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#576 2023-07-11 18:07:22

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For kbd512 re #575

While we wait for Calliban to join the flow, thanks for #575, with assurance the existing weapons material is able to be redeployed to civilian power production.

It may not be possible to know the answer to this, because the nuclear stockpiles are probably classified (unless the arms treaties require publication), but given your estimate of:

548 reactors

I wonder if we (US) have enough nuclear material to support that expanded fleet, plus keeping the existing fleet going.

***
Related issue (completely aside from issues of land allocation and construction challenges) ... I wonder if there are enough qualified human beings to fill out a work force to build and operate that fleet.   If retired military are willing to help out until new employees can be trained and certified, it might be possible to staff a fleet of that size, but I'll bet it would be touch-and-go for that entire 20 years.

(th)

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#577 2023-07-11 22:15:43

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,427

Re: Nuclear power is safe

tahanson43206,

We've had around 250 military HEU reactors operating over the past 50 years.  We've had about 100 to 120 very large power reactors operating that long as well.  We haven't reprocessed much, if any, of that fuel, ever, which is replaced every 18 months using Uranium mining.  We take it out of the reactor after 2% to 5% of the original energy content is gone and the fuel rods crack, and then we put it in steel casks after it cools off for a few years, and call something with almost all of the remaining energy it could generate "nuclear waste".  Well, yeah, if you don't get rid of the neutron poisons and stick it back in the reactor, then it is a waste product.  It doesn't have to be, except that it's viewed as "job security" for the Uranium mining operations.  If we add more plentiful Thorium to the mix, which we also store in steel casks, then we have fuel coming out the wazoo, but we have to be modestly more intelligent about how we use it.

Since almost all of our reactors are at least 50 years old, we have at least 33 fuel loads per reactor sitting in steel casks, multiplied by 100 reactors, which gives us about 3,300 fuel loads.  Rather than keeping the fuel outside of an operating reactor, where it actually could be stolen or otherwise misused, why not build a fuel reprocessing plant instead, start reprocessing the giant pile of fuel we're sitting on that still contains an average of about 97% of its original energy content, and be done with the old and very tired "Where do we put all the nuclear waste?" non-argument?  We decided to make it waste by not reusing the usable fuel, which is almost all of what we call "high level nuclear waste".  It's waste by choice, not because it's actually useless material that can never be used again.

People act like there's not a solution available, but there is, we just have some people who don't want to actually do what needs to be done, for their own personal reasons, most of which relate to their religious beliefs that "green energy" is going to ride in on a golden chariot and save us.  Going around chanting dogma and smacking yourself in the head with "The Good Book", should only ever be a Monty Python skit, not how we approach energy or any other important aspect of life.  We've been tinkering with electronics for the past 50 years.  The only end result is that electronics are more expensive and energy-intensive with each passing year.  Improvements to electronics have only done something useful for improving computing power and the energy required to do that, we still have nothing remotely approaching a viable energy solution.  Elon Musk himself has stated that photvoltaics top out at 25% to 30% efficiency, and that is where they will remain until some fundamentally new technology arrives.  My neighbor had 25% efficient panels when I was a child in the 1980s.  40 years later, they're still no more efficient than they were back then, only modestly cheaper and longer-lasting.  Energy storage gets more expensive with each passing year, as material inputs become more scarce.  Solving the fusion problem is far more likely to occur during the next 50 years than acquiring enough raw materials to run human civilization on electronics.  It's not hard to figure out why.  The tech is at its practical limit.  These days, most electrical and mechanical devices function near their practical limits.  We've had computing advancements since then, major ones, but none of that radical change applies to generating and storing energy.

We can spend about as much as we spend on the military and entitlement programs for 1 to 1.5 years, by solving our energy problems using nuclear power, or we can spend something close to the entire US GDP for 1 to 1.5 years to do some form of "green energy" that only covers electric power generation to replace what we're presently using, which is mostly natural gas / coal / oil.

You need a fleet of 457 brand new 1.25GWe reactors to generate 4PWh of electricity, not 548.  This is the quantity required to provide buffer / excess generating capacity to permit reactors to be taken offline as required, and is what I calculated for equivalent cost to the cost of the solar panels and pumped hydro energy storage alone.  It does not include massive grid upgrades or the actual installation costs, etc- merely buying the most necessary pieces of equipment, without which there is no "green energy".  The 457 to 548 reactors would replace all existing forms of electrical power generation in the United States, to include coal, gas, old nuclear power plants, wind turbines, solar panels, diesel engines, etc.  The fleet of new reactors covers the entire shooting match when it comes to electrical power generation.  This equates to about 9.14 to 10.96 reactors per state, even though they won't be evenly distributed.  If you calculate what the true costs will be for enough storage and panels or wind turbines and grid upgrades, it's an astronomical amount of money in the low tens of trillions of dollars.  Pardon me for thinking that's unrealistic over 20 years.  We still want government science programs, health care, food stamps, a military, foreign aid, etc, right?  How about not taxing everyone into oblivion, rich and poor alike?

