Armed Polite Society
Main Forums => The Roundtable => Topic started by: MillCreek on October 21, 2012, 12:09:44 PM
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In the October Surprise thread, I read with interest your experience in the nuclear industry. So as an expert in this arena, what would you say is the optimum design of nuclear reactor for electric power generation with a minimal amount of waste products or diversion to a nuclear weapons program? Either something currently built or on the drawing boards or design stage?
I have read a few interesting things about the pebble bed reactors and what not, but I am but a simple former analytical chemist, and not well-versed in nuclear issues. If there are any links or articles that you think are on point, I would enjoy reading them.
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I say we just stack a bunch of uranium and graphite blocks together in an old racquetball court and see what happens.
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I'll vote for liquid thorium (fluoride) reactors. The fuel is cheaper too.
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Just stumbled across something. I was under the impression that Pu238 was really expensive to make due to it being a small fraction of the material produced in a breeder reactor, and thus would never be within my reach for building a small RTG. According to this, you can breed Pu238 in a Thorium fuel cycle reactor...
http://www.thoriumenergyalliance.com/downloads/plutonium-238.pdf
Hey Birdman, does this look correct to you?
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I'll vote for liquid thorium (fluoride) reactors. The fuel is cheaper too.
Molten salt reactors have a whole slew of problems...so let's say they are second best
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Just stumbled across something. I was under the impression that Pu238 was really expensive to make due to it being a small fraction of the material produced in a breeder reactor, and thus would never be within my reach for building a small RTG. According to this, you can breed Pu238 in a Thorium fuel cycle reactor...
http://www.thoriumenergyalliance.com/downloads/plutonium-238.pdf
Hey Birdman, does this look correct to you?
Yes.
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My personal favorite is high temperature pebble-bed reactors, (if you know my real name, google it and you will see why). They can be built as breeders or conventional, built youse any enrichment of fuel, run on normal thorium, or MOX fuel, and have the most important thing--a negative temperature coefficient of reactivity.
Basically, a properly designed HTGR cannot melt-down, as the reactivity decreases as the temperature increases--so it can be easily and reliably designed to shutdown due to the laws of physics at a temperature BELOW the temperature at which the fuel fails and releases material. In effect, in operation, you have to keep it cool (by extracting heat and making power) to PREVENT it from shutting down when you don't want it to.
Google "PBMR" for the south African big one (I have worked VERY closely with all of those guys), MIT "modular pebble bed reactor" for work here, or find the jaanese or Chinese programs.
They also tend to be extremely efficient relative to other systems (Carnot and his damn laws help when the reactor is humming at 850degC) and can be built small (10-20MWelectric) or large (100-200MWe) and be built quickly and economically.
I've designed two major ones recently, where the only thing that presented funding was the 2008 financial crisis taking down our investors and political BS pushing the timelines out.
Sad to say, the first thing I have to tell people looking to invest or design reactors is "it's highly profitable, just not in this country"
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I learn the coolest things here. Thank you for the explanation birdman. I read it to my mom and even she understood it.
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When I talk about this with my Dad, his concern is always that nuclear waste is horrible-awful-terrible and lasts basically forever. How is that stuff actually being stored, and how dangerous is it?
As a young lad, in the early '80s, my parents took me along to a "No Nukes" rally. It's not really a major issue for them, but they (or at least Dad) have been consistently opposed to it.
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Pay no attention to those digging sounds coming from under your house.
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When I talk about this with my Dad, his concern is always that nuclear waste is horrible-awful-terrible and lasts basically forever. How is that stuff actually being stored, and how dangerous is it?
As a young lad, in the early '80s, my parents took me along to a "No Nukes" rally. It's not really a major issue for them, but they (or at least Dad) have been consistently opposed to it.
If you reprocess, the following things happen:
1. There is 30-100x LESS waste
2. You need 30-100x less uranium or thorium (in a normal reactor, for every 3kg of U-235 put in, there is 1-2kg of U-235 and 0.5-1kg of plutonium left at the end of the cycle..,which we store as WASTE!
We don't reprocess, thus we have a waste problem.
