loren@dweasel.llnl.gov (Loren Petrich) (01/03/91)
The issue of chemical vs. nuclear poisons was brought up yet again. I feel that this anti-nuclear allergy that too many people have will someday be remembered as one of the irrational phenomena of our time. But I doubt that it is worse that the turn-of-the-century enthusiasm for patent medicines made from radium and other radioactive materials. As to chemical poisons being decomposable, that depends on what kind of chemical poison. Heavy metals cannot be chemically decomposed. And some chemical poisons are difficult to decompose, such as chlorinated hydrocarbons. The persistence of certain pesticides like DDT should be well known. True, DDT and other such non-biodegradable substances can be burned at high temperature, but burning at high temperature is just that. I remember some years back that the EPA was hoping to burn some toxic wastes in a ship at sea, but some environmentalists didn't like that idea very much. I keep on being amazed by the anti-RTG movement. They complain that those who send up RTG's on spacecraft have not done comprehensive studies of possible alternatives. Yet I wonder if the anti-RTG people have done anything similar. Consider the difficulties of doing maintenance on a spacecraft, which usually cannot be brought back to its designers. Millions of dollars and months of work go into designing some spacecraft, so it is important that they be likely to keep on working. One should try to use components that need as little maintenance as possible, and RTG's fit the bill very well. They are continuously "on" and have no moving parts. Solar cells are one common alternative, but they tend to degrade over time and they cannot be used in the outer Solar System, due to the extreme dilution of sunlight there. A focused-sunlight system would have several problems. A mirror would have to be kept pointing at the Sun, and the generating system has an abundance of moving parts, which are an all-too-familiar maintenance headache. There is also the problem of replenishing leaked working fluid. And I am not aware of any focused-sunlight system that has ever been used in a spacecraft. Chemical reactions are out of the question. Buth fuel and oxidizer would have to be taken along, which would add a serious amount of weight for a months-long mission. The power sources usually have an abundance of moving parts, and would have to be made redundant for the sake of safety (if one breaks down, the others could keep on moving). Batteries have a minimum of moving parts, but they usually have a very low available power to mass ratio (ask any designer of a battery-powered car). Fuel cells are relatively efficient, but even they have moving-part problems, and they require liquid hydrogen and oxygen, which must be kept away from heat. Systems using combustion can use fuels and oxidizers that are liquid at room temperature, but they also suffer from problems with moving parts -- consider typical turbines and piston engines. So either solar cells or RTG's are the way to go for spacecraft. I presume that this is the standard argument. In fairness to opponents of nuclear energy, I think that there is a sociological question to be considered. Most nuclear energy has been handled as large-scale projects. Simply consider how big a typical nuclear reactor is and how long it takes to build one. Big organizations have to justify their policies, and they often make excuses for keeping on doing what they have been doing. And they sometimes seem insensitive and arrogant. It's just what computers have seemed like in their early years, before personal computers became common. And on the issue of safety, one should ask what kinds of critical tests are possible. It is much easier to perform really tough tests on an RTG than on a nuclear reactor, so one may feel more confidence in their safety. And another possible difficulty with solar cells -- how much energy does it take to make them? They would not be too good if the amount of energy needed to make them was only equal to their output for several years of running. Has that question ever been addressed? $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Loren Petrich, the Master Blaster: loren@sunlight.llnl.gov Since this nodename is not widely known, you may have to try: loren%sunlight.llnl.gov@star.stanford.edu
Ordania-DM@cup.portal.com (Charles K Hughes) (01/04/91)
