It isn't practical to rapidly change the load on nuke reactors, because it takes a significant amount of time to ramp up and down power output.
It's a bit more complicated than that. In principle the power output of a reactor can be brought up and down very quickly. As you insert or remove control rods the amount of fission in the reactor can change within seconds. There is some decay heat to worry about, but in principle you can bring a reactor down by 94% or so within a few seconds, and similarly up again very quickly.
The problem is that doing so causes a whole lot of other challenges and problems. Firstly to maximise the lifetime of the nuclear fuel in the core and ensure that it burns at a reasonably homogeneous rate across the reactor, the neutron flow density is adjusted with special control rods and absorbers. This is difficult to do efficiently for a reactor running at constant power, and a major headache if you want to vary the power.
Secondly some of the the fission products act as neutron absorbers ( xenon in particular ) and thus the properties of the reactor core depend on what has happened to the reactor in the past. If you constantly change the reactor power you can end up with rather strange and counter-intuitive swings in the reactor's behavior, and these swings can be hard to model. It is just much easier to try to keep it running in something that at least to some degree resembles a steady state.
Thirdly varying the power of the reactor will cause changes in temperature in its components, and this leads to thermal stress. Since a nuclear reactor core is already one of the harshest environments there is from a materials point of view, including high temperatures, neutron embrittlement and corrosion effects from the coolant, you generally don't want to introduce any extra source of stress on the material as that would lower safety marginals.
So basically you probably could build a reactor to do load leveling, but it would considerably more difficult than a regular power plant, and it would likely cost a lot more.
Exercise, diet , makeup, hair removal, clothing, haircuts, healthcare, stress at work / school, sleeping habbits, alcohol , tobacco , dental care, etc...
People seriously underestimate how much of a person's appearance is due to lifestyle factors and how much time you are willing to put into it. Yes, there are genetic factors, but frankly there is a heck of a lot of it that can actually be described in terms of effort.
Which is a far worse argument than the one that has been used by many US opponents of net neutrality, e.i. "Google/youtube/etc. are using soooo much bandwidth we have to make them pay for itâ. Which is a bullshit argument, but easier to hide behind.
Part of the difference might be that european countries are far less forgiving when companies don't behave ( just look at the reaction when Microsoft failed to comply with EU competition law ), and the last thing a company wants is to piss off the people who have the authority to mess up your business.
Basically, because European governments are more willing to regulate corporate enterprises and penalize them when they do wrong, they have to be more honest because the possibility of getting a kick up the rear when they don't play nice is much more probable.
Much of the population growth is presently in poorer nations. In most richer nations, and particularly nations where men and women are seen as equals, the introduction of contraceptives have dramatically reduced population growth to the extent that many western nations would see no population growth at all if it was not for immigration.
In addition our agricultural methods at the moment are not optimized for maximum efficiency. If we would cut our consumption of meat and animal products down to healthy levels, and stop using arable land to feed livestock ( you could still let them graze on land unsuitable for crops ), then this would drastically reduce the amount of land required to feed our population.
Taking it even further the farming methods themselves can be greatly improved. Greenhouses, crop rotation and improved irrigation systems would dramatically increase agricultural yield while simultaneously reducing the need for fertilizers and pesticides.
This is before you even start to consider the controversy that is genetic engineering. While I'm not a fan of GM patents and monsanto's business practices, it is quite feasible to use GE to increase the nutritional value of various food crops.
The problem is that all of the above relies on governments doing their job responsibly, and electorates actually voting sensibly. Sadly we have a great deal of people opposed to contraceptives on religious grounds, inefficient farming subsidies that are little more than a bribe to buy support from the agricultural sector, lack of regulation of pesticides and food quality because "the free market will sort it out", and the ridiculous idea that obtaining a patent, even for living organisms like plants , is some form of inalienable right as opposed to a mere tool to stimulate innovation.
TL,DR: From a technical point of view the problem is easy to solve, but a bunch of moralizing and greedy fucktards are going to mess it up.
Well few other energy sources make an area completely unlivable for decades or centuries when they fail.
Sea level rise from global warming is expected to flood some densely populated areas. Increased temperatures will make some currently hospitable areas inhospitable, and turn land presently viable for agriculture worthless. These changes are likely to be irreversible for thousands of years at the very least, possibly indefinitely, and the problems occur globally, not just within the closest few kilometers of the power plants.
There is very little doubt that the cost of adapting to the consequences of our greenhouse gas emissions will vastly exceed even the worst outcome of nuclear accidents. Yes, that includes Chernobyl. You can't declare the entire world an exclusion zone when it's the global climate you're messing up.
Reprocessing produces more waste than what goes in.
