Next Gen' Nuke Plant
I know some members here like this stuff. Toshiba wants to "donate" one of their next generation nuke plants to a small town in Alaska. Currently the town is running on diesel. Found it on /. here's the article.
Village invited to test cheap, clean nuclear power
Relevant details.
Nice picture.
Village invited to test cheap, clean nuclear power
Relevant details.
Quote:
The reactor has almost no moving parts and doesn't need an operator. The nuclear reaction is controlled by a reflector that slowly slides over the uranium core and keeps the nuclear fission "critical." If the reflector stops moving, the reactor loses power. If the shield moves too fast, the core "burns" more quickly, yielding the same amount of power but reducing the reactor's life, Rosinski said.
Because of its design and small size, the Toshiba reactor can't overheat or melt down, he said, unlike what happened in the 1986 accident at Chernobyl that killed 30 people and spewed radiation across northern Europe.
The nuclear reaction heats liquid sodium in the upper portion of the reactor assembly. It circulates by convection, eliminating pumps and valves that need maintenance and can cause problems, Rosinski said. The liquid is contained in a separate chamber so it isn't radioactive. Because the reactor assembly is enclosed in a thick steel tube, it will withstand earthquakes and floods, Rosinski said.
The reactor has almost no moving parts and doesn't need an operator. The nuclear reaction is controlled by a reflector that slowly slides over the uranium core and keeps the nuclear fission "critical." If the reflector stops moving, the reactor loses power. If the shield moves too fast, the core "burns" more quickly, yielding the same amount of power but reducing the reactor's life, Rosinski said.
Because of its design and small size, the Toshiba reactor can't overheat or melt down, he said, unlike what happened in the 1986 accident at Chernobyl that killed 30 people and spewed radiation across northern Europe.
The nuclear reaction heats liquid sodium in the upper portion of the reactor assembly. It circulates by convection, eliminating pumps and valves that need maintenance and can cause problems, Rosinski said. The liquid is contained in a separate chamber so it isn't radioactive. Because the reactor assembly is enclosed in a thick steel tube, it will withstand earthquakes and floods, Rosinski said.
Nice picture.
Comments
read the article today on slashdot. glad to see i wasn't the only one who thought it was cool.
also better than the 700,000 gallons of diesel fuel they use each year.
The first two reduce the lifetime to 1/10 of current waste, the last one makes it unspillable and (almost) impossible to extract weapons grade materials.
But the DoD and DoE have blocked such research for decades. *sigh*
The french super reactor have this feature : it bring some major problems of maintenance, due to the high pressure and high temperature (300-400 °c).
I am confident in nuclear plant, only if there is a great maintenance around, and the maximum amount of security. The problem is not only the critical mass, but the escape of radioactive materail via fissures : in 30 years fissures can happen.
No maintenance for the reactor is scary.
Concerning Tchernobyl : it did not kill 30 people like the commies said at the time, it killed quickly thousands of people. Add the number of leucemia or thyroide cancer (even in France)and you have a nightmare. And this nightmare is not finish, the sarcophage of this plant is not in good shape ...
Positive feedback loop - lose coolant, the reaction *sped up* and you had a meltdown.
No active US or European reactor uses this approach, to the best of my knowledge (I *think* the last one was shut down in the US in the early 80's, IIRC). They all use a negative feedback loop - lose coolant, the reaction stops cold. Nice and simple... and sane.
The other way tends to be cheaper though.
Originally posted by Kickaha
Textbook asinine design, it was.
Positive feedback loop - lose coolant, the reaction *sped up* and you had a meltdown.
No active US or European reactor uses this approach, to the best of my knowledge (I *think* the last one was shut down in the US in the early 80's, IIRC). They all use a negative feedback loop - lose coolant, the reaction stops cold. Nice and simple... and sane.
The other way tends to be cheaper though.
Yes these feature is good. But as you suspect positive feedback loop certainly lowered the energy efficiency. Like a motor without cooling.
But meldown is not the only problem who can arrive to a nuclar plant : there is also fissures and escape of radioactive products. That's the weak point of the Toshiba project.
Nuclear reactor without any maintenance : i find this scary.