> > The issue of chemical vs. nuclear poisons was brought up yet >again. I feel that this anti-nuclear allergy that too many people have >will someday be remembered as one of the irrational phenomena of our >time. But I doubt that it is worse that the turn-of-the-century >enthusiasm for patent medicines made from radium and other radioactive >materials. I don't think the "allergy" is irrational given 3-mile island, Chernobyl, lists of missing nuclear fuel, 55 gallon drums of nuclear waste carelessly spewn across the ocean floor (& associated tales of using rifles to shoot holes in drums that wouldn't sink), etc. Radioactive materials are dangerous to complex organisms, and the more RM that is around, the more dangerous it is (the probability of an accident increases). > > As to chemical poisons being decomposable, that depends on >what kind of chemical poison. Heavy metals cannot be chemically >decomposed. And some chemical poisons are difficult to decompose, such Heavy metals don't need to be decomposed - they can be refined and reused. >as chlorinated hydrocarbons. The persistence of certain pesticides >like DDT should be well known. True, DDT and other such >non-biodegradable substances can be burned at high temperature, but >burning at high temperature is just that. What we can make, we can unmake. I don't think the environment should be responsible for decomposing the unnatural chemical compounds that we introduce into it. The cost of "unmaking" is very high, mainly because it is cheaper in the short run to just discard the waste byproducts. In the long run, these byproducts will come back to haunt us - cf. Lovecanal, DDT, etc. > > I remember some years back that the EPA was hoping to burn >some toxic wastes in a ship at sea, but some environmentalists didn't >like that idea very much. I can't imagine why. > > I keep on being amazed by the anti-RTG movement. They complain What is RTG? >that those who send up RTG's on spacecraft have not done comprehensive A nuclear power plant? >studies of possible alternatives. Yet I wonder if the anti-RTG people >have done anything similar. Consider the difficulties of doing >maintenance on a spacecraft, which usually cannot be brought back to >its designers. Millions of dollars and months of work go into >designing some spacecraft, so it is important that they be likely to >keep on working. One should try to use components that need as little >maintenance as possible, and RTG's fit the bill very well. They are >continuously "on" and have no moving parts. Solar cells are one common > [solar cells degrade] > [focused sunlight systems require lots of moving parts] > Chemical reactions are out of the question. Buth fuel and >[good reasons deleted] >moving). Batteries have a minimum of moving parts, but they usually >have a very low available power to mass ratio (ask any designer of a >battery-powered car). Fuel cells are relatively efficient, but even >they have moving-part problems, and they require liquid hydrogen and >oxygen, which must be kept away from heat. Systems using combustion >can use fuels and oxidizers that are liquid at room temperature, but >they also suffer from problems with moving parts -- consider typical >turbines and piston engines. > > So either solar cells or RTG's are the way to go for >spacecraft. I presume that this is the standard argument. Hmmm...why not ground or space power generation for those satellites that orbit the earth & moon? Deep space satellites are of little concern here because once they leave, they're gone for good. RTGs (assuming they are small nuclear plants) are dangerous in any orbit that decays before the nuclear fuel becomes non-radioactive. > > In fairness to opponents of nuclear energy, I think that there This is war buddy....you know the saying... :) > > And on the issue of safety, one should ask what kinds of >critical tests are possible. It is much easier to perform really tough >tests on an RTG than on a nuclear reactor, so one may feel more >confidence in their safety. I still don't like the idea of a blob of nuclear goop falling from the sky into my living room. :) > > And another possible difficulty with solar cells -- how much >energy does it take to make them? They would not be too good if the >amount of energy needed to make them was only equal to their output >for several years of running. Has that question ever been addressed? If the energy is free, who cares how much it took to make them? > > >$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ >Loren Petrich, the Master Blaster: loren@sunlight.llnl.gov > >Since this nodename is not widely known, you may have to try: > >loren%sunlight.llnl.gov@star.stanford.edu The real question (as I see it) is the *TRUE* cost. Burning fossil fuels is cheaper than solar, nuclear is cheaper then solar, almost everything is cheaper than solar if only the current fuel costs are looked at. If the total cost of burning fossil fuels, using nuclear energy, etc is totalled, solar will come out the clear winner. Charles_K_Hughes@cup.portal.com
jdnicoll@watyew.uwaterloo.ca (Brian or James) (01/04/91)
