Archived posting to the Leica Users Group, 2006/02/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Thanks for the clarification of the picture - but I still see no radiation escape from the deep granite caves. All the best! Raimo K Personal photography homepage at: http://www.uusikaupunki.fi/~raikorho ----- Original Message ----- From: "Adam Bridge" <abridge@gmail.com> To: "Leica Users Group" <lug@leica-users.org> Sent: Thursday, February 02, 2006 7:55 PM Subject: Re: [Leica] RE: LUG Digest, Vol 31, Issue 221 > When Uranium is fissioned two different elements are created and each > of these elements is unstable (usually quite seriously unstable) and > so they decay into different nuclides by various mechanisms, all of > which give off serious amounts of gamma radiation. The half-lives of > these fission products vary but the entire chain takes tens of > thousands of years to reach low-level proportions. The spent fuel > isn't explosive although it does produce heat as a result of the > radioactive decay. They don't burn, in general they are metals > > The amount of radiation in a reactor core which has never been > critical, that is to say a self-sustaining nuclear reaction has never > happened in it, is quite small. Before the core was loaded into PARCHE > I was able to look up inside it with no protection except for the > requirement to keep everything VERY clean. > > But at the end of life the amount of radioactivity is quite vast - > many mega-Curies of radioactivity. (The Curie itself is a huge amount > of radioactivity, it represents a certain number of disintegrations > per second. Normal limits for things are normall expressed in > micro-micro-Curies to give you an idea.) > > As a rough approximation, if you are 1 meter away from a 1 Curie > source of gamma-emmiting you'll receive an exposure of 1 REM/hr. REM > is a measure of biological damage produced by radiation. > > The limit for non-radiation workers are .1 REM/year over and above > what you get from normal background radiation - ie cosmic rays etc. If > you live at altitude you get more than if you live at sea level for > example. Medical/Dental x-rays aren't counted in this either. You > typically get about 200 mili-rem from natural souces - radon gas which > happens naturally is the biggie - and 40 mili-REM from x-rays per > year. > > An exposure of (oh boy these numbers are hazy, it's been a long time) > of 50 REM over a short period will produce identifiable changes in > your blood. 100 Rem acute will make you ill, the threshold of > mortality is 150 REM and I think the 50/50 dose is 500 REM IF you get > the best medical treatment - meaning 50% of the people exposed will > die. 100% mortality is 800 REM. > > Radioactive waste from nuclear reactors is in the realm of mega-REM. > The decay of the fission products produces heat. Many of the elements > are themselves corrosive. So it's a tricky problem - especially if you > want to have something stored unguarded. Most fuel-rods are stored > deep under water in pools that are on the grounds of the reactor plant > that produced them. In fact, in the US this is where they have to STAY > since there is no long-term storage facility. > > As you might guess they are not easy to steal, either. Somehow you'd > have to take over a facility, find a big lead container, use remote > handling equipment, remove the rods, put them into the container, > move them. They are typically in stainless steel or zirconium cladding > of some sort or other. Trying to grab one without the remote handling > would be seriously ugly for the people attempting it. It ain't like > the movies. > > I hope this was useful and not too technical. My days as a reactor > operator are three decades past. I know that new units of measure are > now included in the SI system but I haven't had a reason to keep up. > > Adam Bridge > > On 2/2/06, Raimo K <raimo.m.korhonen@uusikaupunki.fi> wrote: >> How can used stuff have more radiation than unused? If it had, it would >> be >> usable. >> OK, it is concentrated into granules but if you store it deep in stable >> rock >> caves (like we plan to do in Finland) and take into account the immense >> mass >> of stone around the storage I see no way it can have increased radiation >> compared with hot uranium mines. >> All the best! >> Raimo K >> Personal photography homepage at: >> http://www.uusikaupunki.fi/~raikorho >> >> >> ----- Original Message ----- >> From: "Douglas Sharp" <douglas.sharp@gmx.de> >> To: "Leica Users Group" <lug@leica-users.org> >> Sent: Thursday, February 02, 2006 12:51 AM >> Subject: Re: [Leica] RE: LUG Digest, Vol 31, Issue 221 >> >> >> > Hello Frank, >> > the refined stuff has a much higher radiation output than the ores - >> > think >> > of tiny granules of uranium mixed in with great chunks of rock which, >> > at >> > least partially stop the radiation, and, btw, make uranium mines so >> > hot. >> > There is one method of sealing nuclear waste which is effective as far >> > as >> > it goes, sealing it in glass with a large proportion of lead (which >> > doesn't shield from radiation, it absorbs it and changes over time) >> > this >> > has again the inherent problem of heat, the energy has to come out >> > somewhere. Before somebody suggests dropping it into volcanos, the >> > molten >> > lava is much too close to the surface, getting sprayed with molten rock >> > is >> > bad enough, but making it radioactive too is a bit much. >> > >> > As to the plastics, there are some fascinating developments on the way >> > with high quality plastics made from potato starches and waste straw >> > from >> > maize crops, then there's always multitudes of natural vegetable oils >> > which haven't really been tested for making the polymers we need for >> > plastics. >> > The power of biological products can be seen in the recipe for casein >> > glue - just mix curds and chalk - one of the best and oldest glues >> > there >> > is. >> > The energy business is going to become one of the main areas for the >> > development of genetically