It increases the volume of the waste because mass is added, but this is irrelevant to most storage schemes since it is heat generation, not volume, that limits repository capacity. If the extracted transuranics are used in a fast spectrum then the resulting waste will consist of mostly fission products that decay to safe levels much quicker than unprocessed waste. If the plutonium only is reused in a thermal spectrum ( as with LWR MOX fuel ) then more americium and curium will be produced, which is generally a bad thing.
You see, real safety, not mickey-mouse make believe duck-and-cover safety is much too expensive to the folks in the executive class
Back when the Fukishima style reactors were constructed not much attention were paid towards safety, and environmentalism was just getting started. That's why many reactors built back then have rubbish containments and unreliable cooling systems. In contrast at least a few of the designs currently suggested ( ESBWR , Advanced CANDU , ABWR, APR ) have dramatically higher quality containment structures and rely on natural convection during emergency situations. I will give you that the Japanese nuclear industry is really rather corrupt, and the whole cover-up surrounding Monju should leave no doubt of that. You are however wrong that much better safety cannot be built at competitive prices. The Canadians have been doing a good job with their CANDU as an example.
Uranium is a very limited resource, but thorium reserves are truly vast.
Because a thorium thermal breeder would require a very good neutron economy, they can only work in self-sufficient mode if reprocessing is very frequent or continuous ( as is envisioned in molten salt systems). Unfortunately it adds considerably to the cost to do reprocessing frequently or continuously. In addition the very short doubling time of such a system means they would likely have to be started using reprocessed plutonium.
Now if you have to do plutonium reprocessing anyway, then there is little reason not to simply go for a Pu-fast breeder reactor. Since fast breeders have by far the best neutron economy ( less parasitic losses in coolant and cladding, higher neutron yields from fast fission , more fission in fertile nuclei ) they would have much better burn-up, and hence the costs associated with reprocessing would be less. In addition they are better at destroying actinides. Granted, thorium would produce less transuranics than your typical LWR, but since you would have to start them using plutonium accumulation of curium would still be a problem. In addition a thermal spectrum would not be very good at destroying the transuranic elements in our existing waste.
Granted the sodium technology will likely not be economical. But an LFR , fast spectrum SCWR or perhaps even a fast-spectrum molten salt reactor would probably work quite well. This is of course a long-term alternative, since in the near future uranium is likely to remain cheap, and hence simply making LWRs safer by the use of natural circulation ( as in the ESBWR ) is probably a better choice for the next couple of decades.
They don't need to have the same driving range as a petrol vehicle if the recharge time can be improved. This is especially true when we start running out of oil. The latest battery tech that is on the market can recharge in 15 minutes or so. Yes, it is longer than to fill a gas tank, but in a decade or two the price of petrol will justify it. So basically you will find that people will be quite fine with a range of 150km or so ( more has already been demonstrated ) when it saves them money. Governments will issue legislation in order to fight air pollution and carbon emissions, and thus the change will happen.
The problem at the moment is not the battery performance, capacity or recharge time. The major issue is the price. With current technology batteries that will last for 10 years costs as much as the rest of the car. Today this is a showstopper, but with rising Oil prices and possible improvements in battery tech, it is far from unlikely that it will not be the most economical option a few decades from now.
Ok, so lets say they manage to reduce their total energy consumption by a factor of 2 within 20 years ( yea right ), despite of population growth. You'd still need to produce the 50% of energy that remains, and unless you plan to continue to use petroleum for transportation, an increasing fractional share of that will need to be electric.
In terms of energy produced, averaged over a year, wind and solar in Germany today supplies a few percent of total energy consumption. ( No, you can't just add up peak power production for electricity, while ignoring capacity factors and non-electric energy consumption like petrol ). Even if you tripled solar and wind output within 2 decades, and reduced overall energy consumption by 50% , you'd still not reach a majority of energy from renewables. The remainder would have to be fossil,nuclear or imports.
In practice that will likely mean increased reliance on imports ( French nuclear and Polish coal ) and increased consumption of natural gas.
Oil is likely to run out or become very expensive during the next few decades, if plug in hybrids and electric cars is the most likely replacement for gasoline ( and it seems to be the case at the moment ) then much more electricity will be needed.
Environmental concerns mandate a large reduction in the use of coal for electricity. EU-member states have committed to such reductions through several treaties and directives, and it is unlikely that they will simply be dropped.
Wind cannot contribute a majority of electricity generation out of load levelling concerns.
Solar is prohibitively expensive and only does well in Germany due to strong economic incentives that would be very costly to scale. It also doesn't work during the night, and large scale energy storage is prohibitively expensive.
