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Dentrassi
GOLD Member since Apr 2003

Dentrassi

ZORT!
Location: Brisbane

Total posts: 3044
Posted:josh's thread on fossil fuels reminded me of a rant i was going to post a while ago but forgot about it. i cant find it so ill retype it.

The Nuclear Debate eek

to alot of people nuclear = bad full stop, so heres some pros/cons thoughts for you to ponder, and because im feeling argumentative im going to play devils advocate devil

the green movement often uses greenhouse gas emissions comparisons to european countries to criticise our [australias] emissions volume. something often neglected is the much higher proportion of nuclear power in europe - with produced zero greenhouse emissions - whereas australias energy is primarily fossil fuel based.

this is the trade off - millions of tons of CO2 in the atmosphere -vs 1 barrel of highly radioactive material. which is easier to control? [i havent done the maths, but if you insist i will]

lets look at another aspect - nuclear accidents such as chernobyl, 3 mile island, and the other one that eludes me. some of the effects of the radiation are well publicised as good reason to ban nuclear power - some of the birth defects from around the chernobyl region over the last 20 years are horrific frown . ok - 3 incidents. now lets look at the track record of coal mining, gas, and hydro power industries - and the associated incidents. the fatalities from coal mine collapses, gas/oil? perhaps the piper alpha oil platform is a good recent example, hydro? a surprising amount of people died building dams over the last century.

it could be argued that we can only look at the last 50 years when nuclear power has been available - but compare to nuclear, fossil fuels still have alot to answer for. its really only been in the last 20 years in which the safety revolution has swept industry -so hopefully that will decrease. i believe last night 10 miners perished in a mine in china.
the effect of nuclear seem to be worse, but in scale to frequency of accidents, and persons killed - it raises some questions.....

ok - how about extraction - the kakadu national park in australia is a world heritage listed area - yet for some reason they inexplicably mine uranium?! ultimately the process isnt any particularly more harmful than any other minerals extraction process - consider the gold extraction process, with uses a cyanide solution... [case study: Rio Tinto disaster at their Papau New Guinea gold operations]. in the scheme of the minerals extractions in australia, which is a country based on primary resources, volumetrically speaking, uranium isnt too significant - although its worth sh*tloads - which is why they mine it anywhere they can - eg kakadu frown

what about the location of the nuclear facilities? lets use the only reactor [i think?] in australia at lucas heights near sydney - which features regular residental protests [despite the fact that the plant was there before most of the residents, but we'll leave that one alone]. do they think the scientists and engineers working in the plant would be there if it was unsafe? do they have a concept of the rigorous safety protocols, monitored by epa amoungst multiple other organisations.
but lets think of this objectively - everyone makes mistakes - the gas explosion near melbourne 5 years ago is a classic example of that... where safety procedures were inadequate.
Seriously - who knows what could happen - a small incident happened in japan about 4 years ago where there was a complete disregard for safety and training, and the employees did something stupid involving buckets and the cooling system [cant remember details]. thankfully australian industrial standards are a bit higher - but still - consider the conseqences if something happened?

there is the question of how to safely dispose of the waste -seriously who wants it in their backyard - whats easier to control? greenhouse emissions or nuclear byproducts? ones relatively harmless shortterm, but hard to control, potentially catastrphic long term - but still under much speculation.
the other is extremely dangerous both short and long term - but it relatively simple to control [as long as the right people know what to do with it - which goes into another arguement as well]

the waste could be made into a nuclear weapon? yup! youd be an idiot to try yourself - but the US and various other nations have been doing it for years, making nuclear weapons out of uranium, and the plutonium byproduct of the uranium fission reaction. definitely a negative aspect of nuclear.

ok - heres my key point - particularly regarding the nuclear situation in australia, where the reactor contributes bugger all to the power grid.
what it is used for???? let start with a small one - smoke alarms [which use a radioactive compound curiously called 'americum']. but onto a big issue - the lucas heights reactor produces the isotopes for almost all chemotherapy drugs in australia - and new zealand for that matter. not to mention the other uses of radioactivity in medicine such as imaging - ever had an xray?
and in our everyday lives - things we wouldnt think twice about. every flown in a plane? material weakness are detected during routine engine maintainance using radiation. ever used plastic? guess how the thickness of the plastic is measured to give a consitent product? then onto things like radiocarbon dating, forensics etc.

so whos to blame for having a nuclear power plant in australia? the users of the isotopes? having no nuclear in australia means we offload the responsability to anther country to supply us?

personally - it would be great if we could give up nuclear - but whats the trade off vs fossil fuels? and the trade off vs all the application of radioactive isotopes in our society?
will we ever be free of nuclear weapons? - one can only hope. will we be free of nuclear? thats a more complicated question.

thoughts? ubbidea ubbangel happy ranting! some of you probably feel very passionate about this, so lets keep things cool cool

hugs to all
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"Here kitty kitty...." - Schroedinger.