If we can't find 3 sites per state to cluster 3 to 4 reactors in one place, then that should tell you how practical it's going to be to build the greatest expansion of the electrical power grid infrastructure, plus hydro and battery energy storage, plus land area devoted to power generation using wind turbines or solar panels, that the world has ever seen.  There is nothing in the way of material resource constraints using nuclear power- at all or ever if we're talking about the next 1,000 years for the existing industrialized world.  Let's pretend we only had 500 years, though.  That's still more breathing room, is it not?  Nuclear power buys us time to figure out how to devise practical and affordable transportation solutions that don't involve burning things.

If this is done over 20 years, then there are no educational constraints, either.  The US Navy trains brand new reactor operators over 2 to 4 years.  For all intents and purposes, it's going to a special college where you're taught about math, nuclear physics, chemistry, radiology, and running a steam power plant.  You leave Naval Nuclear Power School with an Associate's Degree, and a couple short years later while in service running a power plant, you earn a Bachelor's Degree, EE, ME, NE (a generalized degree more about design and "big picture"), or radiology for the ones going into nuclear medicine.  Naval power reactors are not like commercial power reactors, but the fundamentals are the same.

People involved in nuclear engineering tend to exhibit the following desirable character traits:

1. tend to keep their jobs, because getting another one isn't easy unless you're really good at it
2. don't tend to do drugs or exhibit other self-destructive habits
3. have good salaries for owning homes and starting families
4. actually have families (future tax payers for all you Democrats)
5. are generally a credit to science and civilized society

This is not rhetorical in nature, or "just my opinion".  It's basic math, reasonable extrapolation about what the future will hold (more of what the past held), combined with the admission that what we want and what we can actually achieve need to be the same thing.  Nuclear power is not a panacea, merely the least bad option.

Look at those Copper and Lithium and Rare Earth strip mines?  Think anyone or anything will ever live and grow there again?  It's every bit as lethal as the worst nuclear accidents, but on an unimaginably larger scale.  Arsenic is Arsenic forever, it is a poison, and it does kill.  Even if you include both actual nuclear weapons attacks and the various rare but serious nuclear accidents over the decades, we've killed absurdly more people by poisoning the environment in places like China and Africa in pursuit of all these rare elements that feed into electronics production.  Put the damn reactors a mile underground if we're really worried about nuclear contamination.  COVID was a massively greater threat to humanity than all the nuclear reactors on the planet.  The absolute freak-out over COVID killed more Americans than Hiroshima and Nagasaki combined.  Burning Tokyo to the ground killed more people than both bombs.  It's sheer dumb luck that those idiots in Wuhan didn't kill 25% of the people on the planet, which is probably why the communists executed them.

If we want to move beyond technological adolescence, then we're going to have to leave dogmatic ideology and favoritism behind, in deference to what is pragmatic and achievable.  Nature doesn't have favorites.  We're not going to run out of Uranium and Thorium for at least the next 300 to 3,000 years.  We can and should include solar thermal power in our energy mix as a backup plan or primary enrgy source for ground transport.

You can stand outside all day.  You'll get a sunburn, but you won't die.  Take an 8 kilo baseball-sized chunk of Uranium critical for less than a second and you'll kill or seriously injure everyone dumb enough to be in the room with you.  That's real power.  You don't have to worry about being 99% efficient when you have that kind of power.  It helps, obviously, but is not required.  That's the major difference between what nature uses to heat planetary cores or power stars and what some people are asserting humanity should use to heat a steam kettle.  Nature doesn't lust after efficiency.  Nature uses pure brute force.  Overkill is the best kind of kill when it comes to power.  "I really wish these engines made less power", said no pilot or race car driver ever.  How much power do we need?  More.  Men with broadswords don't worry about how much more efficient scalpels might be, because they don't need to.  That's why we made broadswords.  Captain Kirk knows what the answer is, even if it's up to Scotty to give him what he needs.  We can only figure out what to do with it after we have it.  Until we have it, we're dead in the water.  I detest being on ships that imitate barges, because ships without power have no reason to exist.

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#578 2023-07-27 05:28:37

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

The economic case for reprocessing has always been weak in an LWR dominated system.  Light water reactors have a conversion ratio of about 0.6, meaning that for every fissile atom that fissions in the reactor, 0.6 fissile atoms of (mostly) plutonium-239 are produced.  But some of this is consumed in the reactor due to fuel shuffling.  So, discharged fuel ends up containing 94-95% 238U, 1% 235U, 1%Pu isotopes and 3-4% fission products.  In theory, reprocessing could reduce uranium requirements by 25% using standard LWRs.