Scaling bio-mass to supply a nation the size of Germany would have a dramatic environmental impact associated with its cultivation, growth and combustion. It is presently very expensive for applications other than heating, and the more advanced bio-fuels (cellulosic ethanol ) that actually seem feasible are still experimental. Brazil kinda makes etanol from sugar cane work, but it is dubious if the practice would be sustainable outside of tropical climates.
So basically unless they overturn this decision it seems likely that Germany will end up importing electricity or making themselves reliant on Russian natural gas. This is what happens when you make policy based on populism and wishful thinking rather than reality.
The splitting of atoms stops the moment you drop in the control rods ( i.e in a second or two ), but the waste products are still intensely radioactive, generating megawatts of heat. This is still a lot better than having the reactor running, because the heat generation from the waste is very predictable and stable, and it is also less than 10% of the full reactor power, dropping to less than 1% within a day or two.
The reason passive cooling is believed to be safer is pretty much that it does not rely on any machinery, electric power or moving parts. In this particular situation the problem was that all the water from the tsunami short-circuited the electronics of the plant, so the cooling pumps ceased to work. It is possible to build a nuclear plant in such a way that pumps are not needed at all. As an example in the ESBWR design by Hitachi the reactor is tall and positioned further down than the turbines and heat exchangers. Thus the hot steam rises upwards while the colder water flows down, with no need for pumps.
You are correct that if the water itself is lost then a meltdown is very likely to occur unless it can be replaced quickly. However if the reactor's containment structure is solid enough then most of the radioactive fallout would still be contained without contaminating the environment. One of the problems with the Fukushima Daiichi power plant was that its containment is of a poor design and was unable to withstand the pressure. Contrast this with the three mile island plant where the containment dome kept almost all of the radioactive gases inside.
Another issue is that many reactors have teh nuclear fuel in zirconium tubes. This is good in one way because zirconium does not absorb very many neutrons so you don't need to enrich the uranium so much. However, if the zirconium overheats then it can react with the cooling water to form explosive hydrogen gas. This need not cause a problem if the containment is strong enough to contain a hydrogen explosion, or if the plant has the ability to safely vent the hydrogen to the atmosphere. Neither of this was the case at Fukushima, and it is strongly suspected that hydrogen explosions were involved in damaging the containment.
I have to disagree here. The stronger stuff, cocaine and heroin in particular, are so addictive that the vast majority of users don't have any chance to quit using them without intensive care. There may be a case for supplying them to people who are already addicted, in order to reduce the black market and relation to crime, but they are hardly even comparable to things like pot, which is at best only mildly addictive.
That said punishments should be proportional to the offence. "Hard on crime" doesn't work very well.
The fission products that are a problem during this kind of accident are almost completely dominated by beta and gamma emitters. At least during the first few hundred years. Also, after a alpha or beta decay there is very frequently a subsequent gamma that is much easier to detect. The isotope that emitted it can be determined by the energy spectrum ( but a Geiger tube will not do that very well ). Furthermore, since most of the transuranic alpha emitters do not exist in nature, it is quite feasible to detect them by chemical means using soil samples and so on. Neptunium, Plutonium, Americium and to some extent Curium will be responsible for the bulk of alphas, and since neither exist in nature there is no need to check for their radiation directly. Simply detecting their presence is sufficient.
Basically you are the one without practical knowledge. You know the theory, but it's not how these things are done in practice.
As I understand it the Lithium Iron Phosphate batteries pretty much solve the major issues with EV cars.They're fast charging ( 10 min or so ) , long lifespan ( 10+ years ), can output a tremendous amount of power, and have a wide operating temperature range. The issue at the moment seems to be that the price is too steep for them to be economically used in cars.
Anybody know more than wikipedia on what is being done to get them down in price? It seems to me that if those can be made more cheaply then you've basically cracked the entire problem with EV cars.
The proposed law is ambiguous as hell and make explicit exceptions for cookies that are necessary to perform a service the user has requested. Thus session cookies should still be fine, as should the "remember me" checkbox you see on most web forums.
There are multi-junction solar cells with a decent efficiency. That's teh kind that go on expensive sattelites. The problem is that such cells cost an arm and a leg so it is still cheaper to use the single-junction cells that get a much poorer efficiency. The kind of solar breakthroughs that might make photovoltaic competitive is reductions in the cost of teh manufacturing process. If you can find a cheap way to make the multi junction cells then the price per kWh will come down drastically.
Btw: The price per watt is useless as a metric because most of the time the cells don't give you their maximum power rating. What is interesting is the price per unit of energy averaged over a year. I.e $/kWh.
The energy returned on energy invested is actually quite good. The issue is that the manufacturing process is so darn expensive that it isn't very economical at the moment. This is also why terrestrial applications rarely use the kind of solar cells that go on satellites. There are cells with close to 40% efficiency, they're just stupidly expensive.
