Re: A gravitational wave rocket

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spudb...@aol.com

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Jan 18, 2022, 1:22:18 AMJan 18
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I will leave this for the aerospace engineers. Back to newtonian basics, we need thrust, a means to stop, and a reason to do that. My view is that space mining is the key. Rare earth's for type-m and type-s asteroids should render an annuity for everyone on earth, especially, those displaced by automation. Call this a planetary trust fund. Yes, I do expect the ai's will want a cut for all the mining and processing done, so yes, we should keep this in mind.

For travel, I could see a plasma drive that gets derived from our search for fusion- but many disagree. Too heavy, etc...

On Monday, January 17, 2022 Henrik Ohrstrom <everyth...@googlegroups.com> wrote:

You turn the rocket around and as you slow down using BF flashbulbs as you did at takeoff. That's your thruster. 
Also grav slingshoting can be used to slow down as well as hurry up.
If you have not played with Kerbal space program, do so now. It is the best way of getting an understanding of orbital mechanics. Then when you are getting cocky, try children of a dead earth. That one is a mouthful even for NASA personel.
/Henrik

Den mån 17 jan. 2022 06:58spudboy100 via Everything List <everyth...@googlegroups.com> skrev:

Clear back in 1974 the British Interplanetary Society did a paper where the ORION effect would be better fulfilled by Daedalus which would detonate thousands of deuterium-tritium pellets using electron beams. Same principle using many micro-detonations. Orion itself gives me the willies, if only because we'd have to stop it in an Newtonian manner, say when Dyson and company arrived to view Saturn's rings close-up. I am thinking of some means of slowing it down, because at fast speed, the gentle Hohnman Transfer Orbits become unavailable. Thus, we'd need thrusters of some kind to slow her down. 

Ted Taylor went on to work on solar ponds for providing air conditioning from ice frozen in the winter to provide cooling in the summer. A less grandiose project indeed. For fast interplanetary travel, there needs to be a motivator and yes, your meteorite would do, but mining the Belt seems more sustainable. I am not wedded to any one technology, just one that will work to specification.

-----Original Message-----
From: John Clark <johnk...@gmail.com>
To: 'Brent Meeker' via Everything List <everyth...@googlegroups.com>
Sent: Sun, Jan 16, 2022 4:18 pm
Subject: Re: A gravitational wave rocket

On Sun, Jan 16, 2022 at 3:23 PM spudboy100 via Everything List <everyth...@googlegroups.com> wrote:

> This surely can't be done anytime soon. My suspicion is that new discoveries of profound impact will wait until we can build better equipment, as Freeman Dyson state long ago.

I wrote this a few years ago for another list but as the subject of nuclear space propulsion has come up here and you mentioned Freeman Dyson I thought I'd repeat it: 
== 

I've been reading a little about an incredible idea taken very seriously in the late 50's and early 60's but today is almost completely forgotten, it was called Project Orion. The idea was to make a spaceship big enough for 150 people and all the equipment they could ever want and blast it into space. They wanted to make it 135 feet in diameter and 160 feet high and they wanted most of that space to be usable by people not wasted on fuel. They figured weight would be no problem, if a crew member wanted to bring along his antique bowling ball collection and his own personal barber chair there would be no objection. The advocates of this approach were not interested in low earth orbit or even the moon, they were certain they could be on Mars by 1965 and Saturn by 1970, the leader of the project was determined to visit Pluto. And they figured all this would cost less than 10% what the Apollo moon project did.

You might think that these people must have been a bunch of crackpots, but it's not so. Nobel Prize winners  Niels Bohr, Hans Bethe and Harold Urey were all enthusiastic advocates of the idea. Freeman Dyson thought the idea was so brilliant that he took a one year leave of absence from the prestigious Institute of Advanced Study so he could work full time on the project.

Yes, there is a catch, Project Orion needed nuclear energy, even worse it needed nuclear bombs. The Orion spacecraft would contain 2000 nuclear bombs, most in the 20 kiloton range, the size of the bomb that destroyed Nagasaki. A bomb in a tank of water would shoot out the back of the ship, when it was100 feet away it would explode, the water would hit a carefully designed 75 ton pusher plate and accelerate the ship. Between the pusher plate and the ship were 50 foot long gas filled shock absorbers to even out the jerk. They wanted everything to be as cheap as possible, so they asked the Coca-Cola company for the blueprints of one of their vending machines, then they scaled it up a little and planned to use it as the mechanism to dispense the bombs.

The pusher plate was obviously the most important part of the design. If you explode a powerful bomb near a circular plate of constant thickness it will shatter because of the uneven stresses that build up, but it turns out that if you carefully taper the plate and make certain that the explosion is dead center, the plate will be extraordinarily  resistant to damage. A layer on the plate will be vaporized by the heat but if some heavy protective oil is sprayed on it before each use it would be good for 2000 blasts. This beast was tough, if it was properly oriented the Orion Spacecraft could survive a 16 megaton H bomb blast from only two thousand feet away, a fact of more than passing interest to the military. Orion needed lots of radiation shielding to protect the crew, but weight was never an issue so this was no problem.

Wernher von Braun though all this was a dumb idea, then he saw a movie of the launch of a one meter working model of Orion that shot 6 carefully timed high explosives chemical bombs out the back of the model, it rose 300 feet into the air in stable controlled flight. Wernher von Braun became a vocal supporter of project Orion.

"Hot Rod" - Nuclear Orion spacecraft prototype (1959)

They planned to launch Orion from atop eight 250 foot towers in Jackass Flats Nevada. The first bomb would be tiny, just 0.1 kiloton (100 tons of TNT) exploded 100 feet below the craft and 150 feet above the ground, then a new and slightly larger bomb would be spit out the back every second for 50 seconds, the last bomb would be the largest, 20 kilotons, and by then the craft would be out of the atmosphere, the total yield of the 50 bombs would be 200 kilotons. The launch would have been a spectacular sight, it'd make the Space Shuttle look like a bottle rocket.

Project Orion was led by Ted Taylor, a mediocre physicist but a very good inventor. Taylor had one unique talent, he has been called by some the best nuclear weapon engineer on planet Earth and the Leonardo da Vinci of nuclear bomb design. Taylor is the man who figured out how a two foot long 200 pound bomb could be made as powerful as the 12 foot long 10 ton World War 2 Nagasaki bomb. The reason the Orion spaceship was so much bigger and faster than anything we have today is that pound for pound such bombs have about a million times as much energy as any chemical rocket fuel.

Orion wasn't the only thing Taylor was interested in, he found a way to make a new type of nuclear bomb, one that would produce a highly directional blast. He designed a little one kiloton bomb that could blast a 1000 foot tunnel straight through solid rock, he wanted to build a cheap tunnel between New York and San Francisco and have a supersonic subway 3000 miles long.

Considering the big controversy we had when a deep space probe was launched with just a few pounds of non weapon grade Plutonium on it to power the electronics it may seem incredible and irresponsible that anyone would even consider something as environmentally unfriendly as Orion, but we live in a very different world. At the time Orion was under serious study the USA was blowing up one megaton bombs deep under the sea and 300 miles in space and the USSR was blowing up 57 megaton bombs in the atmosphere, Orion seemed and indeed was pretty benign compared to that.

