Yes you can. A long and slow process maybe, but you can prove mathematically that computer code performs the correct functions. So if you can put down the developer's intent in a suitable form then you can prove the code achieves those aims. Things like formal methods are used for this purpose.
I've seen red-light cameras go here in the uk - but very rarely and due to idiots. I've seen plenty of junctions where I wish they had them because people repeatedly run the red lights. I don't think they have slowed the yellow light time down in the UK, which seems to be the biggest grievance. That's like putting speed cameras in that trigger below the proscribed limit...
Not that I condone drink driving, but if you applied that kind of punishment to every example of ignorant and dangerous driving out there you wouldn't have many people left on the roads. Perhaps the punishment isn't harsh enough, but the 'life/death sentence for everything' is obviously flawed. I know someone who got caught (UK) drink driving, he got a two year ban and a fine. If he gets caught again he's got a prison sentence, 10 year ban, etc. etc. Enough to really destroy the life of any normal person. It doesn't justify the first time, but I can assure you he'll _never_ do it again because he has too much to lose. If they'd locked him up the first time (and they would have done if it was a more serious case or if there was an accident) then what have we gained? One more prisoner and one less productive member of society.
The cost overruns are due to the legal complications with every person who misunderstood physics lessons 30 years ago becoming an expert and taking everyone and sundry to court. In some parts of the world reactors are being built ahead of schedule. It's not construction, it's courts that cause delays.
So you make sure that the code is tied to the transaction amount and destination account and other details. In the UK (and presumably other bits of Europe) we have card readers that are a separate device about the size of a pocket calculator. When you make an online banking transaction - usually if it's to an account you've never paid money to before - it will ask you to enter some part of the account number and the amount into the card reader (as well as your PIN). It gives back an authorisation code, which I presume is a signed hash of the provided details.
Unless there's a flaw in the encryption used by the cards that would allow you to sign transactions then it seems pretty safe to me. It satisfies the something you know (PIN) and something you have (card). The only way I can see someone getting in the middle is if people don't know that the numbers you put into the card reader should match your transaction: If they blindly type what they are told I can see a man-in-the-middle scenario. I'm fairly happy that it's a good system. I'm sure due to some idiot design decision it will be broken in the future, but for now it seems pretty secure to me.
I thought they did do infrastructure tests using reactor 'cores' that were basically big electrical heaters. They'd test the critical systems and scale up to the full size plant.
It's not the pro-nuclear group that's the problem. Most pro-nuclear people want to see newer plants built, research into better designs etc. The second group should be politicians, who pander to the first group by not building new plants, and pander to everyone else by not having to courage of their convictions to turn the existing ones off and deal with the consequences. Germany is now the exception to this (ironically due to Frau Flip-Flop Merkell), let's see what happens there...
I think that was the point - 'functional programming is popular because it's easy to verify functional programs'. Writing in one of these languages means that you can prove the correctness of the code, presumably automatically, so presumably very quickly.
Is this an automated account or an actual person? Either way, promoting nutrition and exercise to geeks? Methinks your efforts are wasted - the ones (few?) that do exercise and eat healthily probably already know more about it than the average personal trainer/nutritionist, and the rest aren't going to care. Even then, the clickthrough rate from slashdot has got to be 0?
Why do you think the risk is so great? There are plenty of people who moved back to their homes in the zone of alienation that, contrary to popular expectations, don't seem to be dying too fast.
Presumably because you have some static running costs that aren't particularly dependent on the amount of power being generated (wear and tear etc.) so as you generate less electricity the cost of each Watt-hour of electricity increases. There's going to be a point where the amount you can sell the electricity for is less than the amount it cost you to make it, hence it is not economical to run the plant at decreased capacity - and there's probably a point where you lose less by stopping production altogether.