People keep pretending they are fundamentally different, they're not.
A runaway nuclear reaction is quite similar to a nuclear bomb, and a poorly constructed nuclear bomb would probably produce a blast of similar yield to the Chernobyl explosion. The main difference between a runaway reactor and a bomb is that the latter is built to optimise the rate of the reaction, and that's also why it has more devastating effects. If the bombmaker is careless and makes some mistake in the design, then the reaction will not be so quick, and then the explosion will probably not be much more powerful than the chernobyl explosion. It is this latter fact that should be emphasized. The reason we expect that a reactor will never detonate with a power comparable to a warhead is not because it is not nuclear. The energy most certainly comes from the same type of reactions. The difference is simply that making a nuclear chain reaction proceed rapidly enough for the kind of devastating explosions you see from a warhead absolutely requires the conditions to be just right.
In the same way a paper will burn, but if you grind it into a fine powder and pump air through it when you ignite the mix, the combustion will be much more rapid. Chemically speaking the difference is not that huge. It's still a combustion process that oxidises the cellulose with atmospheric oxygen. The only real difference is that the conditions under which it occurs make the reaction much more rapid.
I guess if you assume that Chernobyl never went prompt critical then the two situations are bit more different, but we can't really tell if the main explosion was a prompt critical event or not because there is not sufficient information to determine if that was the case.
This type of connector should ideally have data pins associated with it in order for the car to be able to communicate with the charger, thereby determining what voltages and power ratings the car can accept. This is also useful in order to optimise the charging process. Modern batteries are ideally charged at different rates depending on their state of charge, so using a dumb connector could reduce charging performance.
Basically for this kind of application you want a more flexible connector than simply "red cable supplies X ampere at Y volt".
Sure, but background radiation, and especially radon exposure, is generally accepted as causing numerous cancer deaths. Increasing the radiation received thus causes more cancer cases than would otherwise occur. That something exists in nature does not make it all nice and dandy. The only reason we're not doing more to limit background radiation is that it is completely impractical trying to do so. When it comes to nuclear plants it is quite practical to prevent events like Fukushima, but Japan's industry and regulatory framework is absolutely rotten. Japan also appears to have a bit of a cultural thing against admitting mistakes, as failure is seen as shameful, so cover-ups are preferred to actually fixing things, even when it would be in a company's self interest to do the latter.
I very much do believe nuclear power can be done safely, but like so many other industries it relies on actually having effective and transparent government regulation. The same applies to pharmaceuticals, food production, transportation and so on. The free market is useful for setting prices and basic resource allocation, but it will not magically create safety and environmental regulations and ensure that they are followed. You need a transparent government with a spine to do that.
If that was the only problem then I wouldn't mind Greenpeace. The far bigger issue is that they will flat out lie and even promote environmentally damaging alternatives in order to portray the issue as one of evil polluting companies with them offering the solution. To take a particular example the alternative they offered to England's plan to build modern nuclear power plants was to use combined heat and power generation, which would of course be fuelled by fossils fuels. While combined heat and power is an improvement over fossil fuels, it still emits orders of magnitude more pollutants than nuclear.
I find this kind of nonsense a big headache when trying to convince others that we ought to worry about pollution. To have an idea where I'm coming from I'm a vegan out of ethical and environmental concerns. During my physics education at uni I deliberately choose courses relating to global warming, power generation, radiation safety, energy conservation. etc... I don't drive a car, my home is heated with district heating, my lighting is from low energy bulbs etc... and I freaking hate Greenpeace. That organisation makes it incredibly difficult to get taken seriously when promoting environmental concerns , animal rights, sustainable development and so on.. They are the ones who get headlines, and hence that is how those of us who actually care are frequently perceived. Clueless hippies that protest for the sake of protesting without having a clue.
I also happen to live in a city where we have a number of medical companies. Every now and then these same activists stand there with megaphones going on about animal rights, how animal testing is unethical and so on. There's a butcher about 30m down the road, with the meat on display in the window. They never go there. Apparently killing animals because they taste nice is more acceptable than for life saving research.
As I said. I bloody hate these hypocrites. They make it hard for the rest of us to be taken seriously when we voice our concerns.
Sweden has an even more aggressive schedule -- 49% of energy by 2020. They're already at 44%. Sweden Leads the European Union
The vast majority of which is biofuels and hydroelectrics. We have made it policy not to expand hydroelectrics further because it causes large ecological damage to create the artificial dam, and biofuels are mostly in the form of district heating ( i.e burning spill material for heat). Trying to expand them further would cause ecological problems and rising food prices since most of our arable land is either forest or agricultural. Electricity generation is still completely dominated by Nuclear and Hydroelectrics. Wind is less than 1% , and Solar doesn't even show up in our statistics.