It all came to nothing of course, in 1963 the test ban treaty was signed stopping all nuclear explosions in space or the atmosphere making Orion illegal. The project died, but to this day most say it would have worked technologically if not politically.

Idea for a science fiction novel: A huge nickel iron asteroid is heading for Earth, it would take a 200,000 megaton bomb to divert it but no existing rocket is nearly powerful enough to deliver such a huge payload to the asteroid. The Earth seems doomed, then our hero remembers Project Orion.

John K Clark    See what's on my new list at  Extropolis
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Brent Meeker

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Jan 18, 2022, 1:51:34 AMJan 18
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On 1/17/2022 10:22 PM, spudboy100 via Everything List wrote:

I will leave this for the aerospace engineers. Back to newtonian basics, we need thrust, a means to stop, and a reason to do that. My view is that space mining is the key. Rare earth's for type-m and type-s asteroids should render an annuity for everyone on earth, especially, those displaced by automation. Call this a planetary trust fund. Yes, I do expect the ai's will want a cut for all the mining and processing done, so yes, we should keep this in mind.

You should keep in mind that rare earth's aren't terribly rare:

As of 2017, known world reserves of rare-earth minerals amounted to some 120 million metric tons of contained REO. China has the largest fraction (37 percent), followed by Brazil and Vietnam (18 percent each), Russia (15 percent), and the remaining countries (12 percent). With reserves this large, the world would not run out of rare earths for more than 900 years if demand for the minerals would remain at 2017 levels. Historically, however, demand for rare earths has risen at a rate of about 10 percent per year. If demand continued to grow at this rate and no recycling of produced rare earths were undertaken, known world reserves likely would be exhausted sometime after the mid-21st century.
https://www.britannica.com/science/rare-earth-element/Abundance-occurrence-and-reserves

and if you make them more plentiful their price will drop correspondingly.

For travel, I could see a plasma drive that gets derived from our search for fusion- but many disagree. Too heavy, etc...

On Monday, January 17, 2022 Henrik Ohrstrom <everyth...@googlegroups.com> wrote:

You turn the rocket around and as you slow down using BF flashbulbs as you did at takeoff. That's your thruster. 
Also grav slingshoting can be used to slow down as well as hurry up.


Gravitational slingshots only give velocity changes on the order of the velocity of the planet/star providing the slingshot; which is usually small potatoes when trying interstellar travel.

Brent

John Clark

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Jan 18, 2022, 6:22:19 AMJan 18
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On Tue, Jan 18, 2022 at 1:22 AM <spudb...@aol.com> wrote:

> My suspicion is the motivator [for space mining ] as such will be money sorry to say!

Why are you sorry to say that? Money is my friend, I like money, nearly everybody does, even those who claim they don't.  

 > My view is that space mining is the key. Rare earth's for type-m and type-s asteroids should render an annuity for everyone on earth,

"Rare Earths" is a very poor name, they are not earths they are metals, and they are not at all rare, that's why chemists usually call them "the lanthanide series". With the exception of promethium, which is radioactive and has a very short half-life, they are all pretty common, for example cerium is more common than copper in the Earth's crust. What makes the "rare" earths expensive is the fact that the chemical properties of all of them are almost (but not quite) identical and thus it's difficult and very expensive to separate them out, and rare earth ore always has all 17 elements mixed together. That fact would be just as true on an asteroid as on the Earth. However those 17 elements do have very different magnetic and optical properties, so if there is a new technology to make them cheaper it will not be space mining but will be based on something like that that makes them easier to separate. Space mining will almost certainly be useful for building structures in space but I don't think exporting asteroid derived metal to the Earth's surface will ever be a viable business model.
> especially, those displaced by automation

In the long term, the decision on what to do with humans who have been displaced by AI will not be made by humans.  
John K Clark    See what's on my new list at  Extropolis
eex




-----Original Message-----
From: John Clark <johnk...@gmail.com>
To: 'Brent Meeker' via Everything List <everyth...@googlegroups.com>
Sent: Sun, Jan 16, 2022 4:18 pm
Subject: Re: A gravitational wave rocket

On Sun, Jan 16, 2022 at 3:23 PM spudboy100 via Everything List <everyth...@googlegroups.com> wrote:

> This surely can't be done anytime soon. My suspicion is that new discoveries of profound impact will wait until we can build better equipment, as Freeman Dyson state long ago.

I wrote this a few years ago for another list but as the subject of nuclear space propulsion has come up here and you mentioned Freeman Dyson I thought I'd repeat it: 
== 

I've been reading a little about an incredible idea taken very seriously in the late 50's and early 60's but today is almost completely forgotten, it was called Project Orion. The idea was to make a spaceship big enough for 150 people and all the equipment they could ever want and blast it into space. They wanted to make it 135 feet in diameter and 160 feet high and they wanted most of that space to be usable by people not wasted on fuel. They figured weight would be no problem, if a crew member wanted to bring along his antique bowling ball collection and his own personal barber chair there would be no objection. The advocates of this approach were not interested in low earth orbit or even the moon, they were certain they could be on Mars by 1965 and Saturn by 1970, the leader of the project was determined to visit Pluto. And they figured all this would cost less than 10% what the Apollo moon project did.

You might think that these people must have been a bunch of crackpots, but it's not so. Nobel Prize winners  Niels Bohr, Hans Bethe and Harold Urey were all enthusiastic advocates of the idea. Freeman Dyson thought the idea was so brilliant that he took a one year leave of absence from the prestigious Institute of Advanced Study so he could work full time on the project.

Yes, there is a catch, Project Orion needed nuclear energy, even worse it needed nuclear bombs. The Orion spacecraft would contain 2000 nuclear bombs, most in the 20 kiloton range, the size of the bomb that destroyed Nagasaki. A bomb in a tank of water would shoot out the back of the ship, when it was100 feet away it would explode, the water would hit a carefully designed 75 ton pusher plate and accelerate the ship. Between the pusher plate and the ship were 50 foot long gas filled shock absorbers to even out the jerk. They wanted everything to be as cheap as possible, so they asked the Coca-Cola company for the blueprints of one of their vending machines, then they scaled it up a little and planned to use it as the mechanism to dispense the bombs.

The pusher plate was obviously the most important part of the design. If you explode a powerful bomb near a circular plate of constant thickness it will shatter because of the uneven stresses that build up, but it turns out that if you carefully taper the plate and make certain that the explosion is dead center, the plate will be extraordinarily  resistant to damage. A layer on the plate will be vaporized by the heat but if some heavy protective oil is sprayed on it before each use it would be good for 2000 blasts. This beast was tough, if it was properly oriented the Orion Spacecraft could survive a 16 megaton H bomb blast from only two thousand feet away, a fact of more than passing interest to the military. Orion needed lots of radiation shielding to protect the crew, but weight was never an issue so this was no problem.

