The U.S. has a number of different reactor designs, both within the PWR class and the Boiling Water Reactor class entirely because the reactors were still being evolved. It's not that we made a poor decisions per se, its just that other countries had the benefit of our development experience. You see similar build out programs in other nuclear dependent countries such as Korea which derives the majority of their power from the KSNP a System-80 plant design purchased from Combustion Engineering.
Obviously it's easier to maintain a lot of the same type of technology which allows you to take advantage of well known economies of scale. Westinghouse's new reactor design the AP1000 takes full advantage of such standardization in components and design.
One of the largest constituents of nuclear waste is plutonium which itself is suitable for making nuclear fuel. This process is called breeding and all uranium fueled reactors operate at least partially off of this reaction. For instance modern PWR fuel is burned for three 18 month cycles, during the third cycle as much as 30% of the thermal output of a fuel assembly comes from plutonium fissioning.
At the end of the fuel's "useful" life only 1.5% of its energy potential has been developed. We're currently throwing away the rest of that energy because of a political decision that was made in the 70's forbidding the use of reprocessing technologies here in the U.S. due to proliferation concerns. France has been reprocessing their nuclear fuel for decades.
There is an immense amount of energy in the uranium nucleus, all of it within the reach of our current technology (actually within reach of 30 year old technology).
Radioactive waste actually has very short half-lives which is why the waste is so acutely radioactive. Garden variety U238 has a halflife of approximately 4 billion years. The plutonium that results from the various nuclear reactions has a much shorter half life (approximately 25,000 years). Plutonium has other properties that make it unsavory to just have lying around of course.
The more radiotoxic isotopes like Xenon and Iodine are very short lived and also extremelly dangerous, fortunately they burn out completely in a very short period (several months not years or millenia)
The nuclear part of a nuclear power station heats high pressure coolant (ultra pure water) which is then used to create steam either directly in a BWR or through a water-water heat exchanger in a PWR. This steam is then passed through a turbine to generate electricity. The steam is cooled and then recirculated. This coolant loop is known as the primary loop and it is constantly recirculated at a rate of up to 100,000 gallons per minute.
Outside of the nuclear source of heat the plants are operationally identical to fossil plants w.r.t the steam turbines, condensation towers, etc.
The waste comes from the spent nuclear fuel assemblies which burn out over time and need to be replaced periodically during a refueling outtage. Every refueling outtage generates approximately 60-90 tons of waste which is a very small amount compared to the amount of ash and CO2 produced in a fossil plant.
The most intense sources of radiation in spent nuclear fuel have very short half-lives. The longer lived isotopes, like Uranium-238 (half life of ~4 billion years) are much less radiotoxic than the short lived isotopes like Xenon and Iodine.
That's about the same amount of output as 17 modern LWRs. THe PBMR is well suited to areas without an existing electrical infrastructure. Using PBMRs to power the U.S. isn't practical and that's not what they're designed to do.
Now if you built 100 additional LWRs and double the nuclear power production in the U.S. (up to 40% from today's 20%) you'd have a massive impact on greenhouse gas emissions (We'd be able to join the Kyoto protocol) and reduce our reliance on foreign sources of natural gas. Very little oil is used for electricity generation in the U.S.
The monitors in the jury box were not used to show the defendant, only bits of evidence like security cam video, pictures and maps. Witnesses were similarly not shown on the monitors. In fact there were no cameras in the courtroom whatsoever, aside from an overhead projector that fed the courtroom monitor system.
The defendants sit at most 40 feet away from the jury - witnesses sit right next to the jury box. There was no video trickeration as the parent implies, not saying it's impossible, but in the SC Federal Court where I served as a juror there was no closed circuit TV system in evidence at all.
I just finished Jury Duty in SC Federal Court...
on
Order in the e-Court!