modified plant strains, the other area is >> > the >> > creation of bacteria which can reduce waste plastics to their original >> > source materials - but that is a pandora's box I don't care to think >> > about - just let a bacterium like that get out of hand or mutated and >> > start chewing up plastics just where it shouldn't, I shudder at the >> > thought. >> > It's interesting that most of the large oil companies are working very >> > hard in this direction, particularly Shell and BP, they want to have >> > the >> > market cornered when the time is ripe. There was a research project for >> > loosening up heavy oil deposits in a reservoir by dropping anaerobic >> > bacteria down through the borehole, but I left the business before >> > hearing >> > more about it. >> > The last stuff I was working on was the localisation of deep seated >> > magma >> > bodies for geothermal energy production in Tuscany (Larderello,where >> > they've been doing it since the early 1920s) my theory for variations >> > in >> > their heat production was that these bodies are also subject to tidal >> > forces caused by the position of the moon pulling them closer to the >> > surface, unfortunately I never did hear what came of that either. At >> > least >> > there was a significant increase in microseismicity (tiny earth >> > tremors) >> > at full moon, which seems to support my theory. >> > To get back on track, the visit to ENEL GreenPower in Pisa was a >> > wonderful >> > opportunity to wander around that beautiful city with a camera. >> > cheers >> > Douglas >> > >> > Frank Dernie wrote: >> > >> >> Douglas, >> >> I have always wanted to ask a specialist this question, and it looks >> >> like you may just be the person......... >> >> What is wrong with burying nuclear waste in the exhausted mines from >> >> which it originated? Presumably it won't be any more dangerous there >> >> than the raw nuclear material originally mined???? >> >> The biggest concern I have re oil is not its use as a fuel, that >> >> seems a >> >> terrible waste to me, but as the raw material for manufacturing >> >> materials such as plastics for which we have no reasonable >> >> alternative. >> >> Frank >> >> >> >> On 1 Feb, 2006, at 19:30, Douglas Sharp wrote: >> >> >> >>> The technologiy is clean enough, and close to being as safe as it >> >>> can >> >>> be - the problem is still nuclear waste. As a production and >> >>> exploration geophysicist I've worked on nuclear waste storage sites, >> >>> working and prospective, in Germany, Belgium, Switzerland and a few >> >>> other places. For the long-term storage of nuclear waste there is NO >> >>> really safe solution, that stuff stays highly radioactive on a >> >>> geological time scale. >> >>> Salt dome caverns are no good - salt moves and migrates so you've >> >>> never got a constant thickness shielding your waste, the Swiss >> >>> solution >> >>> of putting it in caverns blasted out of native impervious >> >>> (supposedly) >> >>> rocks is better but radiactive gases (Radon for example) always >> >>> manage >> >>> to find a way to the surface. The Belgian method of hiding it under >> >>> a >> >>> thin layer of impervious clay isn't a long term solution either. >> >>> So what do we do with it? Shooting it into the sun is the only real >> >>> way of getting rid of it, there's been enough dropped into the sea >> >>> and >> >>> more than enough buried already, these "fly-dumps" will take their >> >>> revenge on the environment one of theses days. >> >>> You say that present day technologies are safe, I agree - problem >> >>> is, >> >>> even the most recent reactors just haven't been built with these new >> >>> technologies, Temsvar in the Czech Republic is one of the newest >> >>> NPSs >> >>> and is just not safe, the same applies to the latest French >> >>> reactors, >> >>> Germany's reactors have been plagued with problems and Sellafield in >> >>> the UK is a dirty word already. No need to mention reactors in the >> >>> former soviet block countries....... >> >>> >> >>> Fusion power is pie-in-the-sky (unless the billions for defence are >> >>> re-channeled), you might just as well try a further development of >> >>> Nikolaus Tesla's idea by building orbiting spaceborne solar power >> >>> stations transmitting power as high energy microwave frequencies >> >>> back >> >>> to earth, though I dread to think what would happen if a plane flew >> >>> through one of those tight banded transmissions. >> >>> The only clean options are terrestrial solar energy farms, wind and >> >>> tidal energy and geothermal energy - these are the only future I can >> >>> see in power production. >> >>> >> >>> Some of the latest developments reek of science fiction but could be >> >>> effective - half mile high chimneys set up in desert regions, the >> >>> temperature differential between ground level and the top creates >> >>> winds >> >>> of incredible velocities, all you have to do is put aturbine in the >> >>> way >> >>> of it. Using waste energy (off peak production is always too high >> >>> and >> >>> just gets wasted) from conventional power stations to pump water >> >>> into >> >>> high level reservoirs >> >>> to run hydroelectric turbines at peak demand times, storing energy >> >>> as >> >>> compressed air in salt domes is another option, use it to supply the >> >>> energy needed to get gas turbines running. >> >>> >> >>> None of these, however give us any kind of solution for automotive >> >>> transport - when the oil runs out we're going to back with sailing >> >>> ships and steam engines again, individual or personal transportation >> >>> will be the rich man's game. >> >> >> >> >> >> >> >> _______________________________________________ >> >> Leica Users Group. >> >> See http://leica-users.org/mailman/listinfo/lug for more information >> >> >> >> >> > >> > _______________________________________________ >> > Leica Users Group. >> > See http://leica-users.org/mailman/listinfo/lug for more information >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information