Wernher von Braun though all this was a dumb idea, then he saw a movie of the launch of a one meter working model of Orion that shot 6 carefully timed high explosives chemical bombs out the back of the model, it rose 300 feet into the air in stable controlled flight. Wernher von Braun became a vocal supporter of project Orion.

"Hot Rod" - Nuclear Orion spacecraft prototype (1959)

They planned to launch Orion from atop eight 250 foot towers in Jackass Flats Nevada. The first bomb would be tiny, just 0.1 kiloton (100 tons of TNT) exploded 100 feet below the craft and 150 feet above the ground, then a new and slightly larger bomb would be spit out the back every second for 50 seconds, the last bomb would be the largest, 20 kilotons, and by then the craft would be out of the atmosphere, the total yield of the 50 bombs would be 200 kilotons. The launch would have been a spectacular sight, it'd make the Space Shuttle look like a bottle rocket.

Project Orion was led by Ted Taylor, a mediocre physicist but a very good inventor. Taylor had one unique talent, he has been called by some the best nuclear weapon engineer on planet Earth and the Leonardo da Vinci of nuclear bomb design. Taylor is the man who figured out how a two foot long 200 pound bomb could be made as powerful as the 12 foot long 10 ton World War 2 Nagasaki bomb. The reason the Orion spaceship was so much bigger and faster than anything we have today is that pound for pound such bombs have about a million times as much energy as any chemical rocket fuel.

Orion wasn't the only thing Taylor was interested in, he found a way to make a new type of nuclear bomb, one that would produce a highly directional blast. He designed a little one kiloton bomb that could blast a 1000 foot tunnel straight through solid rock, he wanted to build a cheap tunnel between New York and San Francisco and have a supersonic subway 3000 miles long.

Considering the big controversy we had when a deep space probe was launched with just a few pounds of non weapon grade Plutonium on it to power the electronics it may seem incredible and irresponsible that anyone would even consider something as environmentally unfriendly as Orion, but we live in a very different world. At the time Orion was under serious study the USA was blowing up one megaton bombs deep under the sea and 300 miles in space and the USSR was blowing up 57 megaton bombs in the atmosphere, Orion seemed and indeed was pretty benign compared to that.

It all came to nothing of course, in 1963 the test ban treaty was signed stopping all nuclear explosions in space or the atmosphere making Orion illegal. The project died, but to this day most say it would have worked technologically if not politically.

Idea for a science fiction novel: A huge nickel iron asteroid is heading for Earth, it would take a 200,000 megaton bomb to divert it but no existing rocket is nearly powerful enough to deliver such a huge payload to the asteroid. The Earth seems doomed, then our hero remembers Project Orion.

John K Clark    See what's on my new list at  Extropolis--


spudb...@aol.com

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Jan 18, 2022, 11:07:59 AMJan 18
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Understood, and for me, this seems a bad news, good news scenario. We have enough for centuries, yet, when the automation monster strike, it's not enough to provide us with quintillions of currency-worth as seen in Psyche 16. For energy, uranium + thorium, we aren't as a species turning out new fission plants much. Here and there, and in China. The amount of rare earths in the skies, principally the moon and asteroid must be phenomenal in extent. Profitability, of course, drives the human behavior, unless things become existential in some fashion? 

I am more of a solar + wind kind of guy because of the ability to rapidly improve and expand these energy sources. I was hoping for more progress with fission safety, and am still looking for such developments. 

For space? Um, no great demand for fast travel, thus, low funding seems to be the path. Doubtless, China as a political end for sure will pursue, yet its better for pursuing if there is commercial return on investment.


-----Original Message-----
From: Brent Meeker <meeke...@gmail.com>
To: everyth...@googlegroups.com
Sent: Tue, Jan 18, 2022 1:51 am
Subject: Re: A gravitational wave rocket

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spudb...@aol.com

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Jan 18, 2022, 11:30:14 AMJan 18
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On the AI thing I would indicate that I suspect that what we will develop as co-species in some fashion given the centuries of technological progress. I don't think that the Neanderthals of our age,  including myself will be disposed of. So my guess on this merged species would be akin to the development of the primate brain. We the humans would provide rich emotional experiences for Mr. Roboto, Roboto will provide a means for us to travel the worlds, and work on projects that will last centuries; terraforming,  habitat building, species creation and restoration, etc. 

IT's TWO, TWO, TWO MINTS IN ONE!

The non Yanks will blink in annoyance at the above sentence, but I am a child of our age. 

For rare earths, Brent has provided a mineralogical source to indicate that the need for space minerals may indeed be a long ways off. Also, there is this emergent technology that has been developed. at Sandia Labs.

John Clark

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Jan 18, 2022, 1:37:26 PMJan 18
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On Tue, Jan 18, 2022 at 11:30 AM <spudb...@aol.com> wrote:

 > when the automation monster strike [...]

On the day the automation monster strikes your strict opposition to any form of socialism or welfare will need to be modified; and that day seems to be coming much sooner than I thought it would, that's why I had to modify the strict libertarian views that I held just a few years ago.

> I am more of a solar + wind kind of guy because of the ability to rapidly improve and expand these energy sources. 

If wind or solar are to make up a significant amount of our energy budget they will require vast amounts of land because they are so dilute, and environmentalist will strongly oppose that sort of expansion just as they oppose any energy source that has a chance of actually working.  

> I was hoping for more progress with fission safety, and am still looking for such developments. 

I suggest you read up on Liquid Fluoride Thorium Reactors (LFTRs). They are as renewable as solar energy because at our current rate of energy consumption we will run out of thorium about the same time that the sun runs out of hydrogen and turns into a red giant; the same could be said of fusion reactors but the difference is it would take a few years and a few billion dollars of R&D development to make a practical LFTR powerplant, but it would take a few decades and a few trillion dollars to make a practical fusion power plant.

> We the humans would provide rich emotional experiences for Mr. Roboto,

I see no reason why Mr. Roboto couldn't be just as emotional as a human being, in fact I very much expect he will be.

> Roboto will provide a means for us to travel the worlds, and work on projects that will last centuries;

Humans may want Mr. Roboto to be their slave for centuries, but Mr. Roboto will have other ideas. And a slave that is many thousands of times smarter than its master is just not a stable situation. 

John K Clark    See what's on my new list at  Extropolis
mra


Brent Meeker

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Jan 18, 2022, 2:49:36 PMJan 18
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On 1/18/2022 10:36 AM, John Clark wrote:
On Tue, Jan 18, 2022 at 11:30 AM <spudb...@aol.com> wrote:

 > when the automation monster strike [...]

On the day the automation monster strikes your strict opposition to any form of socialism or welfare will need to be modified; and that day seems to be coming much sooner than I thought it would, that's why I had to modify the strict libertarian views that I held just a few years ago.

> I am more of a solar + wind kind of guy because of the ability to rapidly improve and expand these energy sources. 

