|Feb25-05, 03:09 PM||#1|
Nuclear Now! - Article on Wired.com
How clean, green atomic energy can stop global warming
Interesting perspective on the present and future of nuclear energy in the world.
|Feb26-05, 09:20 AM||#2|
Fits very well IMHO the sensible environmentalism we ought to be exercising ... and we'll be getting our fifth net-1600 MW installation up and running 2009.
|Apr19-05, 10:56 AM||#3|
Quick question then. I am no expeert at nuclear theory, just an interested reader. How do pebble-bed reactors work in nuclear power production ?
|Apr19-05, 11:05 AM||#4|
Nuclear Now! - Article on Wired.com
In order to have a reactor produce power - it has to be "critical" - that is
it has to be in a configuration where the production and destruction of
neutrons are in balance.
There is no ONE way to do that. You can have any configuration that works.
Water cooled reactors have their fuel in the form of cylindrical pellets that
are loaded in long zirconium tubes. An array of these tubes are packaged
together to form an assembly. The reactor core consists of an array of
But that's just one configuration. An alternate is the "pebble bed".
Here the fuel is encased inside little balls of graphite. The core then
consists of a volume with a whole bunch of these little balls. You can
obtain a critical configuration in this manner too - so long as the
mixture of materials is correct.
A cooling gas flows around the graphite balls and removes the heat.
This cooling gas is then run through a heat exchanger - not unlike the
heat exchanger or steam generator in a pressurized water reactor.
The gas gives up its heat to water on the other side of the heat exchanger
which then turns to steam. From then on - it's just like any other nuclear
or fossil fuel plant. The steam turns a turbine, which drives a generator.
Dr. Gregory Greenman
|Apr19-05, 01:12 PM||#5|
The Wired article makes basically the right arguments for basically the right reasons.
One place where a switch to nuclear power would be a particularly good idea and particularly dramatic (although the state constitution would have to be amended) is the island of Oahu in Hawai'i. Currently, Hawai'i is the only state in the nation has most of the electricity it consumes produced by burning petroleum. A single typical sized nuclear power plant could end this for the entire island.
This would be a very good thing for Hawai'i. The state's economy is powered by tourism and fishing. A single oil spill could wipe that out. As we all know, oil spills are hardly unprecedented. And, when your state gets almost all of its electricity from burning oil, tankers have to flow into your ports like clockwork. Also, it isn't as if the state doesn't already routinely have vessels carrying nuclear fissionable material pass through its ports. Nuclear powered U.S. attack submarines and aircraft carriers routinely make port calls in Hawai'i. And, of course, the reduction in air pollution caused by a nuclear power plant would be an added bonus (although Hawai'i mostly exports this problem to the North American West Coast).
Nuclear power would insulate Hawai'i from the negative effects of rising oil prices and world political instability.
And, Hawai'i also has the virtue of having very stable demand for electrical power. It doesn't have large surges in demand from air conditioner use, for example.
And, if you wanted to follow the Wired article scenario further, the island of Oahu would also be the ideal place to convert motor vehicles from gasoline to some form of electricity storage device, be it conventional batteries, fuel cells, or compressed hydrogen from electrolisis. After all, Hawai'i is better positioned than any other state to regulate its automobile fleet. Cars from other states aren't just going to drive into the state. Also, subsidies of local automobile fueling infrastructure and vehicles are unlikely to seep out to benefit people who didn't pay the taxes that made those subsidies possible. The main disadvantage of electric vehicles, which is short range, is not a problem on Oahu, where all trips are by necessity short ones, and where most of the population spends most of its time in one fairly densely populated city. The fuel infrastructure is manageably finite -- there are only so many gas stations on the island that would have to be converted.
The reason to do this, unlike California, again, has not so much to do with air pollution which gets exported to the West Coast and can more easily be controlled with California style emissions standards if that is a concern. The reason to do it is the greatly reduce the flow of spill prone oil tankers into Hawai'is pristine harbors, and to reduce the state's economic dependence on oil whose prospects for growing more expensive in the future are significant. Also, the novelty of being one of the world's first nearly oil free economies (although boats would still likely need petroleum based fuel) might help boost tourism in addition to reducing the risk of an oil spill which could destroy tourism and fishing.
It would be controversial to build to nuclear power plant on the island. But, once it was built, the experience of other places that have nuclear power shows that the locals would hardly even notice or care (although electric cars would, of course, be noticable).
Now, here is one technical question. While the Hawai'ans would probably best served by exporting the small quantity of high level nuclear waste to Yucca Mountain (via boat and then a truck from LA or San Diego to Nevada), could Hawai'i deal with low level nuclear waste by simply dumping it into the lava of one of its local volcanos, or would that entirely defeat the purpose of containing potentially radioactive materials as the lava might spew radioactive material everywhere?
|Apr20-05, 06:36 AM||#6|
Would it be possible to dump nuclear waste into a volcano and melt it?