France has nearly the same number of reactors, and ALL their waste fits in a relatively small, and heavily shielded facility.
We (carter) made the decision to "set an example for the world and curb nuclear proliferation" by not reprocessing (since reprocessing is how you get plutonium...bear in mind, normal nuclear reactor power plant fuel cycles can't make bomb grade plutonium, only reactor grade mixed oxide fuel.
Since then, everyone reprocesses but us, no one else has a waste problem, and at least 4 more countries joined the nuclear club...smart guy, that mr. Peanut.
Also, you can use a concept like LIFE (laser initiated fission/fusion energy) or accelerator transmutation of waste (ATW) to take what waste you do have left and treat it.
Basically, the fission products come in three groups
Short and hot (10s-100s of year half life)
Annoying and hot (1000s-10000s year half life)
Long and cold (million year half lives)
Remember, the shorter the half life, the more radioactive a given amount of stuff is.
Category 1 (short and hot) is no big deal, you vitrify it, and store it in a building for 100-200yrs and it's gone.
Category 3 (long and cold) is no big deal, you dilute it sufficiently with dirt and bury it back in the ground...it's about as radioactive as uranium ore.
Category 2 is the annoying stuff, but it's a small quantity relative to the others. That stuff you blast with a neutron source and turn it into category 1 or 2. This takes power (about 10-20% of what the original reactor produced, or basically you need 11 where you used to need 10), but blammo, no waste problem.
With the above strategy, we have enough uranium ALREADY MINED to last hundreds of years, and no waste problem.
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We (carter) made the decision to "set an example for the world and curb nuclear proliferation" by not reprocessing (since reprocessing is how you get plutonium...bear in mind, normal nuclear reactor power plant fuel cycles can't make bomb grade plutonium, only reactor grade mixed oxide fuel.
Since then, everyone reprocesses but us, no one else has a waste problem, and at least 4 more countries joined the nuclear club...smart guy, that mr. Peanut.
Mr. Peanut was right on pretty much every point in his famous "Moral Equivalent of War" (M.E.O.W.) speech. (Too bad Reagan dismantled the whole energy policy but didn't disband the Department of Energy.) I wonder how Carter squared this particular wastefulness (of plutonium 239) with his philosophy of conservation and good stewardship of natural resources?
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Mr. Peanut was right on pretty much every point in his famous "Moral Equivalent of War" (M.E.O.W.) speech. (Too bad Reagan dismantled the whole energy policy but didn't disband the Department of Energy.) I wonder how Carter squared this particular wastefulness (of plutonium 239) with his philosophy of conservation and good stewardship of natural resources?
No clue. Not only that, he was a navy nuc.
Are you saying you agree with what he said? Other than the potential socio-economic issues of not having a good energy policy, much of his premature push toward "renewables" was flawed.
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Mr. Peanut was right on pretty much every point in his famous "Moral Equivalent of War" (M.E.O.W.) speech. (Too bad Reagan dismantled the whole energy policy but didn't disband the Department of Energy.) I wonder how Carter squared this particular wastefulness (of plutonium 239) with his philosophy of conservation and good stewardship of natural resources?
"Its for the children"?
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No clue. Not only that, he was a navy nuc.
Are you saying you agree with what he said? Other than the potential socio-economic issues of not having a good energy policy, much of his premature push toward "renewables" was flawed.
He was a Rickover nuke. Other than being pretty sharp in a "do it my way or I'll make your life a living hell if I let you have one" kind of way, Rickover was nucking futz. His primary criteria for nuke officer selection seemed to be how well the candidates could kiss his ass. Some were able to fake it but a good many didn't have to.
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"Its for the children"?
And children LLLLLOOOOOOVVVVVVEEEE plutonium.
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If we had continued on a path of energy conservation and a shift away from petroleum, we could have crippled the Middle East during the oil glut of the mid-1980's. (probably crippled Houston and New Orleans too) and we might not be fighting the Islamic extremists now -- they would no longer be relevant. We had them on the run, and instead we went back to big inefficient cars for the next 10 years.