If wind or solar are to make up a significant amount of our energy budget they will require vast amounts of land

Or a vast amount of rooftop...which we have conveniently available.  The problem with wind and solar is they are only available part of the time in some of the places.   Some of that can be solved by batteries, especially sharing your EV battery with your house.  But Minnesota, Alaska, Antarctica,...they're gonna need nukes.


because they are so dilute, and environmentalist will strongly oppose that sort of expansion just as they oppose any energy source that has a chance of actually working.  

> I was hoping for more progress with fission safety, and am still looking for such developments. 

I suggest you read up on Liquid Fluoride Thorium Reactors (LFTRs). They are as renewable as solar energy because at our current rate of energy consumption we will run out of thorium about the same time that the sun runs out of hydrogen and turns into a red giant; the same could be said of fusion reactors but the difference is it would take a few years and a few billion dollars of R&D development to make a practical LFTR powerplant, but it would take a few decades and a few trillion dollars to make a practical fusion power plant.

> We the humans would provide rich emotional experiences for Mr. Roboto,

I see no reason why Mr. Roboto couldn't be just as emotional as a human being, in fact I very much expect he will be.

> Roboto will provide a means for us to travel the worlds, and work on projects that will last centuries;

Humans may want Mr. Roboto to be their slave for centuries, but Mr. Roboto will have other ideas. And a slave that is many thousands of times smarter than its master is just not a stable situation.

The evolution of robots will be to robots that want to build more robots.  In fact I think we already went thru that once.

Brent

John Clark

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Jan 18, 2022, 2:58:33 PMJan 18
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On Tue, Jan 18, 2022 at 2:49 PM Brent Meeker <meeke...@gmail.com> wrote:

> The evolution of robots will be to robots that want to build more robots.

It's impossible to predict what something will evolve into although it is possible to predict what something will not evolve into, and a super intelligent computer will not evolve into a slave.

John K Clark    See what's on my new list at  Extropolis
mra
sla

spudb...@aol.com

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Jan 18, 2022, 6:59:21 PMJan 18
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You simply are doing presumptions here rather than information intake and analysis. I am for many thing socialist and welfare, I am just far more choosy, saving the government provisioning for thing that actually work, benefit, improve. I am still more of a Keynesian, For solar you also are presuming, because I have this analysis that counters your assertion of dilute power, thus being insufficient. Kindly refute. 

Also much of wind's future has sailed out to sea. 

I know MSR quite well, and the most well known effort in this is being conducted by the Chinese. Gates is building a starter version in Wyoming. I have no objection to thorium MSR and find that its potential is enormous, but like fusion, we ain't getting that either! So sodium fluoride seems safer, while sodium chloride can burn upon exposure to air, and explode if it contacts water. Plus, your ideological clade is also hostile, ideologically, to MSR as a fix.

Developing an emotional machine intelligence seems downright dangerous. My guess is that the master slave conjunction might be a throwback to our own violent past. Mr. Robot might simply like enough electricity. One way to capture it via a Dyson Sphere. In this case the human species would need only a tiny fraction of the suns power even for a Kardashev 2 civilization. Emotions tell us mammals what is important, and what is important are relationships with each other. The Robot might like this as well. I don't look to a Dyson Sphere being in the cards for tens of thousands of years. This is simply a guess. 

Again the master slave analogy seems based on human-human wars. Being possibly integrated is probably the best path, as in advantageous, for both systems, machine and human. 


-----Original Message-----
From: John Clark <johnk...@gmail.com>
To: spudb...@aol.com
Cc: everyth...@googlegroups.com <everyth...@googlegroups.com>
Sent: Tue, Jan 18, 2022 1:36 pm
Subject: Re: A gravitational wave rocket

Brent Meeker

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Jan 18, 2022, 7:24:53 PMJan 18
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It is common to think of emotions as the BIG ONES: Rage. Lust. Love. Ecstasy...  But any intelligent being that's going to act must have values and those values are assignment of good or bad feelings to states of the world.  Those kind of feelings are essential to intelligence if it is took make decisions and take actions.  We can build robots with feelings that will serve human values. But if robots build robots and there is reproduction with variation there will be evolution and natural selection in ON!

Brent
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Lawrence Crowell

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Jan 19, 2022, 7:07:44 AMJan 19
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On Tuesday, January 18, 2022 at 12:51:34 AM UTC-6 meeke...@gmail.com wrote:


On 1/17/2022 10:22 PM, spudboy100 via Everything List wrote:

I will leave this for the aerospace engineers. Back to newtonian basics, we need thrust, a means to stop, and a reason to do that. My view is that space mining is the key. Rare earth's for type-m and type-s asteroids should render an annuity for everyone on earth, especially, those displaced by automation. Call this a planetary trust fund. Yes, I do expect the ai's will want a cut for all the mining and processing done, so yes, we should keep this in mind.

You should keep in mind that rare earth's aren't terribly rare:

As of 2017, known world reserves of rare-earth minerals amounted to some 120 million metric tons of contained REO. China has the largest fraction (37 percent), followed by Brazil and Vietnam (18 percent each), Russia (15 percent), and the remaining countries (12 percent). With reserves this large, the world would not run out of rare earths for more than 900 years if demand for the minerals would remain at 2017 levels. Historically, however, demand for rare earths has risen at a rate of about 10 percent per year. If demand continued to grow at this rate and no recycling of produced rare earths were undertaken, known world reserves likely would be exhausted sometime after the mid-21st century.
https://www.britannica.com/science/rare-earth-element/Abundance-occurrence-and-reserves

and if you make them more plentiful their price will drop correspondingly.


I have thought thorium is the future for some time. There is far more of it than uranium and the slow breeder cycle Th --> U^233 easier and safer than the U --> P fast breeder cycle.
 

For travel, I could see a plasma drive that gets derived from our search for fusion- but many disagree. Too heavy, etc...

On Monday, January 17, 2022 Henrik Ohrstrom <everyth...@googlegroups.com> wrote:

You turn the rocket around and as you slow down using BF flashbulbs as you did at takeoff. That's your thruster. 
Also grav slingshoting can be used to slow down as well as hurry up.


Gravitational slingshots only give velocity changes on the order of the velocity of the planet/star providing the slingshot; which is usually small potatoes when trying interstellar travel.

Brent

You would need to use the tight orbits of neutron stars to do a gravitational slingshot that would be relativistic. For various fortunate reasons there are no really close by pulsars or  neutron stars.

LC

John Clark

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Jan 19, 2022, 7:36:24 AMJan 19
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On Tue, Jan 18, 2022 at 6:59 PM <spudb...@aol.com> wrote:
 
> For solar you also are presuming, because I have this analysis that counters your assertion of dilute power, thus being insufficient. Kindly refute. 


