[pfdietz]

Fast reactors have been disappointing all over the world. The harder neutron spectrum is more damaging to materials, and liquid sodium has serious drawbacks. Fabrication of fuel elements with mixed actinides is also difficult. Fast reactors also require a higher density of fuel (due to the lower fission cross section at high neutron energy), which presents safety issues.

[jki275]

The French reprocess all their fuel as I understand it. We could do the same, we choose not to.

That's probably the wrong choice.

[pfdietz]

The french choice was clearly the wrong one. It's a net economic loss for them. It was predicated on the use of the separated Pu in fast reactors, but their experience with fast reactors was dismal.

[jki275]

It's not about whether it makes money.

It's a way to drastically reduce the waste from the process.

[pfdietz]

If they weren't going to use the plutonium immediately, reprocessing was stupid. Spending the money they didn't have to, in order to make Pu they didn't need, just to have the Pu sit around, made no economic sense. And no, it doesn't improve the economics of waste disposal.

Understand where reprocessing came from. Way back then, the story was that nuclear was going to be dirt cheap, but would ultimately be limited by the cost of uranium. The solution was breeding, to provide all the expensive fuel those thousands of cheap reactors would need. Reprocessing was needed to close this fuel cycle.

But this story bears no resemblance to reality. Reactors turned out to be expensive, the number of installed reactors was far below projections, and uranium is not in short supply.

One still hears echoes of this old narrative from people who don't really understand where it came from, and why it doesn't apply.

[jki275]

Again, the point isn't to save money. The point is to reduce waste.

[pfdietz]

No, the point is to minimize the cost of dealing with waste. Reprocessing doesn't do that.

But let's stipulate that they want to destroy the waste. What's the cheapest way to do that? If they wait to reprocess the fuel, and destroy the actinides in the future, it comes out cheaper than if they reprocess now. That's because reprocessing, and developing and building fast reactors, is quite expensive, and the net present value of that cost is minimized by moving it off into the future. Moreover, reprocessing becomes easier as the fuel cools off.

So, reprocessing NOW is a pointless waste of money, even if ultimately you want to do it. The ONLY reason you'd want to reprocess now was if you needed the actinides now for use in energy generation. And no one needs them for that.