When they went around looking for plutonium they found 5 samples with it, two or three were attributed to Fukushima Daiichi, and the others to plutonium that was in the soil from atmospheric weapons testing. Why do you think all these food regulators seem to be prepared to measure the isotopes present in foodstuffs? Because they do it all the time - that's why there are limits - it's a part of the world we live in. I take it you don't eat bananas or brazil nuts? Radiation is everywhere, and the limits for consumption are very low, so when something is regarded as safe, it probably is. The irrational fear that any exposure to any ionizing radiation will definitely cause you cancer and you will die horribly is more harmful than the radiation itself.
That's quite a lot of activity. Which when you have people shouting 'One single piece of ionizing radiation can cause mutations that lead to cancer, we should ban everything nuclear' makes me think that we should all be dead already. It's almost like it's not as bad as those people make out...
How is it locked down? AFAIK Firewire devices have by default complete access to system memory - it's probably the nicest way to use the windows kernel debugger. It's a shame that the linux firewire kernel debug seems to be unsupported, but I digress. The _proper_ way to secure DMA from any device is with an IOMMU that would only allow DMA access to approved memory sections from specified devices. Then you at least push the security problem to software running on the host - so long as nothing opens up a DMA accessible window to a sensitive memory location you are safe.
All the fuel that's been in a reactor for a while contains plutonium. Towards the end of the fuel cycle it is providing most of the power. This whole 'it's MOX it's got plutonium, it's even more super-duper-extra-nasty' thing seems a red herring to me. It's a useful way of using up atomic weapons material at the presumed cost of having to change the fuel more often (because you aren't getting the initial energy from the uranium fission).
The concept that fuel rods were discovered two miles away from the plant and not reported by the media is preposterous. An event of that significance could not be downplayed, and is far too big a story for the media to let go. Given the wild and sensationalist reporting that surrounds anything nuclear it seems rather odd that they'd suddenly decide to ignore or cover up something that significant.
If there were fuel rod fragments thrown 2 miles away, then there should be a lot more a lot closer to the plant. There should also be some pretty large chunks of reactor pressure vessel lying around. I don't imagine 5 inch thick steel disintegrates that easily, you'd think there'd be the odd chunk of reactor pressure vessel lid lying around if it let go. If the reactor fuel had been ejected then surely the nuclide analyses from the area would show the presence of elements and isotopes that would normally remain contained within the fuel rods?
This is probably the most closely covered Nuclear incident in history, and the idea that there is a cover-up of the scale required to hide an explosion that breached the pressure vessel and ejected fuel rods over a two mile area is probably one of the more outlandish conspiracy theories that I have heard in a long time. If there really was that much fuel released then now, several weeks later, someone would have found inexplicable traces of it, whether in the US or mainland Asia.
Yes. I ride a motorcycle, I used to smoke, I go rock climbing and snowboarding. I drink too much, eat too much red meat, don't get enough exercise and many other things that mean the risk to me from a trace amount of radioactive material in my food is negligible. I don't particularly like bananas though, so I've probably got some slack in my radioactive intake compared to the average (just a guess). They do actually test the plants before letting people eat them, and out of all the things they've tested they've found the vast majority to be safe. I worked over the summer in a grain store once, part of the job was making sure we had the right numbers - things like protein, moisture etc. in the grain for sale. You also had things like ergot. Some loads would come in outside the accepted level for these various things, so you'd juggle a few tens of thousands of grain around and dilute the bad stuff amongst the good. You mix that spinach that's at twice the 'safe' limit (numbers pulled out of the air) with two parts spinach well below the safe limit and you no longer have 'unsafe' spinach. People get annoyed about the dilution idea, but the reality is that there is already radioactive material in so many things, that you can't avoid it. You and me both contain radioactive isotopes - how does carbon dating work? So long as you aren't exposing yourself to a dangerous level then what's the problem?
I'm not sure that Sellafield counts as monitored and controlled - there are certainly bits of it that aren't safe. It, like many other sites that were used in the glory days of the quest for atomic weapons, has many areas that contain undocumented and unknown materials. Like this: http://en.wikipedia.org/wiki/Sellafield#Dirty_Thirty The Fukushima workers haven't been in the reactor buildings, I'd hazard a guess that it will be the long slow cleanup that runs the greatest risk of exposure for workers, just as the long, slow cleanup of Sellafield does. See also http://news.bbc.co.uk/1/hi/business/7773593.stm It's pretty shameful, but I'd hazard a guess that there are a lot of industrial (non-nuclear) sites that are as dangerous to the environment and those who are trying to clean them up.