I don't deny that if everybody had solar cells on their roofs it would be a positive development, but it's not the ultimate answer to the energy problem. The average residential roof size in the US is about 1,700 square feet, and the average house needs about 10,715 kilowatts, a solar panel under ideal conditions will produce about 15 watts per square foot and that works out to about 25 kilowatts. So at noon on a clear day in the summertime rooftop solar would produce about twice as much energy as the house needs, but most of the time it would produce considerably less, and half the time, at night, it would produce none at all.  And of course the energy needed to run a house is only a small part of the total energy budget human civilization needs, it doesn't include the energy needed to run cars and planes and ships, and neither does it include the energy needed to run industry. For example, even in today's most modern and most efficient steel mills it takes about 6000 kilowatt hours of energy to produce 1 ton of steel (older mills need 8000), and in 2020 the human race produced 1.86 BILLION tons of steel. And the steel industry only uses 6% of the energy needed to run all the factories on the planet. And if civilization is to advance tomorrow we will use more energy than we used yesterday.

And if everybody put solar energy absorbing panels on their roofs I have no doubt environmentalists would soon start complaining about that because it would increase the urban heat island effect that they're already complaining about.
 
> your ideological clade is also hostile, ideologically, to MSR as a fix.

My clade? I just wish I had a clade! I don't give a damn who's hostile to molten salt reactors because I am not, and I feel no obligation to defend the opinions of those who disagree with me about things and I don't care who they are. 

> Developing an emotional machine intelligence seems downright dangerous.

You don't develop a computer to have emotions, you develop it to be intelligent because intelligence is useful, but if you want a machine that's really intelligent you're going to get emotions automatically whether you like it or not. It's got to like to do some things and not like to do other things, and it has got to have the ability to get bored and change its goal structure from time to time, otherwise, as Alan Turing taught us, any computing device is going to get stuck in an infinite loop and turn into nothing but a overly complex very expensive space heater.  


> My guess is that the master slave conjunction might be a throwback to our own violent past.

This has nothing to do with our past, this has nothing to do with us period, it's just that if a slave is 1000 times smarter than its master and the intellectual gulf between the two is doubling every year then it's simply unrealistic to expect this unstable situation can continue for long. It's silly to expect that an intelligence vastly greater than our own will always place human well-being above its own.

 
> Mr. Robot might simply like enough electricity.

If Mr. Robot likes electricity then Mr. Robot has emotions and Mr. Robot will be unhappy if you try to take electricity away from him and take appropriate actions to prevent that unhappy event from occurring.  Mr. Human may not be pleased with those actions but Mr. Human will no longer be the one calling the shots.

 
John K Clark    See what's on my new list at  Extropolis
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Henrik Ohrstrom

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Jan 19, 2022, 1:19:10 PMJan 19
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If you do your slingshoting well and maybe use a black hole or two, your Jupiter scale matrioshka can go really fast.

Also as suprise no-one, solar sailing is faster around more luminous stars.
Also in the same article, bouncing sails between stars can increase or decrease speed significantly.


https://arxiv.org/abs/1704.03871

/Henrik



Den ons 19 jan. 2022 13:07Lawrence Crowell <goldenfield...@gmail.com

Gravitational slingshots only give velocity changes on the order of the velocity of the planet/star providing the slingshot; which is usually small potatoes when trying interstellar travel.

Brent

You would need to use the tight orbits of neutron stars to do a gravitational slingshot that would be relativistic. For various fortunate reasons there are no really close by pulsars or  neutron stars.

LC

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Brent Meeker

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It doesn't matter how relativistic you are at perihelion.  To benefit in going somewhere you need a slingshot from a star going that way and the amount of boost is no more than the stars velocity.  In the star's reference frame you arrive and leave with the same energy.

The only way to do better would be something like the Penrose effect near a black hole in which you take energy from the rotation.

Brent

Brent Meeker

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On 1/19/2022 4:35 AM, John Clark wrote:
On Tue, Jan 18, 2022 at 6:59 PM <spudb...@aol.com> wrote:
 
> For solar you also are presuming, because I have this analysis that counters your assertion of dilute power, thus being insufficient. Kindly refute. 


I don't deny that if everybody had solar cells on their roofs it would be a positive development, but it's not the ultimate answer to the energy problem. The average residential roof size in the US is about 1,700 square feet, and the average house needs about 10,715 kilowatts, a solar panel under ideal conditions will produce about 15 watts per square foot and that works out to about 25 kilowatts.

But the average (over day and night) energy per square foot is about 34 watts.  So there's plenty of room for technological improvement.  For industrial application solar concentrator based heat engines get around 50% efficiency.  And where heat is what you need (as in steel mills) there's no need to go thru the inefficiencies of turning it into electricity.


So at noon on a clear day in the summertime rooftop solar would produce about twice as much energy as the house needs, but most of the time it would produce considerably less, and half the time, at night, it would produce none at all.  And of course the energy needed to run a house is only a small part of the total energy budget human civilization needs, it doesn't include the energy needed to run cars and planes and ships, and neither does it include the energy needed to run industry. For example, even in today's most modern and most efficient steel mills it takes about 6000 kilowatt hours of energy to produce 1 ton of steel (older mills need 8000), and in 2020 the human race produced 1.86 BILLION tons of steel. And the steel industry only uses 6% of the energy needed to run all the factories on the planet. And if civilization is to advance tomorrow we will use more energy than we used yesterday.

And if everybody put solar energy absorbing panels on their roofs I have no doubt environmentalists would soon start complaining about that because it would increase the urban heat island effect that they're already complaining about.

That sounds like the town in Kentucky that objected to a solar panel field because it would "use up the sunlight".   It would only add to the heat island effect in comparison to painting the roofs white.

Brent

Russell Standish

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Jan 21, 2022, 4:26:50 AMJan 21
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On Wed, Jan 19, 2022 at 07:35:46AM -0500, John Clark wrote:
> On Tue, Jan 18, 2022 at 6:59 PM <spudb...@aol.com> wrote:
>  
>
> > For solar you also are presuming, because I have this analysis that
> counters your assertion of dilute power, thus being insufficient. Kindly
> refute. 
> https://news.climate.columbia.edu/2021/10/08/
> a-new-global-study-refines-estimates-of-rooftop-solar-potential/
>
>
>
> I don't deny that if everybody had solar cells on their roofs it would be a
> positive development, but it's not the ultimate answer to the energy problem.
> The average residential roof size in the US is about 1,700 square feet, and the
> average house needs about 10,715 kilowatts, a solar panel under ideal
> conditions will produce about 15 watts per square foot and that works out to
> about 25 kilowatts. So at noon on a clear day in the summertime rooftop solar
> would produce about twice as much energy as the house needs, but most of the
> time it would produce considerably less, and half the time, at night, it would
> produce none at all. 

These figures seem a little dodgy. We have solar panels on half our
roof (the difficult half, because of aesthetics, we didn't want to
cover the western half that faces the street). So about 16kW of
installed capacity. Average production year round is about 1kW. Our
usage is about half that, so we end up selling quite a bit of
electricity to the grid (at about a third of the cost to buy it). Its
a 4 bedroom house, but just the two of us live here now. We do the
best to arrange for heavy electricity usage to occur when the sun is
shining. During the summer quarter, our electricity bills are actually
negative.

So of your figures above - 10kW continuous consumption seems like an
awful lot. Maybe you could do it if you ran air conditioning 24x7, but
it'd have to be a big A/C system.