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Pyrolific
BRONZE Member since Jan 2001

Returning to a unique state of Equilibrium
Location: Adelaide, South Australia

Total posts: 3288
Posted:I think the Greenhouse Gas emissions can be much reduced from what they are, even to the stage where we are doing something serious about the problem (unlike Kyoto). However, the waste from Nuclear reactors takes such a long time to become safe, that I simply dont believe we have the means to store it safely. I mean we are talking 1/2 life of 10k+ years arent we? and a leak into the ground water and we (and the rest of the environment) have a very very serious problem. There are other ways to produce power tho - put massive solar arrays in orbit and beam microwaves at the surface for eg. Offshore wind farms, tidal etc.

Your point about ppl dying in the coal mines is a good one - however AFAIK except for chernobyl there hasnt been any other full meltdowns. People say Nuclear power is safer now, but I'm not sure. There's also the issue of transporting the waste, and what would happen in the case of an accident or a spill.

Id be surprised if we dont go Nuclear tho. Its the easy way out. Let the petroleum industry keep polluting but convert the energy industry to nuclear. perhaps then even convert all transport to electric. wed have cleaner air. Let the ppl in 1000 years deal with the millions of gallons of radioactive substances.

Josh


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Dentrassi
GOLD Member since Apr 2003

Dentrassi

ZORT!
Location: Brisbane

Total posts: 3044
Posted:or we could fire all the waste off into space and not think about it - until we piss of captain kirk in 500 years when another 44 gallon drum of plutonium bounces off the enterprise ubblol

"Here kitty kitty...." - Schroedinger.

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Pyrolific
BRONZE Member since Jan 2001

Returning to a unique state of Equilibrium
Location: Adelaide, South Australia

Total posts: 3288
Posted:hehe - yeah if only there was a fool proof way of getting the spent fuel out of the earths orbit without risking a rocket misfire and spreading the waste all through the upper atmosphere smile

That reminds me, wasnt there recently a really close call with a nuclear powered space probe that only just missed out atmosphere on a return journey from another planet? I remmeber the scarey stories about what would happen if it broke up in the upper atmosphere...Shooting the waste into the sun would be a good way to get rid of it, I dont think it will make a lot of difference there smile

Josh


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Dentrassi
GOLD Member since Apr 2003

Dentrassi

ZORT!
Location: Brisbane

Total posts: 3044
Posted:im sure we can trust the engineering track record of NASA to do it safety. after all, this is the organisation who had a mars explorer miss mars because one team was working in metric, and the other in miles!

"Here kitty kitty...." - Schroedinger.

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Astar


member
Location: Nova Scotia, Canada.

Total posts: 1591
Posted:people keep citeing the harmful biproducts of nuclear fission as a reason not to use it.

But if you consider the fact that there are harmful biproducts involved in mineral refineing, that are pretty damn nasty (hello the lovely joys of heavy metals and chemicals used for refineing, and biproduct chemicals of refineing)

What are people hundreds of years from now going to do with toxic radio active waste? I assume they will do what we do with it, avoid it like the plague.

Is there really so little room on earth we don't have somewheres to store thousands of gallons of toxic waste?


To me, the real worrying problem is earth quakes, war, tidal waves and various other abnormal forces that could crack open any concrete sarcophogus full of nuclear waste and leak it into the ground water. But I worry about this happening with the waste from industry in general.

I dunno, I think nuclear stuff just scares the hell out of people because of A)cancer and B)crappy movies. But, there's lots of other nasty waste in the world that can cause A) and isn't interesting enough for B).

Im not for shutting down reactors unless the specific reactor has problems and im not for building more, because I think if nuclear power becomes to common, people really will get arrogant about it and an accident is bound to happen. From what I know of modern reactors if they are run properly a melt down is nearly impossible. chernobyl was a very good reactor which never would have melted down if a lowlife didn't think he could "hop it up" and make it run more efficiently.

