Plutonium and the Return to Nuclear Power

I’m on board when it comes to restarting the nuclear industry – with reservations. What’s not to like? No carbon footprint. Less release of dangerous radionuclides into the atmosphere than coal plants. No need to pave thousands of square miles of environmentally fragile desert with solar collectors, windmills, and similar “environmentally friendly” and “sustainable” energy sources.

There is one big potential problem, though. When you burn uranium in a conventional nuclear reactor, you breed plutonium. The spent fuel rods currently stored on site at every nuclear plant in the country are laced with the stuff. You don’t need fancy centrifuges or gas diffusion plants to separate the plutonium. Any reasonably skilled chemist could do it. Once you’ve separated the plutonium, you have the one key ingredient you need to make a nuclear weapon. Oh, I know, it won’t be weapons grade plutonium, but no matter. The United States conducted a successful nuclear test with reactor grade plutonium.

Why, you ask, haven’t terrorists already stolen a batch of fuel rods if it’s so simple. Well, at the moment, the problem is that they’re so highly radioactive that bad actors would probably fry themselves before they could do any damage. They won’t stay that way, though. The radionuclides that make fuel rods so “hot” when it comes to emitting radiation have a certain half life. They decay, and become less radioactive at an exponential rate. At some point, they will become safe enough to handle, even without specialized equipment. The exact time will depend on the material configuration of the fuel rods when they were produced, and the degree of risk the person handling them is willing to take. True, we’re probably talking hundreds or thousands of years in the future, but beyond what date can we ignore the welfare of future generations? When does it become OK to subject them to the risk of nuclear annihilation?

Fortunately, there are solutions to the problem. One is fuel recycling, in which the plutonium from spent rods would be extracted and recycled into new fuel rods. An even better one is building breeder reactors to go along with the recycling. The problem with conventional reactors is that they use up the U235 in natural uranium as fuel. Unfortunately, only seven tenths of one percent of natural uranium is isotope 235, and the rest is 238. Depleted uranium is mostly U238, being what’s left over when the U235 is separated.

With breeder reactors, the U238 can be gradually converted into plutonium 239, a reactor fuel. In that way, a much greater percentage of the natural uranium could be converted to energy, greatly extending the time available to us for figuring out what to do when that fuel supply runs out. Alternatively, thorium, which can be converted into U233, another fissile material, could be used in the breeders. U233 has the very significant advantage of not being chemically separable from other uranium isotopes, and would, therefore be much more difficult to weaponize than plutonium.

Plutonium-based energy production is not benign. It would require tight security standards at every step along the fuel chain. But, then again, no known method of producing energy is benign, including the “environmentally friendly” ones noted above. If the choice were mine to make, I think I would agree with the guys over at Atomic Insights.

Meanwhile, it strikes me as a little crazy that we are gratuitously pumping potentially energy rich depleted uranium slugs out of the barrels of gatling guns. If we really start running out of energy, others might notice there are better uses for the stuff as well.

fuel-rods

4 thoughts on “Plutonium and the Return to Nuclear Power”

  1. What’s all this nonsense that nuclear has no carbon footprint? Mining the uranium, concentrating the fissile isotopes and transporting to the power station, as well as disposing of the spent fuel and waste, are all carbon intensive. Nuclear is low carbon but NOT no carbon! Even renewables carry a carbon cost, but much lower than nuclear.

    I agree that the risk of a terrorist group building a nuclear bomb is probably quite low, but the risk of them setting of a conventional explosion at a nuclear waste storage site, near to spent fuel for example, is a real risk, especially if that fuel is stored outside a containment vessel.

  2. We need more nuclear power plants in the US period. Why the american people allow a very small group of people hold back our generation of cheap safe energy is beyond me.Yucca mountain just completed has been close president Obama said it would never be used. I believe they want the Us to be on the same level as a third world country. Cheap energy is so very important to our way of life. The whole idea of the carbon foot print is a joke. It is just another way to control you, your loosing your freedoms everyday in every way. The idea of the smart grid, yea thats a super idea. I lived in England, the taxes there are unreal, look into it. Wake up people, We need more nuclear power plants until we find something that is better and cheaper for americans, screw the rest of the world…God Bless

  3. It’s crazy to think that only about 2% of nuclear waste in the United States is from power plants, the vast majority is military and the health care industry.

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