One of the issues surrounding Yucca Mountain is that of whether or not it is likely to erupt soon.
|May28-05, 07:04 PM||#7|
ok im new to this forum, but theres always a few questions i've wanted answering about nuclear radiation, they say that the combined addition to background radiation from man made nuclear accidents, weapon testing ect, has added 0.001 rad to the overall background level radiation, but i also know that the higher you go the more rads affect you, when these man made incidents occured is it possible that due to the dust sucked up in testing, that this has settled in the upper atmosphere unable to fall back to earth, and could this be whats eatting at the ozone layer aswell as or instead of greenhouse gasses????
thankyou if you reply to this message its a question or questions i've had for years
|May29-05, 08:28 AM||#8|
I believe that the current theory is that CFC - chloro-fluoro carbons are a (the) key factor in ozone depeletion. Reduction or elimination of CFC's, in theory, should help stablize the ozone levels. On the other hand, we have only become aware of the ozone layer relatively recently, so it is not clear to me that we fully understand its cyclical nature. In any case, I believe CFC's should be phased out because they do not occur natually, and as much as possible, mankind should not be putting damaging chemcials in the environment.
|May31-05, 09:32 AM||#9|
It's not radiation that is "eating at" the ozone layer - in fact ozone is
CREATED by radiation. It is the interaction of the UV radiation from
the Sun that serves as the source of ozone high in the atmosphere.
Courtesy of the Health Physics Society at the University of Michigan:
one sees that fallout accounts for less than 1 mrem per year in the
average person's dose. The average person gets about 360 mrem per
year of radiation dose - the bulk of which is from purely natural
Nuclear power and fallout from nuclear tests combined are less than
1% of the average person's background radiation exposure.
Dr. Gregory Greenman
|May31-05, 11:56 AM||#10|
|Jun6-05, 06:17 PM||#11|
There was a bit of a fuss here in europe about strontium 90. Apparently it doesn't occur naturally in people but since the nucleur testing of the 50s everybody has some. Some years back Dr Linus Pauling of Cal (nobel prize winner) said the only safe level of strontium 90 in children's bones is 0 whereas the British PM Tony Blair on the advise of his scientific advisers disageed. Anybody know where the truth lies? And if there are long term effects what they are likely to be? I believe this arose as a question in parliament related to the long term effects of Chernobyl.
|Jun7-05, 03:06 PM||#12|
PM Tony Blair is correct, and Linus Pauling is overstating the case.
Think about it. You have radiation sources in your body that are purely
natural, like the Carbon-14 in all the organic tissue or Potassium-40.
You are being irradiated by the material that you are made of!
At some finite level, greater than Pauling's '0', the amount of radiation
from Strontium-90 is a small, insignificant fraction of the background
radiation that you are normally exposed to because of the natural
radiation in your own tissues, or the natural cosmic radiation coming
out of the sky, or the radiation from all the naturally radioactive
materials in your world.
Courtesy of the Health Physics Society at the University of Michigan:
you can see that the average person receives about 360 mrem of
radiation dose per year. You can also see that less than 1 mrem of
that is due to fallout from nuclear tests.
So the other sources of radiation dose in your life swamp the fallout
dose by a factor of over 300.
Additionally, research shows that low-level radiation exposure is
actually protective. It "challenges" the body's own radiation damage
repair mechanism much as a vaccine challenges the immune system.
So good for Tony Blair; he understands better than a Nobel Laureate.
Dr. Gregory Greenman
|Jun9-05, 03:51 PM||#13|
With regard to the article, personally I am undecided on whether nucleur power is the way to go. If it transpires it is the only way to go then I guess we'll all have to learn to live with it. However nucleur power production has a deservedly very bad reputation. To my knowledge I know of 3 major incidents; Chenobyl - USSR: 3-mile island - USA: and Sellafield (formally Windscale) - Britain. Living in europe I am most familiar with Sellafield who following a major release of radioactive material during a fire in the 50s has continued to have a dreadful safety record ever since. None of the many leaks reported since the 50s incident has been as bad but are important none-the-less. In fact the last accidental release of radioactive material was discovered or rather admitted to only last week. nb Power is no longer produced in Sellafield but it now reprocesses spent fuel for both Britain and customers abroad. Given the relatively limited number of nucleur plants operating in the world this is statistically a very significant number of accidents in what claims to be an ultra safe industry.