I can only assume your other claims are equally misleading and full of it. Heck, if renewables were as competitive as you claim there wouldn't be any discussion to begin with.
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The law of most civilized nations explicitly state the opposite. You are INNOCENT UNTIL RULED GUILTY IN A COURT OF LAW.
This is certainly the law in the US , and it is also part of the European convention of human rights.
Thus at least legally speaking, you are very much not a criminal if you've never been convicted for anything.
It's a bit more complicated than that. In principle the power output of a reactor can be brought up and down very quickly. As you insert or remove control rods the amount of fission in the reactor can change within seconds. There is some decay heat to worry about, but in principle you can bring a reactor down by 94% or so within a few seconds, and similarly up again very quickly.
The problem is that doing so causes a whole lot of other challenges and problems. Firstly to maximise the lifetime of the nuclear fuel in the core and ensure that it burns at a reasonably homogeneous rate across the reactor, the neutron flow density is adjusted with special control rods and absorbers. This is difficult to do efficiently for a reactor running at constant power, and a major headache if you want to vary the power.
Secondly some of the the fission products act as neutron absorbers ( xenon in particular ) and thus the properties of the reactor core depend on what has happened to the reactor in the past. If you constantly change the reactor power you can end up with rather strange and counter-intuitive swings in the reactor's behavior, and these swings can be hard to model. It is just much easier to try to keep it running in something that at least to some degree resembles a steady state.
Thirdly varying the power of the reactor will cause changes in temperature in its components, and this leads to thermal stress. Since a nuclear reactor core is already one of the harshest environments there is from a materials point of view, including high temperatures, neutron embrittlement and corrosion effects from the coolant, you generally don't want to introduce any extra source of stress on the material as that would lower safety marginals.
So basically you probably could build a reactor to do load leveling, but it would considerably more difficult than a regular power plant, and it would likely cost a lot more.
Exercise, diet , makeup, hair removal, clothing, haircuts, healthcare, stress at work / school, sleeping habbits, alcohol , tobacco , dental care, etc ...
People seriously underestimate how much of a person's appearance is due to lifestyle factors and how much time you are willing to put into it. Yes, there are genetic factors, but frankly there is a heck of a lot of it that can actually be described in terms of effort.
Part of the difference might be that european countries are far less forgiving when companies don't behave ( just look at the reaction when Microsoft failed to comply with EU competition law ), and the last thing a company wants is to piss off the people who have the authority to mess up your business.
Basically, because European governments are more willing to regulate corporate enterprises and penalize them when they do wrong, they have to be more honest because the possibility of getting a kick up the rear when they don't play nice is much more probable.
Much of the population growth is presently in poorer nations. In most richer nations, and particularly nations where men and women are seen as equals, the introduction of contraceptives have dramatically reduced population growth to the extent that many western nations would see no population growth at all if it was not for immigration.
In addition our agricultural methods at the moment are not optimized for maximum efficiency. If we would cut our consumption of meat and animal products down to healthy levels, and stop using arable land to feed livestock ( you could still let them graze on land unsuitable for crops ), then this would drastically reduce the amount of land required to feed our population.
Taking it even further the farming methods themselves can be greatly improved. Greenhouses, crop rotation and improved irrigation systems would dramatically increase agricultural yield while simultaneously reducing the need for fertilizers and pesticides.
This is before you even start to consider the controversy that is genetic engineering. While I'm not a fan of GM patents and monsanto's business practices, it is quite feasible to use GE to increase the nutritional value of various food crops.
The problem is that all of the above relies on governments doing their job responsibly, and electorates actually voting sensibly. Sadly we have a great deal of people opposed to contraceptives on religious grounds, inefficient farming subsidies that are little more than a bribe to buy support from the agricultural sector, lack of regulation of pesticides and food quality because "the free market will sort it out", and the ridiculous idea that obtaining a patent, even for living organisms like plants , is some form of inalienable right as opposed to a mere tool to stimulate innovation.
TL,DR:
From a technical point of view the problem is easy to solve, but a bunch of moralizing and greedy fucktards are going to mess it up.
Sea level rise from global warming is expected to flood some densely populated areas. Increased temperatures will make some currently hospitable areas inhospitable, and turn land presently viable for agriculture worthless. These changes are likely to be irreversible for thousands of years at the very least, possibly indefinitely, and the problems occur globally, not just within the closest few kilometers of the power plants.
There is very little doubt that the cost of adapting to the consequences of our greenhouse gas emissions will vastly exceed even the worst outcome of nuclear accidents. Yes, that includes Chernobyl. You can't declare the entire world an exclusion zone when it's the global climate you're messing up.
Salt makes it a non-issue when used correctly.
