Well, since car parts have been manufactured for decades now to break down..
No they haven't. Any metallurgist will tell you that current life times on modern cars is pretty dam close to miraculous. think you need a new tin foil hat.. Hay perhaps the guy making your hats designed it to break down....
The guns i own, or more accurately rifles. Are indeed made for one purpose. Hunting game. They are in fact not great at other roles, such has home defense.
In NZ we have a lot of introduced animals and the conservation groups are begging us to hunt more.
There are plenty of reasonable reasons for personal gun ownership.
You know other countries provide such things for free or so close to free and have had no problems. Medical tests are even designed that way. If you test positive to the first test your still 99% sure to be clear. The much more expensive test is then carried out. Doing just the expensive test on 100% of the relevant population would be stupid and expensive.
Just because it can be understood, does not mean it can be re implemented. Or that you can be improved or remapped or whatever. It is quite easy to come up with a physical system that is impossible to copy/clone perfectly.
How many accidents are the result of some sort of mechanical failure? Hint its much more than none. It has in fact killed people. We have court cases on it. One case i know of, a tire blowout resulted in a head on crash with 4 killed and only one survivor. The court case cleared the survivor (driver of the car with the blowout). I personally had the breaks fail on my car, and narrowly missed getting t boned by a truck.
I'm probably only an average driver, but it's hard to judge.
your probably a fairly good driver in that as least your objective about your own abilities and your abilities to judge them. So many just assume they are awesome drivers and its everyone else that is bad... no mater how many accidents they get into.
Your a fool if you think there is anything about driving that can't be replicated by a machine. Only better. With response times 1000x faster a machine can work out the conditions its driving far faster and with more accuracy than any human. Doesn't get tired, angry, drunk or in a otherwise emotionally compromised state. Can have far better sensor coverage, with more redundancy. Recover and adapt to mechanical failure and changes better and just otherwise make humans look like the bad drivers we are.
There is a reason traction control and such is banned from F1 racing. It was because then its no longer human vers human. There is also a reason why the best drivers in the world *use* such computer aided driving.
And that doesn't make the "10 Katrina per year" any more credible. Like i said. Read what the scientists say. Not what some Hollywood disaster move plot.
Who said anything about not doing something about it? Did you reply to the right post? I was addressing the "HUNDREDS or THOUSANDS of years" factoid. Which is wrong.
Well the ocean fisheries, as far as we can tell. Are decimated. Stocks that are no longer fished are not recovering. We don't know if they can. But the data at this point suggests they can't recover. Ocean fish will not last our lifetime.
Run the numbers. The heat flow is so stupidly low, that geothermal power uses hot rocks that *cool* down since the heat from below cannot flow fast enough. The geothermal heat from under our feet is something like 1W/m2. Its tiny.
Every geothermal plant has a steady reduction in heat after opening. It is not sustainable on terms of decades and useful power densities.
However geothermal is based on stored heat in rocks. That stored heat is good a few decades at best. Try and at least run the numbers. If you don't believe that BOTE calculation, do your own.
Turns out that isotope separation (through mass difference) is easy or hard based on absolute difference of the isotopes, not the ratio. That is Tritium enrichment from hydrogen (2au) is harder than 235U from 238U (3au)! Or more to the point UF_6 with only 3au mass difference. However the real hard part is how dilute it is in the first place. This makes it much harder. 235U is.7% of naturally occurring uranium. Compared to the amounts of tritium everyone jumps up and down about this is much more dilute by many orders of magnitude. This is what makes it really hard.
There is this false belief that LFTR is some magical totally safe fixes all things wrong with nuclear.
This is quite false.
Lets start with the basics. 232Th is fertile and is not a fuel. It absorbs a neutron to become 233Pa which, appart from being a neutron poison, decays after about 26 days into 233U which is the fuel in a Thorium fuel cycle. So now if we compare with a U fuel cycle we can only do so with a reprocessing fuel cycle, not as is often done with a once through cycle which Th can't even do. Note that with reprocessing the waste stream is reduced by about a factor of 65. Also fuel usage goes up by about the same factor.
Now note we are burning 233U rather than 235U in a traditional reactor. Turns out that is about the same in terms of fission products they are about the same from a waste management perspective. Of course you get less actinides since there isn't all this U238 sitting around causing problems. However its not the same as none, and actinides can be dealt with in a reprocessing cycle.
Because we are dealing with plain old Uranium fission we have all the same issue. We have decay heat. That is turn it off and the fuel still produces significant amount of heat for some time. So you still get all the same issues if you can't maintain cooling after a scram with Th fuel cycles as with U fuel cycles. Sure you can have passive systems. That doesn't mean they work when you need them too. There is more than enough decay heat to melt significant amounts of concrete.
For the same reason as above any core breach (you don't get to plan these btw). Would also be similar to traditional PWR core breach. It could even be worse since many designs have graphite moderators which would burn on exposure to water or air.
