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NUCLEAR POWER (Read 37816 times)
freediver
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Re: NUCLEAR POWER
Reply #105 - Jun 10th, 2008 at 12:08pm
 
Muso, I don't think geothermal involves the extraction of anything other than heat.
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muso
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Re: NUCLEAR POWER
Reply #106 - Jun 10th, 2008 at 7:08pm
 
At least one of the batholiths where  geothermal projects are planned contains radioactive material. (That's what produces the heat)
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muso
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Re: NUCLEAR POWER
Reply #107 - Jun 10th, 2008 at 7:16pm
 
BatteriesNotIncluded wrote on Jun 10th, 2008 at 12:03pm:
muso wrote on Jun 10th, 2008 at 10:58am:
The geothermal projects  or Uranium mines could provide a good location for a nuclear waste dump. Put the waste underground along with the natural stuff that has a higher activity anyway. What's the problem with that? 


My problem with that idea is it supports an irresponsible industry desperate for a get-out-of-jail-free card and if democracy means a thing I will not vote for it!

  Cheesy Cheesy Cheesy


In what way is it irresponsible? - and what makes you think you'll get to vote on it?  It just needs to go through the Environmental Impact Assessment.

People run around like headless chooks when you talk about radioactive material - probably because it's something they don't understand.   Human beings are naturally radioactive. Cadavers are exempt from the legislation governing radioactive waste, but radioactive waste with the same activity as you and me (very low I presume) is subject to extremely careful control.

Which kind of gamma radiation do you think is most harmful - natural or artificial?   Tongue
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Re: NUCLEAR POWER
Reply #108 - Jun 10th, 2008 at 8:39pm
 
At least one of the batholiths where  geothermal projects are planned contains radioactive material. (That's what produces the heat)

But that doesn't mean it is a good place to store radioactive material which we produce. Digging a 4km pipe down to pump water is not that same as digging a 4km deep mineshaft and excavating. By digging the hole, you would be bringing more radioactive material to the surface.
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Re: NUCLEAR POWER
Reply #109 - Jun 10th, 2008 at 8:51pm
 
Actually fission has been know to occur naturally underground in uranium deposits:

http://www.ans.org/pi/np/oklo/

Oklo's Natural Fission Reactors

More than 1.5 billion years ago (that's more than 1,500 million years) a nuclear fission reaction took place in an underground uranium deposit in Oklo, Gabon, Africa.  The fission reaction continued - off and on - for hundreds of thousands of years.  Eventually, the reactor shut down.

While it was active, the natural reactor generated fission products (wastes) very similar to those produced when fission occurs in modern nuclear reactors at power plants.

When evidence of the Oklo reactor was discovered in 1972, the fission products had been lying in Mother Nature's repository for about a billion years (that's 1,000 million years).  In fact, it was studies of the fission products found in the uranium mine which showed that a natural reactor had operated there.

The Oklo reactor provided an interesting natural analog for waste management.  Studying what happened to the fission products in the reactor has provided valuable insight into the requirements for a long-term waste repository.

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Re: NUCLEAR POWER
Reply #110 - Dec 22nd, 2009 at 12:24pm
 
I have no particular objection to nuclear technologies being used in conjunction with other renewables.

Amidst the nuclear power debate mid 2007 I wrote (and more recently reposted in July):

Quote:
The Canadian Deuterium Uranium reactor type is probably the best choice if Australia is to pursue a nuclear future.

This type of reactor and generating facility has a projected service life of over 60 years which means including establishment cost, commissioning cost, maintenance cost and decommissioning cost its projected wholesale power cost in current prices is $0.0356 au per kilowatt hour. The current NEMMCO wholesale purchase price is $0.115 au per kilowatt hour, as this is approximate to three times the cost commercial power generators will be attracted to this investment opportunity. It should be noted that the cost of power generation by Nuclear means in Canada is 0.0260 $per kWh but the industry is has greater development and infrastructure.