There was a book out in the 1970's about alternative energy sources. I can't remember the title well enough to find it on google; I'll have to search upstairs and see if I can find my old copy. One example from it that stuck in my mind was to build a hydroelectric dam across the mouth of a long narrow bay [unfortunately it was in the Middle East] and wait about a year for evaporation to drop the water level enough to begin electricity generation. The cool part was the water in the bay would get more and more concentrated until the salts would start precipitating out and could be dredged out to harvest the metals. The gold that could be mined would be worth more than the electricity. They had the technology to do all that 40 years ago.
We should have taken on a national challenge to see how far we could drive down the price of oil ($2 a barrel?) just to screw with the Arabs.
ETA: I remembered the author's first name (thought it was his last name), and that was enough to track it down: Energy for Survival: The Alternative to Extinction by Wilson Clark.
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And children LLLLLOOOOOOVVVVVVEEEE plutonium.
If you burn uranium in a nuclear reactor, you get plutonium whether you want it or not. (oversimplification, I know) Why not recycle it?
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I wish I could afford a small modular pebble bed reactor. Unlimited electricity to power my
nefarious plans minor and benign hobbies and sell back a good bit to the local power grid. Hopefully it would be enough to cover the payments on the reactor.
Since everywhere seems to have a bunch of NIMBY morons, I wonder if it would be practicable to build a super giant NPP complex out in the middle of fracking no-where, say the old nuclear test range in Nevada, and then just pipe the power to the rest of the nation?
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How could it be less practical than kissing a camel herder's butt for decades and then carting his oil halfway around the world one small load at a time? Of course even in the middle of nowhere idiots do the nimby, see yucca mountain, blocked for years. Virginia has a chance to become filthy rich mining uranium and every damn hippie is trying to stop it.
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I wish I could afford a small modular pebble bed reactor. Unlimited electricity to power my nefarious plans minor and benign hobbies and sell back a good bit to the local power grid. Hopefully it would be enough to cover the payments on the reactor.
Since everywhere seems to have a bunch of NIMBY morons, I wonder if it would be practicable to build a super giant NPP complex out in the middle of fracking no-where, say the old nuclear test range in Nevada, and then just pipe the power to the rest of the nation?
Probably not quite profitable due to line losses, unless someone comes up with a room temp superconductor that doesn't require high amounts of rare earths. And of course, even a room temp. superconductor that uses the most expensive elements possible hasn't been found either.
So there's generally an economic sweet spot between plant placement to users, and transmission distance.
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Another question for the Birdman: Can our huge pile of DU be used in a heavy water reactor, or is that sort of thing only viable with the natural isotope composition (.7% U235)?
I seem to recall seeing somewhere that the U.S. is sitting on some 480,000 tons of DU.
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Another question for the Birdman: Can our huge pile of DU be used in a heavy water reactor, or is that sort of thing only viable with the natural isotope composition (.7% U235)?
I seem to recall seeing somewhere that the U.S. is sitting on some 480,000 tons of DU.
U238 (DU) should work just fine as the fertile material in a breeder reactor. I don't think it will sustain a reaction without a neutron source to convert it to plutonium 239.
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U238 (DU) should work just fine as the fertile material in a breeder reactor. I don't think it will sustain a reaction without a neutron source to convert it to plutonium 239.
Correct. U-238 is bred with neutron flux from a reactor to make Pu-239 (and 240,241 if you leave it in too long...the presence of those it what makes the difference between reactor and bomb grade Pu).
Let's put it this way, at 30-40,000 MW-days/ton metal burnup, our 450,000 tons of DU in breeder reactors would be enough to produce ALL of the US energy needs for 20-25 YEARS (and that's replacing ALL fossils fuels including oil/gas with synthetic hydrocarbons). with ATW, there would be virtually no waste issues.
The big advantage of breeders is the saying we have in the industry:
You have a breeder reactor, a ton of DU or thorioum, and a ton of U-235 or Plotonium...what do you have after the end of the year?
A breeder reactor and TWO tons of U-233 or Plutonium (for a thorium or MOX cycle respectively)
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Correct. U-238 is bred with neutron flux from a reactor to make Pu-239 (and 240,241 if you leave it in too long...the presence of those it what makes the difference between reactor and bomb grade Pu).