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· Score: 1
The courtroom was similarly equipped with LCD monitors in the jury box and a touch sensitive display at the witness stand. This particular trial made extensive use of an aerial photo which served as a map of the crime scene. Witnesses were able to point to specific places on their monitor and everyone in the court including the jurors could clearly see what was being indicated. Much more effective than a posterboard sized map on the other end of the room.
If you go and buy a library of media that you can't read, well you're a dumbass. People don't rush out and buy vinyl and then return home and face the disappointment of their CD player not being compatible with vinyl records.
Properly managed nuclear power is indeed very clean and affordable. There is unfortunately a lot of incorrect information available about the topic.
The Pebble Bed Modular Reactor (PBMR) uses billard ball sized balls of enriched uranium with a graphite moderator matrix. These types of reactors are gas cooled and intrinsically safe - as coolant temperature increases the reaction rate slows. This type of reactor is sometime called "walk away" safe. You could walk away from them, turn out the lights and never come back and the reactor wouldn't overheat.
The CANDU reactor (CANadian Deuterium Uranium) reactor is a heavy water cooled and moderated reactor that burns natural uranium. Heavy water is required due to the low concentration of fissile U235 found in natural uranium. These reactors, like all water cooled and moderated reactors have a negative void coefficient - as the coolant temperature increases the nuclear reaction rate decreases. These aren't quite walkaway reactors, but they have an imporant safeguard built into the very mechanism that allows the nuclear reaction to occur.
The negative void coefficient safeguard is also inherent to the light water reactors that are the predominant source of nuclear power in much of the world, these include pressurized and boiling water reactors which use normal water as a coolant with slightly enriched uranium 5% U235.
The reactor that exploded at Chernobyll was of the RBMK design. The RBMK has a positive void coefficient. As the coolant increases in temperature the reaction rate rapidly increases. This is an inherent instability in the design of the reactor making huge power increases possible from an initially low power state, producing an immense feedback response. That, combined with a number of other safety shortcuts like the lack of a proper containment structure, allowed the Chernobyll disaster to happen.
Comparing the RBMK to a water moderated reactor is like comparing Vaseline to Napalm. Both are petroleum products but the similarity stops there. The reactor designs in use throughout the world are orders of magnitude safer than the RBMKs that the Soviets built, they're cheap, but definitely not inherently safe.
If you don't have a well established grid in place a PBMR is a good choice. The concept was meant for countries like China with very little infrastructure in a lot of place and rapidly rising demands for electricity. China is also heavily pursuing the much higher output Gigawatt scale nuclear plants that are currently used throughout the Western world as well as other parts of Asia in the areas that do have an existing distribution network.
PBMRs are only cost effective to a point. You wouldn't want to power a city the size of Beijing with PBMRs, it would be far more cost effective to build two or three 1100 MWe plants instead.
Hydrogen will rapidly diffuse through just about any material, even things that are very "solid" looking like glass or metal. The size of the molecules in question plays a significant role in determine how quickly a given material will move through another material. This phenomenon causes all manner of problems in a wide range of areas where hydrogen isn't welcome. Welding and hydrogen embrittlement being an especially good example. Hydrogen is also very reactive, forming hydrides with most metals. These hydrides weaken the microstructure of their host materials, reducing their ductility and toughness and making them less safe/suitable for storing high pressure gas.
I'm assuming that you're talking about last August's outage in the northeastern U.S. and Canada. If so that outage resulted from a failure in the distribution network, not from a lack of generating capacity. Your area of Michigan was not affected because it wasn't on the same grid as the areas that were affected. Parts of Manhattan were entirely dark while just across the river Jersey was fully lit. At least twenty of the powerplants in that region had to shutdown because of the outage since they had nowhere to dump their output because the grid had failed.
Fossil plants generally do load-follow production and change their output levels to match demand. Nuclear plants tend to run best at constant power levels for a variety of reasons, but it ultimately comes down to a cost/benefit analysis. In many places you'll find nuclear plants alongside man-made lakes fitted with hydroelectric generators. At night the excess electricity from the nuclear station is used to pump water into the lake, converting electrical energy into potential energy. During the daytime this potential energy is converted back into electricity by the hydro plant to help even out the load and meet peak demands.