Im more worried about nuclear powered sub's and ships having accidents then reactors.


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Dentrassi
GOLD Member since Apr 2003

Dentrassi

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Location: Brisbane

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Posted:Written by:

Im more worried about nuclear powered sub's and ships having accidents then reactors



as long as they're not purchased from the british navy we should be fine wink

im probably concerned with russia's nuclear weapons. the russians have never had the best safety record when it comes to a wide variety of industrial and military incidents.


"Here kitty kitty...." - Schroedinger.

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Kat
BRONZE Member since Dec 2000

Kat

Pooh-Bah
Location: London

Total posts: 2211
Posted:Nuclear power has gained a bad rep - I don't see it as been a good replacement for fossil fuels. On the other hand - I'm not out there campaigning that all the plants be immediately shut down. In Sweden, about half of domestic production is nuclear and its projected that a full nuclear phase-out would increase Sweden's carbon dioxide emissions by about 50% above the 1990 level as in the short term the replacement generation or imports would be fossil fuelled. On the other hand, quite a few Eastern European countries are using their commitment to reducing emissions as an excuse to hold on to their antiquated reactors!
The Blair Poodle Project have looked into Nuclear as a stopgap for sorting out the energy crisis and have granted licences to stations to keep operating until about 2010 but for Magnox units originally licensed for 30 years in some cases extended to 50 years, their time is up, all are expected to close by 2011 as they are not cost-effective. I reckon the length and cost of the decommissioning process will deter Nuclear being reconsidered as the wonder fuel to solve the energy crisis though. The Hunterston reactors which have been permenantly shut down are estimated to take 135 year or so to decommission! Its now thought that the other 2 Hunterston reactors will close within the next 2 years as they are not cost effective either. In other cases, plants were shut down as they had 'technical problem' - you don't want nuclear plants to be experiencing technical problems - yegads!


Trade off is to update technology there is so that the fuels are less damaging -implement CCGT / LNG technology that will see us through the next 10-15 years are so until renewable sources of energy become more commercially viable. Economics dictate in general where our energy sources come from but on the bright side, commercial sector engineering is now seriously investigating renewable sources of energy. From 2005 Australia will have its first Enviromission solar tower - with a capability of 200MW thats quite impressive and the tower looks very pretty too! Over this side of the world wind power and wave turbines are the most viable options for now - I know some folks gripe about them but I think they look beautiful!


Come faeries, take me out of this dull world, for I would ride with you upon the wind and dance upon the mountains like a flame.

- W B Yeats

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NOn


activist for HoPper liberation.
Location: ffidrac

Total posts: 1643
Posted:woo nuclear fuel, fun!!

'k. well I'm all for green energy, and I personally think that the majority of energy should be gathered using wind turbines, solar panels etc, especially for houses, as even in the UK (where we love rain) one voltaic panel could (i think, i haven't checked my figures) halve a household electricity bill. BUT, there would still need to be a substantial amount of other energy pumped into the Grid, and the reality is that relying on fossil fuels... well it's going to piss a lot of people right off when the supplies get really low.... (and then they might get the nuclear bombs out anyway, and make a hell of a lot more radioactive mess than a power station)!!

The problem with nuclear, is that people basically are scared of it, if we could be reassured that the waste is disposed of properly and that the operation systems are safe and reliable, then I'm sure it would be more accepted. If handled correctly it is a much cleaner fuel.

Also cost efficiency... i think this problem could be solved if people actually put some proper thought into the amount needed and how many power stations needed. It seems to me that whenever a government decides such-a-such is the better energy solution, they go a bit mad on it, and build them everywhere, then realise that people are complaining and they have too many anyway so take them out. This is surely far more dangerous and expensive then to properly maintain and keep it running?

Finally, I don't know whether anyone has heard about this and knows a bit more, but I heard about a process that is being developed that uses water molecules and a process very similar to nuclear fission to create energy. Something that could quite easily energise the world and uses a renewable resource. I wish i could remember what it was called, but i know there is stuff on the internet somewhere... or if anyone knows more?


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Fine_Rabid_Dog


Internet Hate Machine
Location: They seek him here, they seek ...

