the manufacture of cement, so one plant could be making cement and using the "lost" heat to generate electricity to run the plant (and likely the city around it.

That's a non-starter on the civilisation scale, Tyler.

What I take from it is that in the interim, while energy is costly, either financially or environmentally, or both, we would do well to be more efficient.

But you know what we need a shit tonne of? Cheap, clean energy. You know why? Decarbonisation.

A high-speed electric rail system, or even something like a hyperloop that accommodates shipping containers, could deliver food and goods more efficiently and cleanly than anything burning hydrocarbons.  If that electricity is produced with a minimum of waste and without a carbon expenditure, and if it replaces dirtier transportation, it's a net benefit to humanity.

To take it a step further, we could have a massive global hyperloop if tubes ran under the ocean. No more wasteful planes burning hydrocarbons where they do the most harm.

And if you run a hyperloop spur 22 km up a convenient mountain into the atmosphere, you've just created an earth-based rail gun for launching cargo and people cheaply into orbit.

Why do we need any of this, you might be wondering? Permaculture.

Humans have been largely the same in our wants and proclivities since we fell on our asses out of the trees and couldn't figure out how to get back up. Constant growth has been a thing ever since we started herding and agriculture. Everything is fine until we run up against the boundaries of our system and continue to want constant, steady growth.

Malthus' ideas on population growth versus food supply tells us all we need to know about how good we are at looking to the future (we're not. In a nutshell, our populations expand as long as there's food, to the point of starvation, echoing predator/prey patterns seen in nature).

So the real solution is not to eschew everything that can't be grown on a homestead, but to match the pace of our growth to the expansion of our system.

Is industry destroying our biosphere? Well ship it off-planet, where there can be no waste, because any such would be a cheaper feedstock for another process than either shipping it up from earth or mining and refining it from asteroids.

Earth needs more food for its inhabitants, work for them to contribute to society, and places to live? Well let's start sea floor communities that support vertical mariculture.

Islands are sinking into the sea, leaving people homeless? The ocean is acidifying, and reefs can't adapt, and their biospheres are collapsing? Let's grow islands with seacrete on the scale of icebergs, and let's populate their undersides with coral reefs to replace what's dying. They thrive on seacrete, and the act of causing sea minerals, including calcium carbonate, to electrochemically accrete into artificial reefs should reduce the acidity of the oceans.

My point is that decreasing our individual footprints is necessary in the short-term, but ultimately either futile or self-destructive in the medium-to-long term.

So instead of looking backwards, perhaps we should look where we're going, instead.

-CK

And sorry, Bob. I should have specified what I meant by post-steam.

I would like to know if there's a fuel cell analogue in the future for nuclear, wherein a fission-specific material absorbs the radiation directly and produces electricity, like solar energy hitting a solar panel. I want to know if it will be possible to eliminate the heat cycle. Does fission require the release of heat, or is that a detectible and easily-used byproduct? Consequently, could fission generate electricity without heat, and wouldn't that be more efficient and safer, requiring reactions on a much smaller scale?

Largely just spitballing, but I would genuinely like to know.

-CK

Without doubt, reducing energy consumption would be the very best thing we could do for the planet.  In fact, I labored long and hard on this very premise.  Without sounding defensive or sanctimonious, let me respectfully ask what one can do to reduce our own energy consumption.  Does one take big, important steps to seriously reduce consumption of energy?  I ask this as a serious, not a sarcastic question.

Perhaps one dives a Prius and uses LED lighting.  Perhaps one makes serious efforts, conscious efforts to reduce energy consumption.  Given the nature of the people that hang out here I would not be surprised if many of the users and visitors to this site already do this.

While doing my masters research into the history of energy, I ran across something called the Jevon’s Paradox.  In a nutshell, the Jevon’s Paradox states that the more efficiently we use energy the more energy we will use.  This was a very, very bitter pill for me to swallow, but I saw the evidence (and there is an absolute mountain of evidence) that the Jevon’s Paradox is a real phenomenon.  The JP states that as we use energy more efficiently, it becomes easier to consume and thus the more we will consume.  

A person individually may well use less, but tragically that means one then has cheapened that energy for someone else who will not have the same moral aversion to energy consumption and therefore uses as much as he can afford.  As far as I can see, there are only two ways to actually reduce energy consumption and there is absolutely no public appetite for either.

Option number 1 is to actually restrict the amount of energy one is allowed to consume.  Simply put, this means rationing—some very significant rationing.

Option number 2 is energy taxation, and again, this means very serious energy taxation as in downright draconian taxation.

Either option could work, but almost no one would be pleased.

