kbd512 Postings

kbd512 · 2025-01-07 17:51:27

tahanson43206,

The most pragmatic use of nuclear power is as stationary power plants creating electricity or fuels and oxidizers to use aboard vehicles that, for all practical purposes, cannot be equipped with a suitably powerful nuclear reactor at any reasonable mass. Ships and trains can accommodate onboard nuclear reactors in a practical way. A mining truck can potentially be powered by its own nuclear reactor, but it's near the lower limit of a vehicle with sufficient size and mass to carry the weight of the reactor shielding.

Rocket engines used for in-space propulsion, that burn for a handful of hours, can use nuclear power in a practical way. Kirk Sorensen, Thorium advocate extraordinaire, explains in his Selenium Boondocks blog why using a nuclear rocket engine for leaving Earth is "not just wrong, but super wrong". Thrust-to-weight matters quite a lot, and chemical engines provide more of that than any competing alternative. The power provided by a liquid rocket engine suitable for a booster / first stage is measured in terms of gigawatts, even for a small rocket engine like Merlin. An off-road 4-wheel drive pickup truck is never going to be powered by an onboard fission reactor in a practical way. An aircraft needs to have the same mass as a WWII era frigate, and a wing area larger than the flight deck area of our largest super carriers, to use a nuclear reactor in a practical way. Anything short of that is diving deep into fantasy expectations of nuclear reactors.

I'm 100% in favor of developing nuclear power and propulsion for space applications, but I want to see someone fly their reactor design in space before I believe that NASA or anyone else is serious about doing it, and has shown real commitment to using the tech for what it's good for- namely, supplying megawatts of power to support exploration and colonization objectives. Furthermore, they need to demonstrate a coherent program of record that justifies why we're doing it. The justification is fairly obvious to me, but it needs to be put into writing and then into action. That is the sole reason I've been looking at all the potentially viable tech alternatives to nuclear power. I don't think any of these alternatives are objectively "better" than nuclear power, but if nobody is serious about pursuing nuclear power, then it's rather pointless to sit around fantasizing about what we could conceivably accomplish using nuclear technology that is not flight-rated hardware.

Closer to home, I'm 100% in favor of using nuclear reactors to provide the cleanest electricity we're ever going to get, but nobody is doing that in a serious way, either. Nuclear power was a CO2-free electricity source that was viable for large scale deployment back in the 1970s, but the people claiming they "love the environment / climate" are the very same people who prevented us from deploying civil nuclear power as a cleaner alternative to coal / oil / natural gas. I do not feel inclined to listen to the complaints of people who did their utmost to prevent the deployment of dramatically cleaner energy technology back when it would've mattered far more than it does now. A staggering amount of coal, oil, and gas has been burned since the 1970s because they were too ignorant / arrogant to accept what was clearly a better option than any other option of that era. Since they subsequently spent boatloads of public money on their non-working electronic energy fantasies, which they still pretend are working, despite all objective evidence to the contrary, I'm even less inclined to listen to what they want.

World Economic Forum Global Energy Usage in 2018:

World Economic Forum Global Energy Usage in 1973:

World Economic Forum Global Energy Usage, from 1973 to 2018:

The way I see it, if you want electricity and an "electronic future", then you should support nuclear power. If you don't want nuclear power, then support synthesis of coal and oil from collected CO2 or waste products and solar thermal power. I don't care which option is selected, but pick one and stick with it. Either option is economically viable. Unless there is nuclear power, there is no "beyond coal and oil", there is only "pretending we're not burning more coal and oil to use the green energy machines, while actually burning a lot more coal and oil". So-called "green energy" is anything but clean, and the only thing "green" about it is the color of the money squandered on it. It's only producing a world of poor people using the dirtiest energy options available, because they can't afford the latest techno-nonsense made from "clean green coal" burned in Asia. A global CO2 problem doesn't magically go away because you burned the coal in someone else's country, either.

Anyway, we can see why coal and oil consumption hasn't changed much since. Coal and natural gas should've been replaced by Uranium and Thorium if the all our "big thinkers" (more like, "futurism fetishists") were politely told to sit over in the corner and keep quiet while the grown-ups discussed how to best assure our future energy supply. Instead, we allowed the anti-humanist elements of academia to apply their insanity to a wider swath of humanity than they otherwise had access to. We have now stored, rather than reprocessed into fresh fuel, enough Uranium to power the entire US (100% of everything that uses energy- the homes, the cars, the ships, the trains, and the planes) for the next 100 to 300 years. That stuff is sitting around in spent fuel ponds across the entire US, doing nobody any good, over an ideological belief held by people who can't count. We're "so worried" about proliferation that we've left who knows how much Plutonium in every reactor in America, rather than spending the money to stick it back into a reactor to make more power. I think that qualifies as an epic level of stupidity to placate the doomsday elements within the Democrat Party who pretend to care about the environment when they really just hate people.