Originally posted by Kickaha
No active US or European reactor uses this approach, to the best of my knowledge (I *think* the last one was shut down in the US in the early 80's, IIRC). They all use a negative feedback loop - lose coolant, the reaction stops cold. Nice and simple... and sane.
Actually, Chernobyl was not a melddown, but a reaction going supercritical, triggering a chemical explosion and a graphite fire.
Concerning western reactor technology: there is no negative feedback cycle. Control personnel needs to insert moderator rods to stop the chain reaction. If this fails, the reactor core melts. Worst consequences: meltdown through the reactor base, steam explosion destroying the containment, hydrogen explosion destroying the containment. Three mile island came pretty close to this in '79, simply by failure of a safety valve and loss of feedwater. Link.
The three mile island reactor technology is the most abundand on earth. It is a more secure design than the old soviet RBMK reactors, though.
Originally posted by Anders
Put up 20 wind turbines and you have your energy needs covered.
Doubtfully.
Nobody wants to build nuclear plants if there's no need. I think that's something most people don't grasp. (Along with the fact that the marketplace is not an entity). Anyway, Nuclear power exists because it can be cheap and effective, unlike wind turbines have proven to be. While I have little knowledge about reactor design, I'd be willing to bet that this Toshiba design is pretty damn solid.
Put up 20 wind turbines and you have your energy needs covered.
and what happens when there isn't enough wind for a few weeks at a time?
nuclear is a constant stream of energy. wind is a nice filler technology, but it will never have a main role in providing energy. not consistant enough.
If consumers using nuclear energy had to pay the actual cost of the energy that they were using, they would soon be shutting off their lights. Furthermore, there still is not an economical, long-term solution to the waste.
Renewables can work and can provide us with all of our energy needs. Issues of storage of energy when the sun is not shining and the wind is not blowing will be resolved through storage of energy in hydrogen cells?
Originally posted by Splinemodel
Anyway, Nuclear power exists because it can be cheap and effective, unlike wind turbines have proven to be.
Without wanting to be a complete tree-hugging hippy about it, Nuclear power is only really cheap and effective if you massively discount decomission costs, environmental risks and security threats that lie in the future.
Originally posted by stupider...likeafox
Without wanting to be a complete tree-hugging hippy about it, Nuclear power is only really cheap and effective if you massively discount decomission costs, environmental risks and security threats that lie in the future.
Understood, but fossil fuel plants, I'd argue, are more deleterious to the environment than are nuclear plants. Even "clean burning natural gas" produces lots of CO2, which environmentalists note as a "greehouse gas."
Supposedly there are some big advances being made in solar power, which is nice. But I don't know if it will ever be in a position to compete with nuclear, especially if fusion ever comes around. Even so, I could see myself roofing a house with solar panels, going for the de-centralized power thing.
And as far as security threats are concerned, there is a large cancer risk if a coal plant is detonated. Nuclear plants pose a greater risk, but they tend to be better protected and better engineered. If a 747 can crash into a nuclear core and not even scratch the reinforced concrete housing (which is a design requirement), I'm not too worried. Also consider the fact that the bridge that was the actual target in Hiroshima, which was built very strongly out of reinforced concrete, didn't go down.
Originally posted by Splinemodel
And as far as security threats are concerned, there is a large cancer risk if a coal plant is detonated.
Indeed? Because of what chemical reactions?
Nuclear plants pose a greater risk, but they tend to be better protected and better engineered. If a 747 can crash into a nuclear core and not even scratch the reinforced concrete housing (which is a design requirement), I'm not too worried.
At least over here, the requirement was the impact of a fighter jet, not a 100 ton commercial airliner. After 9/11, this prompted some worries about terrorist attacks using hijacked planes. To the best of my knowledge, no nuclear powerplants' containment can withstand the impact or fire this would cause.
And the potential devastating effects of spent nuclear fuel used in a dirty radioactive bomb have not been addressed yet...
Plus, '30 people dead'? I saw something on Chernobyl last night and over 3,000 died trying to build the concrete dome around the reactor, and hundreds died in the initial disaster inside the plant almost instantly.
Plus, the birth defects, radiation poisoning, and the threat of the concrete dome collapsing means that more and more people are continuing to die as a result of this 'accident'.