Total posts: 10530
Posted:I have been studying Radioactivity at school, and was freaked to find that most smoke detectors have a radioactive source in them. Its emits alpha particles so it cant even pierce paper and its range is particulary short, but its still a scary thought.
We are also stuck with backround radiation, which is created by the sun and the breakdone of rocks underground, producing radon gas (especially in cormwall).
So no matter what we do, were stuck with radiactivity, so we might as well harness the energy created from it, so im pretty cool with the whole nuke plant thing as it is pretty safe in the right hands, but its dumping on nuke waste that really pisses me off! It's downright dangerous, even with the gr8est of percautions.

However, I am all for recycable energy. The only problem is its cost effictiveness. They dont create much power to supply our demands and they are variable to weather or whatever. Its a tuff choice, as there are so many factors to take into consideration.

If only thery could think of a way to recycle nuke waste, (they do already, but they turn it into glass, to keep it contained for saftey, not for energy).

*wanders off thinking if any1 can be bothered to read rant*


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Mark P
BRONZE Member since Oct 2001

Mark P

old hand
Location: Bath, England

Total posts: 1031
Posted:Not had time to read this thread fully but I imagine it contains a lot of very relevant info.

Just thought I would bring a little light heartedness to it all smile

What about nuclear fueled poi?!?! no soaking, no carrying aroung huge ammounts of smelly paraffin ~ ok you might need to invest in some lead lined clothing, but hey sounds like a good idea to me smile

M x


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Eera


old hand
Location: In a test pit, Mackay

Total posts: 1107
Posted:Forgive me for being a bit vague, but a few years ago one of the US plutonium waste repositories was given a stocktake and they found that something like 50 000 gallons of radioactive waste had leaked out into the water table. Bill Bryson put it nicely: "Plutonium has to be kept safe for 100 000 years, the US government had managed it for rather less than 30."

There are huge issues behind waste disposal, and there are fairly large areas of the world that are stable enough to house underground caverns (any Precambrian shield will do, Canada and Australia have nice big ones) there's another factor that most people don't realise; public expectation.

When NIREX did their fieldwork to locate a waste repository in the UK they identified an area of Yorkshire that fitted the bill; stable ground, low water table, little seismicity, but instead of going ahead with their plans to build a new dump they abandoned them and kept everything at Sellafield, the reasoning was that people see the name "Sellafield" and automaticaly think of women giving birth to mutant flies, other locations they don't.

People have a knee-jerk reaction against nuclear power. Anyone who has worked in the field of contaminated land can tell you the location of an industrial town by the high levels of arsenic in the soil; this is concentrated and liberated through coal burning. Plutonium may give you grief for thousands of years but arsenic is forver.

My personal opinion is "meh!" I don't really care where my energy comes from because I (maybe) naively trust the industry professionals to do a good, safe job at the best of their abilities to provide it.


There is a slight possibility that I am not actually right all of the time.

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Ade
SILVER Member since Mar 2001

Are we there yet?
Location: australia

Total posts: 1897
Posted:"Is there really so little room on earth we don't have somewheres to store thousands of gallons of toxic waste?"

yes and yeah

politicians have shown they can't plan for more than a few years ahead - and I can't see them actually giving a toss about waste that will be there long beyond their death - there's not much incentive to do the right thing for the long term.

soapbox
Call me irrational, but I will never ever support nuclear power or weapons under any circumstances. soapbox


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Dentrassi
GOLD Member since Apr 2003

Dentrassi

ZORT!
Location: Brisbane

Total posts: 3044
Posted:Written by:
Finally, I don't know whether anyone has heard about this and knows a bit more, but I heard about a process that is being developed that uses water molecules and a process very similar to nuclear fission to create energy. Something that could quite easily energise the world and uses a renewable resource. I wish i could remember what it was called, but i know there is stuff on the internet somewhere... or if anyone knows more?


that process is called nuclear fusion - similar to the reaction in the sun. and the reaction so far has only been successfully created in nuclear weapon at extremely high temperatures, thus the name 'thermonuclear'. there is no known way at present to initiate this reaction at industrially controllable temperatures. if we could do it, it would be called 'cold fusion.'
unfortunately, we seem to be a long way from that.

the trouble with politicians is that their definition of 'long-term' only reaches the next election.


"Here kitty kitty...." - Schroedinger.

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MiG
GOLD Member since Apr 2004

MiG

Self-Flagellation Expert
Location: Bogged at CG

Total posts: 3415
Posted:umm, i think there is a couple of reactor like places that can get cold fusion going, but they use more power keeping it going than they gt from it. but we're close.

