Contemplating nuclear power

Posted on: Mon, 04/17/2006 - 18:50 By: Tom Swiss

Discussion over at Slashdot about nuclear power, touched off by this piece in the Washington Post. (See also this response the Daily Kos: "Patrick Moore is a paid consultant for the mining, logging, biotech and energy industries, and putting him out as "ex-Greenpeace" is a lot like calling Scooter Libby an "ex-Hill staffer.")

Some excerpts from my posts on the topic:

Is fission less dangerous to the environment than coal? Perhaps. If it were a choice between only between building more coal plants and building fission ones, it's possible that fission might win out. (Though I think it would have to depend of the specifics of the technologies and implementations involved.)

But that's the wrong question.

At best, fission is still a stop-gap: supplies of fissionables are limited, on the order of a century or two at most, perhaps much less. So is it not more reasonable to divert resources to solving the problem right - with fusion reseach, renewables (i.e., using that big fusion reactor in the sky, including ideas like orbital photovoltaics) and better energy efficiency - than to build fission reactors and [push] the problem onto our great-grandchildren? (Or rather, for us non-breeders, our friends' great-grandchildren?)

[The Moore editorial] mentions the Iran situation only to gloss over it, but there are massive security concerns with fission technology.

Also [the Moore editorial] is inaccurate in talking about nuclear waste; the problem is not the U and Pu in spent fuel, which can be processed and reused, but thorium, radium, radon, and radioactive lead isotopes.

Is some of the opposition to fission irrational? Yes. But so is some of its support, based on an almost romantic notion of "man harnassing the mighty power of the atom!"

[Regarding a claim that pebble bed reactors are "super safe"], they're not. Surrounding your fissionable with graphite - the stuff that fueled the Chernobyl fire - is not really bright. And a 1986 accident in Germany with a damaged "pebble" led to the release of radiation.

[Regarding reprocessing, it] leaves around plenty of thorium, radium, radon, and radioactive lead isotopes.


Of course there's a "peak uranium", thorium doesn't change that. But thorium is a lousy fuel, it has to be "bred" into U233. And then you've still got a "peak thorium"; as thorium is about three times as abundant as uranium, maybe that's in 150 years instead of 50. (But then you need more thorium to get the same energy, so maybe sooner.)

Actually, after posting this I did some more research on thorium as a power source. I got the math wrong; there is much more thorium than I suggest here. Also, there is an approach called "accelerator-driven nuclear energy", in which instead of trying to control a chain-reaction, thorium is bombarded with a neutron beam - shut off the beam and the reactor shuts down, instantly.

It does seem that if a safe and practical method is found to run fission from thorium, it would be a long-lived solution. (Modulo reactor safety, security/proliferation, and waste issues; which are all less with thorium than uranium, but still significant.)

I'd tentatively move it into the same category as fusion, then; currently theoretically promising, but needing much more research to be practical. So I'll modify my stance to say that uranium fission is at best a short-term stopgap, and we'd be better served putting those resources into renewables, efficiency, and research into fusion and thorium-based fission. Tom Swiss - proprietor,