Well, next time you're in or near a crowd of idiots I hope you have a plan for making them aware of their stupidity in case anything bad happens. There's an element of pragmatism here - people are not educated and it is difficult to educate them in the midst of a disaster. For every one of you standing on your chair asking people to politely remain calm and exit patiently there are a hundred people panicking, screaming that everyone is already dead and that Satan himself is holding the doors closed. But hey, they're stupid people, let them whip themselves up into a frenzy and cause their own short sighted downfall, you couldn't possibly be affected.
Since all those official reports are readily available on the websites of the organizations that produce them, could you provide a link? All I could find was a few forums that seemed to have fairly limited technical content.
Scary as it seems, meltdown is one of the failure mechanisms. It's a fair way down the list, and it makes for some tricky cleaning up, but the reactors are designed with meltdown as a failure mode. TMI melted down remained contained within the pressure vessel, as did the cores at Fukushima. Also I'd like to see the manually operated valve for a system that pushes the amount of water needed to dissipate 2MW of heat - I guess you'd need a pretty big wrench. We should build more modern designs with passive emergency cooling systems, but people keep opposing new Nuclear plants. Shutting down the old ones doesn't happen, apparently we need that electricity, so what we end up with is 40 year old plants having their lives extended rather than safer newer plants.
I thought the detected amounts of plutonium were no higher than the amount they expected to find. I seem to recall 5 samples being analysed, and only two of them being linked to Fukushima Daiichi - the rest being from atmospheric nuclear weapons testing. Or in other words, there is no more a plutonium 'problem' now than there was before the tsunami.
'Burn' is quite commonly used regarding nuclear power generation to describe the mechanism by which fuel is consumed. Maybe it's not the _best_ word to use but it doesn't strike me as a particularly unreasonable or misleading term. Also you do know that every reactor there will have plutonium in its fuel? It might have been put in the fuel for Reactor 3 to start with, but it will have been generated in every other reactor as part of the standard operation. Towards the end of their useful lives _all_ fuel rods will be releasing more energy from plutonium than from uranium. Fast breeders were mainly used for weapon production because they will produce Plutonium faster than they consume it (hence 'breeder'). That plutonium can then be extracted. Or it can be 'burnt' in a conventional nuclear reactor (or presumable the same reactor. A normal reactor makes use of a tiny proportion of the uranium in the fuel. A fast breeder makes use of nearly all of it, so producing a lot less waste. The molten salt reactor designs - of which experimental models have been built - can 'burn' all the actinides with a 10^2 - 10^5 scale half life. That means the resulting waste is a much smaller radiological problem - the stuff with 100,000+ year half lives is pretty much inert for practical purposes, and the stuff with 100 year half lives is not so hard to deal with.
Is that including the thyroid cases, that whilst terrible for those affected, are cured with a very high success rate? Didn't that same organisation state that the psychological impact of the disaster (caused by thinks like forcing people out of their homes and letting ignorant hysteria lead them to believe that their lives were blighted by radiation) was far more significant than any radiation related health effects?
I thought that the radiation levels measured were pretty damn low almost everywhere except Litate village. 4 micro sievert an hour is approx 35 milli sieverts a year. That's quite high, but significanty less than places like Ramsart in IRan which read up to 260 milli sieverts a year without noticeable effects. That's just over 4 years living in Cornwall. Once the plant is stable and there is no risk of significant further releases then there will be no need for an evacuation zone. Maybe people will have to be a bit careful about eating a lot of dirt - perhaps farming will have to be restricted, it will definitely be monitored. The scenarios in which there remains an evacuation zone in more than a couple of years are either due to a further significant problem at the Daiichi plant, or because of irrationaly hysteria about trace amounts of radiation that are statistically insignificant.