This isn't a hard and fast rule for nuclear plants, rather it depends on the market and the fuel management strategies being used by the utility. For instance many French nuclear stations do use load-follow generating strategies, the operating strategies in France are sufficiently different such that load-follow there is cost effective for the way they operate their plants.
Buy any commodity in bulk and you'll get a better per-unit rate than if you're buying smaller chunks. It's easier (and thus more profitable) to sell larger chunks of something, particularly once the production cost is fixed.
Those bulk customers are also exchanging a level of service for cheaper rates. In the event of a power outtage higher rate customers like residences get priority for service restoration.
The price that electricity is sold for is only partially tied to the generating cost. There's a lot of overhead in terms of distribution networks, emergency services, customer support and front office stuff that you pay for as well. Large users of electricity use a smaller share of the overhead resources and thus their rates are closer to the generating cost since the overhead costs can be amortized across a much larger amount of kw-hrs.
The payoff time is very long... after a couple of decades you'll be beating the power company, but there's a hell of a lot better way to invest your money:-)
For comparison purposes a typical power plant will produce on the order of 1000 Megawatts (some are more, some are less but that's a good ballpark). Such a solar panel clad building would produce a fair amount of electricity for a solar application, but it's still a miniscule amount compared to the power demands of even a small city.
My electricity runs about $0.08 per kilowatt-hour. A 1 square foot panel would produce 3.8 Watts X 8 hours (assuming 8 good hours of sunlight) or ~.03 kW-hr at a cost of $45, which works out to $1500 per kilowatt hour. Cheap for solar, owing to the higher efficiency of the panels, but dismal by commercial generation.
Let's take a super-skyscraper, assuming a 200' square base that's as high as the Sears tower (roughly 1450' to the roof top). Assuming the building maintains its rectangular cross section from the ground to the top gives us an area of 1.16 million square feet which would generate ~4.4 megwatts of electricity, which is a lot of electricity.
The article calls out a price of $45 per square foot, making the solar panels for such a building cost about $52 million dollars. Surprisingly cheap for that much electrical capacity, though the usage factor would be pretty low, what with it being dark at night and all.
The production and extraction of plutonium uses a very different type of reactor than the Pressurized Water Reactors that are used for power generation in much of the world. A lot of the waste at Hanford isn't due to the reactor operation per se, but rather the chemical extractions that are necessary to recover the plutonium. These extractive processes generate a lot of waste chemicals (like acids that have been used to dissolve fuel) that are contaminated with hot particles. That's the origin of the liquid radioactive waste at Hanford.
Waste from a PWR is solid and it predominantly consists of used or burned fuel assemblies that are still radioactive but no longer capable of producing electricity efficiently. The fuel assemblies contain the fuel rods which encapsulate the fuel pellets and the daughter products of the fission reaction (various isotopes of noble gases trapped in the fuel rods).
The mass of waste produced by a nuclear plant in a given year of operation is miniscule compared to the thousands of tons of ash, soot, and greenhouse gases emitted by your typical coal plant with a similar electrical output.
There were two plutonium implosion devices and one enriched uranium gun-type device. The Trinity device was a plutonium implosion bomb. Hiroshima was the gun-type Little Boy, Nagasaki was the second plutonium implosion device, called Fat Man. The implosion device was a much more complicated and efficient weapon, but the U.S. had to be sure it would work, hence the test at Trinity.
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
Your credit card and medical information can easily be argued to be your "papers and effects." Privacy is one of the few rights that is specifically defined by the Constitution.
Real's Collapse is Inevitable...
on
Real Problems
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· Score: 1
Real is a lot like a super-dense star: both will eventually suck so hard that they destroy everything around them immediately prior to collapsing into a blackhole from which no useful information can ever escape.