We can wait another century for a miracle to happen with these so-called "green energy" technologies, or we can make more pragmatic choices, which are going to be made anyway, regardless of what the people who grew up watching "The Jetsons" think about it. Personally, I would prefer that we use more nuclear power because it's the least environmentally destructive and has empirically led to the fewest directly-caused human deaths of all competing options. Anyone dead-set on acquiring nuclear weapons will find a way to do it, so that's not a real reason for blocking the use of nuclear power in industrialized countries. North Korea has already proven that, and nothing effective was ever done to stop them, so worrying about what might happen versus what did happen is a pointless endeavor. If we can make fusion or anti-matter work in a practical way, then we should start using more of that instead of fission.

Coal needs to stay in the ground, where it's been for millions of years.

Carbon is being pulled out of the ground at record rates because people need energy and that very attractive "nuclear option" was flatly rejected by the very same people who now claim to care about "climate change", so we're burning more coal than we ever have, because "green energy" didn't deliver. The nuclear reactors were shut down or blocked from being built by those green energy ideologues, who then resumed burning coal. In the absence of nuclear energy, which was the only practical option for CO2-free electricity, and by far the cleanest, coal / oil / natural gas is what we were left with to provide energy. Our "green energy" tech failed to come anywhere near meeting the increase in demand, never mind the total demand. I don't actually care about what the selected solution is, so long as it doesn't violate basic math when it comes to supply chain availability of resources.

Energy will forever be a basic math problem. You either have the quantities of materials and machines to provide it, or you don't, so then you get less desirable options as alternatives to meet demand. We should've pursued nuclear "right now", then wind and solar after we figured out how to make it work at a grand scale. We have wind and solar farms that can be seen from space. They provide no energy more than 50% of the time. There's no energy storage, either, so a good chunk of what it could provide gets dumped into the ground.

Carbon, on the other hand, needs to come out of the atmosphere.

When we stop wasting money on nonsense that doesn't work, or paying off Democrat Party campaign donors with money that's supposed to fund "Climate Change Action", then we can do that. I'm 100% onboard with sourcing all of our Carbon from CO2 recaptured from the atmosphere and oceans. That ensures we never run out of coal / oil / natural gas. Photovoltaics and wind turbines are the wrong kinds of machines to recycle CO2. CO2 recycling tech has already been proven way more feasible than powering cities with photovoltaics or wind turbines. It kinda makes you wonder why pursuing CO2 recycling wasn't selected as the best option for us to spend capital on.

Until your innovative thinking occurred, every other human thinking about this has imagined a combination of carbon with hydrogen in one of their many configurations.

There's nothing innovative about my thinking, merely more pragmatic than some others. Coal is Carbon and Hydrogen, but mostly Carbon, which is why it burns so hot (up to 3,000C when combusted with pure O2). I can all but guarantee that someone else thought of everything I've ever stated here, long before I ever thought of it.

tahanson43206 · 2025-01-07 18:46:07

For kbd512 re #201

Thanks for another comprehensive survey of chemistry of carbon and related subjects, along with historical examples and commentary.

I've created a topic that I hope you might be willing to develop a bit. I see this topic as similar to the Optical Plane topic, in that you've identified a potential opportunity that might be practical but also may NOT be practical.

The idea of burning pure carbon with pure oxygen looks to me like a very attractive option at Venus. No one has pursued it on Earth (as far as I can tell) simply because carbon is so conveniently packaged with hydrogen on Earth that there is no reason (other than curiosity) to try to use carbon by itself.

However, ** if ** there is a way to store carbon in a tank of some kind, and deliver it to a combustion chamber reliably, then it seems possible to me such a system might be competitive with carbon-hydrogen combinations.

We have at least one experienced chemist in the present active membership, so hopefully this new topic will attract other members.

***
I met a retired Senior Scientist chemist at lunch today. The last thing on this gent's mind right now is chemistry. However, while he was working he helped to design and implement a database for rapid/instantaneous lookup of hundreds of thousands of chemical reactions, and my guess is that number will have risen in the 10 years since he retired. I'll attempt to find out if this trove of data can be accessed by the public. I do know he's traveled all over the world to teach others how to use the system.

(th)

tahanson43206 · 2025-01-09 07:39:57

for kbd512...