Now we come to the implementation issues. Th breeding ratios are marginal at best. A breeding ratio of 1 has never been shown. The theoretical models and numerical results seem to show it can be done. But its very close and is a show stopper if can't be managed. Note that the only MSRs ever run did not do any breeding whatsoever. This creates a very tight neutron economy and makes design more difficult and even more expensive. Even small traces of some elements in the materials used would simply mean they don't work as a complete fuel cycle.
The only big advantage of these things is the MSR part.ie molten salt. This is part of a larger class of reactor called homogenous reactors where the primary coolant is also the fuel. There are quite a few nice features with this type of reactor, but none of it has anything to do with Th and using U reprocessed fuel cycles look basically the same. The features include negative void/thermal coefficients (boiling/hotter slows down the reaction), potentially simpler passive cooling and scram systems (but these exist for PWR too...), load following (quick power response). Not under pressure. No fuel elements to compromise. None of these things has anything to do with Th.
But its not all pancakes and picnics. In particular the salts are either reactive with water (fluorides) or soluble in water (chlorides). Fluorides are pretty corrosive and that restricts material choice. The neutron economy makes this even more difficult. Any off design issue can cause serious problems just like at a pwr. And don't start with the "it can't happen in this design". That is what they said about pebble bed reactors. See the prototype for how well that turned out!
And last but not least we have particular issues related to just Th. MSR was suggested to overcome the many problems that Th fuel cycle has. But it doen't remove them. The neutron economy issues are mitigated with constant reprocessing and pulling out the 233Pa. You still get some 234Pa and so you still get 234U which is a nasty gamma emitter. Its so nasty that Th proponents claim that prevents or inhibi
This is being done.. sort of in england. The problem is that the oceans only turn over on very long time scales. On the order of a 1000 years or so. So your not mixing it with the ocean, but the local area, or at least a localized area which may or may not be that close to the dumping/dilution site.
There are other problems too. Some of the radioactive components bio accumulate. So that the waste is concentrated in the food chain.
Slashdot Mirror
you can't watch porn on a text terminal.
Its Spider Pig!
Well, since car parts have been manufactured for decades now to break down..
No they haven't. Any metallurgist will tell you that current life times on modern cars is pretty dam close to miraculous. think you need a new tin foil hat.. Hay perhaps the guy making your hats designed it to break down....
a grenade in an RPG is not much more complicated than a the tube either you know. The hard part is the chemistry.
I would like to see you print that!
Speak for yourself. I am now the proud owner of 1000s of tulips!
They are made to maim and kill people.
Wrong!
The guns i own, or more accurately rifles. Are indeed made for one purpose. Hunting game. They are in fact not great at other roles, such has home defense.
In NZ we have a lot of introduced animals and the conservation groups are begging us to hunt more.
There are plenty of reasonable reasons for personal gun ownership.
Armed to the teeth? I only have 5 rifles and one shotgun. I would like a few more. And cheaper ammo.
You know other countries provide such things for free or so close to free and have had no problems. Medical tests are even designed that way. If you test positive to the first test your still 99% sure to be clear. The much more expensive test is then carried out. Doing just the expensive test on 100% of the relevant population would be stupid and expensive.
I see no evidence that this would save any lives, unlike free mammograms. It would however have a lot of false positives, or not work at all.
Just because it can be understood, does not mean it can be re implemented. Or that you can be improved or remapped or whatever. It is quite easy to come up with a physical system that is impossible to copy/clone perfectly.
Right now its too early to say.
How many accidents are the result of some sort of mechanical failure? Hint its much more than none. It has in fact killed people. We have court cases on it. One case i know of, a tire blowout resulted in a head on crash with 4 killed and only one survivor. The court case cleared the survivor (driver of the car with the blowout). I personally had the breaks fail on my car, and narrowly missed getting t boned by a truck.
I'm probably only an average driver, but it's hard to judge.
your probably a fairly good driver in that as least your objective about your own abilities and your abilities to judge them. So many just assume they are awesome drivers and its everyone else that is bad... no mater how many accidents they get into.
If a human can drive in these conditions then why the hell can't a machine? The DARPA challenge was not on a road.
Humans, on the other hand, can see the sign warning of changed traffic pattern, and signs marking detours.
Why can't a machine see? I mean we have had passive optical sensors for some time now. They are called cameras.
Your a fool if you think there is anything about driving that can't be replicated by a machine. Only better. With response times 1000x faster a machine can work out the conditions its driving far faster and with more accuracy than any human. Doesn't get tired, angry, drunk or in a otherwise emotionally compromised state. Can have far better sensor coverage, with more redundancy. Recover and adapt to mechanical failure and changes better and just otherwise make humans look like the bad drivers we are.
There is a reason traction control and such is banned from F1 racing. It was because then its no longer human vers human. There is also a reason why the best drivers in the world *use* such computer aided driving.
Your not as good a driver as you think you are.
And that doesn't make the "10 Katrina per year" any more credible. Like i said. Read what the scientists say. Not what some Hollywood disaster move plot.
How do you imagine life on US east coast with 10 Katrina-class hurricanes every year?
You just pulled that out of a place where the sun don't shine.