Slashdot Mirror
The U.S. has a number of different reactor designs, both within the PWR class and the Boiling Water Reactor class entirely because the reactors were still being evolved. It's not that we made a poor decisions per se, its just that other countries had the benefit of our development experience. You see similar build out programs in other nuclear dependent countries such as Korea which derives the majority of their power from the KSNP a System-80 plant design purchased from Combustion Engineering.
Obviously it's easier to maintain a lot of the same type of technology which allows you to take advantage of well known economies of scale. Westinghouse's new reactor design the AP1000 takes full advantage of such standardization in components and design.
One of the largest constituents of nuclear waste is plutonium which itself is suitable for making nuclear fuel. This process is called breeding and all uranium fueled reactors operate at least partially off of this reaction. For instance modern PWR fuel is burned for three 18 month cycles, during the third cycle as much as 30% of the thermal output of a fuel assembly comes from plutonium fissioning.
At the end of the fuel's "useful" life only 1.5% of its energy potential has been developed. We're currently throwing away the rest of that energy because of a political decision that was made in the 70's forbidding the use of reprocessing technologies here in the U.S. due to proliferation concerns. France has been reprocessing their nuclear fuel for decades.
There is an immense amount of energy in the uranium nucleus, all of it within the reach of our current technology (actually within reach of 30 year old technology).
Radioactive waste actually has very short half-lives which is why the waste is so acutely radioactive. Garden variety U238 has a halflife of approximately 4 billion years. The plutonium that results from the various nuclear reactions has a much shorter half life (approximately 25,000 years). Plutonium has other properties that make it unsavory to just have lying around of course.
The more radiotoxic isotopes like Xenon and Iodine are very short lived and also extremelly dangerous, fortunately they burn out completely in a very short period (several months not years or millenia)
The nuclear part of a nuclear power station heats high pressure coolant (ultra pure water) which is then used to create steam either directly in a BWR or through a water-water heat exchanger in a PWR. This steam is then passed through a turbine to generate electricity. The steam is cooled and then recirculated. This coolant loop is known as the primary loop and it is constantly recirculated at a rate of up to 100,000 gallons per minute.
Outside of the nuclear source of heat the plants are operationally identical to fossil plants w.r.t the steam turbines, condensation towers, etc.
The waste comes from the spent nuclear fuel assemblies which burn out over time and need to be replaced periodically during a refueling outtage. Every refueling outtage generates approximately 60-90 tons of waste which is a very small amount compared to the amount of ash and CO2 produced in a fossil plant.
The most intense sources of radiation in spent nuclear fuel have very short half-lives. The longer lived isotopes, like Uranium-238 (half life of ~4 billion years) are much less radiotoxic than the short lived isotopes like Xenon and Iodine.
That's about the same amount of output as 17 modern LWRs. THe PBMR is well suited to areas without an existing electrical infrastructure. Using PBMRs to power the U.S. isn't practical and that's not what they're designed to do.
Now if you built 100 additional LWRs and double the nuclear power production in the U.S. (up to 40% from today's 20%) you'd have a massive impact on greenhouse gas emissions (We'd be able to join the Kyoto protocol) and reduce our reliance on foreign sources of natural gas. Very little oil is used for electricity generation in the U.S.
I think they're called "Parents."
The monitors in the jury box were not used to show the defendant, only bits of evidence like security cam video, pictures and maps. Witnesses were similarly not shown on the monitors. In fact there were no cameras in the courtroom whatsoever, aside from an overhead projector that fed the courtroom monitor system.
The defendants sit at most 40 feet away from the jury - witnesses sit right next to the jury box. There was no video trickeration as the parent implies, not saying it's impossible, but in the SC Federal Court where I served as a juror there was no closed circuit TV system in evidence at all.
