<More Tools for Rita The Oil Drum The third CERA increment>

18 comments on Open Thread and News Drop

Comments can no longer be added to this story.

| Show without comments | PDF version

isaiah on September 21, 2005 - 8:32pm Permalink | Subthread | Parent | Comments top
solar chimneys seem like an interesting and viable technology, but i would like to see a real 100-200MW chimney built before we invest in it heavily.  the 50kW protype in Spain is ok, but scaling-up (1000X power output) is never simple from an engineering perspective.  i'd be concerned about building in areas with earthquakes or hurricanes/typhoons. also, what kind of long-term durability do these things have?  we really don't know yet, as the protype only ran for around 3 years.    

you are right that more investment needs to be made into solar thermal and PV, wind, tidal/wave power, geothermal, thermal depolymerization, biodiesel, hemp, etc.  and of course the large energy corps are not doing the investment in serious R&D, it's the smaller companies and government that we have to rely on for that.  

as for being "demonstrated" the Russian breeder, BN-600 has been in operation since 1986, with 600MW (electric) output.  BN-350 (130MWe) is in Kazakhstan, reached criticality in 1973, and serves the dual purpose of electricity generation and water desalination.  

http://www.jnc.go.jp/zmonju/mjweb/world1.htm#USSR

as well, Phenix in France has been operating since 1973 and has a output capacity of 250MWe.  

http://www.jnc.go.jp/zmonju/mjweb/world.htm#France

the parabolic solar trough seems like a good solar thermal design.  to get $0.07/kW-hr is pretty darn good.  that's much better than PV solar, last i heard around 20-25cents/kW-hr, and around the same as nuclear electricity costs.  NG is still lower at around 3-5cents/kW-hr, while coal is even lower.  

i agree that nuclear energy (whether breeders or not) does require enormous capital investment (more than solar/wind/renwables).  perhaps its not entirely justified, but i think if we can use them to get rid of long-lived hot, radioactive waste, that in itself is a good thing.  

Comments can no longer be added to this story.
Everett on September 22, 2005 - 1:14am Permalink | Subthread | Parent | Comments top
I think that we will see a return to nuclear, though not just for electricity.  Cogeneration seems like a great match with heat-hungry processes for extracting and transforming LQHCs.

Uranium and plutonium are not the end of the story for nuclear energy.  Thorium is a significant alternative.

I am a bit puzzled by the mention of getting rid of "long-lived hot, radioactive waste."  Almost by definition, hot waste is short-lived, since high activity implies a short half-life, so it gets rid of itself in a few decades.

Comments can no longer be added to this story.
isaiah on September 22, 2005 - 4:26am Permalink | Subthread | Parent | Comments top
i understand your logic, Everett, and i'm not a nuclear physicist, but here's an excerpt from Wikipedia on "nuclear waste".

"High level Waste (HLW) arises from the use of uranium fuel in a nuclear reactor and nuclear weapons processing. It contains the fission products and transuranic elements generated in the reactor core. It is highly radioactive and hot. It can be considered the "ash" from "burning" uranium. HLW accounts for over 95% of the total radioactivity produced in the process of nuclear electricity generation.

There have been proposals for reactors that consume nuclear waste and transmute it to other, less-harmful nuclear waste. In particular, the Integral Fast Reactor was a proposed nuclear reactor with a nuclear fuel cycle that produced no transuranic waste; in fact, it could consume transuranic waste. It proceeded as far as large-scale tests but was then cancelled by the US Government.

To solve the waste disposal problem, the IFR had an on-site electrowinning fuel reprocessing unit that recycled the uranium and all the transuranics (not just plutonium) via electroplating, leaving just short half-life fission products in the waste. Some of these fission products could later be separated for industrial or medical uses and the rest sent to a waste repository (where they would not have to be stored for anywhere near as long as wastes containing long half-life transuranics). It is thought that it would not be possible to divert fuel from this reactor to make bombs, as several of the transuranics spontaneously fission so rapidly that any assembly would melt before it could be completed. The project was canceled in 1994, at the behest of then-Secretary of Energy Hazel O'Leary."

from the IFR site:

"Fuel recycling greatly reduces the amount of the radioactive wastes that must be buried in geologic repositories. After 300 to 400 years, IFR waste - the products of fissioning - are as safe as the natural ore the fuel came from. "

i think most transuranics (elements beyond uranium) have very long-half lives (100kyrs+).  they can still emit quite a bit (high radiation flux) but the transitions can have very long decay times.   perhaps the transuranics and actinides are not as "hot" as the short half-life (<300yr) fission products, but they are still hot enough to be a serious health and environmental problem.  

you're right about the thorium, they are using that for some breeders/burners as well.  

Comments can no longer be added to this story.

18 comments on Open Thread and News Drop

Comments can no longer be added to this story.

| Show without comments | PDF version