The CANDU 9 has a double valance enclosure around the reactor containment vessel and uniquely the heavy water moderator is also the medium for critical fission, as the moderator, its temperature, density and level in the reactor are controlling the process. A simple thermometric and pressure activated valve system make this reactor impossible to meltdown or suffer other catastrophic failure, excluding deliberate sabotage or attack. The double valance enclosure ensures that with the exception of specific military deep penetration ordinance it has a one point failure rating, thus minimizing the risk of nominal terrorist action. The fuel used in this reactor is un-enriched uranium but it is also capable of using transuranics as a partial source, thus allowing the reactor to continually recycle old fuel until full fission is completed, it also allows the use of plutonium and other wastes generated from external sources to be incorporated into the fuel.

The operating temperature of the CANDU 9 is 290 degrees Celsius, substantially below critical heat levels found in many other reactors. This has the desirable effect of extending metallurgical stability, eliminating the risk of burn through or containment failure and giving a high degree of flexibility to operational parameters.

The ability to recycle wastes and other transuranics such as plutonium is also a desirable feature, in many nations the partial fission caused by the use of Fast Breeder and similar reactors has produced a storage problem, it has also created the possibility of Nuclear Arms Proliferation, this reactor is a capable partial solution, weapons grade plutonium and other materials can be used in the fuel, this allows Australia for the first time to account for it uranium exports as the use of this material in these reactors would substantially minimize the chance of Australian Uranium becoming part of the weapons cycle.

This coupled with the technology of Synroc, to encapsulate only fully fissioned fuel wastes, wastes that will have a lesser radioactive emission than the original uranium ore in less than 1000 years. It is a primary fundamental that nuclear energy in Australia will be a closed fuel cycle, it will be safe and the need is temporary, but critical to our needs and transition to a non carbon energy cycle.

To facilitate this storage in safety for future generations is paramount, it must be stored in a manner that is both economic and safe. The first option is logically to store the wastes in an area that is geologically stable, is not environmentally sensitive and has a workforce skilled and aware of nuclear safety. The logical conclusion then is to store the nuclear wastes in a repository that has these conditions, the exhausted shafts and reaches of existing Uranium mines are such places. The use of these cavities is not only logical but ensures the fuel cycle is fully closed, as the storage of the wastes return them to their place of origin, into a sealed system, that is completely and irrevocably sealed once processing stops. It would also provide a secondary income stream for the mining operations, to facilitate greater safety and productivity.

http://senexx.wordpress.com/2009/07/21/nuclear-power/


Alternatively a Pebble-Bed Reactor would do.  Even Homer Simpson could run one of those safely.  And we have moved towards portable nuclear power now (click the image) and plenty of well nuanced information (before clicking) there as well.
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Adam
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Re: NUCLEAR POWER
Reply #111 - Sep 21st, 2010 at 9:57am
 
Is it true that coal power stations emit radioactive particles (such as Uranium), and toxic chemicals (such as methyl mercury)?
What kinds of emissions are there from nuclear reactors?
What levels of radiation have been released from modern reactors, and how does that compare to other sources of radiation to which we are exposed?
Can we reprocess nuclear waste and use it again, to reduce the quanty of waste?
Can a modern reactor melt down like in the movies?
How does the volume of waste (and toxicities) from nuclear power compare to the volume of waste (and toxicities) from other power sources?
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Re: NUCLEAR POWER
Reply #112 - Sep 21st, 2010 at 9:20pm
 
Quote:
Is it true that coal power stations emit radioactive particles (such as Uranium), and toxic chemicals (such as methyl mercury)?


I have heard similar claims. You need to burn huge quantities of the stuff to get the same energy as you would from nuclear, and there is little effort to prevent the small percentage of radioactive components going up the chimney. I suspect it may be comparable or even more than what has been released by nuclear energy, but I haven't chased up the numbers.
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Re: NUCLEAR POWER
Reply #113 - Sep 30th, 2010 at 1:11pm
 
A price on carbon would make nuclear power much more attractive.
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Re: NUCLEAR POWER
Reply #114 - Sep 30th, 2010 at 1:23pm
 
The idea that there may be spent uranium rods stored in hermetically sealed containers languishing in some remote, inaccessible location in this country someday is just too terrifying for me to think about.
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Re: NUCLEAR POWER
Reply #115 - Sep 30th, 2010 at 2:17pm
 
aikmann4 wrote on Sep 30th, 2010 at 1:23pm:
The idea that there may be spent uranium rods stored in hermetically sealed containers languishing in some remote, inaccessible location in this country someday is just too terrifying for me to think about.