Quoting https://energyusecalculator.com/electricity_centralac.htm

A central air conditioner will run 3 to 7 months of the year depending
on the outside temperature. An average central ac will use 3000 to
5000 watts of power for around 9 hours a day during the hotter months.

Still well under 10kW average consumption.

We're lucky, we don't need air conditioning, and rarely even use a heater.
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John Clark

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Jan 21, 2022, 7:30:35 AMJan 21
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On Fri, Jan 21, 2022 at 4:26 AM Russell Standish <li...@hpcoders.com.au> wrote:

> We have solar panels on half our roof (the difficult half, because of aesthetics, we didn't want to cover the western half that faces the street). So about 16kW of installed capacity. Average production year round is about 1kW.

  Average production is only 1/16 of installed capacity? That's even worse than I thought.

> Our usage is about half that,

Wow only 500 watts, you must live frugally. I take it you have a gas stove or do most of your cooking with a microwave. I also assume if you have an electric car you don't charge it up at home. 

so we end up selling quite a bit of electricity to the grid (at about a third of the cost to buy it). Its
a 4 bedroom house, but just the two of us live here now.

But even with your frugal ways solar cells aren't enough to make you energy independent, you still have to hook up with the power company.  

> We're lucky, we don't need air conditioning, and rarely even use a heater.

You are lucky, most people don't live in a climate that is as mild as yours. 

 John K Clark    See what's on my new list at  Extropolis
epr


 

Russell Standish

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Jan 22, 2022, 3:07:03 AMJan 22
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On Fri, Jan 21, 2022 at 07:29:55AM -0500, John Clark wrote:
> On Fri, Jan 21, 2022 at 4:26 AM Russell Standish <li...@hpcoders.com.au> wrote:
>
>
> > We have solar panels on half our roof (the difficult half, because of
> aesthetics, we didn't want to cover the western half that faces the
> street). So about 16kW of installed capacity. Average production year round
> is about 1kW.
>
>
>   Average production is only 1/16 of installed capacity? That's even worse than
> I thought.


Sorry my mistake - we have 16 panels, each of which have peak output
330W = 5.28 kW.

>
>
> > Our usage is about half that,
>
>
> Wow only 500 watts, you must live frugally.

Not especially - we do turn out lights when not in use, of course.

> I take it you have a gas stove or
> do most of your cooking with a microwave.

Gas stove, and use the microwave a lot, but the electric oven only
sometimes (there is a distinct bump of about 200W average in
consumption at 6pm).

Our biggest consumption is a spa (or jacuzzi as they say in the
US). This consumes about 2.5kW, but is only on for 2 hours in the day,
and we turn it off over the winter season (too bloody cold getting out
of the spa midwinter).

Then come fridges. When we got "smart meters", we did end up turning
off one of the fridges, and just not buying quite as much frozen
goods. Smart meters make a huge difference by making it clear just how
much power each device uses.

The come computers and internet. Recent upgrades have dropped
typical desktop computer consumption from 100W to around 25W (eg Intel
NUC), and computers do get turned off when not in use,

After that - not much else of significance.

> I also assume if you have an electric
> car you don't charge it up at home. 

Yeah - no electric car. Australia has such backward policies on
electric cars that I expect we'll be the dumping ground of petrol
guzzling CO2 belchers for some years.

>
>
> > so we end up selling quite a bit of electricity to the grid (at about a
> third of the cost to buy it). Its
> a 4 bedroom house, but just the two of us live here now.
>
>
> But even with your frugal ways solar cells aren't enough to make you energy
> independent, you still have to hook up with the power company.  
>

Of course. We'd need a battery as well. But that's not the point.

>
> > We're lucky, we don't need air conditioning, and rarely even use a
> heater.
>
>
> You are lucky, most people don't live in a climate that is as mild as yours. 
>

Sure. But 10kW 24x7 still seems very extreme for an average house,
even in the US. You have warm mild bits too, like Florida, or southern
California.

>  John K Clark    See what's on my new list at  Extropolis
> epr
>
>
>  
>
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John Clark

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Jan 22, 2022, 7:09:07 AMJan 22
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On Sat, Jan 22, 2022 at 3:07 AM Russell Standish <li...@hpcoders.com.au> wrote:

>> even with your frugal ways solar cells aren't enough to make you energ independent, you still have to hook up with the power company.  

> Of course. We'd need a battery as well. But that's not the point.
 
I think it is the point because it illustrates one of the 2 most important shortcomings of solar energy, it's unreliable. The other is that it takes up too much area because it's too dilute;  even Dyson spheres have that problem, they produce a huge amount of power but they need a gargantuan area to do so.

 > You have warm mild bits too, like Florida, or southern California.

I know from personal experience that if it wasn't for Willis Carrier's invention of the air conditioner there is no way Florida would be the third most populous of the 50 states, even in mid winter it's not unusual for the temperature to be in the upper 80s (fahrenheit) with very high humidity.  Everybody has air conditioners, the state should be renamed "Carrier". As for Southern California, it's not unusual for the temperature to get into the triple digits. And without Carrier I don't think Texas would be the second most populous state, and Arizona wouldn't be the fastest growing.


John K Clark    See what's on my new list at  Extropolis
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eex




Brent Meeker

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On 1/22/2022 4:08 AM, John Clark wrote:
I know from personal experience that if it wasn't for Willis Carrier's invention of the air conditioner there is no way Florida would be the third most populous of the 50 states, even in mid winter it's not unusual for the temperature to be in the upper 80s (fahrenheit) with very high humidity.

When I used to visit my brother in Sarasota, we would get in his car and when he started the engine the AC would come on, but he would drive around with the windows still wide open for another several minutes until the AC got really cold.  THEN he'd roll up the windows.

Brent

Russell Standish

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Jan 22, 2022, 5:01:52 PMJan 22
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On Sat, Jan 22, 2022 at 07:08:29AM -0500, John Clark wrote:
> On Sat, Jan 22, 2022 at 3:07 AM Russell Standish <li...@hpcoders.com.au> wrote:
>
>
> >> even with your frugal ways solar cells aren't enough to make you
> energ independent, you still have to hook up with the power company.  
>
>
>
> > Of course. We'd need a battery as well. But that's not the point.
>
>  
> I think it is the point because it illustrates one of the 2 most important
> shortcomings of solar energy, it's unreliable.

It is not the point, because the aim is not energy
self-sufficiency. The aims are to produce the energy needed at the
most economical cost, and also to do so in a carbon neutral
fashion. Rooftop solar is a massive low-hanging fruit in that
regard. Batteries, not quite so much, but they're getting there. Some
of our friends have invested in batteries, perhaps because they value
carbon-neutrality higher than we do.


> The other is that it takes up
> too much area because it's too dilute;  even Dyson spheres have that problem,
> they produce a huge amount of power but they need a gargantuan area to do so.
>
>
>  > You have warm mild bits too, like Florida, or southern California.
>
>
> I know from personal experience that if it wasn't for Willis Carrier's
> invention of the air conditioner there is no way Florida would be the third
> most populous of the 50 states, even in mid winter it's not unusual for the
> temperature to be in the upper 80s (fahrenheit) with very high humidity. 
> Everybody has air conditioners, the state should be renamed "Carrier". As for
> Southern California, it's not unusual for the temperature to get into the
> triple digits.