The courtroom was similarly equipped with LCD monitors in the jury box and a touch sensitive display at the witness stand. This particular trial made extensive use of an aerial photo which served as a map of the crime scene. Witnesses were able to point to specific places on their monitor and everyone in the court including the jurors could clearly see what was being indicated. Much more effective than a posterboard sized map on the other end of the room.
If you go and buy a library of media that you can't read, well you're a dumbass. People don't rush out and buy vinyl and then return home and face the disappointment of their CD player not being compatible with vinyl records.
Properly managed nuclear power is indeed very clean and affordable. There is unfortunately a lot of incorrect information available about the topic.
The Pebble Bed Modular Reactor (PBMR) uses billard ball sized balls of enriched uranium with a graphite moderator matrix. These types of reactors are gas cooled and intrinsically safe - as coolant temperature increases the reaction rate slows. This type of reactor is sometime called "walk away" safe. You could walk away from them, turn out the lights and never come back and the reactor wouldn't overheat.
The CANDU reactor (CANadian Deuterium Uranium) reactor is a heavy water cooled and moderated reactor that burns natural uranium. Heavy water is required due to the low concentration of fissile U235 found in natural uranium. These reactors, like all water cooled and moderated reactors have a negative void coefficient - as the coolant temperature increases the nuclear reaction rate decreases. These aren't quite walkaway reactors, but they have an imporant safeguard built into the very mechanism that allows the nuclear reaction to occur.
The negative void coefficient safeguard is also inherent to the light water reactors that are the predominant source of nuclear power in much of the world, these include pressurized and boiling water reactors which use normal water as a coolant with slightly enriched uranium 5% U235.
The reactor that exploded at Chernobyll was of the RBMK design. The RBMK has a positive void coefficient. As the coolant increases in temperature the reaction rate rapidly increases. This is an inherent instability in the design of the reactor making huge power increases possible from an initially low power state, producing an immense feedback response. That, combined with a number of other safety shortcuts like the lack of a proper containment structure, allowed the Chernobyll disaster to happen.
Comparing the RBMK to a water moderated reactor is like comparing Vaseline to Napalm. Both are petroleum products but the similarity stops there. The reactor designs in use throughout the world are orders of magnitude safer than the RBMKs that the Soviets built, they're cheap, but definitely not inherently safe.
If you don't have a well established grid in place a PBMR is a good choice. The concept was meant for countries like China with very little infrastructure in a lot of place and rapidly rising demands for electricity. China is also heavily pursuing the much higher output Gigawatt scale nuclear plants that are currently used throughout the Western world as well as other parts of Asia in the areas that do have an existing distribution network.
PBMRs are only cost effective to a point. You wouldn't want to power a city the size of Beijing with PBMRs, it would be far more cost effective to build two or three 1100 MWe plants instead.
Hydrogen will rapidly diffuse through just about any material, even things that are very "solid" looking like glass or metal. The size of the molecules in question plays a significant role in determine how quickly a given material will move through another material. This phenomenon causes all manner of problems in a wide range of areas where hydrogen isn't welcome. Welding and hydrogen embrittlement being an especially good example. Hydrogen is also very reactive, forming hydrides with most metals. These hydrides weaken the microstructure of their host materials, reducing their ductility and toughness and making them less safe/suitable for storing high pressure gas.
I'm assuming that you're talking about last August's outage in the northeastern U.S. and Canada. If so that outage resulted from a failure in the distribution network, not from a lack of generating capacity. Your area of Michigan was not affected because it wasn't on the same grid as the areas that were affected. Parts of Manhattan were entirely dark while just across the river Jersey was fully lit. At least twenty of the powerplants in that region had to shutdown because of the outage since they had nowhere to dump their output because the grid had failed.
Fossil plants generally do load-follow production and change their output levels to match demand. Nuclear plants tend to run best at constant power levels for a variety of reasons, but it ultimately comes down to a cost/benefit analysis. In many places you'll find nuclear plants alongside man-made lakes fitted with hydroelectric generators. At night the excess electricity from the nuclear station is used to pump water into the lake, converting electrical energy into potential energy. During the daytime this potential energy is converted back into electricity by the hydro plant to help even out the load and meet peak demands.