Let's put it this way, at 30-40,000 MW-days/ton metal burnup, our 450,000 tons of DU in breeder reactors would be enough to produce ALL of the US energy needs for 20-25 YEARS (and that's replacing ALL fossils fuels including oil/gas with synthetic hydrocarbons). with ATW, there would be virtually no waste issues.
The big advantage of breeders is the saying we have in the industry:
You have a breeder reactor, a ton of DU or thorioum, and a ton of U-235 or Plotonium...what do you have after the end of the year?
A breeder reactor and TWO tons of U-233 or Plutonium (for a thorium or MOX cycle respectively)
What's ATW? ???
On a mostly-unrelated topic, how does plutonium even have a critical mass? All its isotopes are just alpha-emitters. Spontaneous fission? Or maybe one of the isotopes decays into something throws off a neutron or three when IT decays...
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What's ATW? ???
On a mostly-unrelated topic, how does plutonium even have a critical mass? All its isotopes are just alpha-emitters. Spontaneous fission? Or maybe one of the isotopes decays into something throws off a neutron or three when IT decays...
Accelerator Transmutation Of Waste (http://www.lanl.gov/orgs/pa/science21/ATW.html)
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Accelerator Transmutation Of Waste
Thanks. I'm usually pretty good at acronyms but had nothing to draw from.
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BTW, on the related subject of the DoE, does anyone here recall what their original charter was?
I'm not even going to hint.
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BTW, on the related subject of the DoE, does anyone here recall what their original charter was?
I'm not even going to hint.
Before I google it, I'm going to make a WAG and say to promote nuclear power (and handle our nuclear weapons stockpile).
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BTW, on the related subject of the DoE, does anyone here recall what their original charter was?
I'm not even going to hint.
Make sure the price of oil didn't shoot through the roof?
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Before I google it, I'm going to make a WAG and say to promote nuclear power (and handle our nuclear weapons stockpile).
It was to make weapons. Energy was secondary.
The missile is a DOD item, the warhead is a DOE controlled item (and AEC before that)
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If we had continued on a path of energy conservation and a shift away from petroleum, we could have crippled the Middle East during the oil glut of the mid-1980's. (probably crippled Houston and New Orleans too) and we might not be fighting the Islamic extremists now -- they would no longer be relevant. We had them on the run, and instead we went back to big inefficient cars for the next 10 years.
There was a book out in the 1970's about alternative energy sources. I can't remember the title well enough to find it on google; I'll have to search upstairs and see if I can find my old copy. One example from it that stuck in my mind was to build a hydroelectric dam across the mouth of a long narrow bay [unfortunately it was in the Middle East] and wait about a year for evaporation to drop the water level enough to begin electricity generation. The cool part was the water in the bay would get more and more concentrated until the salts would start precipitating out and could be dredged out to harvest the metals. The gold that could be mined would be worth more than the electricity. They had the technology to do all that 40 years ago.
We should have taken on a national challenge to see how far we could drive down the price of oil ($2 a barrel?) just to screw with the Arabs.
ETA: I remembered the author's first name (thought it was his last name), and that was enough to track it down: Energy for Survival: The Alternative to Extinction by Wilson Clark.
The conservation /alternative fuels push in the 70's was economically flawed (conservation restricts economic growth...basically, we wouldn't have had the 80's) or technologically premature (alternative fuels)
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If you burn uranium in a nuclear reactor, you get plutonium whether you want it or not. (oversimplification, I know) Why not recycle it?
Not if it's weapons grade. Then you don't get any plutonium.
That's why the initial load for thorium plants uses HEU when possible.
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What's ATW? ???
On a mostly-unrelated topic, how does plutonium even have a critical mass? All its isotopes are just alpha-emitters. Spontaneous fission? Or maybe one of the isotopes decays into something throws off a neutron or three when IT decays...
Plutonium is fissionable, just like uranium, and both spontaneously fission. When fissioned, neutrons are released. If number of neutrons/fission at cause additional fissions is 1, (the remaining 2.2-2.8 leave the mass) the mass is critical.
