Sodium-cooled reactors have a long and troubled history.
* Sodium Reactor Experiment (Leak, minor sodium explosion, decommissioned)[1]
* Monju Nuclear Power Plant (Sodium fire, never worked properly, decommissioned)[2]
There's even been a sodium fire at a solar plant, one of those big focused mirror systems.
Many of these new reactor designs are based on complex arguments that the worst-case accident doesn't require a huge, expensive secondary containment vessel capable of containing a major accident. That's a tough sell, since Chernobyl didn't have a containment vessel and Fukushima's reactors had ones that were too small. On the other hand, Three Mile Island had a big, strong containment vessel, and in that meltdown, it held, containing the problem. In all three accidents, the actual accident was worse than the design maximum credible accident.
The NRC is right to be skeptical of weak containment designs.
It's frustrating. The reactor designs that have worked reliably for long periods are very simple inside the radioactive portion of the system.
Sodium reactors had leaks and fires. Pebble bed reactors had pebble jams. Helium gas-cooled reactors had leak problems. Molten salt reactors include a radioactive chemical plant. So nuclear power is stuck with water as a working fluid.
EBR-II and FFTF were 100% successful in the USA. Russia has also had very good experience with fast reactors. Sodium fires are a problem, but fires happen in industrial facilities all the time, you just detect them and then you put them out.
Monju had many things wrong with the design, it was a loop-type reactor that nobody is talking about building anymore. Also it was nowhere near adequate from a seismic perspective it is kinda shocking they were allowed to build it at all.
Water reactors have no future for the same reason nobody has built a coal plant since 1980. The steam turbine and associated heat exchangers are unacceptably large and capital intensive compared to modern fossil fuel power plants based on gas turbines. (Look at how huge the steam generators are for the PWR)
Even if the construction problems were solved for the LWR, the economics will not work, you are better off capturing the carbon from a fossil fuel gas turbine plant and pumping it underground.
For nuclear power to be competitive we have to develop closed cycle gas turbine powersets. The 1970s model was that a fast reactor would be more capital intensive than an LWR but with the CCGT advanced reactors could be possibly be competitive -- if we can develop the powerset and reactors that run at high enough temperatures (not water) to support the powerset.
> Water reactors have no future for the same reason nobody has built a coal plant since 1980. The steam turbine and associated heat exchangers are unacceptably large and capital intensive compared to modern fossil fuel power plants based on gas turbines.
Hmm, seems China, India and Indonesia are still building them at a rate of one per week or so, unfortunately. Heck, even Germany opened a new coal plant last year.
The hard coal power plant Dattel was planned in the 2000s and serves as a replacement for three shut down power plants. It was the last coal-fired power plant that will ever go online in Germany. It has to be shut down in 2038 due to the general phase-out of coal.
Not all MSRs have the radioactive chemical plant, just the thorium-fueled ones. Several MSR companies are working on uranium-fueled versions; e.g. Terrestrial Energy, where the reactor core is a sealed can that gets swapped out every few years.
In addition to be bad news for fast reactors, this also means France does not see nuclear being a major factor in avoiding global warming (a nuclear powered world using burner reactors would run out of uranium very quickly, or would need to tap vast new sources at dubiously low cost.)
The French Superphenix is the butt of jokes, but France really has led the world in (1) reprocessing spent fuel, and (2) really fabricating the extracted plutonium into MOX fuel and putting it back into reactors. Everybody else has been too scared of the high energy ball mill and the plutonium nanoparticles that it makes.
(Ok, the Russians are serious too about using MOX in fast reactors but they've developed an alternative to the high energy ball mill.)
The supply of uranium is vast if you consider seawater as a resource. If burner reactors can be made economical in terms of capital cost we could possible make seawater uranium work. With a breeder cycle seawater uranium would certainly be affordable, we'd wind up spending a lot more on the rest of the fuel cycle.
Reprocessing only makes sense if you're going to put that separated plutonium into a fast reactor. MOX fuel's value for LWRs is so marginal that it's not worth reprocessing spent fuel to make it.
Seawater uranium extraction would have to be scaled up by a factor approaching a trillion if nuclear w. LWRs is going to fuel the world (to in excess of 1 million tonnes of natural uranium per year), and it would only last a few thousand years.
It's illustrative of the scale of U extraction that would be needed. A single 1 GW(e) burner reactor would require a field of U absorbers covering 170 km^2 of continental shelf (and to supply 18 TW of primary thermal energy would need about 6000 such reactors). The power/area would be considerably worse than solar (with solar capacity factor taken into account).
Anyway, I don't believe France (or anyone else) has any major program to bring seawater uranium extraction to market either.
At least it gave up building them as public projects. They really want to control costs. Get the most boring thing possible and make more of it cheaper. (The EPR 2 project.)
* Sodium Reactor Experiment (Leak, minor sodium explosion, decommissioned)[1]
* Monju Nuclear Power Plant (Sodium fire, never worked properly, decommissioned)[2]
There's even been a sodium fire at a solar plant, one of those big focused mirror systems.
Many of these new reactor designs are based on complex arguments that the worst-case accident doesn't require a huge, expensive secondary containment vessel capable of containing a major accident. That's a tough sell, since Chernobyl didn't have a containment vessel and Fukushima's reactors had ones that were too small. On the other hand, Three Mile Island had a big, strong containment vessel, and in that meltdown, it held, containing the problem. In all three accidents, the actual accident was worse than the design maximum credible accident.
The NRC is right to be skeptical of weak containment designs.
It's frustrating. The reactor designs that have worked reliably for long periods are very simple inside the radioactive portion of the system. Sodium reactors had leaks and fires. Pebble bed reactors had pebble jams. Helium gas-cooled reactors had leak problems. Molten salt reactors include a radioactive chemical plant. So nuclear power is stuck with water as a working fluid.
[1] https://en.wikipedia.org/wiki/Sodium_Reactor_Experiment
[2] https://en.wikipedia.org/wiki/Monju_Nuclear_Power_Plant