HolyMoley(carbon) + HolyMoley(photons) >> HolyMoley(Squared)

I wonder if there might be an optimum ratio between CO2 and pure Carbon in the feed line that would reduce the unwanted behavior of pure carbon? Pure carbon by itself is (obviously) thirsty to bind with other atoms and it is not too choosy about who it favors.

Feed lines and storage tanks might be made of material that is resistant to carbon's grabby behavior.

On Earth Hydrogen tames Carbon via the hydrocarbon family tree, but on Venus Hydrogen is going to be hard to come by.

(th)

tahanson43206 · 2025-01-09 18:55:12

For kbd512 re sCO2...

If we decide to create a topic for sCO2, this link might be worth considering for a post:

https://www.energy.gov/sco2-power-cycles

(th)

tahanson43206 · 2025-01-11 17:32:35

For kbd512...

GW has provided a foundation block .... possibly a cornerstore .... for the counter rotating habitat ship topic.

http://newmars.com/forums/viewtopic.php … 28#p229028

I'm hoping to enlist your support for development of a set of detailed plans for an exploration vessel, including drawings supported by numbers.

I am not convinced by the 1 G argument, simply because we ** have ** to live at Mars G levels if we plan to settle Mars.

However, we can play with the RPM to achieve whatever G level seems to make sense to the personnel on the expedition.

GW has provided plenty of reasons to seriously consider the baton configuration for a small expedition.

We have so many topics in play right now, I'm not sure you have the bandwidth to spend much time on the counter rotating ship design. What I'm hoping you might be willing to consider is a leadership position (to be defined).

You provided a good example of that in your role as Webmaster. You set up the conditions for a project that took many months to complete, and you looked in from time to time, but for the most part you let the project team soldier on until the time came to put all that work into motion.

We might be able to do something similar with the Dual Counter Rotating Exploration ship concept.

This is decidedly different from your 500 passenger transport concept, but (as I think about it) the two vessels would have a lot in common.

The physical diameter of the vessel is fixed by physics, given a decision about RPM. The length of the vessel is entirely up to the project team. The ship can have as many bells and whistles as might be desired, or none at all, and the diameter will not change. The mass will certainly change as bells and whistles are added, but there is some minimal mass that is required to support the personnel in this vessel for a years long expedition.

GW has a commitment to finish projects he has already started, so if the rotating vessel topic is going to advance it will have to be without his participation.

(th)

tahanson43206 · Yesterday 21:45:36

For kbd512 re fiber habitats...
http://newmars.com/forums/viewtopic.php … 63#p229263

Thank you for this substantial contribution to the topic!

I'm coming away from my first reading thinking that creep may be a concern for duration of expeditions that employ inflatable habitats.

I'm wondering how to tell the condition of a habitat that might be placed in service. It seems possible that there might be a way to build sensors into the fabric itself, for example.

GW is talking (seriously as far as I can tell) about using these habitats for his deep space exploration vehicle for human transport.

My impression is that the Bigelow BEAM is the only working example that is in service. Is there any way to tell how well it is holding up?

You've recommended particular fabrics as best for particular purposes.

The systems in development by Sierra Space are having to pass NASA requirements testing. It would be interesting to see how their materials and fabrication choices compare to your recommendations.

Update a bit later: Anti-creep ???

I don't know the answer to this but hope you (kbd512 or other readers) will find the question at least interesting....

Concrete is routinely strengthened with metal elements. The advantage is that the strength of concrete in compression is combined with the strength of metal in tension. I bring this up in the context of fabric habitat structures.

In his recent post, kbd512 has identified creep of plastic fabric as a significant factor limiting service life. It occurred to me to wonder if a mixture of materials in the weave of an inflatable structure wall might help to overcome creep by (somehow?) shrinking while the plastic is relaxing.

(th)

kbd512 · Today 02:23:45

tahanson43206,

"Fiber creep" refers to the phenomenon where a fiber, when placed under constant tension, gradually elongates over time due to a time-dependent deformation, essentially stretching slowly and irreversibly under sustained stress; this is a significant factor in materials like ropes, cables, and composite structures where fibers are under load for extended periods.

At the molecular level, creep occurs due to the movement of molecules within the fiber, allowing for gradual plastic deformation even at stresses below the material's yield strength.

It was also found that fibers fail under a constant load for a prolonged loading time and it is termed as creep failure. When a constant stress is applied to a fiber, deformation, so called creep strain, occurs with time. This creep strain eventually results in fracture.

https://www.samsonrope.com/docs/default … 12_web.pdf

My assumption is that this requires careful materials testing and design analysis to remain within design limits. The hoop stress in large pressurized structures can be quite high, even at fairly low pressures.

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