The problem is that a reprocessing plant is an expensive piece of equipment.  It needs to be heavily shielded because of the gamma emissions from fission products.  It needs to be maintenance free because of those gamma emissions.  It needs to deal with fission product heat generation.  Criticality hazards are a problem because of the low critical limits of aqueous plutonium solutions.  Sedimentation complicates this problem even more.  At the end of reprocessing, you are left with a mixture of solid precipitates and aqueous solutions, of seperated plutonium, uranium, fission products and transuranics.  You could reuse the seperated uranium in new fuel.  But 232U makes it difficult to handle, because its daughter is a strong gamma emitter.  You could use the plutonium to make MOX.  But plutonium is expensive to work with, because of its toxicity and low criticality limits.  This is why MOX fuels tend to be high burnup.  If you are paying a lot more for fuel, then you want to be buying less and refuelling less often.

Unless uranium prices are high, reprocessing doesn't save money.  This is the real reason why the US and Canada don't do it and Britain no longer does it.  Some breeder reactor concepts like the reduced moderation BWR, would need reprocessing in order to work.  There are other concepts like the travelling wave reactor, that might work without reprocessing.  DU or LEU is inserted into the outer blanket.  As it gradually shuffles in towards the central core, it absorbs neutrons, breeding plutonium, which then fissions within the core without needing any reprocessing.  That is a really neat idea.  But it is technically challenging because it requires both a hard neutron spectrum to produce enough surplus neutrons and a high burnup of discharged fuel - about 30 atom% fissioned.  It is difficult to engineer cladding materials that will reliably stand up to that sort of neutron fluence.  There are some specialist stainless steels that show promiss.  But all stainless steels are vulnerable to grain boundary precipitation and cracking under hard neutron flux.  The Natrium concept was all about developing a sodium colled travelling wave reactor.  If they can pull it off, then humanity will receive all of the benefits of a breeder reactor economy, without the need for a large fleet of reprocessing plants.  We would need some to produce starter cores, but only for beggining of life.  Spent fuel waste volumes will be reduced by about 90% compared to LWR cycles.  I really hope they succeed.  But I'm not banking on it.

Last edited by Calliban (2023-07-27 05:36:18)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#579 2023-07-27 06:25:51

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Calliban re updates in this topic!

Thanks for your patience in waiting out the recovery effort by James Burk, kbd512 and others.

And thanks in particular, for your explanation of differing approaches to improved efficiency in utilization of nuclear fission fuel, and dealing with byproducts!

Your closing observations about the Natrium concept are particularly helpful (to me for sure!)

(th)

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#580 2023-07-27 07:12:38

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

TH, it is good to see the board back up and running.  I wasn't sure if it was down due to a fault or if the Mars Society has scrapped it!

For nuclear power deployment on Mars, we never really got to the bottom of how this would be done.  Robert Zubrin's original Mars Direct assumed the existance of SP-100 fast reactors for surface power, each producing 100kWe.  For the ERV, this allowed propellant tanks to be filled in the period between ERV arrival and the manned hab launch window.  Thus the crew woukd not launch until return propellant tanks were confirmed to be full.  Starship is a much larger vehicle than the Mars Direct ERV and Kilopower units have smaller power output (10kWe max).

If the first Starship is to be dispatched unmanned, then the power system must be deployed remotely from Earth.  Solar power is out of the question, as we cannot robotically deploy solar arrays covering several acres of the Martian surface and weighing hundreds of tonnes.  Kilopower units could be mounted on self-propelled vehicles and driven away from the ship, unfurling a power cable behind them.  But a Starship would need to carry a lot of them to produce enough power to fill its propellant tanks.

Musk's longer term ambitions of building a city on Mars, will require large scale power production to allow ISRU and food production.  Estimates have been raised that some 10kW/capita of power will be needed.  The good news is that a lot of that power is needed for food production and could be provided by nuclear waste heat.  By the 2030s, the first small modular reactors will be entering production of Earth.  These are small lightwater reactors.  To support Musk's plan, we should examine how these units could be adapted to function under Martian gravity.  In this way, Martian reactors can be COTS equipment with some modifications.  Fuel will be imported from Earth initially.  As ISRU capabilities expand, we would produce a steadily greater proportion of powerplant components on Mars.

The first ISRU opportunity would be to use locally made concrete and aggregates to produce the shielding and masonry structural components for the plant.  Next, secondary side steam pipework, condenser, turbine casings and some valves can be made from locally made steel and cast iron.  Maybe we could make steam generator pressure shells from native steel as well.  The turbines, generator sets and the primary circuit are all high tolerance components that will be more difficult to make locally.  It may be some time before Martian industry is capable of making main coolant pumps, control rod drive mechanisms, reactor instrumentation, steam generator tubes, pressurisers and reactor pressure vessels.  But secondary side components and masonry structures dominate total mass.  So these are the things that Martian nuclear engineers would be looking for opportunities to replace with ISRU components.