The only thing im worried about is this: if each reactor has about a thousand years between each meltdown, which is a pretty decent safety record in any respect, with the 500 odd reactors about nowadays, does that mean that we should expect one to go up every two years?


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Dentrassi
GOLD Member since Apr 2003

Dentrassi

ZORT!
Location: Brisbane

Total posts: 3044
Posted:yeah... the results are undecided. theres a reactor in UK which once in '97 managed to generate about 60% [?] of the input power. that fusion at 1000000oC or something.

there's two guys who claimed to achieve it in a beaker in 1989, which is still hotly debated. and theres a few guys who claim to have cold fusion set ups at their homes, but nothing is proven.

maybe one day, but it may be a few more decades before anything practical happens.


"Here kitty kitty...." - Schroedinger.

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phiredancer


member
Location: england, uk

Total posts: 61
Posted:Nuclear power plants provide about 17% of the world's electricity. Some countries depend more on nuclear power for electricity than others. In France, for instance, about 75% of the electricity is generated from nuclear power, according to the International Atomic Energy Agency. In the United States, nuclear power supplies about 15% of the electricity overall, but some states get more power from nuclear plants than others. There are more than 400 nuclear power plants around the world, with more than 100 in the United States.

Uranium:
Uranium is a fairly common element on Earth, incorporated into the ground during the planet's formation. Uranium is originally formed in stars. Old stars exploded and the dust from these shattered stars aggregated together to form our planet. Uranium-238 (U-238) has an extremely long half-life (4.5 billion years), and therefore is still present in fairly large quantities. U-238 makes up 99% of the uranium on the planet. U-235 makes up about 0.7% of the remaining uranium found naturally, while U-234 is even more rare and is formed by the decay of U-238. (Uranium-238 goes through many stages or alpha and beta decay to form a stable isotope of lead and U-234 is one link in that chain.)
Uranium-235 has an interesting property that makes it useful for both nuclear power production and for nuclear bomb production. U-235 decays naturally, just as U-238 does, by alpha radiation. U-235 also undergoes spontaneous fission a small percentage of the time. However, U-235 is one of the few materials that can undergo induced fission. If a free neutron runs into a U-235 nucleus, the nucleus will absorb the neutron without hesitation, become unstable and split immediately.

Nuclear Fission:
A U-235 nucleus with a neutron approaching from the top will captures the neutron, it splits into two lighter atoms and throws off two or three new neutrons (the number of ejected neutrons depends on how the U-235 atom happens to split). The two new atoms then emit gamma radiation as they settle into their new states. There are three things about this induced fission process that make it especially interesting:
The probability of a U-235 atom capturing a neutron as it passes by is fairly high. In a reactor working properly (known as the critical state), one neutron ejected from each fission causes another fission to occur.
The process of capturing the neutron and splitting happens very quickly, on the order of picoseconds (1x10-12 seconds).
An incredible amount of energy is released, in the form of heat and gamma radiation, when a single atom splits. The two atoms that result from the fission later release beta radiation and gamma radiation of their own as well. The energy released by a single fission comes from the fact that the fission products and the neutrons, together, weigh less than the original U-235 atom. The difference in weight is converted directly to energy at a rate governed by the equation E = mc2.
Something on the order of 200 MeV (million electron volts) is released by the decay of one U-235 atom (if you would like to convert that into something useful, consider that 1 eV is equal to 1.602 x 10-12 ergs, 1 x 107 ergs is equal to 1 joule, 1 joule equals 1 watt-second, and 1 BTU equals 1,055 joules). That may not seem like much, but there are a lot of uranium atoms in a pound of uranium. So many in fact, that a pound of highly enriched uranium as used to power a nuclear submarine or nuclear aircraft carrier is equal to something on the order of a million gallons of gasoline. When you consider that a pound of uranium is smaller than a baseball, and a million gallons of gasoline would fill a cube 50 feet per side (50 feet is as tall as a five-story building), you can get an idea of the amount of energy available in just a little bit of U-235.
In order for these properties of U-235 to work, a sample of Uranium must be enriched so that it contains 2-3% or more of U-235. 3% enrichment is sufficient for use in a civilian nuclear reactor used for power generation. Weapons-grade Uranium is composed of 90% or more U-235.