I agree. It would be just too terrifying for you to think about.

In addition, it would be highly illegal and a very wasteful practice.

Fortunately that's not how nuclear waste is stored or proposed to be stored in Australia. The fuel rods are broken down and we end up with the unusable chemicals - (they call them daughter isotopes.) - generally not Uranium. Waste is fused with borosilicate glass to provide an immobilised form of waste that can be handled safely for at least a few hours wearing no more than a thick pair of gloves.

The immobilised waste has lower activity than some naturally occurring ores.

That's it in a nutshell. People who work in the field would tell me that I've forgotten to add all kinds of details that don't add anything to the argument either way. 

I remember when I was a radiation safety officer about 10 years ago - Lucas Heights sent me a replacement source, and it was sent on the final leg by a non-licensed courier. I was livid. Apart from the fact that staying back to complete the paperwork deprived me of my evening. I rang the after hours number of Radiation Health and got somebody who quietly recorded the details.

The next morning, I received a verbal blast from Radiation Health. I replied that I was the one who had reported it, and told them to read the report in future before roaring in my ear.  

All this was over a source that you could probably carry in your pocket for a few hours without effect.

The biggest risk with radioactive materials is that they could end up in scrap metal and then contaminate an entire steel mill.

That happened in the USA once. They had to shut down the steel mill and build a new one next to it. It's more of a financial risk than a health risk.
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« Last Edit: Sep 30th, 2010 at 2:32pm by muso »  

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Re: NUCLEAR POWER
Reply #116 - Sep 30th, 2010 at 2:49pm
 
Quote:
I agree. It would be just too terrifying for you to think about.


I'm not entirely sure how exactly radioactive fuel is contained after usage, but that was a sarcastic post. I'm a big advocate of nuclear energy and think that most of the fear mongering claims made regarding it, particularly pertaining to the spent fuel, are silly. I may not have gotten the specific details over its storage correct, but the general message I was trying to get across was that I think that most of allegations about the dangers of nuclear power that get passed around (by an especially vociferous subset of the population) seem like a whole lot of hot air over something that in reality is probably very easily managable. One of the first posts I made on this forum was of a similar nature  Cheesy
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Re: NUCLEAR POWER
Reply #117 - Sep 30th, 2010 at 3:16pm
 
It was just that one line that was sarcastic - and I couldn't resist it  Wink It's the smart arse in me.

I always think it's funny how they decided to call the decay products of a radioactive element "daughter elements"  The daughter elements are what cause most of the problems for nuclear waste.

Maybe somebody had a teenage daughter at the time.
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« Last Edit: Sep 30th, 2010 at 3:35pm by muso »  

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Re: NUCLEAR POWER
Reply #118 - Sep 30th, 2010 at 3:33pm
 
Adam wrote on Sep 21st, 2010 at 9:57am:
Is it true that coal power stations emit radioactive particles (such as Uranium), and toxic chemicals (such as methyl mercury)?

It's true. The actual mass of the various contaminants depends on the source of the coal. If I have time, I'll provide a breakdown at some stage. The radioactive particles are not Uranium. I have a feeling that it's mainly radon gas. You get a certain amount of that in natural gas too.  In my dim and distant past, I recall testing sludge from LPG production for radioactive materials too.

Quote:
What kinds of emissions are there from nuclear reactors?
What levels of radiation have been released from modern reactors, and how does that compare to other sources of radiation to which we are exposed?


Excellent question. I'll try to find an answer for you. Your exposure depends on a lot of factors. The main factor is where you live. If you live on top of a mountain then that dramatically increases your exposure eg La Paz, Mexico City and Salt Lake City.  If you live in a building made from Granite, that significantly increases it again.

The biggest effect is from long haul air flights. I used to do a lot of those in the 1990's and carried my exposure badge with me.  On one occasion, I had 'please explain' phone calls from radiation health, who thought I had been playing with our radiation sources.  

Quote:
Can we reprocess nuclear waste and use it again, to reduce the quanty of waste?


That's exactly what happens.

Quote:
Can a modern reactor melt down like in the movies?


No.

I will try to answer your questions if I get time. These are the right questions to ask.
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Re: NUCLEAR POWER
Reply #119 - Sep 30th, 2010 at 3:38pm
 
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