My friend Hank is involved with a summer science program that he attended and loved many years (decades) ago. He apparently posted something on the group’s FB page recently suggesting there is no viable plan for storage of nuclear waste and got this response (in part):
“We’ve known how to effectively destroy nuclear waste for fifty years, and refuse to do it. Read “Smarter Use of Nuclear Waste” in December 2005 Scientific American. Read “Plentiful Energy” by Charles E. Till and Yoon Il Chang….The stuff we call “nuclear waste” is actually valuable 5%-used fuel — 5% fission products and 95% future fuel. Future fuel needs custody for 300,000 years, which is madness to contemplate. Fission products, unseparated, need custody for 300 years — a trivial problem….. Of course, the American energy economy won’t be all nuclear, so the amount would be less. I don’t foresee a breakthrough in storage, so the options are nuclear, coal, and gas — if firm power is desired. Take your choice.”
Sigh. This is one of the claims that keeps on coming back. But here’s one thing (almost) right in it:
Pressurized light water reactor spent fuel is about 93% U-238, which is not a fuel but which can potentially be turned into plutonium, which is; about 1% U-235, which is fissile, and about 1% plutonium, which can be used as fuel (mostly). The rest is fission products though there are also some minor actinides: neptunium-237 (half-life 2.14 million years) and americium-241 (half-life 432 years).
To convert non-fuel U-238 to Pu-239 fuel you need a “breeder reactor,” which produces more fuel than it uses, the nuclear dream. Alvin Weinberg, nuclear physicist and inventor at Oak Ridge National Lab, called it a “magical energy source” that would need a priesthood to guard the waste and the bomb-usable fissile material — he famously called this the “Faustian bargain”).
The sodium-cooled reactor is an efficient breeder reactor in that it produces excess plutonium in a shorter time than other types of breeders. Roughly $100 billion has been spent globally over nearly seven decades to try to commercialize it. The International Panel on Fissile Materials did a good global survey of the technology in 2010. In fact, two of the most recent demonstration sodium-cooled breeders (Superphenix in France and Monju and Japan) were among the worst operating of the lot; they are both shut. Some sodium-cooled breeders have operated well, others with problems and yet others have had accidents (like Monju) and/or been failures (like Superphenix, with a lifetime capacity factor of about 7 percent — one half to one-fourth of a typical solar installation, depending on where it is). In other words after $100 billion, it is still not commercial. Not that the French and Japanese have given up. They are working on the “ASTRID Project” – target opening date is in the 2030s. If successful, it would be the 2040s and 2050s before they could be deployed in significant numbers. Got time to solve the CO2 problem?
Even if they worked reliably and consistently from one reactor to the next, sodium-cooled breeders are more expensive than current light water reactors, which, in turn are ~2 times the cost of wind and solar. Then there are the proliferation concerns. We currently have more separated commercial bomb-usable plutonium in the commercial sector than in all the nuclear weapons in all nuclear weapon states combined, enough for ~30,000 bombs or more. In addition, reprocessing, needed to recover the extra plutonium and fabricate fuel from it, is also costly and dirty. The French (at La Hague) and British (at Sellafield) reprocessing plants have polluted the oceans all the way to the Arctic and caused neighboring governments to ask them to stop the discharges of radioactive liquids into the seas.
The theory behind it and the gleam in the nuclear engineers’ eyes in the 1950s was this could make non-fuel U-238 (99.3% of natural uranium) into fuel. Uranium was thought to be scarce, and this would give us an inexhaustible energy source for hundreds of thousands of years. But uranium turned out to be plentiful and cheap – it is a small part of the cost of nuclear power. So the economic rationale was gone.
And now solar and wind are much cheaper than nuclear. My hour-by-hour modeling shows that solar plus wind can provide reliable supply at affordable cost, using a balanced solar and wind portfolio, storage, demand response with a smart grid, and peaking generation using hydrogen made when there is no other use for solar and wind electricity. See my 2016 report, Prosperous, Renewable Maryland. Moreover, storage is not needed until solar and wind penetration reaches a much higher level than at present. Costs of storage have come down. A recent commercial solicitation in Arizona for meeting peak load resulted in solar plus battery storage beating out natural gas turbines. The idea that nuclear is needed is as obsolete as the technology. The plutonium in existing waste is just 1% of the spent fuel and hard to separate. It can’t be used to make bombs if it is left there. We don’t have to make a Faustian bargain to have reliable, clean and affordable electricity.
People got too excited based on the physics; but that’s just the starting point. The technology has to work consistently; it has to be affordable; and its other attributes should not pose dire risks — like CO2 from fossil fuels or plutonium from breeders. Every commercial nuclear reactor, ~1,000 MWe, produces about 30 bombs worth of plutonium each year, if separated from spent fuel. Nuclear, in the end, is making plutonium just to boil water.
The 300-year waste claim is wrong. I-129 is one of the fission products: half-life ~16 million years; it is one of the more troublesome ones for a repository. Then there is Cs-135: half-life 2.3 million years; and technetium-99: half life — 212,000 years. In addition there are the above-mentioned minor actinides.
There is another breeder reactor that has many fans: the Liquid-Fueled Thorium Reactor (LFTR). It is promoted by a set of folks who feel very cheated that this approach (Alvin Weinberg’s brainchild) was rejected in favor of the sodium-cooled breeder in the late 1960s or early 1970s. In my view, the LFTR is the most proliferation prone of the various breeder approaches in that it could lead to more countries having the capability to acquire nuclear-weapons-usable material with less difficulty than other approaches to breeders. For one thing the separation plant for the fissile material (in this case uranium-233) would be located at every reactor. The precursor of U-233, protactinium-233, has a half-life of 27 days. Thus, it is available for chemical separation for much longer than the precursor of plutonium-239 (neptunium-239, half-life 2.4 days). Chemical separation of Pa-233 would yield bomb usable U-233 after the Pa-233 decays.
While nuclear-weapon states like the United States or Russia would not go through the bother, an aspiring nuclear weapon state might be tempted to separate Pa-233 and acquire weapons-usable U-233. Policing would be difficult, since there would be so many reprocessing plants (if this reactor comes into widespread use). The fission products are in fluoride form, which poses more difficult long-term management challenges than the oxide form of current spent fuel. A pilot LFTR reactor, 8 megawatts thermal was built at Oak Ridge. It operated reasonably well but was never used to generate electricity or to make more fissile material — that wasn’t the purpose. It cost much less than $100 million in today’s dollars. The decommissioning is estimated to cost north of $400 million — this for a reactor that was about a quarter of one percent the size of a commercial nuclear power plant (~3,300 MW thermal, or ~1,000 MW-electrical). See a debate I did on Science Friday with a proponent and make up your own mind.
You were essentially right — there is no good solution for the problem of spent fuel. The least bad approach to long-term management is disposal in a suitably designed geologic isolation system (the National Academies did an excellent report on this in 1983). It would also be sensible if we would transition to renewable energy so we are not burdening future generations even more with the waste from our economic activities.