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Yes you can. A long and slow process maybe, but you can prove mathematically that computer code performs the correct functions. So if you can put down the developer's intent in a suitable form then you can prove the code achieves those aims. Things like formal methods are used for this purpose.
I've seen red-light cameras go here in the uk - but very rarely and due to idiots. I've seen plenty of junctions where I wish they had them because people repeatedly run the red lights. I don't think they have slowed the yellow light time down in the UK, which seems to be the biggest grievance. That's like putting speed cameras in that trigger below the proscribed limit...
Not that I condone drink driving, but if you applied that kind of punishment to every example of ignorant and dangerous driving out there you wouldn't have many people left on the roads. Perhaps the punishment isn't harsh enough, but the 'life/death sentence for everything' is obviously flawed. I know someone who got caught (UK) drink driving, he got a two year ban and a fine. If he gets caught again he's got a prison sentence, 10 year ban, etc. etc. Enough to really destroy the life of any normal person. It doesn't justify the first time, but I can assure you he'll _never_ do it again because he has too much to lose. If they'd locked him up the first time (and they would have done if it was a more serious case or if there was an accident) then what have we gained? One more prisoner and one less productive member of society.
The cost overruns are due to the legal complications with every person who misunderstood physics lessons 30 years ago becoming an expert and taking everyone and sundry to court. In some parts of the world reactors are being built ahead of schedule. It's not construction, it's courts that cause delays.
So you make sure that the code is tied to the transaction amount and destination account and other details. In the UK (and presumably other bits of Europe) we have card readers that are a separate device about the size of a pocket calculator. When you make an online banking transaction - usually if it's to an account you've never paid money to before - it will ask you to enter some part of the account number and the amount into the card reader (as well as your PIN). It gives back an authorisation code, which I presume is a signed hash of the provided details.
Unless there's a flaw in the encryption used by the cards that would allow you to sign transactions then it seems pretty safe to me. It satisfies the something you know (PIN) and something you have (card). The only way I can see someone getting in the middle is if people don't know that the numbers you put into the card reader should match your transaction: If they blindly type what they are told I can see a man-in-the-middle scenario. I'm fairly happy that it's a good system. I'm sure due to some idiot design decision it will be broken in the future, but for now it seems pretty secure to me.
I thought they did do infrastructure tests using reactor 'cores' that were basically big electrical heaters. They'd test the critical systems and scale up to the full size plant.
It's not the pro-nuclear group that's the problem. Most pro-nuclear people want to see newer plants built, research into better designs etc. The second group should be politicians, who pander to the first group by not building new plants, and pander to everyone else by not having to courage of their convictions to turn the existing ones off and deal with the consequences. Germany is now the exception to this (ironically due to Frau Flip-Flop Merkell), let's see what happens there...
I think that was the point - 'functional programming is popular because it's easy to verify functional programs'. Writing in one of these languages means that you can prove the correctness of the code, presumably automatically, so presumably very quickly.
Is this an automated account or an actual person? Either way, promoting nutrition and exercise to geeks? Methinks your efforts are wasted - the ones (few?) that do exercise and eat healthily probably already know more about it than the average personal trainer/nutritionist, and the rest aren't going to care. Even then, the clickthrough rate from slashdot has got to be 0?
Why do you think the risk is so great? There are plenty of people who moved back to their homes in the zone of alienation that, contrary to popular expectations, don't seem to be dying too fast.
Presumably because you have some static running costs that aren't particularly dependent on the amount of power being generated (wear and tear etc.) so as you generate less electricity the cost of each Watt-hour of electricity increases. There's going to be a point where the amount you can sell the electricity for is less than the amount it cost you to make it, hence it is not economical to run the plant at decreased capacity - and there's probably a point where you lose less by stopping production altogether.
When they went around looking for plutonium they found 5 samples with it, two or three were attributed to Fukushima Daiichi, and the others to plutonium that was in the soil from atmospheric weapons testing. Why do you think all these food regulators seem to be prepared to measure the isotopes present in foodstuffs? Because they do it all the time - that's why there are limits - it's a part of the world we live in. I take it you don't eat bananas or brazil nuts? Radiation is everywhere, and the limits for consumption are very low, so when something is regarded as safe, it probably is. The irrational fear that any exposure to any ionizing radiation will definitely cause you cancer and you will die horribly is more harmful than the radiation itself.