This isn't a hard and fast rule for nuclear plants, rather it depends on the market and the fuel management strategies being used by the utility. For instance many French nuclear stations do use load-follow generating strategies, the operating strategies in France are sufficiently different such that load-follow there is cost effective for the way they operate their plants.
Buy any commodity in bulk and you'll get a better per-unit rate than if you're buying smaller chunks. It's easier (and thus more profitable) to sell larger chunks of something, particularly once the production cost is fixed.
Those bulk customers are also exchanging a level of service for cheaper rates. In the event of a power outtage higher rate customers like residences get priority for service restoration.
The price that electricity is sold for is only partially tied to the generating cost. There's a lot of overhead in terms of distribution networks, emergency services, customer support and front office stuff that you pay for as well. Large users of electricity use a smaller share of the overhead resources and thus their rates are closer to the generating cost since the overhead costs can be amortized across a much larger amount of kw-hrs.
The payoff time is very long... after a couple of decades you'll be beating the power company, but there's a hell of a lot better way to invest your money :-)
For comparison purposes a typical power plant will produce on the order of 1000 Megawatts (some are more, some are less but that's a good ballpark). Such a solar panel clad building would produce a fair amount of electricity for a solar application, but it's still a miniscule amount compared to the power demands of even a small city.
My electricity runs about $0.08 per kilowatt-hour. A 1 square foot panel would produce 3.8 Watts X 8 hours (assuming 8 good hours of sunlight) or ~ .03 kW-hr at a cost of $45, which works out to $1500 per kilowatt hour. Cheap for solar, owing to the higher efficiency of the panels, but dismal by commercial generation.
Let's take a super-skyscraper, assuming a 200' square base that's as high as the Sears tower (roughly 1450' to the roof top). Assuming the building maintains its rectangular cross section from the ground to the top gives us an area of 1.16 million square feet which would generate ~4.4 megwatts of electricity, which is a lot of electricity.
The article calls out a price of $45 per square foot, making the solar panels for such a building cost about $52 million dollars. Surprisingly cheap for that much electrical capacity, though the usage factor would be pretty low, what with it being dark at night and all.
The production and extraction of plutonium uses a very different type of reactor than the Pressurized Water Reactors that are used for power generation in much of the world. A lot of the waste at Hanford isn't due to the reactor operation per se, but rather the chemical extractions that are necessary to recover the plutonium. These extractive processes generate a lot of waste chemicals (like acids that have been used to dissolve fuel) that are contaminated with hot particles. That's the origin of the liquid radioactive waste at Hanford.
Waste from a PWR is solid and it predominantly consists of used or burned fuel assemblies that are still radioactive but no longer capable of producing electricity efficiently. The fuel assemblies contain the fuel rods which encapsulate the fuel pellets and the daughter products of the fission reaction (various isotopes of noble gases trapped in the fuel rods).
The mass of waste produced by a nuclear plant in a given year of operation is miniscule compared to the thousands of tons of ash, soot, and greenhouse gases emitted by your typical coal plant with a similar electrical output.
There were two plutonium implosion devices and one enriched uranium gun-type device. The Trinity device was a plutonium implosion bomb. Hiroshima was the gun-type Little Boy, Nagasaki was the second plutonium implosion device, called Fat Man. The implosion device was a much more complicated and efficient weapon, but the U.S. had to be sure it would work, hence the test at Trinity.
Just like the Germans that bombed Pearl Harbor.
Amendment IV
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
Your credit card and medical information can easily be argued to be your "papers and effects." Privacy is one of the few rights that is specifically defined by the Constitution.
Real is a lot like a super-dense star: both will eventually suck so hard that they destroy everything around them immediately prior to collapsing into a blackhole from which no useful information can ever escape.