Spent fuel reprocessing is something that is tricky even here on Earth.  Most nations do not develop this capability because reprocessing and MOX fabrication has always been more expensive than fresh LEU fuel produced by enrichment plants.  On Mars, there may be a stronger case for reprocessing.  Fuel will initially need to be imported from Earth at high cost, making a Martian colony vulnerable to supply disruptions.  Reprocessing involves dissolving spent fuel in nitric acid and using various chemical seperation techniques to seperate the components.  Actinide nitrates can then be reduced to oxides and used for MOX fabrication.

On Mars, we might try something different.  Instead of attempting MOX fabrication, actinide nitrates could be directly dissolved into moderator-cooling water within aqueous homogenous reactors.  These reactors would operate at low temperature and would be equipped with central core regions that fission residual plutonium and uranium nitrates and a breeder blanket region that converts thorium in 233U.  The 233U can then provide the starting material molten salt reactors that woukd be domestically manufactured on Mars.  This would allow Martian thorium to gradually displace enriched uranium imported from Earth.

Last edited by Calliban (2023-07-27 07:37:00)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#581 2023-07-28 04:58:56

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

At 590 metric tonnes, these Nuscale units are a bit too heavy for Starship to lift into orbit.
https://en.m.wikipedia.org/wiki/NuScale_Power

Even the old ITS design could not have done it in expendable mode.  Maybe the reactor can be broken down into smaller components and welded together on Mars?

A 70MWe powerplant is about the size needed for a large base of ten thousand people.

The Westinghouse eVinci reactor appears to be at licencing stage.
https://www.westinghousenuclear.com/ene … croreactor

It is a 5MWe reactor producing 13MWth, so 8MW of waste heat.  Small enough to fit into a truck mounted iso shipping container.  Ideal for an early base of up to a thousand people and probably small enough to fit as a single Starship payload.  The core life is quoted at 8 years.  We would probably install modular units like this until the base grew large enough to require a larger light water reactor unit.  By this point, ISRU should have developed sufficiently to allow secondary side equipment to be built of Mars.

This boiling water reactor produces up to 300MWe.
https://en.m.wikipedia.org/wiki/BWRX-300

Enough for a small city of 50,000 - 100,000 people on Mars.  The BWR has no primary heat exchangers and operates at only half the pressure of a PWR.  This might be easier to build with ISRU on Mars.  The pressure vessel can be stainless steel clad, low alloy carbon steel.  Easy enough to make and weld on Mars.  The control rods, control rod drivers, feed pumps, reactor instrumentation, main isolating valves and fuel, will all be imported from Earth.  Secondary pipework would be Mars made, along with the turbine casing and condenser.  The turbine itself woukd be a technical stretch for early Mars manufacturing.

Last edited by Calliban (2023-07-28 05:23:00)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#582 2023-07-28 06:12:44

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Calliban re Nuclear Power on Earth and Mars ....

In the region where I live, there are plans in work to build a very large semiconductor manufacturing facility, with a view to pulling back from outsourced expertise to China.  Such a facility is going to need a suitable work force, and I caught a recent broadcast interview with a member of the local education community.  The responsibility for developing that work force is going to fall upon existing education institutions.  The local representative expressed confidence the needed staff would be available when they are needed, but she admitted it would be a challenge.

I bring this up because Mars is going to be a high tech civilization from the beginning, and it will remain that way if it survives. Your description of nuclear reactor options seems (to me at least) to show that there are potential opportunities for Mars planners.

Please give some thought to staffing requirements for the various options you think might be most practical for the Mars venture.

The current lack of detailed material availability on Mars means that a lot of uncertainty is built into ISRU speculation.  Importing everything from Earth would seem to be a reasonable starting strategy.

(th)

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#583 2023-08-04 07:22:22

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,267

Re: Nuclear power is safe

LM contract

NASA’s 1st Nuclear-Powered Rocket Could Launch as Soon as 2025
https://greekreporter.com/2023/08/02/na … et-launch/

project to build $500 million nuclear space rocket

Last edited by Mars_B4_Moon (2023-08-04 07:23:05)

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#584 2023-08-04 08:39:25

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 5,457
Website

Re: Nuclear power is safe

Nuclear rocket testing was done at Jackass Flats on the Nevada nuclear test range from the late 1950's until 1974.  Some of the names were Phoebus,  Kiwi,  and such like.  The final form was NERVA,  in which the core erosion problems were finally fairly-well solved,  minimizing but certainly not eliminating exhaust stream radioactivity.  It was this NERVA engine from 1974 that was to used in a substitute 3rd stage for the S-IVB third stage of the Saturn-5,  to essentially double its payload,  because the specific impulse was roughly double that of the 1st and 2nd stages.