In article <37550@cup.portal.com> Ordania-DM@cup.portal.com (Charles K Hughes) writes: (tons of RTG and nuclear power stuff deleted) >> And another possible difficulty with solar cells -- how much >>energy does it take to make them? They would not be too good if the >>amount of energy needed to make them was only equal to their output >>for several years of running. Has that question ever been addressed? > > If the energy is free, who cares how much it took to make them? *Sigh* Let's say that a solar cell takes 10 arbitrary energy units to make. Let's say it produces 9 AEU during its life. That means every time you install one, the net cost to the power production system is one AEU. Things that use up more of a resource than they produce do not, on the whole, make good sources for that resource. It's reasoning like Mr. Hughes' that gives the anti-nuclear folks a bad name. James Nicoll
gary@ke4zv.UUCP (Gary Coffman) (01/05/91)
In article <37550@cup.portal.com> Ordania-DM@cup.portal.com (Charles K Hughes) writes: > > I don't think the "allergy" is irrational given 3-mile island, >Chernobyl, lists of missing nuclear fuel, 55 gallon drums of nuclear waste Actually Three Mile Island showed that primary confinement works even in an induced loss of cooling accident. Chernobyl showed that even the worst scenario put up by the anti-nukes, core meltdown, *no* confinement, and a core fire for God's sake, didn't result in the fearmongers predicted mega-deaths. >> As to chemical poisons being decomposable, that depends on >>what kind of chemical poison. Heavy metals cannot be chemically >>decomposed. And some chemical poisons are difficult to decompose, such > > Heavy metals don't need to be decomposed - they can be refined and reused. So can nuclear fuels, but we're soooo scared we don't. >> I keep on being amazed by the anti-RTG movement. They complain > > What is RTG? Radioisotope Thermoelectric Generator. A completely sealed, no moving parts, no active control system, lump of radioactive material that gives off enough heat through natural radioactive decay to heat a thermopile enough to generate useful amounts of electrical power. >> So either solar cells or RTG's are the way to go for >>spacecraft. I presume that this is the standard argument. > > Hmmm...why not ground or space power generation for those satellites >that orbit the earth & moon? Deep space satellites are of little concern >here because once they leave, they're gone for good. Beamed power has been very strongly opposed by the enviornmentalists because of the supposed danger of the microwave power beam used to transmit the energy. Or were you planning to use a *really* long extension cord. > > RTGs (assuming they are small nuclear plants) are dangerous in any orbit >that decays before the nuclear fuel becomes non-radioactive. RTGs are designed to survive rentry without breaching their sealed shielding. The designs used have been exhaustively tested by actually sending dummy units up and causing them to renter. They work. >> And on the issue of safety, one should ask what kinds of >>critical tests are possible. It is much easier to perform really tough >>tests on an RTG than on a nuclear reactor, so one may feel more >>confidence in their safety. > > I still don't like the idea of a blob of nuclear goop falling from the >sky into my living room. :) Hook a couple of leads to it and run your computer off of it for a few years. Now that's a UPS! >> And another possible difficulty with solar cells -- how much >>energy does it take to make them? They would not be too good if the >>amount of energy needed to make them was only equal to their output >>for several years of running. Has that question ever been addressed? > > If the energy is free, who cares how much it took to make them? If it takes more fossil fuel to manufacture them than they will produce over their operating lifetime you care. And it does take more energy to manufacture them than they produce over their lifetime. They are net energy losers. Also the manufacture of solar cells requires some very nasty chemicals that must be disposed of after manufacture. > The real question (as I see it) is the *TRUE* cost. Burning fossil fuels >is cheaper than solar, nuclear is cheaper then solar, almost everything >is cheaper than solar if only the current fuel costs are looked at. If the >total cost of burning fossil fuels, using nuclear energy, etc is >totalled, solar will come out the clear winner. > >Charles_K_Hughes@cup.portal.com For solar cells the answer is a clear no on an energy basis and an enviornmental basis. For solar boilers driving freon turbines the energy cost is a net win. But the enviornmental costs are bad considering what the inevitable freon leaks will do to the ozone layer. Maintence costs in general are high since efficiency is very low and you need a lot of them to produce useful power. Perhaps the worst effect of using large scale solar energy to replace fossil fuels or nuclear plants is the effect on the climate. By placing large arrays of solar cells or solar turbines on the surface of the earth, you dramatically change the reflectivity of the earth in that area. A good solar collector absorbs almost all of the solar energy striking it and reradiates very little thus creating a hotspot in the local enviornment. The effects on the weather of the several hundred square miles of solar collectors needed to replace one nuclear plant should be spectacular. Gary