It increases the volume of the waste because mass is added, but this is irrelevant to most storage schemes since it is heat generation, not volume, that limits repository capacity. If the extracted transuranics are used in a fast spectrum then the resulting waste will consist of mostly fission products that decay to safe levels much quicker than unprocessed waste. If the plutonium only is reused in a thermal spectrum ( as with LWR MOX fuel ) then more americium and curium will be produced, which is generally a bad thing.
Back when the Fukishima style reactors were constructed not much attention were paid towards safety, and environmentalism was just getting started. That's why many reactors built back then have rubbish containments and unreliable cooling systems. In contrast at least a few of the designs currently suggested ( ESBWR , Advanced CANDU , ABWR, APR ) have dramatically higher quality containment structures and rely on natural convection during emergency situations. I will give you that the Japanese nuclear industry is really rather corrupt, and the whole cover-up surrounding Monju should leave no doubt of that. You are however wrong that much better safety cannot be built at competitive prices. The Canadians have been doing a good job with their CANDU as an example.
Because a thorium thermal breeder would require a very good neutron economy, they can only work in self-sufficient mode if reprocessing is very frequent or continuous ( as is envisioned in molten salt systems). Unfortunately it adds considerably to the cost to do reprocessing frequently or continuously. In addition the very short doubling time of such a system means they would likely have to be started using reprocessed plutonium.
Now if you have to do plutonium reprocessing anyway, then there is little reason not to simply go for a Pu-fast breeder reactor. Since fast breeders have by far the best neutron economy ( less parasitic losses in coolant and cladding, higher neutron yields from fast fission , more fission in fertile nuclei ) they would have much better burn-up, and hence the costs associated with reprocessing would be less. In addition they are better at destroying actinides. Granted, thorium would produce less transuranics than your typical LWR, but since you would have to start them using plutonium accumulation of curium would still be a problem. In addition a thermal spectrum would not be very good at destroying the transuranic elements in our existing waste.
Granted the sodium technology will likely not be economical. But an LFR , fast spectrum SCWR or perhaps even a fast-spectrum molten salt reactor would probably work quite well. This is of course a long-term alternative, since in the near future uranium is likely to remain cheap, and hence simply making LWRs safer by the use of natural circulation ( as in the ESBWR ) is probably a better choice for the next couple of decades.
They don't need to have the same driving range as a petrol vehicle if the recharge time can be improved. This is especially true when we start running out of oil. The latest battery tech that is on the market can recharge in 15 minutes or so. Yes, it is longer than to fill a gas tank, but in a decade or two the price of petrol will justify it. So basically you will find that people will be quite fine with a range of 150km or so ( more has already been demonstrated ) when it saves them money. Governments will issue legislation in order to fight air pollution and carbon emissions, and thus the change will happen.
The problem at the moment is not the battery performance, capacity or recharge time. The major issue is the price. With current technology batteries that will last for 10 years costs as much as the rest of the car. Today this is a showstopper, but with rising Oil prices and possible improvements in battery tech, it is far from unlikely that it will not be the most economical option a few decades from now.
Ok, so lets say they manage to reduce their total energy consumption by a factor of 2 within 20 years ( yea right ), despite of population growth. You'd still need to produce the 50% of energy that remains, and unless you plan to continue to use petroleum for transportation, an increasing fractional share of that will need to be electric.
In terms of energy produced, averaged over a year, wind and solar in Germany today supplies a few percent of total energy consumption. ( No, you can't just add up peak power production for electricity, while ignoring capacity factors and non-electric energy consumption like petrol ). Even if you tripled solar and wind output within 2 decades, and reduced overall energy consumption by 50% , you'd still not reach a majority of energy from renewables. The remainder would have to be fossil,nuclear or imports.
In practice that will likely mean increased reliance on imports ( French nuclear and Polish coal ) and increased consumption of natural gas.
Oil is likely to run out or become very expensive during the next few decades, if plug in hybrids and electric cars is the most likely replacement for gasoline ( and it seems to be the case at the moment ) then much more electricity will be needed.
Environmental concerns mandate a large reduction in the use of coal for electricity.
EU-member states have committed to such reductions through several treaties and
directives, and it is unlikely that they will simply be dropped.
Wind cannot contribute a majority of electricity generation out of load levelling concerns.
Solar is prohibitively expensive and only does well in Germany due to strong economic
incentives that would be very costly to scale. It also doesn't work during the night, and large
scale energy storage is prohibitively expensive.
Scaling bio-mass to supply a nation the size of Germany would have a dramatic environmental
impact associated with its cultivation, growth and combustion. It is presently very expensive for
applications other than heating, and the more advanced bio-fuels (cellulosic ethanol ) that actually
seem feasible are still experimental. Brazil kinda makes etanol from sugar cane work, but it is
dubious if the practice would be sustainable outside of tropical climates.