In those days,  test firings were conducted out in the open air.  That is no longer considered "legal" these days because of the plume radiation.  Modern nuclear rocket testing facilities must capture the entire mass of the expelled plume,  and deal with it as a very hazardous waste.  That kind of thing has never existed before,  and will be quite expensive,  which is the bulk of the program price tag.

Now does my suggestion make more sense?  To put the nuclear rocket test station on the moon where you can test out in the open?  Where there is no air or water to pollute,  and no neighbors to annoy?  There's no better reason than that,  to go back to the moon.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#585 2023-08-04 08:56:09

Void
Member
Registered: 2011-12-29
Posts: 7,088

Re: Nuclear power is safe

Yes, GW Johnson that is a good idea, and I did not have it before.  Now I do.

Done


Done.

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#586 2023-08-04 15:34:41

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

Testing it on the moon is possible.  But testing it on Jackass Flats was the best solution.  High Earth orbit is another option that doesn't require first landing on the moon.  So long as people insist on treating radioactivity as an infectious disease rather than just a pollutant, any space application of nuclear power is problematic.  People get ridiculous about it.  Remember all the nonsense and media fanfair about the RTG on the Galileo probe when it carried out its Earth gravity assist?  People simply have no way of gauging and understanding relative risk.  They worry and protest about irrelevant things, whilst huge dangers afflict them unnoticed.

Last edited by Calliban (2023-08-04 15:36:43)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#587 2023-08-20 16:25:47

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,267

Re: Nuclear power is safe

Nuclear-Powered Spacecraft That Can Take Humans To Mars To Be Operational By 2027

https://www.adelaidenow.com.au/technolo … ebcaf2e459

The fission-based reactor will use a special high-assay low-enriched uranium, or HALEU, to convert the cryogenic hydrogen into an extremely hot pressurised gas. The reactor will not be turned on until the spacecraft has reached a nuclear safe orbit, making the NTP system very safe.

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#588 2023-08-22 04:38:21

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

I have been doing some background reading on nuclear reprocessing and fission product yields.  I think it unlikely that Mars is going to have a long term nuclear waste problem.  We do not know at present if Mars has significant natural uranium ore reserves.  If the answer turns out to be negative, then it will make sense to reprocess spent fuel and recycle all actinides into fresh fuel.  So actinides will not be part of any waste stream.  The remaining reprocessing output is fission products.
https://en.m.wikipedia.org/wiki/Fission_product_yield

Sr90 and Cs137, make up 11% of fission product yield and dominate decay heat after 5 years out of the reactor. These nuclides can be extracted and used in radiothermal generators.  Both may be useful as power sources for interpkanetary ships and outer solar system probes.  On Mars, we could encase both isotopes in steel spheres and use them to provide heat to greenhouses, preventing freezing.  The decay product of Sr90 is stable Zr90, which can be used to make nuclear fuel cladding or fuel metal alloy.  Cs137 dexays into stable Ba137.  This can be used as an alloying element.

Palladium-107 has a half life of 6.5 million years, making it only weakly radioactive.  It's fission product yield is 0.16%.  It can be extracted from reprocessing waste and used as a catalyst and as coating for chemical rsaction vessels, especially for situations where strong acids must be contained.  It could also be used to coat fuel elements and nuclear reactor internals.

Cs135 has a fission product yield of 6.9% and a half-life of 2.3 million years.  Its activity is so weak, that it poses a negligible hazard.  It will be extracted along with Cs137 and included within radiothermal generators.  It is actually a nuisance, as it will dillute the thermal power of Cs137.

Cs134 has a fission product yield of 6.8% and half life of 2 years.  It will be extracted along with other ceasium isotopes for use in radiothermal generators.

Zr93 has a fission product yield of 5.5% and a half life of 1.53 million years.  It isva weak beta-gamma emitter.  It will be recycled into fuel cladding in LWRs or into fuel metal in U-Pu-10%Zr fast reactor fuel.  It is a beta emitter.

Tc99 has a fission product yield of 6.14% and a halflife of 211,000 years.  It is a beta emitter.  Whilst it is radioactive, its long half-life means that its radioactivity is a relatively minor toxicity concern.  Pottasium Technetate is an excellent corrosion inhibitor in water.  It could be added to coolant water in LWRs and protect primary circuit components from corrosion.  Technetium containing alliys also have potential uses as catalysts.

Samarium 149 & 151 are mostly destroyed by neutron irradiation in the reactor.  They collectively make up about 1.5% of fission products.  These isotopes are neutronic poisons.  If we could harvest them, they could be incorporated into control rods or burnable poisons for controlling reactivity distribution in the core of reactors.

Pm147 accounts for 2.27% fission product yield and has a half life of 2.6 years.  It has been used in radiothermal generators and could be used for this purpose on Mars.  If encased in steel spheres, we could use it to keep greenhouses warm.  Alternatively, we could drop the spheres down wells in permafrost rich areas and draw off the melt water.  Pm147 decays into stable Sm147.  Samarium has uses in permanent magnets.

