Thursday, December 15, 2005

Smarter Use of Nuclear Waste

I have been a fan of nuclear power because it is carbon free, has no emissions, and could scale very easily to produce lots of power. I would add it is an economical choice, but really the economics of energy production get very tricky based on what kind of externalities (like pollution leading to health care costs, or military expenditures to protect "our" Middle East oil) you want to throw into the mix. Also, the price of nuclear energy is dependant on the level of security you want to build into it and how you store the nuclear waste.

But my optimism has always been tempered by three big problems:
1) What do you do with the waste?
2) How do you make sure that the fuel can't be turned into a nuclear bomb?
3) How can you insure there won't be a meltdown/terrorist attack?

In this new article over at Scientific America, scientists have some new techniques that greatly reduce or eliminate these concerns. They are proposing use fast-neutron reactors (rather than the slow-neutron or thermal reactors currently being used) along with recycling of spent fuel by pyrometallurgical processing.

These techniques have the following advantages:
1) Reduce the amount of nuclear waste a 1,000 megawatt (for some reason energy types don't like to call this 1 gigawatt) from 100 tons of spent fuel a year to a little over 1 ton. That is almost a 99% reduction! And it gets even better. Because the recycling removes the uranium, plutonium and other heavy metals (or long-lived transuaranics as they call them), the radioactive half life goes from 10,000 years to several hundred years (at one point they mention 300 years)! Instead of having to create a Yucca Mountain that can handle the waste for 10,000 years without any issues, now such a facility need only handle a tenth of that time or less. Or maybe with the decreased amount of waste and radioactive lifetime, simpler, cheaper solutions could be used such as storing the waste on site.

The reduced waste also decreases the amount having to be transported lessening the possibility of a terrorist attack (this would be a dirty bomb, not to be confused with a nuclear bomb which is several magnitudes of orders worse).

2) The recycling of the nuclear fuel would be done is such a way that plutonium in the fuel is too impure for diversion to weapons. Currently France, Japan, Russia and the UK reprocess their fuel into plutonium. This plutonium can then be used to create a nuclear weapon. This style of recycling therefore greatly reduces the risk of nuclear weapon development (but it is still not clear to me why you couldn't just refine/reprocess the recycled nuclear fuel to pure plutonium).

3) The facilities they are proposing would be built underground (to protect from a 9-11 style attack) and use liquid sodium rather than water to transfer the heat. It would also be designed to automatically shut down in the case of an emergency, so it would be impossible for a Chernobyl style meltdown to occur.

4) These reactors would be able to use not just enriched uranium (with a higher concentration of fissile U-235) but just plain old uranium (or depleted uranium) as a fuel source. Currently the continued growth in the number of thermal reactors could exhaust the available low-cost uranium reserves in a few decades.

This new style of nuclear reactor/recycling greatly alleviates my concerns with nuclear technology. I need to read more about this, but it sounds very promising.

1 comment:

James Aach said...

Dear Mr. Knowledge,

Given your comments in the article above, the following item seems to have been written just for you. I hope you'll take a look, and if you find it useful, pass the word along....

"There is a new techno-thriller novel about the American nuclear power industry, written by a longtime nuclear engineer (me). This book provides an entertaining and accurate portrait of the nuclear industry today and how a nuclear accident would be handled. It is called “Rad Decision”, and is at There is no cost to readers."

Give it a try. (As you'll see from the title page's comments sections, those that have seem to like it.)

James Aach

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