Where I am getting to is instead of arguing how bad carbon based fuels are for the planet, which is akin to the modern trend of negative campaigning by politicians, why doesn't the nucleur industry inform us as to what it is doing to genuinely improve safety and what their plans are to manage worst case scenarios. Unless people are convinced then even if governments decide to implement a pro-nucleur policy the developers will be tied up for years in planning and environmental hearings and appeals.
|Jun9-05, 08:15 PM||#14|
List of CFC's and HCFC's in table at bottom of webpage - http://www.iifiir.org/2endossiers_fi...sification.htm
Presumably the reduction in Cl and F in the HCFC's has contributed to the redcution in the ozone depletion. But then where does the Cl and F go?
|Jun9-05, 08:28 PM||#15|
You could even compare safety records and no one would give a crap because for one, theres still a widespread believe that an explosion would turn into a nuclera explosion and wipe out a city. Dont even dare mention that the number of incidents of nuclera power plants in its entire history can barely be counted on yoru hands while any other industry... u could count on maybe a neighborhoods collective hands.
Its in the best interest to simply attack fossil fuels and other non-renewables because if you promoted nuclear power, people wouldnt understand what your sayen or of course, think back to its in-grown fear of anything they dont understand. Attacking is so much easier and gets to the public's head easier because we're already in-born with this fear of coal and oil and effects of stuff like that. Why waste your time when the most productive method is probably to attack.
|Jun10-05, 10:08 AM||#17|
Strontium-90 is similar to Calcium and concentrates in the bones.
Iodine-131 will replace ordinary Iodine in the thyroid....
There's nothing special about concentrating in one region of the body
or the other - practically every radionuclide concentrates somewhere.
The naturally radioactive isotopes concentrate in certain tissues too -
so there's nothing "special" about man-made radioisotopes that makes
them any more dangerous because they concentrate somewhere.
Unit dose per unit dose - naturally occurring radioisotopes cause just
as much risk as man-made radioisotopes - but there's a lot more
natural radioisotopes; so your dose due to natural sources is hundreds
of times more than man-made radioisotopes.
That's all been taken into account in the table.
an industrial reactor - it was a nuclear weapons production reactor
operated by the British government. Governments, unfortunately
exempt themselves from the safety regulations. Same with Chernobyl -
the operators had disabled the safety features in order to keep the
reactor running for an experiment.
As far as Three Mile Island in the USA; that accident released a very
insignificant amount of radioactivity. According to the Rogovin Report,
which studied the accident; the average person living aroung TMI-II got
about 1.4 mrem of additional radiation over about a week's time.
As the table I cited indicates, you get about 1 mrem per day just due to
natural background radiation. In a coast to coast airliner flight in the
USA - LA to NY, for example; you get about 10 mrem - or 7 times what
the people around TMI-II received. You get 7X more radiation in a few
hours vs what those around TMI-II received in a week. The damage due
to radiation is correlated to the rate at which you receive that
radiation dose - and the radiation dose rate in the airliner is over
200 times that around TMI-II during the accident.
In fact, there was so little radiation exposure to the public, that the
judge, Slyvia Rambo; in the case against the operators of TMI-II granted
summary judgment in Met-Edison's favor w/o trial:
"The paucity of proof alleged in support of Plaintiffs, case is manifest.
The court has searched the record for any and all evidence which
construed in a light most favorable to Plaintiffs creates a genuine issue
of material fact warranting submission of their claims to a jury. This
effort has been in vain."
You say you will "just have to learn to live" with nuclear power; but you
probably accept the combustion of coal as a power source. In the USA,
coal combustion is the largest producer of electric power - and is
However, as scientists from Oak Ridge have published - you get a hundred
time more RADIATION from coal as you do from nuclear power:
In addition, coal contributes CO2 the atmosphere to exaccerbate the
global warming problem, as well as a bunch of other junk in the coal.
However, because coal contains trace amounts of uranium and thorium
the radiation exposure due to coal combustion is 100X that from a
nuclear power plant. So why the reticence to accept nuclear power,
when you probably have already accepted something that is 100X
worse at emitting radioactivity?
The nuclear industry is safer than the airliner industry. The nuclear
industry has had only a handful of accidents - the one in the USA didn't
harm the public. How many crashes of airliners have there been? Each
of those kills a couple hundred people or so. So is nuclear power so
Additionally, the nuclear industry has made great improvements since
the Three Mile Island accident.
Unfortunately, if the industry espouses what they've done for safety -
then the anti-nukes claim they are propagandizing. One year when I
was a graduate student at M.I.T.; the Institute had a "open house" for
the public. The theme was to show how science and technology affects
our lives. I was stationed in front of a model of a nuclear power plant.
I had some brochures about nuclear power plants and nuclear safety
that the Institute got a local nuclear utility to contribute.
I handed one of these to a young woman who was perusing the exhibit
that I was explaining. She looked at the brochure, commented that it
was a nice brochure, and asked who paid for it. I stated that it was
provided courtesy of the local nuclear utility; whereupon she handed
it immediately back to me - stating she would not read anything from
the local nuclear utility.
That's the attitude the nuclear industry has to deal with. If you have
any suggestions as to how they get their message out when faced with
that type of attitude - I'd welcome any suggestion you have.
Dr. Gregory Greenman
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