Ru106 has a half life of about 1 year and a fission product yield of 0.39%.  We would probably store it in solution and use its dexay heat to warm greenhouses around the reprocessing plant.  It decays into stable Pd106, which should form a solid precipitate.  This would be jewellery grade palladium.

Nb95 accounts for 6.5% of fission product yield.  It has a half life of 35 days and shoukd have mostly decayed into stable Mo95 by the time of reprocessing.  Mo can be used as a component of nuclear reactor steels.

Mo99 accounts for 6.1% of fission products and has a half life of 65 hours.  It decays into Tc99m, which in turn decays into Tc99 with a half life of 6 hours.

Nd144 is a stable decay product of Ce144, which decays with a half life of 144 days into Pr144, which has a half lufe of 17.3 minutes and decays into Nd144.  The short half life of Ce144, means that most of it will have decayed into Nd144 by the time we reprocess.  Neodynium is a rare earth element used in strong permanent magnets.

Nd147 is 2.2% of fission products and has a half life of 11 days.  This decays into the forementioned Pm147, which has uses as a radiothermal isotope.

La140 is 6.3% of fission product yield.  It decays with a half life of 1.68 days into stable Ce140.  Cerium oxide is used as an abrasive polish.

Ru103 accountsbfor 3.1% of fission product yield and has a half life of 39 days.  Its decay product is stable Rh103, which is rhodium.  A valuable platinum group metal.  Rhodium is extremely hard and has uses in jewelry, electrical contacts and as a catalyst.

Te132 is 4.3% of fission product yield.  It rapidly decays into stable Xe132, which can be used as a propellant in ion thrusters.

On Mars, we will be wasting nothing.  Spent fuel will be fully recycled and fission products will be seperated and used in various ways.  So there will be no radioactive waste problem because there will be no waste.  Everything will have a productive use.

One thing I find interesting is using fission product palladium to coat nuclear reactor internals and dissolving technetium in cooling water to inhibit corrosion.  If corrosion can be reduced to almost zero in this way, then it should be possible to produce light water reactors that last for centuries.  This would contribute to the Permanence Movement that I posited a while back.  The idea of building things that really last a very long time and reducing energy and resource costs in that way.  For nuclear reactors, this coukd be especially significant.  Most of the lifetime cost of a nuclear reactor is its upfront capital cost.  A reactor that lasts for centuries woukd be a true gift to future generations.  It would allow centuries of really cheap electricity and heat production.  Which is exactly what we need on Mars.  A nuclear reactor that lasts for centuries also substantially mitigates the decommissioning problem.  If a reactor is able to produce power for 200 years, then allowing another 120 years for radioactivity to decay prior to decommissioning, is hardly a big burden.  And a reactor with an effective lifetime as long as that, will produce only 1/5th as much decommissioning waste per kWh, than would a reactor that only generates for 40 years.

Last edited by Calliban (2023-08-22 06:58:55)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#589 2023-08-29 14:46:45

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,267

Re: Nuclear power is safe

Young climate activist tells Greenpeace to drop ‘old-fashioned’ anti-nuclear stance
https://www.theguardian.com/environment … ear-stance

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#590 2023-08-30 06:53:10

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Calliban ...

There is an opportunity for an enterprise to help to meet a pressing need at the Panama Canal by using nuclear power to replenish water that flows from the lake and river system above the locks, when ships enter or leave the system.  The new locks are designed to avoid loss of water, by pumping water into reservoirs adjacent to the locks.  However, the original six locks have no such feature.  Instead, they allow significant quantities of water to escape to the sea.

In the current drought conditions, the Panama Canal authority is unable to meet the needs of it's customers.  At the present time, there is a backlog of ships waiting for service.  The water system above the old locks could be replenished by a nuclear reactor.  Would you be willing to work out the size of reactor that would be needed?

According to a web site: www.rti.org, it takes 50,000,000 gallons of water to move one ship through the older canal locks system.

The cost of the water replacement can be added to the transit fee of each ship during periods when the natural supply of water is insufficient. The reactor can be redirected to other purposes when water is not needed, so Panama would have a valuable resource above and beyond just the water resupply.

The first step in developing a plan to approach the Canal Authority with a proposal, would be to size the reactor needed.

In the modern age, it might be sensible to consider several small modular reactors, instead of one large traditional one. 

For example, since there are two ends to the canal, there could be pumping stations at each end, which means that excess power could be available at each end when water resupply is not needed.

There are large cities at each end of the Canal.