Nuclear Power Plants:
To build a nuclear reactor you need is some mildly enriched Uranium. Typically, the Uranium is formed into pellets with approximately the same diameter as a dime and a length of an inch or so. The pellets are arranged into long rods, and the rods are collected together into bundles. The bundles are then typically submerged in water inside a pressure vessel. The water acts as a coolant. In order for the reactor to work, the bundle, submerged in water, must be slightly supercritical. That means that, left to its own devices, the uranium would eventually overheat and melt.
To prevent this, control rods made of a material that absorbs neutrons, usually boron, are inserted into the bundle using a mechanism that can raise or lower the control rods. Raising and lowering the control rods allow operators to control the rate of the nuclear reaction. When an operator wants the Uranium core to produce more heat, the rods are raised out of the Uranium bundle. To create less heat, the rods are lowered into the Uranium bundle. The rods can also be lowered completely into the bundle to shut the reactor down in the case of an accident or to change the fuel.
The Uranium bundle acts as an extremely high-energy source of heat. It heats the water and turns it to steam. The steam drives a steam turbine, which spins a generator to produce power. In some reactors, the steam from the reactor goes through a secondary, intermediate heat exchanger to convert another loop of water to steam, which drives the turbine. The advantage to this design is that the radioactive water/steam never contacts the turbine. Also, in some reactors, the coolant fluid in contact with the reactor core is gas (carbon dioxide) or liquid metal (sodium or potassium); these types of reactors allow the core to be operated at higher temperatures.

Outside a Nuclear Power Plant:
Once you get past the reactor itself, there is very little difference between a nuclear power plant and a coal-fired or oil-fired power plant except for the source of the heat used to create steam.
The reactor's pressure vessel is typically housed inside a concrete liner that acts as a radiation shield. That liner is housed within a much larger steel containment vessel. This vessel contains the reactor core as well the hardware (cranes, etc.) that allows workers at the plant to refuel and maintain the reactor. The steel containment vessel is intended to prevent leakage of any radioactive gases or fluids from the plant.
Finally, the containment vessel is protected by an outer concrete building that is strong enough to survive such things as crashing jet airliners. These secondary containment structures are necessary to prevent the escape of radiation/radioactive steam in the event of an accident like the one at Three Mile Island. The absence of secondary containment structures in Russian nuclear power plants allowed radioactive material to escape in the accident at Chernobyl.
Uranium-235 is not the only possible fuel for a power plant. Another fissionable material is Plutonium-239. P-239 can be created easily by bombarding U-238 with neutrons -- something that happens all the time in a nuclear reactor.

Subcriticality, Criticality and Supercriticality:
When a U-235 atom splits, it gives off two or three neutrons (depending on the way the atom splits). If there are no other U-235 atoms in the area, then those free neutrons fly off into space as neutron rays. If the U-235 atom is part of a mass of uranium -- so there are other U-235 atoms nearby -- then one of three things happens:
If, on average, exactly one of the free neutrons from each fission hits another U-235 nucleus and causes it to split, then the mass of uranium is said to be critical. The mass will exist at a stable temperature. A nuclear reactor must be maintained in a critical state.
If, on average, less than one of the free neutrons hits another U-235 atom, then the mass is subcritical. Eventually, induced fission will end in the mass.
If, on average, more than one of the free neutrons hits another U-235 atom, then the mass is supercritical. It will heat up.
For a nuclear bomb, the bomb's designer wants the mass of uranium to be very supercritical so that all of the U-235 atoms in the mass split in a microsecond. In a nuclear reactor, the reactor core needs to be slightly supercritical so that plant operators can raise and lower the temperature of the reactor. The control rods give the operators a way to absorb free neutrons so the reactor can be maintained at a critical level.
The amount of uranium-235 in the mass (the level of enrichment) and the shape of the mass control the criticality of the sample. You can imagine that if the shape of the mass is a very thin sheet, most of the free neutrons will fly off into space rather than hitting other U-235 atoms. A sphere is the optimal shape. The amount of uranium-235 that you must collect together in a sphere to get a critical reaction is about 2 pounds (0.9 kg). This amount is therefore referred to as the critical mass. For Plutonium-239, the critical mass is about 10 ounces (283 grams).