Even isotopes WITHOUT spontaneous fission have a critical mass, they just need an initial neutron to get it going (ironically, these can come from cosmic rays quite reliably). Critical mass is a function of geometry, whatever absorption is present, atom density and fission cross section of the material.
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Even isotopes WITHOUT spontaneous fission have a critical mass.....
What's the critical mass to fission Protium? [popcorn]
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What's the critical mass to fission Protium? [popcorn]
Infinity. I left out "fissionable" isotopes (ie those where the neutron energy produced exceeds the minimum neutron energy for fission)
CORRECTION: it's not possible, while protium can be fissioned into a quark-gluon plasma, to do so purely by mass (gravitational compression) would put the mass above the point where the hydrogen would start to fuse. Of course, supernovae create fissionable materials, and it is possible for a natural critical mass to form on a panet, so I guess the amount would -technically- be 3-10 solar masses...and wait about 4-5 billion years.
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Infinity. I left out "fissionable" isotopes (ie those where the neutron energy produced exceeds the minimum neutron energy for fission)
So, if we get Hydrogen-1 to fission, is that like the cosmic equivalent of dividing by zero? :lol:
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Plutonium is fissionable, just like uranium, and both spontaneously fission. When fissioned, neutrons are released. If number of neutrons/fission at cause additional fissions is 1, (the remaining 2.2-2.8 leave the mass) the mass is critical.
Even isotopes WITHOUT spontaneous fission have a critical mass, they just need an initial neutron to get it going (ironically, these can come from cosmic rays quite reliably). Critical mass is a function of geometry, whatever absorption is present, atom density and fission cross section of the material.
Thanks. I didn't know where that first neutron came from. (and I guess it doesn't matter, if you build it they will come :D)
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So, if we get Hydrogen-1 to fission, is that like the cosmic equivalent of dividing by zero? :lol:
Omg what have you done
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Omg what have you done
Nothing that you need to be concerned about... yet... >:D
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So, if we get Hydrogen-1 to fission, is that like the cosmic equivalent of dividing by zero? :lol:
http://en.wikipedia.org/wiki/Proton_decay
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http://en.wikipedia.org/wiki/Proton_decay
Not observed...yet...no theoretical mechanism defined, and well past the heat or EM (hawking radiation) death of the universe timeframe based on current lower limit timeframes.
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Thanks for the answer on waste. Not that I understood it very well, but thanks. =)
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Probably not quite profitable due to line losses, unless someone comes up with a room temp superconductor that doesn't require high amounts of rare earths. And of course, even a room temp. superconductor that uses the most expensive elements possible hasn't been found either.
So there's generally an economic sweet spot between plant placement to users, and transmission distance.
I've actually used this as an example. With current exclusion zone limits, a 1-2GW electric nuclear plant is about 1/2 a mile on a side. We would need about 4000 GW to fully replace all of our energy with synfuels and electric. That is an area about 1000 square miles.
To put in perspective, the:
nevada test site is....1350 square miles
White sands is...3200 square miles
Line losses to distribute the ~1.25 TW to the rest of the US (average distance about 1500 miles) using EHV lines is about 5-10% and are included in the above calculation
That's based on using 1.1MV EHV lines, distributed over individual lines carrying 500A each (3-phase 1.6GW per line-set), with a resistance of ~0.16ohm/mile (or 240ohms, or about 60 MW loss per GW cable)
Burnup of 50 GWd/ton metal in reactors requires 80 tons of fuel per day, 30,000 per year. Using breeder reactors, that means our ALREADY MINED stockpile of DU would last 15 years supplying ALL our energy needs (including synthetic gasoline and diesel).
BTW, it's possible to extract uranium from seawater at about $300/kg...so the above fuel would cost $10 billion per year for an effectively infinite supply (Uranium is present at about 3 tons/cubic km of the ocean, so the above consumption would mean 10% of the uranium in the ocean would be able to supply the US for 100,000 years. Even assuming our energy needs double ever 7-10 years (a FAST economy), this is enough uranium to supply an exponentially growing US for about 2500 YEARS, or the above growth rate for the ENTIRE WORLD for 500-1000yrs.