Follow up: Every day I look in on operations of the Panama Canal, while working on NewMars updates.  Today, I saw something I'd not seen before, but which has a bearing on the water loss problem at the canal.  The Panama Canal Authority provides tugboats and other smaller vessels to manage the flow of traffic through the canal.  Right now, a single tugboat is consuming 50,000,000 / 6 gallons to make the drop from the main canal system to the second level.  Now ** that ** is NOT a revenue producing use of the limited supply of water on hand. A nuclear water resupply system would need to be sized to take into account such non-productive activity.

Follow up to the Follow up: The tugboat I saw riding a lock down all by itself was NOT wasting water after all.  There was a ship just out of view of the webcam, waiting to be lifted up by that same lock, so the tugboat was taking a "free" ride. 

Never-the-less, the reactor (or reactor family) should be sized large enough to meet ** all ** the traffic that the Panama Canal Authority might wish to process.  The maximum capacity of the lock system is given by the time required to perform a single lift. 

Another factor at work is the depth of the canal ... at present, the canal water level is lower than normal, so ships are restricted in draft. Having a sufficient supply of water to maintain the depth needed for the largest ships might factor into the sizing of the reactor or reactor family.

(th)

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#591 2023-09-05 10:51:08

Steve Stewart
Member
From: Kansas (USA)
Registered: 2019-09-21
Posts: 161
Website

Re: Nuclear power is safe

I just saw this on the BBC.
(I think this is related to tahanson's post #529)

Moon base: Bangor scientists design fuel to live in space

The article states:

Scientists have developed an energy source which could allow astronauts to live on the Moon for long periods of time.

...

Bangor University has designed nuclear fuel cells, the size of poppy seeds, to produce the energy needed to sustain life there.

Prof Middleburgh from the Nuclear Futures Institute said the team hoped to fully test the nuclear fuel "over the next few months".

On parts of the Moon, temperatures plummet to astonishing lows of -248C because it has no atmosphere to warm up the surface.

Bangor University is a major player in the quest to generate another way of producing energy and heat to sustain life there.

The researchers have just sent the tiny nuclear fuel cell, known as a Trisofuel, to their partners for testing.

This Trisofuel cell could be used to power a micro nuclear generator, created by Rolls Royce.

The generator is a portable device, the size of a small car and "something you can stick on a rocket," Prof Middleburgh said.

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#592 2023-09-05 17:51:43

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Steve Steward re Post #591

Thanks for this very interesting report and link!

This is Calliban's topic!  While Calliban swings between extreme optimism and extreme pessimism (often on the same day) ** this ** topic was one he created on an up day!  I think your post fits in nicely.

My topic is the more cautious one, about Nuclear Power being Dangerous << grin >>

Your post fits in either!

Please keep watch for any updates that may appear in the weeks or months ahead!

(th)

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#593 2023-09-13 17:01:16

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

Here's an item that should appeal to Calliban:

https://www.yahoo.com/news/remote-air-f … 54927.html

On August 31, the Air Force announced that a California company called Oklo would design, construct, own, and operate a micro nuclear reactor at Eielson Air Force Base in Alaska. The contract will potentially run for 30 years, with the reactor intended to go online in 2027 and produce energy through the duration of the contract. Should the reactor prove successful, the hope is that it will allow other Air Force bases to rely on modular miniature reactors to augment their existing power supply, lessening reliance on civilian energy grids and increasing the resiliency of air bases.

Located less than two degrees south of the Arctic Circle, Eielson may appear remote on maps centered on the continental United States, but its northern location allows it to loom over the Pacific Ocean. A full operational squadron of F-35A stealth jet fighters are based at Eielson, alongside KC-135 jet tankers that offer air refueling. As the Department of Defense orients towards readiness for any conflict with what it describes as the “pacing challenge” of China, the ability to reliably get aircraft into the sky quickly and reliably extends to ensuring that bases can have electrical power at all times.

“If you look at what installations provide, they deliver sorties. At Eielson Air Force base they deliver sorties for F-35 aircraft that are stationed there,” Ravi I. Chaudhary, Assistant Secretary of the Air Force for Energy, Installations, and Environment, tells Popular Science via Zoom. “But if you think about all that goes with that, you’ve got ground equipment that needs powering. You’ve got fuel systems that run on power. You’ve got base operations that run on power. You've got maintenance facilities that run on power, and that all increases draw.”

And it’s not just maintenance facilities that need power, Chaudhary points out; the base also houses communities that live there, go to school there, and shop at places like the commissary.

While the commissary may not be the most immediately necessary part of base operations, ensuring that there’s backup power to send the planes into the air, and take care of families while the fighters are away, is an important part of base functioning.

But in the event that the base needs more power, or an independent backup source, bases often turn to diesel generators. Those are reliable, but come with their own logistical obligations, for supplying and maintaining diesel generators, to say nothing of the carbon impact. As a promotional video for the Eielson micro-reactor project notes, the military is “the nation’s largest single energy consumer,” which understates the outsized role the US military has as a producer of greenhouse gasses and carbon emissions.

This need is where the idea of a small nuclear reactor comes into play.