Oh yea its AGW, we are all gonna die. Everyone is dooomed i tell you. The end is nigh.
What a pile of crap. Do yourself a favor and read what the scientist say and not headlines from tabloids.
Who said anything about not doing something about it? Did you reply to the right post? I was addressing the "HUNDREDS or THOUSANDS of years" factoid. Which is wrong.
Well the ocean fisheries, as far as we can tell. Are decimated. Stocks that are no longer fished are not recovering. We don't know if they can. But the data at this point suggests they can't recover. Ocean fish will not last our lifetime.
So I hope you like jellyfish.
Run the numbers. The heat flow is so stupidly low, that geothermal power uses hot rocks that *cool* down since the heat from below cannot flow fast enough. The geothermal heat from under our feet is something like 1W/m2. Its tiny.
Every geothermal plant has a steady reduction in heat after opening. It is not sustainable on terms of decades and useful power densities.
However geothermal is based on stored heat in rocks. That stored heat is good a few decades at best. Try and at least run the numbers. If you don't believe that BOTE calculation, do your own.
If you cared about ocean ecology, you wouldn't be eating fish anyway ;)
Turns out that isotope separation (through mass difference) is easy or hard based on absolute difference of the isotopes, not the ratio. That is Tritium enrichment from hydrogen (2au) is harder than 235U from 238U (3au)! Or more to the point UF_6 with only 3au mass difference. However the real hard part is how dilute it is in the first place. This makes it much harder. 235U is .7% of naturally occurring uranium. Compared to the amounts of tritium everyone jumps up and down about this is much more dilute by many orders of magnitude. This is what makes it really hard.
There is this false belief that LFTR is some magical totally safe fixes all things wrong with nuclear.
This is quite false.
Lets start with the basics. 232Th is fertile and is not a fuel. It absorbs a neutron to become 233Pa which, appart from being a neutron poison, decays after about 26 days into 233U which is the fuel in a Thorium fuel cycle. So now if we compare with a U fuel cycle we can only do so with a reprocessing fuel cycle, not as is often done with a once through cycle which Th can't even do. Note that with reprocessing the waste stream is reduced by about a factor of 65. Also fuel usage goes up by about the same factor.
Now note we are burning 233U rather than 235U in a traditional reactor. Turns out that is about the same in terms of fission products they are about the same from a waste management perspective. Of course you get less actinides since there isn't all this U238 sitting around causing problems. However its not the same as none, and actinides can be dealt with in a reprocessing cycle.
Because we are dealing with plain old Uranium fission we have all the same issue. We have decay heat. That is turn it off and the fuel still produces significant amount of heat for some time. So you still get all the same issues if you can't maintain cooling after a scram with Th fuel cycles as with U fuel cycles. Sure you can have passive systems. That doesn't mean they work when you need them too. There is more than enough decay heat to melt significant amounts of concrete.
For the same reason as above any core breach (you don't get to plan these btw). Would also be similar to traditional PWR core breach. It could even be worse since many designs have graphite moderators which would burn on exposure to water or air.
Now we come to the implementation issues. Th breeding ratios are marginal at best. A breeding ratio of 1 has never been shown. The theoretical models and numerical results seem to show it can be done. But its very close and is a show stopper if can't be managed. Note that the only MSRs ever run did not do any breeding whatsoever. This creates a very tight neutron economy and makes design more difficult and even more expensive. Even small traces of some elements in the materials used would simply mean they don't work as a complete fuel cycle.
The only big advantage of these things is the MSR part.ie molten salt. This is part of a larger class of reactor called homogenous reactors where the primary coolant is also the fuel. There are quite a few nice features with this type of reactor, but none of it has anything to do with Th and using U reprocessed fuel cycles look basically the same. The features include negative void/thermal coefficients (boiling/hotter slows down the reaction), potentially simpler passive cooling and scram systems (but these exist for PWR too...), load following (quick power response). Not under pressure. No fuel elements to compromise. None of these things has anything to do with Th.
But its not all pancakes and picnics. In particular the salts are either reactive with water (fluorides) or soluble in water (chlorides). Fluorides are pretty corrosive and that restricts material choice. The neutron economy makes this even more difficult. Any off design issue can cause serious problems just like at a pwr. And don't start with the "it can't happen in this design". That is what they said about pebble bed reactors. See the prototype for how well that turned out!
And last but not least we have particular issues related to just Th. MSR was suggested to overcome the many problems that Th fuel cycle has. But it doen't remove them. The neutron economy issues are mitigated with constant reprocessing and pulling out the 233Pa. You still get some 234Pa and so you still get 234U which is a nasty gamma emitter. Its so nasty that Th proponents claim that prevents or inhibi
This is being done.. sort of in england. The problem is that the oceans only turn over on very long time scales. On the order of a 1000 years or so. So your not mixing it with the ocean, but the local area, or at least a localized area which may or may not be that close to the dumping/dilution site.
There are other problems too. Some of the radioactive components bio accumulate. So that the waste is concentrated in the food chain.