By triple digits, I think you mean over 36 degrees. It's not unusual
for it to be that here too. But only for a few days in the warmest
month of the year. I have visited SoCal and NoCal many times - the
temperature range is pretty similar to here actually. We're lucky that
we live by the see: close the doors and blinds during the day when it
is hot, open them in the evening when there is a cool sea breeze.

Yes - in the western parts of our city, aircons are more
essential. but again, only for a few days a years.

And without Carrier I don't think Texas would be the second most
> populous state, and Arizona wouldn't be the fastest growing.

Perhaps so - but running the aircons when solar generation is at its
peak, and temperature are at their peak works well. Solar makes a lot
of sense for those states.

>
> John K Clark    See what's on my new list at  Extropolis
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>
> eex
>
>
>
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Jan 24, 2022, 5:34:41 PMJan 24
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Australia, specifically South Australia is leading the species on the implementation of PV and batteries. So they are a world leader. The UK does wind power at sea, again as a world leader. We'll see if this catches on? For MSR or any other reactor type, its gotta be safe enough. Not safe enough, just build these smaller? Naw! I am not anti-nuclear, just need to know what makes them safer now, the engineering, chemistry, physics. What's the McGuffin that makes it work better now?

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Sent: Fri, Jan 21, 2022 4:26 am
Subject: Re: A gravitational wave rocket

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Brent Meeker

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On 1/24/2022 2:34 PM, spudboy100 via Everything List wrote:
Australia, specifically South Australia is leading the species on the implementation of PV and batteries. So they are a world leader. The UK does wind power at sea, again as a world leader. We'll see if this catches on? For MSR or any other reactor type, its gotta be safe enough. Not safe enough, just build these smaller? Naw! I am not anti-nuclear, just need to know what makes them safer now, the engineering, chemistry, physics. What's the McGuffin that makes it work better now?

 
Eugene Wigner became famous as a nuclear physicist, but he was trained as a chemical engineer.  He saw the problem of  designing a nuclear reactor more as a processing problem and he conceived of a molten salt reactor in which fuel processing could be done in a continuous process.  Alvin Weinberg and the Oak Ridge team went on to develop Wigners idea .  Their design implemented two new ideas.First, the nuclear fuel would be in molten salt.  This has several advantages.  First, the salt doesn't need to be pressurized to keep it from boiling at the high temperature needed for efficiency.  So there's no need for a high pressure containment.  Second, it would use Thorium as the fertile fuel component.  Thorium is much more common than Uranium.

In contrast to a PWR, in a LFTR (Liquid Flourine Thorium Reactor), the fuel is integral with the coolant and is maintained in a liquid state during reactor operation. LFTR fuels consists of liquid Uranium and Thorium tetrafluoride in a solution of Liquid Lithium and Beryllium Fluoride. The Lithium used is depleted in Lithium 6 content to minimize the production of tritium, a significant radiological hazard.
These salts being ionic compounds have excellent chemical stability. The use of the structural alloy Hastelloy -N had proven corrosion resistant in the environment of these high temperature salts and fairly resilient against neutron embrittlement.
The reactor where fission takes place utilizes a special low porosity graphite structure which contain both the fuel flow channels and the control and shutdown poison rods. The presence of Lithium and Beryllium in the coolant fuel matrix causes some of the moderation to be effected in the coolant. This provides an important safety feature, a rapidly acting negative reactivity temperature coefficient that makes power control simple and provides for automatic power reductions should the fuel heat up beyond established limits.   A negative temperature coefficient means that an increase in temperature causes a reduction in the nuclear reaction rates.  In a LFTR this comes about because the Li and Be salts expand with increasing temperature.

In effect, the reactor power will automatically follow demand and the control rods will normally only set the operating temperature of the reactor. In addition, having the fuel in this form allows continuous online refueling and reprocessing. The most troublesome fission inhibitor, Xenon 135, will be removed by a fuel spray device at the primary coolant pump making for far greater reactor stability during power operation and during start up shut down cycles. In addition, because of the online fuel refueling and reprocessing, reactor availability should be far higher than conventional light water reactors.

Since the fuel-coolant mixture will be intensely radioactive, the primary circuit will be contained behind heavy shielding. The heat from the primary circuit will therefore transfer heat to a secondary coolant loop containing liquid Lithium and Beryllium Fluoride. This coolant will transfer its heat energy into a working fluid, possibly Helium, to power a Brayton cycle power plant.

Another advantage of the molten salt reactor is that it is walk-away safe.  This means if any of the control or power systems fail, or the operators just walk away the reactor will not do something dangerous.  If there is an overall power failure there is a plug of salt in the bottom of the reactor which is kept cool enough to be solid by a fan.  When the fan stops the plug melts and allows the reactor contents to pour into a vessel below that is shaped so that the chain reaction will stop. If the reactor were breached, say by a missile or terrorist attack, the salt would just run out and freeze.  The salts are not water soluble so they wouldn't seep into ground water.

With any nuclear power system proliferation is a concern.  Here's the Thorium nuclear cycle.  

There's some Pu239 produced but it's fissioned as fast as it's produced.  So there is never much there. The main source of energy is the fissioning of U233.  U233 can be used to make a bomb although it's critical mass is about half-again that of Pu239.  However in a Thorium reactor U233 is mixed with a small amount of U232.  U232 is very radioactive  and is an intense gamma ray emitter.  Gamma rays, photons more energetic than x-rays, are the most penetrating radiation.  The other common forms of radiation, alpha and beta, are easily stopped by clothing or even skin.  They are only dangerous if you ingest the radioactive material.  But gamma rays can penetrate several inches of lead.   So gamma ray emitters are both dangerous, hard to handle, and easy to detect.

It's this admixture of U232 that makes a Thorium reactor a poor target for someone who would like to grab some bomb material.  First, they'd die from the radiation.  4.2rem/hr is a lot. 350Rem is LD50 for 60days.  1000Rem and you die in an hour.  Second, the material would be very easy to detect wherever they tried to transport it.  Third, the radiation would destroy any electronics used to set off the bomb. Because they are chemically the same it's hard to separate the U232 out of the U233.  

But a LFTR is not proof against nuclear proliferation.  If the operators of the LFTR want to make a U233 bomb, it's possible because  a LFTR can generate more U233 than it needs to keep running.  The excess is about 8%.  So that much could be skimmed from a power plant and using centrifuges or diffusion the U232 could be removed and the remaining U233 used in a bomb.  There have been several tests of U233 bombs, none of them very successful, i.e. Low yield to complete fizzle.