That's quite a lot of activity. Which when you have people shouting 'One single piece of ionizing radiation can cause mutations that lead to cancer, we should ban everything nuclear' makes me think that we should all be dead already. It's almost like it's not as bad as those people make out...
How is it locked down? AFAIK Firewire devices have by default complete access to system memory - it's probably the nicest way to use the windows kernel debugger. It's a shame that the linux firewire kernel debug seems to be unsupported, but I digress. The _proper_ way to secure DMA from any device is with an IOMMU that would only allow DMA access to approved memory sections from specified devices. Then you at least push the security problem to software running on the host - so long as nothing opens up a DMA accessible window to a sensitive memory location you are safe.
All the fuel that's been in a reactor for a while contains plutonium. Towards the end of the fuel cycle it is providing most of the power. This whole 'it's MOX it's got plutonium, it's even more super-duper-extra-nasty' thing seems a red herring to me. It's a useful way of using up atomic weapons material at the presumed cost of having to change the fuel more often (because you aren't getting the initial energy from the uranium fission).
The concept that fuel rods were discovered two miles away from the plant and not reported by the media is preposterous. An event of that significance could not be downplayed, and is far too big a story for the media to let go. Given the wild and sensationalist reporting that surrounds anything nuclear it seems rather odd that they'd suddenly decide to ignore or cover up something that significant.
If there were fuel rod fragments thrown 2 miles away, then there should be a lot more a lot closer to the plant. There should also be some pretty large chunks of reactor pressure vessel lying around. I don't imagine 5 inch thick steel disintegrates that easily, you'd think there'd be the odd chunk of reactor pressure vessel lid lying around if it let go. If the reactor fuel had been ejected then surely the nuclide analyses from the area would show the presence of elements and isotopes that would normally remain contained within the fuel rods?
This is probably the most closely covered Nuclear incident in history, and the idea that there is a cover-up of the scale required to hide an explosion that breached the pressure vessel and ejected fuel rods over a two mile area is probably one of the more outlandish conspiracy theories that I have heard in a long time. If there really was that much fuel released then now, several weeks later, someone would have found inexplicable traces of it, whether in the US or mainland Asia.
Yes. I ride a motorcycle, I used to smoke, I go rock climbing and snowboarding. I drink too much, eat too much red meat, don't get enough exercise and many other things that mean the risk to me from a trace amount of radioactive material in my food is negligible. I don't particularly like bananas though, so I've probably got some slack in my radioactive intake compared to the average (just a guess). They do actually test the plants before letting people eat them, and out of all the things they've tested they've found the vast majority to be safe. I worked over the summer in a grain store once, part of the job was making sure we had the right numbers - things like protein, moisture etc. in the grain for sale. You also had things like ergot. Some loads would come in outside the accepted level for these various things, so you'd juggle a few tens of thousands of grain around and dilute the bad stuff amongst the good. You mix that spinach that's at twice the 'safe' limit (numbers pulled out of the air) with two parts spinach well below the safe limit and you no longer have 'unsafe' spinach. People get annoyed about the dilution idea, but the reality is that there is already radioactive material in so many things, that you can't avoid it. You and me both contain radioactive isotopes - how does carbon dating work? So long as you aren't exposing yourself to a dangerous level then what's the problem?
I'm not sure that Sellafield counts as monitored and controlled - there are certainly bits of it that aren't safe. It, like many other sites that were used in the glory days of the quest for atomic weapons, has many areas that contain undocumented and unknown materials. Like this: http://en.wikipedia.org/wiki/Sellafield#Dirty_Thirty The Fukushima workers haven't been in the reactor buildings, I'd hazard a guess that it will be the long slow cleanup that runs the greatest risk of exposure for workers, just as the long, slow cleanup of Sellafield does. See also http://news.bbc.co.uk/1/hi/business/7773593.stm It's pretty shameful, but I'd hazard a guess that there are a lot of industrial (non-nuclear) sites that are as dangerous to the environment and those who are trying to clean them up.