So basically unless they overturn this decision it seems likely that Germany will end up importing
electricity or making themselves reliant on Russian natural gas. This is what happens when you make
policy based on populism and wishful thinking rather than reality.
The splitting of atoms stops the moment you drop in the control rods ( i.e in a second or two ), but the waste products are still intensely radioactive, generating megawatts of heat. This is still a lot better than having the reactor running, because the heat generation from the waste is very predictable and stable, and it is also less than 10% of the full reactor power, dropping to less than 1% within a day or two.
The reason passive cooling is believed to be safer is pretty much that it does not rely on any machinery, electric power or moving parts. In this particular situation the problem was that all the water from the tsunami short-circuited the electronics of the plant, so the cooling pumps ceased to work. It is possible to build a nuclear plant in such a way that pumps are not needed at all. As an example in the ESBWR design by Hitachi the reactor is tall and positioned further down than the turbines and heat exchangers. Thus the hot steam rises upwards while the colder water flows down, with no need for pumps.
You are correct that if the water itself is lost then a meltdown is very likely to occur unless it can be replaced quickly. However if the reactor's containment structure is solid enough then most of the radioactive fallout would still be contained without contaminating the environment. One of the problems with the Fukushima Daiichi power plant was that its containment is of a poor design and was unable to withstand the pressure. Contrast this with the three mile island plant where the containment dome kept almost all of the radioactive gases inside.
Another issue is that many reactors have teh nuclear fuel in zirconium tubes. This is good in one way because zirconium does not absorb very many neutrons so you don't need to enrich the uranium so much. However, if the zirconium overheats then it can react with the cooling water to form explosive hydrogen gas. This need not cause a problem if the containment is strong enough to contain a hydrogen explosion, or if the plant has the ability to safely vent the hydrogen to the atmosphere. Neither of this was the case at Fukushima, and it is strongly suspected that hydrogen explosions were involved in damaging the containment.
I have to disagree here. The stronger stuff, cocaine and heroin in particular, are so addictive that the vast majority of users don't have any chance to quit using them without intensive care. There may be a case for supplying them to people who are already addicted, in order to reduce the black market and relation to crime, but they are hardly even comparable to things like pot, which is at best only mildly addictive.
That said punishments should be proportional to the offence. "Hard on crime" doesn't work very well.
The fission products that are a problem during this kind of accident are almost completely dominated by beta and gamma emitters. At least during the first few hundred years. Also, after a alpha or beta decay there is very frequently a subsequent gamma that is much easier to detect. The isotope that emitted it can be determined by the energy spectrum ( but a Geiger tube will not do that very well ). Furthermore, since most of the transuranic alpha emitters do not exist in nature, it is quite feasible to detect them by chemical means using soil samples and so on. Neptunium, Plutonium, Americium and to some extent Curium will be responsible for the bulk of alphas, and since neither exist in nature there is no need to check for their radiation directly. Simply detecting their presence is sufficient.
Basically you are the one without practical knowledge. You know the theory, but it's not how these things are done in practice.
As I understand it the Lithium Iron Phosphate batteries pretty much solve the major issues with EV cars.They're fast charging ( 10 min or so ) , long lifespan ( 10+ years ), can output a tremendous amount of power, and have a wide operating temperature range. The issue at the moment seems to be that the price is too steep for them to be economically used in cars.
Anybody know more than wikipedia on what is being done to get them down in price? It seems to me that if those can be made more cheaply then you've basically cracked the entire problem with EV cars.
The proposed law is ambiguous as hell and make explicit exceptions for cookies that are necessary to perform a service the user has requested. Thus session cookies should still be fine, as should the "remember me" checkbox you see on most web forums.
There are multi-junction solar cells with a decent efficiency. That's teh kind that go on expensive sattelites. The problem is that such cells cost an arm and a leg so it is still cheaper to use the single-junction cells that get a much poorer efficiency. The kind of solar breakthroughs that might make photovoltaic competitive is reductions in the cost of teh manufacturing process. If you can find a cheap way to make the multi junction cells then the price per kWh will come down drastically.
Btw: The price per watt is useless as a metric because most of the time the cells don't give you their maximum power rating. What is interesting is the price per unit of energy averaged over a year. I.e $/kWh.
The energy returned on energy invested is actually quite good. The issue is that the manufacturing process is so darn expensive that it isn't very economical at the moment. This is also why terrestrial applications rarely use the kind of solar cells that go on satellites. There are cells with close to 40% efficiency, they're just stupidly expensive.
People keep pretending they are fundamentally different, they're not.