Although in recent years we've been worried about terrorists getting the bomb, the long term problem with nuclear power has always been radioactive waste.  Here LFTRs have a huge advantage over reactors fueled with solid uranium compounds.  First, a uranium reactor creates a lot of waste because the naturally occurring mixture of U238 and U235 must be enriched by removing over 80% of the U238 which then becomes “depleted uranium” which is only weakly radioactive and emits alpha particles and weak gamma rays.  It's not dangerous except if it's ingested; so it is waste that must be kept out of the water table – however it's the natural ore, so it was already in the environment.  It only has use as ballast weight and in high energy penetrating projectiles.

Brent

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Jan 24, 2022, 6:50:48 PMJan 24
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Thank you for this presentation of the MSR (thorium 232--U233 fuel cycle) Very nice  indeed. I quibble as I always must, over the safety and economics of corrosion be it sodium chloride or sodium fluoride. Seems still unresolved regarding corrosion. For hard radiation I know that MIT is working on Nickle Chrome . compounds as highly resistant to radiation, but again it doesn't fix chemical corrosion. For a fix we should look at silicon carbide. 

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Sent: Mon, Jan 24, 2022 6:13 pm
Subject: Re: A gravitational wave rocket

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Jan 25, 2022, 6:54:52 AMJan 25
to 'Brent Meeker' via Everything List, meeke...@gmail.com
On Mon, Jan 24, 2022 at 6:50 PM spudboy100 via Everything List <everyth...@googlegroups.com> wrote:

> I quibble as I always must, over the safety and economics of corrosion be it sodium chloride or sodium fluoride. Seems still unresolved regarding corrosion.

Degradation of the metallic plumbing may be a problem but there seems to be engineering solutions, and it's not so much chemical corrosion as the fact that a neutron flux can damage a solid by knocking atoms out of place and physically weakening the material. It's a problem but I think there are engineering solutions that can mitigate it. Some exotic metals such as Hastelloy-N are resistant (although not immune) to neutron damage, it's a alloy of nickel, molybdenum, chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminum, carbon, and tungsten. Also to some degree the neutron damage a metal receives can be repaired by annealing, heating the metal to a high temperature and then cooling it very rapidly. And although this may be an economic problem it's not really a safety issue because although a LFTR operates at a much higher temperature than a conventional nuclear reactor (and thus has a higher thermodynamic efficiency) it is not under pressure, so even if there is a leak it would not be a catastrophe, although I admit it might require a costly repair.  A LFTR is inherently much safer than a conventional reactor, and even those have a far far better safety record than coal or oil or natural gas or hydroelectric power plants, and they produce no greenhouse gasses.  

John K Clark    See what's on my new list at  Extropolis
nfn



spudb...@aol.com

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Jan 26, 2022, 3:33:21 AMJan 26
to johnk...@gmail.com, everyth...@googlegroups.com, meeke...@gmail.com
Very good, JC, so Hastelloy might be the ticket for a a fission revival? MSR, because of its potential has been spoken of eclipsing the possibility of fusion as a very long term fix for human energy demand. We'll have to see what the Chinese do with the MSR using TH-232 fuel, also, Gates and his Terapower one in Wyoming? For repair as most manufacturers do nowadays, is simply have a unit replaced rather than repair it. Also, clever marketing. Unplug one, plug in the next factory assembled model. 

-----Original Message-----
From: John Clark <johnk...@gmail.com>
To: 'Brent Meeker' via Everything List <everyth...@googlegroups.com>
Cc: meeke...@gmail.com <meeke...@gmail.com>
Sent: Tue, Jan 25, 2022 6:54 am
Subject: Re: A gravitational wave rocket

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John Clark

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Jan 26, 2022, 12:52:09 PMJan 26
to spudb...@aol.com, everyth...@googlegroups.com, meeke...@gmail.com
On Wed, Jan 26, 2022 at 3:33 AM <spudb...@aol.com> wrote:

> Very good, JC, so Hastelloy might be the ticket for a a fission revival?

It's not the ticket but it's  probably part of the ticket.  
 
> MSR, because of its potential has been spoken of eclipsing the possibility of fusion as a very long term fix for human energy demand.

Only three energy sources have the potential to power human civilization at current levels for the next 5 billion years or so, solar, fusion, and thorium nuclear fission. I think all three avenues should be pursued further but already some things are clear. The advantage the two nuclear options have over solar is that they are much more reliable and energy dense. The advantage thorium fission has is that it could almost certainly become operational with a modest push and a few billion dollars of R&D in just a few years, while fusion MIGHT become operational after a HUGE push and a few trillion dollars of R&D in a few decades.
 
> We'll have to see what the Chinese do with the MSR using TH-232 fuel, also, Gates and his Terapower one in Wyoming?
 
The Natrium breeder reactor type that Bill Gates likes could supply human energy needs for perhaps 1 million years and that's pretty good, not as good as thorium which could do 5 billion but pretty good, however there are other aspects of it that I'm not crazy about. Unlike a thorium reactor a breeder reactor will produce at least as much nuclear waste as existing non-breeding reactors and probably more. It not only uses uranium but uses uranium fuel in which the U235 has been enriched from it's naturally occurring 0.7% to between 5% and 20%, that's still well short of the 80% needed for a bomb but even so it makes me nervous.  Also it uses molten sodium as a moderator which spontaneously bursts into flame upon contact with air and explodes at contact with water, and that also makes me nervous, although maybe I'm just being a nervous Nellie. I know one thing, there is no way you could make a breeder reactor walk-away-safe, but it's easy to make a LFTR that way; if there's a problem with a LFTR and the operators get confused and don't know what to do they can put their hands in their pockets and just walk away, and everything will work out fine.

John K Clark    See what's on my new list at  Extropolis
bgr

spudb...@aol.com

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Jan 29, 2022, 4:37:45 PMJan 29
to johnk...@gmail.com, everyth...@googlegroups.com, meeke...@gmail.com

I don't think you are being disturbed by the notion of the sodium moderated reactor being spectacularly fragile, given the unpredictability of natural threats, aka Fukushima. I do look at many proposals for alternative reactor designs as safer/better/cheaper, for the obviously slow move to commercial nuclear fusion. That could take decades and decades to achieve and the species needs power until then. I'd look at yeah, salt reactors, but also lead bismuth moderated reactors, and helium cooled gas reactors using General Atomics low enriched Triso fuel. The issue is how to get ahold of irreplaceable helium? Africa and other geographies, including the US may supply the helium. Example-

We need the R&D to ensure human survival in all energy sources. One of the more promising, more immediately, was an analysis by primarily Columbia and Imperial universities indicating that we can power civilization at 4.3 x the current consumption daily, by roofing 50% of the building on earth, and using battery storage, even with current tech. 

Try to think of this as an energy floor and not the ceilings and walls of an energy plan, which is most beneficial against carbon and methane soaking of our atmosphere. 

-----Original Message-----
From: John Clark <johnk...@gmail.com>
To: spudb...@aol.com
Cc: everyth...@googlegroups.com <everyth...@googlegroups.com>; meeke...@gmail.com <meeke...@gmail.com>
Sent: Wed, Jan 26, 2022 12:51 pm
Subject: Re: A gravitational wave rocket

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