Well, next time you're in or near a crowd of idiots I hope you have a plan for making them aware of their stupidity in case anything bad happens. There's an element of pragmatism here - people are not educated and it is difficult to educate them in the midst of a disaster. For every one of you standing on your chair asking people to politely remain calm and exit patiently there are a hundred people panicking, screaming that everyone is already dead and that Satan himself is holding the doors closed. But hey, they're stupid people, let them whip themselves up into a frenzy and cause their own short sighted downfall, you couldn't possibly be affected.
Since all those official reports are readily available on the websites of the organizations that produce them, could you provide a link? All I could find was a few forums that seemed to have fairly limited technical content.
Scary as it seems, meltdown is one of the failure mechanisms. It's a fair way down the list, and it makes for some tricky cleaning up, but the reactors are designed with meltdown as a failure mode. TMI melted down remained contained within the pressure vessel, as did the cores at Fukushima. Also I'd like to see the manually operated valve for a system that pushes the amount of water needed to dissipate 2MW of heat - I guess you'd need a pretty big wrench. We should build more modern designs with passive emergency cooling systems, but people keep opposing new Nuclear plants. Shutting down the old ones doesn't happen, apparently we need that electricity, so what we end up with is 40 year old plants having their lives extended rather than safer newer plants.
I thought the detected amounts of plutonium were no higher than the amount they expected to find. I seem to recall 5 samples being analysed, and only two of them being linked to Fukushima Daiichi - the rest being from atmospheric nuclear weapons testing. Or in other words, there is no more a plutonium 'problem' now than there was before the tsunami.
'Burn' is quite commonly used regarding nuclear power generation to describe the mechanism by which fuel is consumed. Maybe it's not the _best_ word to use but it doesn't strike me as a particularly unreasonable or misleading term. Also you do know that every reactor there will have plutonium in its fuel? It might have been put in the fuel for Reactor 3 to start with, but it will have been generated in every other reactor as part of the standard operation. Towards the end of their useful lives _all_ fuel rods will be releasing more energy from plutonium than from uranium. Fast breeders were mainly used for weapon production because they will produce Plutonium faster than they consume it (hence 'breeder'). That plutonium can then be extracted. Or it can be 'burnt' in a conventional nuclear reactor (or presumable the same reactor. A normal reactor makes use of a tiny proportion of the uranium in the fuel. A fast breeder makes use of nearly all of it, so producing a lot less waste. The molten salt reactor designs - of which experimental models have been built - can 'burn' all the actinides with a 10^2 - 10^5 scale half life. That means the resulting waste is a much smaller radiological problem - the stuff with 100,000+ year half lives is pretty much inert for practical purposes, and the stuff with 100 year half lives is not so hard to deal with.
Is that including the thyroid cases, that whilst terrible for those affected, are cured with a very high success rate? Didn't that same organisation state that the psychological impact of the disaster (caused by thinks like forcing people out of their homes and letting ignorant hysteria lead them to believe that their lives were blighted by radiation) was far more significant than any radiation related health effects?
I thought that the radiation levels measured were pretty damn low almost everywhere except Litate village. 4 micro sievert an hour is approx 35 milli sieverts a year. That's quite high, but significanty less than places like Ramsart in IRan which read up to 260 milli sieverts a year without noticeable effects. That's just over 4 years living in Cornwall. Once the plant is stable and there is no risk of significant further releases then there will be no need for an evacuation zone. Maybe people will have to be a bit careful about eating a lot of dirt - perhaps farming will have to be restricted, it will definitely be monitored. The scenarios in which there remains an evacuation zone in more than a couple of years are either due to a further significant problem at the Daiichi plant, or because of irrationaly hysteria about trace amounts of radiation that are statistically insignificant.
I presume the US is like everyone else - eight fingers and two thumbs. Excepting Norfolk, of course...