Fuel from seawater is unimportant. The size of the reactor within a hull is important. The more difficult fuel cycles have larger magrid diameters, and thus larger sizes overall.EricF wrote:For the prospect of the navy, do you think D+D reactors are the most likely candidates, due to the availability of fuel from the seawater? Or is the process of extracting the deuterium from seawater too involved to make it worth the space and weight of equipment involved, and be better off just stocking up on pB11 fuels when they return to port between deployments?
Polywell = Navy Advantage
Vae Victis
I keep seeing a perceived connection between "inexpensive" electricity from a BFR and the death of the petrochemical industry. Nothing could be farther from the truth.El Sledgo wrote:(de-lurking, hi everyone)
I think the benefit for humankind would be unsurpassed. As MSimon said above that most of the unrest around the world is because of oil. Take oil out of the equation and we'll see a level playing field.
The transportation infrastructure is the largest consumer of petro-products by far. Energy generation is mostly handled by coal, nuclear and natural gas, with King Coal being the largest contributor. Until we have some enabling technology that will allow us to use all that inexpensive BFR electricity in the transportation sector, the Sheiks are still going to be rolling in petro-dollars.
So why, you may ask, will the BFR mean more oil use? All of the GDP that is spent on buying electricity will be free for use in other use. Households will have that extra $ to spend on consumer items. Manufacturing costs will come down since power-consumption is a non-trivial component of any manufactured goods. So the consumer will have more $ with which to buy goods, and those goods will cost less. That will enable a spending boom which will cause transportation use to go up as those goods are distributed. Additionally, more $ available for households to spend means more travel which translates into more petro-spending.
However, once the enabling technology is developed that allows inexpensive electricity to be used in the transportation sector, the spending boom (in *this* country) will dwarf the spending boom described above. The % of GDP spent on electricity use is at least kept in this country, so the scenario described above is more of a redistribution of $, not a significant savings. In comparison, the % of GDP that's spent on petroleum for transportation largely flows out of this country and into unfriendly/unstable parts of the world. Once we're no longer shipping all of that $$$ out of the country, that *will* be a true savings, and the economic boom that follows will be as historically important as the spending spree that followed the Black Death plague and the wealth generation of the Industrial Revolution.
My hope for our country's financial problems lies in the BFR plus significant improvements in batteries over the next 20 years. That combination will free up so much capital that we'll be able to pay off our rediculous debt-load at last. Or so my dreams go.
wouldnt the larger magrid diameter requirement be offset greatly by benefitting from direct conversion and actually save space if it works, where the DD reactor would require the accompanying steam turbine assembly to create the electricity?djolds1 wrote:Fuel from seawater is unimportant. The size of the reactor within a hull is important. The more difficult fuel cycles have larger magrid diameters, and thus larger sizes overall.EricF wrote:For the prospect of the navy, do you think D+D reactors are the most likely candidates, due to the availability of fuel from the seawater? Or is the process of extracting the deuterium from seawater too involved to make it worth the space and weight of equipment involved, and be better off just stocking up on pB11 fuels when they return to port between deployments?
Since the Nimizt reactors are about 100MW, the pB11 reactor wouldnt need to be all that large. I think Tom Ligon said something around 3m radius in the youtube vid? Thats not really all that large, and since the net power increases by r^5 making a more powerful reactor need not be much larger, to power equipment such as the new railguns.
As EricF said, eliminating the steam plant would probably elimate alot of steam plant complexity, cost, reliability and safty concerns, mass and volume for the power plant. This assumes that direct conversion is reliable, and not too difficult.EricF wrote:wouldnt the larger magrid diameter requirement be offset greatly by benefitting from direct conversion and actually save space if it works, where the DD reactor would require the accompanying steam turbine assembly to create the electricity?djolds1 wrote:Fuel from seawater is unimportant. The size of the reactor within a hull is important. The more difficult fuel cycles have larger magrid diameters, and thus larger sizes overall.EricF wrote:For the prospect of the navy, do you think D+D reactors are the most likely candidates, due to the availability of fuel from the seawater? Or is the process of extracting the deuterium from seawater too involved to make it worth the space and weight of equipment involved, and be better off just stocking up on pB11 fuels when they return to port between deployments?
Since the Nimizt reactors are about 100MW, the pB11 reactor wouldnt need to be all that large. I think Tom Ligon said something around 3m radius in the youtube vid? Thats not really all that large, and since the net power increases by r^5 making a more powerful reactor need not be much larger, to power equipment such as the new railguns.