What Can Go Wrong:
Well-constructed nuclear power plants have an important advantage when it comes to electrical power generation -- they are extremely clean. Compared with a coal-fired power plant, nuclear power plants are a dream come true from an environmental standpoint. A coal-fired power plant actually releases more radioactivity into the atmosphere than a properly functioning nuclear power plant. Coal-fired plants also release tons of carbon, sulfur and other elements into the atmosphere.
Unfortunately, there are significant problems with nuclear power plants:
Mining and purifying uranium has not, historically, been a very clean process.
Improperly functioning nuclear power plants can create big problems. The Chernobyl disaster is a good recent example. Chernobyl was poorly designed and improperly operated, but it dramatically shows the worst-case scenario. Chernobyl scattered tons of radioactive dust into the atmosphere.
Spent fuel from nuclear power plants is toxic for centuries, and, as yet, there is no safe, permanent storage facility for it.
Transporting nuclear fuel to and from plants poses some risk, although to date, the safety record in the United States has been good.
These problems have largely derailed the creation of new nuclear power plants in the United States. Society seems to have decided that the risks outweigh the rewards.


i must be loosing my mind.............come back!!!!!

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Dentrassi
GOLD Member since Apr 2003

Dentrassi

ZORT!
Location: Brisbane

Total posts: 3044
Posted:at least type up your own thoughts on the debate! any idiot can cut and paste the results of a google search. mad



this is an issue im divided about myself, and ive made the effort to write a fair bit from my own head, so would appreciate genuine opinions rather than transplanted text.


EDITED_BY: Dentrassi (1098457706)


"Here kitty kitty...." - Schroedinger.

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MiG
GOLD Member since Apr 2004

MiG

Self-Flagellation Expert
Location: Bogged at CG

Total posts: 3415
Posted:still, some good facts there for the people that havent grown up with nuclear reactor talk.

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NOn


activist for HoPper liberation.
Location: ffidrac

Total posts: 1643
Posted:Written by: Dentrassi

that process is called nuclear fusion - similar to the reaction in the sun. and the reaction so far has only been successfully created in nuclear weapon at extremely high temperatures, thus the name 'thermonuclear'. there is no known way at present to initiate this reaction at industrially controllable temperatures. if we could do it, it would be called 'cold fusion.'
unfortunately, we seem to be a long way from that.




oh. i thought it had a more complicated name than that and involved the word 'hydro' but it's only something I've heard about through someone else - said person mentioned that they were close to being able to build the first powerstation?

I agree radioactive waste disposal is a HUGE issue, and someone needs to come up with some really bright ideas of exactly where it could go (preferably ones that don't involve shooting it into space or leaving it on someone elses planet...)


Aurinko freedom agreement reached 10th Sept 2006

if it makes no sense that's because it's NOn-sense.

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=Flashpoint=
SILVER Member since Sep 2004

=Flashpoint=

Pasta of Muppets
Location: in the interwebs...

Total posts: 2719
Posted:Fusion: The only deal with nuclear fusion is getting a sufficient magnetic flux to contain the HUGE energy that a plasma creates (Plasma : gas at so high a temperature it goes liquid again: the sun)

Fuel cell technology: Hydrogen powered fuel cells for cars

They are the best methods for environmentally good power. However, I think that oil barons and car companies are deliberately retarding their development, something I think to do with something called money

Gits

10 years we will have the first fusion reactor. 20 years there will be a very nasty accident with a reactor containment failiure and everyone will be scared of that too due to tabloid reporting.

And the huge crater where Sheffield used to be...


ohmygodlaserbeamspewpewpew!
ubbrollsmileubbrollsmileubbrollsmileubbrollsmile

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Dentrassi
GOLD Member since Apr 2003

Dentrassi

ZORT!
Location: Brisbane

Total posts: 3044
Posted:hydrogen for cars? thats an interesting one in itself...



where do they get the hydrogen from? from memory either water or nat gas- how? they use energy to separate water into O2 and H2 - where do they get that electricity from? a power station, which if fossil fuel based, which generates greenhouse gases.



or from natural gas reforming, which from memory doenst use as much power, but does produce heaps of CO2.



the situation is always more complicated than it seems...

EDITED_BY: Dentrassi (1098669134)


"Here kitty kitty...." - Schroedinger.

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Ezza
BRONZE Member since Oct 2004

newbie
Location: Bunbury, Western Australia

Total posts: 9
Posted:There has been some interesting points raised on the topic, but I thought I might add a different perspective.

Coal has on average
* 1.3 parts per million of uraniaum
* 3.2 parts per million of thorium
* Other bad stuff

To run your average 1000 megawatt coal-fired power plant for one year, you need to burn about 4 million tonnes of coal.