“When you have a core micro reactor source that can provide independent clean energy to the installation, that's a huge force multiplier for you because then you don't have to rely on more vulnerable commercial grids,” says Chaudhary. These reactors would facilitate a strategy Chaudhary called “islanding,” where “you take that insulation, you sequester it from the local power grid, and you execute operations, get your sorties out of town and deploy.”

The quest for a modular, base-scale nuclear reactor is almost as old as the Air Force itself. In the 1950s, the US Army explored the idea of powering bases with Stationary Low-Power Reactor Number One, or SL-1. In January 1961, SL-1 tragically and fatally exploded, killing three operators. The Navy, meanwhile, successfully continues to use nuclear reactor power plants on board some of its ships and submarines.

In this case, for its Eielson reactor, the Air Force and Oklo are drawing on decades of innovation, improvement, and refined safety processes since then, to create a liquid-metal cooled, metal-fueled fast reactor that’s designed to be self-cooling when or if it fails.

And importantly, the Air Force is starting small. The announced program is to design just a five megawatt reactor, and then scale up the technology once that works. It’s a far cry from the base's existing coal and oil power plant, which generates over 33 megawatts. Adding five megawatts to that grid is at present an augmentation of what already exists, but one that could make the islanding strategy possible.

If a base can function as an island, that means attacks on an associated civilian grid can’t prevent the base from operating. This works for attacks with conventional weapons, like bombs and missiles, and it should work too for attempts to sabotage the grid through the internet, like with a cyber attack. Nuclear attack could still disrupt a grid, to say nothing of the resulting concurrent deaths, but Chaudhary sees base resilience as its own kind of further deterrent action against such threats.

“We've recognized in our national defense strategy that strong resilient infrastructure can be a critical deterrent,” says Chaudhary. “Our energy is gonna be the margin of victory.”

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(th)

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#594 2023-09-14 02:38:52

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

Small reactors producing 5MWe are about the right size to provide power to propellant synthesis plants for Starship on Mars.  On Earth, these units are ideal for powering a small military base.  They could also provide propulsive power for ships.  If we can source more information on plant mass and volume, we can make a judgement on how well the reactor plant fits each application.

Another company, Newcleo, is developing lead cooled fast reactors.  Two designs are being developed: A 30MWe and a 200MWe.
https://www.newcleo.com/what-we-do/

The 30MWe unit is an ideal power for large cargo ships.  It could also be adapted to power a Mars base.

Last edited by Calliban (2023-09-14 02:43:33)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#595 2023-09-14 06:27:16

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Calliban re #594

First, thanks for noting the US military base application! Second, thanks for the update on Newcleo, which does indeed sound promising.

I presume lead is the primary coolant, so there must be a secondary fluid that draws off thermal energy for power and simple heating for habitat warmth.

The use of lead is intriguing, because I understand lead is the end product of fusion.  I assume it can be split into fragments by fission produced neutrons, but these would not be heavier than lead itself.

Please continue your investigation of both companies!

I am still looking for a solution that can be offered to Panama (government and agency) to provide base power and emergency water pumping.

The pay back for the investment is income from shipping that transits the canal.  That income is reduced when water levels are low, so any income produced when water is pumped goes directly into repayment of the loan to build the pumping system.

(th)

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#596 2023-09-25 10:36:06

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,267

Re: Nuclear power is safe

Poland issues environmental permit for first nuclear power plant

https://www.reuters.com/business/energy … 023-09-22/

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#597 2023-10-28 18:30:54

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,267

Re: Nuclear power is safe

Thorium Reactors: A Safer and Sustainable Nuclear Future

https://www.azocleantech.com/article.as … cleID=1749

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#598 2023-11-14 19:22:05

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,858

Re: Nuclear power is safe

Just a small problem Nuclear Project Failure Is a Blow to Industry’s Future

NuScale announced it is scrapping plans to build a first-of-its-kind nuclear plant in Idaho, as the Portland-based NuScale (SMR) makes small modular nuclear reactors due to cost rise.

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#599 2023-11-14 20:11:27

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For SpaceNut .... when you get time to read the article, you'll find that it wasn't so much that costs were rising, as that the early customers got cold feet. The company is exploring other options with vigor.  From my perspective, the substantial bet made by the US to encourage this technology is going to pay off in the long run, unlike with the solar panel company which (I gather) was pursuing a dead end branch of photon capture technology. I'm pretty sure the Small Modular Reactor is going to survive the early growing pains, and become a successful development, with thousands of installations.  It may take a while to get the first one, apparently.

(th)

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#600 2023-11-15 18:28:39

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,858

Re: Nuclear power is safe

Indirectly the rise in cost is due to fixed price for the selling of the energy.
First U.S. small nuclear reactor project canceled as costs soared
SMR project as construction costs climbed from $5.3 billion to $9.3 billion.

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