cage@fmeed1.UUCP (Russ Cage) (01/05/91)
In article <37550@cup.portal.com> Ordania-DM@cup.portal.com (Charles K Hughes) writes: > I don't think the "allergy" is irrational given 3-mile island, >Chernobyl, lists of missing nuclear fuel, 55 gallon drums of nuclear waste >carelessly spewn across the ocean floor (& associated tales of using rifles >to shoot holes in drums that wouldn't sink), etc. Three-Mile Island neither killed nor harmed anyone. It was also about the worst possible accident for that reactor type. Chernobyl was a bad design, and thus a special case. Just because an airplane built by an idiot is likely to crash and kill him does not mean all airplanes are dangerous. Lists of "missing" nuclear fuel can mean nothing more than bookkeeping errors. They do not imply hazard except to the hysterical; nuclear fuel != nuclear bombs. Said drums sound like an apocryphal horror story. However, a steel drum would not last long in the sea, and would be crushed by ocean-floor pressure anyway. If it contained, say, machine parts with enough air space to float it, shooting holes in it to sink it is perfectly reasonable. (A barrel full of heavy sludge wouldn't float.) > Radioactive materials are dangerous to complex organisms, and the more >RM that is around, the more dangerous it is (the probability of an >accident increases). Really? Then tell me why there have been far more medical disasters (Minimata (sp?) syndrome) caused by chemical poisons than by nuclear ones? > Heavy metals don't need to be decomposed - they can be refined and reused. How are you going to refine the 5 ppm of lead in your drinking water into metallic lead for re-use? Do you have any concept of the thermodynamic property of ENTROPY, and the ENERGY input required to reduce it? I thought not. > What we can make, we can unmake. I don't think the environment should be >responsible for decomposing the unnatural chemical compounds that we >introduce into it. The nice thing about short-lived radionuclides is that they un-make themselves, and many of them have useful properties while so doing. (Iodine for radio-immuno-assays and treatment of thyroid disorders. Cobalt for radiation therapy and food preservation. Krypton for lights which require no power, for safer roads in remote places.) > The cost of "unmaking" is very high, mainly because it is cheaper in the >short run to just discard the waste byproducts. In the long run, these >byproducts will come back to haunt us - cf. Lovecanal, DDT, etc. Yet another reason why nuclear power is a good idea. For a few tons of material per year (which is EASY to track, comparatively), you can avoid using millions of tons of something else which is likely to yield chemical poisons like Love Canal's sometime during its production or use. > What is RTG? > A nuclear power plant? RTG = Radioisotope Thermal Generator. They are not "reactors"; they generate power using the heat given off by certain isotopes, which are refined from spent nuclear fuel. These are ideal for powering space probes which go far from the sun, and are yet another useful byproduct of nuclear power. > Hmmm...why not ground or space power generation for those satellites >that orbit the earth & moon? Deep space satellites are of little concern >here because once they leave, they're gone for good. Satellites built for trips inside Mars orbit typically use solar cells. Galileo (bound for Jupiter) and Ulysses (heading for the south pole of the Sun via Jupiter), plus the Pioneer and Voyager probes (remember the Voyager-Saturn encounter on TV?) are all powered by RTG's. Lander probes (such as the lunar ALSEP packages and the Viking Mars landers) use RTG's to get through the night. > RTGs (assuming they are small nuclear plants) are dangerous in any orbit >that decays before the nuclear fuel becomes non-radioactive. Wrong. They are sufficiently well-encapsulated to survive re-entry and impact without loss of fuel, unless they strike rock. The RTG's on board the Apollo 13 LEM re-entered and hit the Pacific somewhere. No trace of radioactive material was found. > This is war buddy....you know the saying... :) A war on truth, perhaps? > I still don't like the idea of a blob of nuclear goop falling from the >sky into my living room. :) You won't see one from us. The chances of seeing one from the Soviets goes down steadily. > If the energy is free, who cares how much it took to make them? If you have to put energy in to make something, is it "free"? (Is this the best thinking you can present?) -- Russ Cage Ford Powertrain Engineering Development Department Work: itivax.iti.org!cfctech!fmeed1!cage (CHATTY MAIL NOT ANSWERED HERE) Home: russ@m-net.ann-arbor.mi.us (All non-business mail) Member: HASA, "S" division.