Also, as P-B11 is aneutronic, alot less shielding would be required. And there would be alot less waste heat to handle with pipes, radiaters, vents, etc. And, with direct conversion you might get 80-90% conversion efficiency instead of ~ 30% with steam, so a direct conversion P-B11 reactor may need not to be much larger in order to deliver the same amount of usefull power.
A side note. With direct conversion reducing the heat load on the ship, the infared signature from smoke stacks or radiaters dumping the heat into the water, would be less. Some mist sprayers over the ship combined with radar stealth, and minimizing the wake of the ship could make the ship very difficult to detect by sight, IR or radar. Quiet electric engines would also make the ship more difficult to detect by sound. Some new chemically powered subs are apparently quieter than the best nuclear subs, presumably due to the steam plant in the nuclear subs. A direct conversion Polywell would presumably be very attractive to the silent service.
Dan Tibbets
To error is human... and I'm very human.
All true as far as it goes (and all very good for Mr. and Mrs. Consumer). However, one of the few papers Bussard was allowed to release while studying the Polywell concept involved the idea of floating ships that would use an electrochemical process to convert waste biomass into fuel cheaper than that derived from oil.So why, you may ask, will the BFR mean more oil use? All of the GDP that is spent on buying electricity will be free for use in other use. Households will have that extra $ to spend on consumer items. Manufacturing costs will come down since power-consumption is a non-trivial component of any manufactured goods. So the consumer will have more $ with which to buy goods, and those goods will cost less. That will enable a spending boom which will cause transportation use to go up as those goods are distributed. Additionally, more $ available for households to spend means more travel which translates into more petro-spending.
Currently this is not very practical because electricity is too expensive (unless oil starts sitting over $120/bbl again). But a BFR might be cheap enough for this to be feasible.
Waste biomass actually has negative cost (people will pay you to take it off their hands). Couple that with BFRs and we can proudly fill up our Hummers with patriotic Made In America trasholine at $2/gal, and the sheiks of OPEC can go back to rolling in camel dung.
I'll let you be in my dream if you let me be in yours.My hope for our country's financial problems lies in the BFR plus significant improvements in batteries over the next 20 years. That combination will free up so much capital that we'll be able to pay off our rediculous debt-load at last. Or so my dreams go.
Engineering is the art of making what you want from what you can get at a profit.
The transportation costs of biomass is one of the two greatest problems facing the creation of biofuels to power our transportation infrastructure. The other, not surprisingly, is the energy cost for the biomass-to-biofuel transformation process. All studies I've seen on this problem discuss the logistical problem of getting biomass to the bio-conversion facility without eating up more fuel than they are going to make. Even with "free" electricity available from a co-located BFR, the current transportation problem still makes biofuels unfeasable. The same limitation would apply to transporting biomass to the ports where BFR-equipped ships could use it. Actually, if we had BFR-equipped ships, why go through the extra step of messing with biomass-to-biofuel conversion? I guess I missed something in your response. Yes, "free" electricity would make a liquid-fueled ship able to run on biomass-created biofuel. But that seems to add two layers of complexity over just using the electricity directly to power the ship. Can you explain what Bussard proposed a bit more? Thanks.TallDave wrote:All true as far as it goes (and all very good for Mr. and Mrs. Consumer). However, one of the few papers Bussard was allowed to release while studying the Polywell concept involved the idea of floating ships that would use an electrochemical process to convert waste biomass into fuel cheaper than that derived from oil.So why, you may ask, will the BFR mean more oil use? All of the GDP that is spent on buying electricity will be free for use in other use. Households will have that extra $ to spend on consumer items. Manufacturing costs will come down since power-consumption is a non-trivial component of any manufactured goods. So the consumer will have more $ with which to buy goods, and those goods will cost less. That will enable a spending boom which will cause transportation use to go up as those goods are distributed. Additionally, more $ available for households to spend means more travel which translates into more petro-spending.
Currently this is not very practical because electricity is too expensive (unless oil starts sitting over $120/bbl again). But a BFR might be cheap enough for this to be feasible.
Waste biomass actually has negative cost (people will pay you to take it off their hands). Couple that with BFRs and we can proudly fill up our Hummers with patriotic Made In America gasoline at $2/gal, and the sheiks of OPEC can go back to rolling in camel dung.