Crazy no?
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The DoE original charter is described here (http://www.eqna.org/70100/doe-department-of-energy-what-was-its-original), and also here (http://www.chacha.com/question/what-was-the-original-purpose-for-the-department-of-energy), as well as other places.
And, while the various nuclear programs, including weapons, were placed in its domain, the main point of this exercise:
The Department of Energy was formed after the oil crisis on August 4, 1977 in order to end the United States dependence on foreign oil by President Jimmy Carter's signing of legislation, The Department of Energy Organization Act of 1977.
I would say the DoE needs to be gently reminded of it's original purpose -- energy independence -- and guided back onto the tracks that lead there.
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The DoE original charter is described here (http://www.eqna.org/70100/doe-department-of-energy-what-was-its-original), and also here (http://www.chacha.com/question/what-was-the-original-purpose-for-the-department-of-energy), as well as other places.
And, while the various nuclear programs, including weapons, were placed in its domain, the main point of this exercise:
I would say the DoE needs to be gently reminded of it's original purpose -- energy independence -- and guided back onto the tracks that lead there.
We DON'T NEED ENERGY INDEPENDENCE thats not how global markets work. We need cheap energy. Not we can get it cheaper here than there, fine.
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Perhaps a better phrasing would be "not dependent for energy on unstable regions in the world."
If we're getting cheap oil from Petrolistan, and one day that country decides they hate us, or they have a little war that cuts off that supply, we can suddenly be hosed economically.
All well and good to have cheap oil (or what have you) on the world market. Not so good to have our economy depend on the vagaries of the political alignments du jour in some distant land(s).
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Actually, I seem to remember something about a shale oil operation in Utah some years back. It seemed that the operation could be profitable as long as oil was running at or above $35/barrel or something like that. The response from OPEC (as i recall) was to drop the price of their oil to make shale economically infeasible.
There was some discussion a little while back about reviving that operation. The break-even would be considerably higher than $35 nowadays, but in the discussion I heard, it seemed that above $85/barrel they were viable again.
Don't recall the details.
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Perhaps a better phrasing would be "not dependent for energy on unstable regions in the world."
If we're getting cheap oil from Petrolistan, and one day that country decides they hate us, or they have a little war that cuts off that supply, we can suddenly be hosed economically.
All well and good to have cheap oil (or what have you) on the world market. Not so good to have our economy depend on the vagaries of the political alignments du jour in some distant land(s).
What we need is energy here, at a cost for what we currently get it there (or cheaper). With the birdman nuke plan, we suddenly become a major oil exporter (in fact, that alone could easily pay for the a significant fraction of the cost of the nuke and synfuel plants). It also would give us a huge long term edge...we have substantial oil/gas/coal resources, just less than we need....but if we got our energy from nuclear, then we could sell that to countries not as advanced...or just not use it, so we can sell it for more in the future :)
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Plastics and other oil byproducts might get interesting. Yes, I know. Gradual phase in, just saying it is another consideration.
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This is what I like about APS.....lots of DIY advice....
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BTW, it's possible to extract uranium from seawater at about $300/kg...so the above fuel would cost $10 billion per year for an effectively infinite supply (Uranium is present at about 3 tons/cubic km of the ocean, so the above consumption would mean 10% of the uranium in the ocean would be able to supply the US for 100,000 years. Even assuming our energy needs double ever 7-10 years (a FAST economy), this is enough uranium to supply an exponentially growing US for about 2500 YEARS, or the above growth rate for the ENTIRE WORLD for 500-1000yrs.
Crazy no?
You didn't mention the BEST part. Rivers deliver more uranium to the oceans every year due to natural erosion. To the tune of about 32,000 tons/year. Which is on the same order of how much is needed to completely replace our energy use each year.
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BTW, it's possible to extract uranium from seawater at about $300/kg...
What's the cost per KG when you dig it out of the ground?
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Plastics and other oil byproducts might get interesting. Yes, I know. Gradual phase in, just saying it is another consideration.
