nuclear power plant

[whitepointer23]

Originally Posted by ancient kayaker

Given the events at Fukushima in Japan I am surprised to find anyone interested in nuclear power. It comes in 2 flavors, fission and fusion. Current fission technology is inherently complex as cthippo explained.

Fusion technology should be cleaner since it can be designed so it does not generate radioactive by-products with long half-lives, so such a reactor should theoretically be safe enough to recycle most of its components after a few years shut-down. Fusion is critically dependent on confinement which cannot be provided by any material since it involves a temperatures similar to those at the sun's core, and a magnetic field is the only practical way. Currently magnetic confinement is receiving most of the research. Like fission, it is inherently complex and large - wall-to-wall superconducting magnets etc.

As far as anyone I have met knows, cold fusion does not and will not work. It seems to be a bit like global heating, triggering furious debates but no usable theory. Lots of energy in the hot air but as yet not usable.

Inertial confinement fusion may be down-scalable, though not within our lifetimes. Inertial confinement fusion is referred to by cognizant types as Infernal Con-Fusion which gives you some idea of its current state of development. It consists of triggering a series of microscopic thermo-nuclear bombs. The fuel comes pre-packaged like a wood-pellet stove and is brought to ignition temperature by a laser.

In theory it can be made so small that the inverse square law will provide sufficient attenuation of levels of radioactivity that the weight of shielding can be manageable but the efficiency of current methods of energy conversion at that size would be ludicrously poor. If the energy can be tapped at the nuclear level that problem maybe can be fixed, but the probability of that happening is not much better than making a success of cold fusion. In practice it hasn’t been made to work at all - AFAIK I don’t think an experimental test setup even exists but I am long out of touch. Don’t hold your breath . . .

i think the japanese problems are a chance for the industry to learn to make nuclear power even safer, don't forget the earthquake and tsunami were way bigger than anyone anticipated. here in australia people are completely against nuclear power and i think it will cost us in the long run, all these new carbon tax rules that are coming in are going to make our dirty coal power very expensive. the idea of clean nuc power really appeals to me and a lot of other people i have spoken to. a recent survey conducted on wind and solar power for australia concluded that they are just not viable on their own.

[daiquiri]

Originally Posted by cthippo

The systems Daquiri refers to are Nuclear Thermal Generators or NTGs. They are not true reactors at all since an ongoing reaction does not take place within them, but rather they are powered by natural decay heat of the material inside. This heat is converted to electricity by thermocouples which are notoriously inefficient. Due to the fact that they aren't reacting they don't produce as much radiation as a real reactor, thereby greatly reducing the mount of shielding required, however they also cannot produce much power.

Thanks for the additional info. The only small correction: I was talking about RHU's, because the thread starter talked about steam production, and it doesn't require a conversion to electric energy via thermocouples. What you're talking about is Radioisotope Thermoelectric Generator (RTG), which is essentially a RHU with a thermocouple electricity generator.

For those interested in history of the use of atomic energy for space exploration, there is a nicely written book, "Atomic Power in Space: A History", which can be downloaded from the US DOE site: http://www.osti.gov/cgi-bin/rd_accom...Pages=188&fp=N

Cheers

[whitepointer23]

i did start the thread thinking of steam power because i thought that was the only way nuclear power could rotate a shaft, i just looked up the story on the b 36, absolutely amazing for the 50's , now i understand about the extreme measures taken for the shielding which would limit the size of boat it could go in.