In my description above, I mentioned that there will need to be one or more enabling technologies in order to get the electric power from a BFR to the transportation sector. The obvious enabling technology is an increase in battery efficiency. But if all I meant was "better batteries" I would have said that. I said "enabling technologies" specifically to include biomass-to-biofuel-to-gas tank in the mix. If we were to find a way to create biofuels efficiently given "free" electricity, then that would be a technology that would enable BFR electricity to "power" the transportation sector. Hydrogen-from-water would be another way, but the enabling technology needed for that is more complex than is needed for better batteries, so I'm not holding my breath.
By the time that the transportation of biomass on a massive scale is feasable, by definition we'll have solved the electrified transportation sector problem. So I can't see any real need for biomass-to-biofuel on a large scale. There will always be a need for liquid fuels in the transportation sector, but it will be relegated to a niche market for off-grid applications as soon as BFR+<<enabling technology>> comes along.
Did I hit close to the point you were making? I have a bad habit (ask my wife!) of throwing lots of words at a problem when I don't have a clear picture of the question.
You've been in my dreams for quite a while. ... Over in the very-conservative, sometimes scary corner, but present none-the-less. (Our views are largely different in degree, not in kind.)MSimon wrote:I'll let you be in my dream if you let me be in yours.My hope for our country's financial problems lies in the BFR plus significant improvements in batteries over the next 20 years. That combination will free up so much capital that we'll be able to pay off our rediculous debt-load at last. Or so my dreams go.
One of the nice things about BFRs is they can probably be economic in units of around 100MW. That's probably small enough to solve the transport problem in non-rural areas -- just build your BFR trasholine plants where the dumps already are, and if you have excess electricity you can dump it onto the grid at a profit (a smaller profit per watt than your trasholine operation, but still profitable since you're competing with coal/nukes/etc). Someone is already paying to transport the stuff there, so the marginal transport cost is zero (in that sense, it really doesn't matter if you burn more gas getting it there than you can make with it -- you had to bring it there anyway, and now you're getting more than the zero gas you got from it before).The transportation costs of biomass is one of the two greatest problems facing the creation of biofuels to power our transportation infrastructure. The other, not surprisingly, is the energy cost for the biomass-to-biofuel transformation process. All studies I've seen on this problem discuss the logistical problem of getting biomass to the bio-conversion facility without eating up more fuel than they are going to make.
In rural areas, I suspect bioengineered switchgrass will soon be cheap and energy-dense enough to be on an economic par with waste biomass in non-rural areas.
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kunkmiester
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Overhead wires on the highways, and certain truck routes--I doubt large battery packs would be reasonable for big rigs. Much like satellite or cable TV, you buy prepaid power cards for power, instead of complex or invading schemes. Enforcement is a bit harder, but chances are there'd be enough honest people the company doing it could make a profit without trouble, or with the cards, you'd need a less invasive method of enforcement.
Evil is evil, no matter how small
How do you figure that simon?MSimon wrote:About half as much. That is some less, not a LOT less.Also, as P-B11 is aneutronic, alot less shielding would be required.
I'd say the majority of cost and complexity has less to do with direct shielding and more to do with safety, chemistry and control of activation products. Once you can literally turn off the reactor with a switch and kill all the radiation, it'll be an entirely different thing.
No Co-60 = No Nuke craziness.
Tom.Cuddihy
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Faith is the foundation of reason.
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Faith is the foundation of reason.
This is a hypothetical but will give you the general idea.cuddihy wrote:How do you figure that simon?MSimon wrote:About half as much. That is some less, not a LOT less.Also, as P-B11 is aneutronic, alot less shielding would be required.
I'd say the majority of cost and complexity has less to do with direct shielding and more to do with safety, chemistry and control of activation products. Once you can literally turn off the reactor with a switch and kill all the radiation, it'll be an entirely different thing.
No Co-60 = No Nuke craziness.
1. 6" of concrete reduces neutron flux by a factor of 10
2. A nuke produces 1E12 neutrons/sq cm sec
3. A BFR produces 1E6 neutrons/sq cm sec
4. For safety the neutron flux should be no higher than 1 neutron/sq cm sec
To reduce the flux by a factor of 1E12 requires 12 X 6" of concrete
To reduce the flux by a factor of 1E6 requires 6 X 6" of concrete
It seems perverse that reducing the neutron flux by a factor of 1 million only cuts shielding requirements in half. But there you have it.
Engineering is the art of making what you want from what you can get at a profit.