This releases
* 5.2 tonnes of uranium
* 12.8 tonnes of radioactive thorium
* 0.22 tonnes of radioactive pottasium-40

In 1991 (my data is a bit old), the worldwide usage of coal was 5100 million tonnes. When that coal was burnt, some 6630 tonnes of uranium and 16 320 tonnes of thorium was released into the biosphere. (All in one year)

The amount of coal that is predicted to be burnt in the 100 year period from 1937 - 2037, your looking at 640 billion tonnes of coal. That enourmous pile contains about 830 000 tonnes of uranium, 2 000 000 tonnes of thorium and 35 000 tonnes of potasium-40. All of it free to enter the biosphere.

Its unsure where it all goes. Uranium and thorium are not very mobile, but potassium-40 can easily enter the food chain.

If in the year 2037, there are 8 billion people on the planet, then for every person there will be a paddle pop's worth of uranium (about 100 grams), and three paddle pop's worth of thorium - all thanks to coal burning.

References
* All references were sited from "Sensational Moments in Science" by Dr Karl Kruszelnicki. I have a full list of the science journals he references, but will not bore you with it here, unless it is asked.

The above is pretty crazy stuff. Nuclear power has got a faily bad rep but it would be interesting to see how opinions would change if the nuclear content of coal reached the general public awareness in the same way that the greenhouse effect or the ozone layer has.


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Prometheus


Prometheus

Diamond In The Rough
Location: Richmond, Virginia

Total posts: 459
Posted:The hydrogen cell method is still in it's developmntal stage, only because last I heard, its unstable (so they say). And yes, I'm sure OPEC is slowing the release of new technology to the public. I've seen engines that run on vegetable oil, alcohol, even water.

Nuclear waste can be stored in a few places on earth without problems, such as a site in the Rocky Mt.s that's all ready to go, but no one wants to move it because of the potential for an accident or terrorist attack. Shooting it into the sun would be expensive, problematic, and has the potential to cause solar flares.

I would like to see a lot more done with solar, wind and hydro power. In Arizona, for example, there is absolutely no reason they couldn't be self sufficient on solar power year-round...


Dance like it hurts; Love like you need money; Work like someone is watching.

Never criticize someone until you've walked a mile in their shoes. That way, when you DO criticize them, you are a mile away, and you have their shoes.

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Dentrassi
GOLD Member since Apr 2003

Dentrassi

ZORT!
Location: Brisbane

Total posts: 3044
Posted:the main problem in regards to long term environmental sustainability is politics. the definition of long-term thinking in politics means up til the next election. wink

"Here kitty kitty...." - Schroedinger.

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Astar


member
Location: Nova Scotia, Canada.

Total posts: 1591
Posted:Well, like electric cars (which could be a lot cheaper) hydrogen cell cars would be far cleaner then burning gasoline or diesal. Yes the power ultimatly is still comeing from a power plant, but the power grid which in most countrys is a combination of hydroelectric nuclear and fossil fuels generally are better for tor the enviroment per joule of energy produced then a gasoline engine is (Consider that even in places with tight emission standards, a very large amount of cars on the road still don't meet the standards, even ones which meet the standards when they are built but due to neglect and abuse the engines run dirtier then they should)

A oil plant (coal is falling out of favour mainly due to economic reasons) when modern and when it is maintained carefully is capable of being cleaner then even the best average car engines in the newest
cars)

There's also the practical aspects of where the pollution actually goes.
A gasoline car burns fossil fuels and all the emissions are at ground level right where people can breath them. Power plants tend ot have very high stacks and even with little wind the emissions aren't actually breathed by many people and they dissipate into the atmosphere (where they may or may not cause global warming but certainly cause other enviromental problems)

If everyone who lived in urban enviroments that could practically use electric vehicles when feasible used them, the air in urban areas would be a hell of a lot cleaner. Really people who live in urban areas should A)use public transit B)walk C)use a bike D)Use an electric vehicle E)use a small CC vehicle such as a motorcycle or a tiny car with a tiny engine (which people for some reason wont buy even though they are increadibly practical)

Also there is absolutly no engine that runs on water, it's a myth.
But the alternative fuels (besides alcohol) aren't actually better for the enviroment (if you believe in the whole global warming thing). As of now gasoline is the cleanest fuel for an internal combustian engine, assumeing it is refined in a concientous refinery which strives to keep pollution low (very unlikely)


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