The Fischer-Tropsch process used to create liquid fuels also provides tail products for plastic feedstocks, for example methane, methanol, etc
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What's the cost per KG when you dig it out of the ground?
http://uxc.com/review/uxc_PriceChart.aspx?chart=spot-u3o8-full
http://www.cameco.com/investors/uranium_prices_and_spot_price/spot_price_5yr_history/
http://www.uraniumminer.net/market_price.htm
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Birdman speaks true - lots of thorium sands in the Indian Ocean part of the globe.
That's how they get their program fueled, and it's another precursor one can look for in the proliferation monitoring business.
Just thinking about how many sniffer planes my agency would need if all those reactors were built to eliminate fossil fuel energy...
Speaking of enrichment and preventing weapons grade U-235/U-238 ratios, I had to do a bit of work with the now-defunct AVLIS program at Lawrence Livermore National Labs.
It was pretty darned neat, and walking through the galleries of dye lasers which pushed sputtered uranium atoms into two separate streams inspired awe.
They offered me a job there, glad I didn't take it now.
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Birdman speaks true - lots of thorium sands in the Indian Ocean part of the globe.
That's how they get their program fueled, and it's another precursor one can look for in the proliferation monitoring business.
Just thinking about how many sniffer planes my agency would need if all those reactors were built to eliminate fossil fuel energy...
Speaking of enrichment and preventing weapons grade U-235/U-238 ratios, I had to do a bit of work with the now-defunct AVLIS program at Lawrence Livermore National Labs.
It was pretty darned neat, and walking through the galleries of dye lasers which pushed sputtered uranium atoms into two separate streams inspired awe.
They offered me a job there, glad I didn't take it now.
They were going to put my lab in the basement where the AVLIS Copper pump lasers were....you know those big concrete footings? I was standing on them about 3 years ago :)
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Got some more questions for Birdman (see what happens when you let slip you're and SME?) ;)
Is it practicable to build single reactors in the terawatt range?
Is it more energy efficient to simply split water and use the hydrogen as fuel as opposed to synthesizing gasoline and diesel with the Fischer-Tropsch process? (electricity consumed to split the water versus electricity consumed to separate CO2 from seawater, purify the seawater with reverse osmosis, and then using those building blocks to make the long chain hydrocarbons)
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@kgb
I don't know the answer to the first question.
But as to F-T process...
Yes, it is more energy efficient if one can use the hydrogen directly and avoid F-T. But this only works at short range with extremely short term storage schedule.
Hydrogen is a low density gas. So storage and transportation is a big issue for use in vehicles, which do a lot of storing and transporting. Hydrogen also likes to leak out of containers, not dangerously, just enough to lose money.
The options are:
liquid - compress and cool it to 20K [-250C, -423F] (only an option for NASA)
high pressure gas - compress and store as gas (takes huge tanks, and much lower energy storage)
Both of these options suck. They suck almost as much as batteries. So the storage and transport issue kills the efficiency when automotive and vehicle use is considered. Pipeline use to a chemical factory is probably not a problem.
Converting to methane/nat gas is the next step of difficulty in the potential choices. Nat gas is far and away easier to deal with than H2. Methane is a natural feedstock to make any plastic. For transportation, cryogenic liquid methane is plausible. But still too much of a pita to really catch on. Or use compressed gas storage. Again, tank sizing issue. These options are being heavily explored right now due to the cheapness of nat gas. We have several locomotives and heavy equipment designs slated for introduction in a few years to take advantage of nat gas.
Next level is methanol and ethanol synthesis. Liquid, minor change to engine design, good enough energy storage, maybe cheap enough. Methanol can be converted to DME (dimethyl ether) for a good diesel substitute. Methanol is also a good plastics feedstock.
I strongly suspect that the industry may settle for this compromise.
Next level of difficulty is full replacement synthesis. Full synthetic gasolines and diesels and waxes and plastics. This is probably the most capital expensive route, but also provides drop in replacement of fuel for all older vehicles. I doubt the whole industry is converted to this path.
We may end up at a place in between.
25% methanol + 25% ethanol + 50% octane
Here is why we might end up at that kind of strange compromise...