Option 3 would be to use a form of energy that has the most minimal impact on the environment as possible.  My thoughts on this are pretty obvious, but I simply ask the question, "what is one to do?"

This is a topic that is near and dear to my heart and while my own conclusions are not shared by everyone, I certainly appreciate having the diversity of opinions.

Eric

Chris,

I really don’t know what lies beyond post MSR, but getting past steam is doable.  One technology that has been seriously discussed is a closed loop of supercritical CO2 (SCO2).  SCO2 takes CO2 and compresses it to its critical point where it strangely adopts principles of both a liquid and a gas because it can’t decide which state it should be in.  It is quite dense stuff, having about 2/3’s the density of water, but it expands to fill a chamber like a gas.  It’s actual density varies widely with even small changes in temperature which means that heating or cooling induces significant motion and currents which can drive a turbine quite well.  Because there is no need to induce a phase change, they are very efficient from a thermodynamic standpoint, getting upwards of 45% efficiency, which is amazing compared to other technologies that are lucky to get to 20% efficient.

At present there is a fair amount of money devoted to SCO2 turbines even for coal plants to make them more efficient—and I wholly support this goal as I do for all thermal energy producing technologies.

Eric

Chris,

You wanted a glimpse of nuclear beyond the MSR, so I will give an example of a rather extreme reactor known as the nuclear lightbulb.  In this exotic reactor, you have some fissile material like uranium, plutonium or even a more exotic material shaped like a bell.  The inside of the bell is hollow and coated in quartz.  A moderator like liquid hydrogen is pumped into the cavity.  If you remember from previous posts, hydrogen is an excellent moderator.  This causes a nuclear reaction that can reach into the tens of thousands of degrees.  The quartz is almost completely transparent to X rays and at these extreme temperatures, the heat is radiated not in infrared or visible wavelengths, but in X rays.  This means the quartz does not heat up nearly as much as you might think.  And the liquid hydrogen conducts away the heat that would otherwise melt/evaporate the whole device in under a second.

Obviously, I cannot possibly get behind any type of this reactor operating on earth.  The idea is beyond absurd.  But the idea has been proposed for high speed space travel.  One of the interesting aspects of this reactor is that it could potentially operate with a quartz layer on the outside as well as on the inside and then be wrapped in a type of photovoltaic that operating in hard X rays would be surprisingly efficient.  The outgassed hydrogen would be propellant, moderator and coolant.  The resulting thrust would be both very high and highly efficient, a true rarity in the rocket world.

I should probably end this post here before I get moderated for straying off topic, but you asked for a glimpse of a reactor technology beyond MSR, and the most exotic reactor technology I know of is the nuclear light bulb.  Just to reiterate, this is in my opinion (and I am sure just about anyone’s) totally impractical and irresponsible for use on earth.  But believe it or not, it has been proposed for launching HUGE payloads into space as the fissile material is kept sealed in quartz which won’t melt, and the hydrogen moderator/propellant/coolant does not become radioactive as it never actually touches the fuel.  But launching would melt almost any conceivable material underneath and would irradiate a huge area with hard X rays.

And again, I will go no further, but Chris, if you just wanted to know how bizarrely exotic these reactors can get, this is my personal candidate for most exotic proposals out there.

Eric

That's fascinating, and you're right, absolutely insane to suggest building and operating on earth.

That bit about the photovoltaic array tuned to x-rays is exactly what I was talking about, though. What I would love is a photo- or radiovoltaic (is that a thing?) array that converts the radiation directly into electricity. Unfortunately, I bet it requires an inconveniently large quantity of unobtainium to construct.

-CK

CK,

I thought you might get a kick out of the concept even if it is totally absurd for a terrestrial power generator.  I know that the idea of making use of thermionics (sort of a solar panel for heat), photovoltaics, and as you nicely put it, radiovoltaics has been investigated.  

A property of all energy conversions is that the greater the differential, the greater the efficiency of energy transfer.  Think voltage, wind speed, temperature as examples.  The greater the voltage, winds speed or temperature, the higher the potentially harvestable energy.  For instance, if you had an entire Pacific Ocean worth of water elevated to a quarter inch, you would have a tremendous potential energy, but you could only usefully harvest a tiny amount.  In fact, what could a person practically do with a mere 1/4 inch drop in height?  You could probably run a watch for an eternity, but what else?  I doubt one could even manage to generate enough power to run a decent light bulb (though it would run for longer than humanity).

On the other hand, a mere 100 gallons (excluding piping) but raised up to 10000 feet (a good sized mountain) has the potential to do a lot of useful, practical work, but not for very long.