Nuclear waste is contained, we know where it is, we can do something about it.
All those emissions from the past century? Not a damned thing we can do about them, they're just... out there. And they continue to be pumped out there at an ungodly rate.
I'll take a concentrated poison that can be contained over a more dilute one that's escaped, thanks.
Vitrification, vitrification, vitrification. It seems so bloody simple. Turn it into glowing glass, and you have no spillage danger. No seepage. Shield the crap outta it, and let it be.
Honestly, people act like the radiation is somehow created out of nothing through man's unholy manipulations... it's not. It's just sped up. The same amount of radiation would eventually be pumped into the environment naturally if it were allowed to remain in the ore. In fact, one the *coolest* things I think I've ever seen is the Oklo Reactors Natural reactors created from the combination of uranium ore and ground water seepage.
*shrug*
Originally posted by Smircle
Indeed? Because of what chemical reactions?
At least over here, the requirement was the impact of a fighter jet, not a 100 ton commercial airliner. After 9/11, this prompted some worries about terrorist attacks using hijacked planes. To the best of my knowledge, no nuclear powerplants' containment can withstand the impact or fire this would cause.
And the potential devastating effects of spent nuclear fuel used in a dirty radioactive bomb have not been addressed yet...
I went for a tour of the Calvert Cliffs Nuclear Power Plant in Maryland once as part of a school trip (way before 2001). They made a big deal about how a 747 could crash into the core containment block, and it would be fine.
And thank you, kickaha. I was about to mention that, while very unfortunate, the eventual average radiation level that Chernobyl made rise was something like 1 unit. (I forget the unit). There are parts of the world that have 400units of background radiation naturally. (Europe is extremely low, so Chernobyl brought it from like 1 to 2.) A great deal of areas have the radiation higher than 5. Most people's basements are between 5 and 20 due to naturally occuring Radon. A study was done once that found US nuclear submariners to get less radiation exposure than virtually any of us surface dwellers.
Because existing coal-fired power plants vary in size and electrical output, to calculate the annual coal consumption of these facilities, assume that the typical plant has an electrical output of 1000 megawatts. Existing coal-fired plants of this capacity annually burn about 4 million tons of coal each year. Further, considering that in 1982 about 616 million short tons (2000 pounds per ton) of coal was burned in the United States (from 833 million short tons mined, or 74%), the number of typical coal-fired plants necessary to consume this quantity of coal is 154.
Using these data, the releases of radioactive materials per typical plant can be calculated for any year. For the year 1982, assuming coal contains uranium and thorium concentrations of 1.3 ppm and 3.2 ppm, respectively, each typical plant released 5.2 tons of uranium (containing 74 pounds of uranium-235) and 12.8 tons of thorium that year. Total U.S. releases in 1982 (from 154 typical plants) amounted to 801 tons of uranium (containing 11,371 pounds of uranium-235) and 1971 tons of thorium. These figures account for only 74% of releases from combustion of coal from all sources. Releases in 1982 from worldwide combustion of 2800 million tons of coal totaled 3640 tons of uranium (containing 51,700 pounds of uranium-235) and 8960 tons of thorium.
taken from here
Originally posted by Splinemodel
I went for a tour of the Calvert Cliffs Nuclear Power Plant in Maryland once as part of a school trip (way before 2001). They made a big deal about how a 747 could crash into the core containment block, and it would be fine.
Truth be told, there are (as usual) claims and counterclaims. What I did come up with some 10min of googling:
The NRC currently has no criterion that requires nuclear power plant containment vessels to be designed to withstand the crash of a Boeing 747
Report shows airliner could decimate nuclear power plant
No power plant in the world could withstand an airborne terror attack like the one on September 11
U.S. nuclear plants were not designed to withstand such an impact
They have been designed to sustain a large bomb impact, and the impact of a small plane, but if you're talking about a 747, I'm not sure
even if the reactor building remains largely intact, there is a high probability that as a result of the damage caused by the aircraft, a core meltdown could still occur.
I'd rather not bet the farm on them being wrong. At least, if an airliner crashes into a coal powered plant, the consequences are forseeable.