We already run E10-E15, taking that away will hurt the lobby. We will also have oil for a good long while, but everyone understands that we need additional supplement. So as we supplement in methanol and ethanol to higher and higher levels, there will still be a need for full octanes to balance the gasoline formula. So that may come from oil and a few F-T plants, but since full F-T process is expensive, there will be a push to use more and more meth and eth until we hit some backwards compatible limit. Then will come the political decision to completely jump ship to pure meth/eth mixtures or stick with a meth/eth/octane mixture.
But this will take decades of transition before decision point. Forecasting beyond that is difficult, because who really knows? Maybe one day, batteries won't suck. Maybe at that point the politics of oil will be passe and nobody will feel any pressure to switch further.
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Got some more questions for Birdman (see what happens when you let slip you're and SME?) ;)
Is it practicable to build single reactors in the terawatt range?
Is it more energy efficient to simply split water and use the hydrogen as fuel as opposed to synthesizing gasoline and diesel with the Fischer-Tropsch process? (electricity consumed to split the water versus electricity consumed to separate CO2 from seawater, purify the seawater with reverse osmosis, and then using those building blocks to make the long chain hydrocarbons)
Reactors at a terawatt? Sure, consider that most 3GW thermal (1GW electric) cores are only 15' in diameter and about the same in height, meaning a 1TW thermal power (300GW) reactor core would 'only' be 150ft in diameter and 50ft tall (geometry change for a variety of thermal hydraulic and criticality reasons), require a pressure vessel with 7 foot thick steel walls (instead of 8"), and likely have to be a molten salt system.
It's the balance of plant that would be very hard...heat exchangers would be of comparable size, and the generators are larger than current tech reasonably allows. However, you could couple that with 300 or so 1GW class generators and go with it.
But why? It's better to take advantage of mass production and just make 300 identical 3GW cores and put them in one place if that were your goal.
As for the hydrogen question, drew had it right. The reason I pick methanol/DME is from a transition capital cost for infrastructure and end user equipment changes required, it's the most cost effective as it requires minimal modification to distribution and use infrastructure and vehicles. (cost minimization between efficiency loss of going beyond hydrogen vs equipment changes).
Also, for that large of scale, hydrogen generation is likely a hybrid thermal/electrical process rather than straight electrolysis.
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Is it practicable to build single reactors in the terawatt range?
Is it more energy efficient to simply split water and use the hydrogen as fuel as opposed to synthesizing gasoline and diesel with the Fischer-Tropsch process? (electricity consumed to split the water versus electricity consumed to separate CO2 from seawater, purify the seawater with reverse osmosis, and then using those building blocks to make the long chain hydrocarbons)
1. No. Possible, yes. Practical, no. When it goes down for maintenance, that's a huge hole. Standardized conventional reactors would be cheaper, more durable (well, more overall uptime), and easier to build due to capital allocation. You can turn on one as soon as it's built, while the next in the series is being installed. Same reason why all "supercomputers" these days are just clusters of nearly COTS servers.
2. Using hydrogen as a conventional fuel would suck. Hence why it's not used as regularly as plenty of other gasses. Don't get me wrong, it has LOTS of uses. But for the average person? There's a reason why we use profane, gas, diesel, etc. It's relatively easy to work with. Hydrogen is a slippery bugger, if nothing else.
Drew is very much correct.
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There's a reason why we use profane, gas, diesel, etc.
:rofl: :rofl:
If we could use profane as a fuel, we'd never need another source of energy!!! Imagine a good rush hour!!
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:rofl: :rofl:
If we could use profane as a fuel, we'd never need another source of energy!!! Imagine a good rush hour!!
Can vehicles designed to run on scream and laugh use that? =D
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Can vehicles designed to run on scream and laugh use that? =D
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fpixartimes.com%2Fwp-content%2Fuploads%2F2011%2F03%2Fmonsters-inc.jpg&hash=93c17e3afe7c338585fbfe366671c4ee4f3035a6)
http://youtu.be/431KmmNU8rA
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:rofl: :rofl:
If we could use profane as a fuel, we'd never need another source of energy!!! Imagine a good rush hour!!
I swear, Autocorrect is the devil at times.