It is theoretically possible to run a small reactor very hot that could produce radiovoltaic electricity, but it would (as of present) need a LOT of cooling and be extremely unstable.

Get me going even further and you will get me talking about the Nuclear Salt Water Rocket, but that will have to be a different post.

Eric

My post was in response to the notion that that it is possible to compare the cost of nuclear with other energy forms. I said from it the perspective of a Ph D in economic history, specializing in the human\technology interface of renewable energy. In connection therewith I have read widely about the introduction of new energy technology comparing states to markets. Ironically the most interesting, as well as the most well documented, of these is of course the transition to oil in North America 1880s to 1930s :) Lastly I  spent 2015-2017 doing primary research on the introduction of renewable energy to 8 communities country wide and have recently completed the report.

Nuclear is only cost comparable with other energy forms in relation to current costs. A full cost calculation including accident clean up and disposal of waste cannot be made and for this reason the technology is not cost comparable.

Please find me an econometrician who can make 300 year cost calculations and I will show you a snake oil salesman. 'Nuff said.

While no doubt insurance companies are capitalists with a reasonable proportion of sneaking lying thieves amongst them, for that very reason they would insure nuclear energy if they saw a way to make money off it. They don't, and I see no reason to doubt their sincerity. Instead, nuclear has always remained a state funded technology - it has in five decades not been able to render itself relevant in the market. i personally feel the vote is the single most ineffective way to make market decisions about new technologies (though obviously nice in other ways).

My point in relation to human error is that, for the technology to not appear to pose a threat to human survival, its proponents have to convince me
a/ that the theory is infallible
b/ that the plan is infallible
c/ that the people who are to execute the plan are infallible.


I am willing to be convinced. In the meantime it is autumn and a very busy time preparing new beds and then harvest. I shall build compost heaps and meditate on compassion. Or as permies.com puts it: "Be nice"

The real reason comparisons are difficult to make is that there is no data on MSRs. Unless I missed something, nobody outside of an MIT experiment has operated one.

Nobody is going to argue about the unsuitability of PWR, for all the reasons Eric has mentioned. But none of what you have said, Natasha, addresses MSRs, which is the permaculturally acceptable nuclear option currently being discussed, largely because, as Bob and Eric point out, they eat the waste you're concerned about, and we've produced about a thousand years' worth of it.

That's a thousand years of free fuel, that companies pay to have disposed of nowadays.

How do you figure that will affect the economic picture?

-CK

Natasha,

i personally feel the vote is the single most ineffective way to make market decisions about new technologies (though obviously nice in other ways).  

I am not sure I am understanding the "vote" aspect. If you are saying that the market has not shown this to be a cost-effective solution, there was a good deal of discussion about that in prior posts. The NRC has basically dictated that only two types of reactor are allowed, breeder and pressure-water. One is literally from the 1930s and one is all the way from the 1940s. This is like the FAA regulating that only biplanes made of cloth wings could be used for transport (hyperbole) and everyone saying rail is clearly the only way to travel based on the economics, but I take your point. The "market" doesn't exist, at least until (my opinion) the Chinese started looking at power generation and the US realized it is far behind.

So to really assess pricing, you have to look at subsidies and hidden costs. Leaving behind the unknowable costs, just looking at the non-catastrophic cost.

Subsidies as you have mentioned are massive. These are upwards of $10 Billion (I believe) to design and build. This investment is subject to political vagaries. As the video Bob linked notes, the plant on Long Island was built, run briefly, and shut down. The cost was probably 90% accrued for the lifetime of the plant. That is a HUGE amount of money wasted. No private investor I know would even consider such a crap shoot with a 30 year payout! I don't actually know any with $10 Billion, just to be brutally honest. The video points out that this was lobbied for by the construction industry, they got their cut (and this is NYC so it is highly corrupt) and then turned on the project and lobbied for it to be shut down. It meant there were no more plants built in the last 30 years in the US.

Hidden cost is largely environmental impact, probably 10 different federal agencies lobbied and scores of politicos "funded", and as mentioned no one really knows the actual cost of a catastrophic event. Most of the cost of a catastrophic event would be psychological I truly believe. People could move back to the vicinity of Chernobyl (actually there are something like 10,000 people living in the initial evacuation zone now). Their cancer rates are undetectably different than someone on the upwind side. But as you can see in this article people are protesting the plan to move soil that has 8000 becquerels release per kilo. If you are in a crowd of people, you get that much release from just the human bodies around you! It is purely a psychological aversion. But that has a cost just like deodorant has a cost, or not eating organ meats.