Nuclear giant's green push splits environmentalists
Join the discussion below, or Read more at Chicago Tribune.
#1 Oct 21, 2007
Nukes are never given credit for converting
uranium to shorter-life fission products. The real
issue is phosphate fertilizer. It may come as a
huge surprise, but crop rotation fixes nitrogen and
not phosphates. 200 Mt-P2O5/year is needed to feed 9 billions and save the rain forests.
Phosphates must be produced from mining and
converted to soluble P2O5 by either reacting with
sulfuric acid or in an electric furnace. World phosphate
requirement is 200 Mt/y (1,000,000 metric tonnes P2O5
per year.) Restoring north Africa to productivity requires
10 Mt/y. Saving the rain forests will require at least
an extra 20 Mt/y.
Phosphates have roughly 100 ppm uranium. 200 MT
phosphates/y will liberate 20,000 tonnes uranium per
year. A 1.0 GWe light water reactor converts roughly
1 tonne uranium to fission products per year. A 1.0 GWe
breeder will use up less, maybe as little as 0.8 tonnes
uranium per year. A breeder can approach 50% net thermal efficiency using a dual-reheat cycle, if the heat is
rejected at a low enough temperature.
The phosphates alone produce enough uranium to
fuel 20,000 to 25,000 breeder reactors. Otherwise the
uranium sits around for billions of years liberating four-day-half-life radon gas. Radon gas decay daughters are a major source of environmental radiation exposure.
Atomic power plants convert the billion year half life
uranium to fission products. After less than 1000 years,
the fission product curies is less than the uranium that
was consumed. Fission products do not release radon gas. The crow: "Awk-eek! radioactive waste!" is in reality a lie by omission, unless the human race is expected to starve to death.
#2 Oct 21, 2007
William Ernest Schenewerk is correct that fission products released by fast breeder reactor do not release radon. As a biologist I am not so very concerned about radon gas. Evolution has endowed us to thrive in background levels of radiation up to 1000 millirems. This amount may be benifical to our health. DNA repair mechanisms are induced by slightly elevated levels of radiation. DNA damaged by coal smoke chemicals may also be repaired by radiation induced repair mechanisms. Our current radio active waste may be a golden egg. Breeder reactors can be fueled with it for more than a century. There will be no need to mine uranium for generations.
#3 Oct 21, 2007
William, I really liked your discussion on phosphate. I have a PhD in a plant physiology. It is true that phosphate and nitrogen and the energy to make the anhydrous ammonia and mine and solublize the phosphate has had a lot to do with adding to carrying capacity of the planet. I suppose plant breeding and genetic engineering has had a role to play. Anyway, Paul Erlich of "The Population Bomb" was certainly proved wrong. It is interesting to consider the amount of uranium in phosphate fertilizer. Uranium has such low specific activity that it really does not in most currcumstances constitute a radiation threat. As long as we can keep our annual explosure to under a 1000 mrem we are probably healthier for having it around. I view nuclear waste as a non issue. Fast breeder reactors will eliminate most of that threat. No one has been injure by nuclear waste in the past 50 years why should we think the nexr 50 should be different? After that nuclear waste will be an asset for fueling fast breeder reactors
#4 Oct 23, 2007
Nuclear will always, always be deadly. Nuclear will never, never be cost-effective. It should NOT be on anyone's green plate. There is way to much to lose.
#5 Oct 23, 2007
You have taken a very extreme position here. I could take the exact opposite extreme position and say that nuclear power is good to eat but that would not be correct either. The objective truth is always somewhere between the extremes. If you would seek more balanced sources of information it could change your outlook. It did for the founder of Greenpeace.
#6 Oct 23, 2007
You asked in another post why I had reservations with Gen IV nuclear that used more plutonium. By what I have been told by a physicist that taught college physics ,long ago and far away. The toxicity difference between uranium and plutonium is huge. Uranium,bad,plutonium more badder. Something about the difference of toxicity such as exposure to milligrams of uranium,bad,exposure to micrograms of plutonium,worse. It's not that Gen IV is not a better plan than clean coal,with sequestered CO2. The problem is making damn sure none of the "spent" reactor balls find their way into the environment by any means,terriorist or stupid! The Gen IV reactor balls are portable enough to conceal or just plain loose. O.K. physics guys,gals, weigh in on this.
#7 Oct 23, 2007
Toxicity is not the issue. Virtually all the heavy metals are toxic, such as lead, mercury, cadmium, uranium and plutonium, et al. Whether one is more toxic than another is a moot point. None is good to eat, so don't eat any. If these were components used in food production you might have a problem with toxicity. But since we are talking about the fissioning, or splitting, of atoms of primarily uranium and plutonium in highly isolated and sealed containers operating at extremely high temperatures, for purposes of making heat for electricity, toxicity means nothing. Your other concern of fuel balls getting into the wrong hands would be difficult to say the least. More accurately, it would be impossible. The substances are totally sequestered throughout their entire existance. After a stint in a fissioning pot, the contents become laden with highly radioactive fission products and must be remotely handled with automated equipment. I hope you don't think anyone could just walk up and sneak a few ball into their pockets and walk out with them. They would be crispy critters if they did. But as I pointed out to you earlier, the uranium and plutonium are placed in the balls to be consumed by fission. The process of being split apart gives off heat. Once having undergone fission, plutonium is not plutonium any more. It has been split into two smaller pieces of matter plus a few neutrons and neutrinos and toxicity has most likely been reduced. But forget abot food, it makes a great reactor fuel in a self-annihilating way. France is currently making about 70% of its electricity from reprocessed fuels containing plutonium and happily getting rid of some of the nuclear waste while doing it.
#8 Oct 24, 2007
Yet nobody has ever died from plutonium poisoning. People have died from gasoline poisoning.
#9 Oct 24, 2007
I have read a report that traced the myth that claims plutonium to be the most toxic substance on earth to Ralph Nader. He is a kook. Microbial toxins are many orders of magnitude more toxic. What is problematic about plutonium is that its specific activity is high enough to constitue a radiation hazard for thousands of years. If its half life was in the billions of years we would not be so fearful of exposure. If it were in tens of years it would decay away in a few hundred years. Plutonium must be safely stored for a few tens of thousands of years. What is so wonderful about fast breeder reactors is their ability to completely destroy plutonium leaving only fission products which need storage for a few hundred years. This is still a disadvantage, but most feel that waste embedded in glass and stored in stainless steel containers for 300 years has little probability for contaminating water or soil that would harm the world in which future generation will live. Compare that threat to waht global warming might do to the world our grandchildern will live and it is definately the lesser evil.
#10 Oct 24, 2007
But not very problematic. As the old vet noted above, nobody has ever died from plutonium poisoning. Also, nobody has ever died from the specific activity in plutonium. It is an alpha emitter. So all you have to do is wrap it like a loaf of bread and it can't hurt you. If plutonium is a radiation hazard; then salt substitute, courthouses, Brazil nuts and bananas are radiation hazards.
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