A runaway nuclear reaction is quite similar to a nuclear bomb, and a poorly constructed nuclear bomb would probably produce a blast of similar yield to the Chernobyl explosion. The main difference between a runaway reactor and a bomb is that the latter is built to optimise the rate of the reaction, and that's also why it has more devastating effects. If the bombmaker is careless and makes some mistake in the design, then the reaction will not be so quick, and then the explosion will probably not be much more powerful than the chernobyl explosion. It is this latter fact that should be emphasized. The reason we expect that a reactor will never detonate with a power comparable to a warhead is not because it is not nuclear. The energy most certainly comes from the same type of reactions. The difference is simply that making a nuclear chain reaction proceed rapidly enough for the kind of devastating explosions you see from a warhead absolutely requires the conditions to be just right.
In the same way a paper will burn, but if you grind it into a fine powder and pump air through it when you ignite the mix, the combustion will be much more rapid. Chemically speaking the difference is not that huge. It's still a combustion process that oxidises the cellulose with atmospheric oxygen. The only real difference is that the conditions under which it occurs make the reaction much more rapid.
I guess if you assume that Chernobyl never went prompt critical then the two situations are bit more different, but we can't really tell if the main explosion was a prompt critical event or not because there is not sufficient information to determine if that was the case.
This type of connector should ideally have data pins associated with it in order for the car to be able to communicate with the charger, thereby determining what voltages and power ratings the car can accept. This is also useful in order to optimise the charging process. Modern batteries are ideally charged at different rates depending on their state of charge, so using a dumb connector could reduce charging performance.
Basically for this kind of application you want a more flexible connector than simply "red cable supplies X ampere at Y volt".
Sure, but background radiation, and especially radon exposure, is generally accepted as causing numerous cancer deaths. Increasing the radiation received thus causes more cancer cases than would otherwise occur. That something exists in nature does not make it all nice and dandy. The only reason we're not doing more to limit background radiation is that it is completely impractical trying to do so. When it comes to nuclear plants it is quite practical to prevent events like Fukushima, but Japan's industry and regulatory framework is absolutely rotten. Japan also appears to have a bit of a cultural thing against admitting mistakes, as failure is seen as shameful, so cover-ups are preferred to actually fixing things, even when it would be in a company's self interest to do the latter.
I very much do believe nuclear power can be done safely, but like so many other industries it relies on actually having effective and transparent government regulation. The same applies to pharmaceuticals, food production, transportation and so on. The free market is useful for setting prices and basic resource allocation, but it will not magically create safety and environmental regulations and ensure that they are followed. You need a transparent government with a spine to do that.
If that was the only problem then I wouldn't mind Greenpeace. The far bigger issue is that they will flat out lie and even promote environmentally damaging alternatives in order to portray the issue as one of evil polluting companies with them offering the solution. To take a particular example the alternative they offered to England's plan to build modern nuclear power plants was to use combined heat and power generation, which would of course be fuelled by fossils fuels. While combined heat and power is an improvement over fossil fuels, it still emits orders of magnitude more pollutants than nuclear.
I find this kind of nonsense a big headache when trying to convince others that we ought to worry about pollution. To have an idea where I'm coming from I'm a vegan out of ethical and environmental concerns. During my physics education at uni I deliberately choose courses relating to global warming, power generation, radiation safety, energy conservation. etc... I don't drive a car, my home is heated with district heating, my lighting is from low energy bulbs etc... and I freaking hate Greenpeace. That organisation makes it incredibly difficult to get taken seriously when promoting environmental concerns , animal rights, sustainable development and so on.. They are the ones who get headlines, and hence that is how those of us who actually care are frequently perceived. Clueless hippies that protest for the sake of protesting without having a clue.
I also happen to live in a city where we have a number of medical companies. Every now and then these same activists stand there with megaphones going on about animal rights, how animal testing is unethical and so on. There's a butcher about 30m down the road, with the meat on display in the window. They never go there. Apparently killing animals because they taste nice is more acceptable than for life saving research.
As I said. I bloody hate these hypocrites. They make it hard for the rest of us to be taken seriously when we voice our concerns.
The vast majority of which is biofuels and hydroelectrics. We have made it policy not to expand hydroelectrics further because it causes large ecological damage to create the artificial dam, and biofuels are mostly in the form of district heating ( i.e burning spill material for heat). Trying to expand them further would cause ecological problems and rising food prices since most of our arable land is either forest or agricultural. Electricity generation is still completely dominated by Nuclear and Hydroelectrics. Wind is less than 1% , and Solar doesn't even show up in our statistics.
I can only assume your other claims are equally misleading and full of it. Heck, if renewables were as competitive as you claim there wouldn't be any discussion to begin with.
Ahhhh. I love the smell of slahsdot in the morning.