Archived posting to the Leica Users Group, 2006/02/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Most of Cornwall (UK) is built on granite bed-rock, many houses there suffer from high concentrations of naturally occuring radioactive radon gas seeping into cellars through the bedrock. Douglas Raimo K wrote: > 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 > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > >