"There are funny things that happen to steel piping at 2250 psi and 600 degrees Fahrenheit."
And why we have to use steel piping at 153atm and 300C?
The fact is that we are using a design that is totally obsolete and designed for creating nuclear bombs, not for giving us energy.
The good thing about startups is that they could think different, use creativity to innovate and invent new methods. Einstein was not very intelligent a la Von Newman, contrary to popular belief, but he was super creative.
Hold on there buddy. All Western designed PWRs or BWRs (which is nearly all of them) are not designed to be yielding bombs. Their neutron flux is simply not high enough to give enough enrichment.
Two other types of plants you might be thinking of when taking bomb materials into account. The russian design for Chernobyl was meant to produce electricity and bomb fuel which is why it had a graphite moderator which creates a very high neutron flux.
The other one is the sodium cooled breeder reactor which we chose instead of the molten salt design discussed in the article. The sodium breeder was good at making plutonium but still was never designed to have that plutonium removed in any usable fashion. Sodium is a tricky substance it reacts with water violently. The french still have a plant or two going as do the Chinese but it's really not a stellar design.
Now, I agree about the temps and pressures being unnecessary. The reason for these is about efficiency of scale. In a power grid like America's where we need 1 gigawatt and greater plants, plus with licensing a plant being so difficult, you build the biggest baddest plant you can which can output the most power. This means you go with the highest temps and pressures while still being ultra safe to create a more power efficient reactor.
Smaller reactors which would be better for the power grids of the world. Like 250 mega watts would not need these extreme environments. There are some great designs for a back of trailer truck reactor which can just hook up to a coal plant's secondary systems (steam turbines and such).
The best part of nuclear startups is nuclear is not a 'if' question. It's a when. I just hope we can disrupt quickly enough to bring that sort of power production here sooner rather then later.
"Now, I agree about the temps and pressures being unnecessary. The reason for these is about efficiency of scale. In a power grid like America's where we need 1 gigawatt and greater plants, plus with licensing a plant being so difficult, you build the biggest baddest plant you can which can output the most power. This means you go with the highest temps and pressures while still being ultra safe to create a more power efficient reactor. [P] Smaller reactors which would be better for the power grids of the world. Like 250 mega watts would not need these extreme environments."
This isn't actually accurate. Reactor core water is pressurized to raise the boiling point -- at 0.1 MPa (atmospheric) it's 100 ºC, at 15 MPa (reactor coolant) it's 342 ºC, so they can push water to around 300 ºC and still keep it liquid in the core. The higher the temperature, the higher (in general) the efficiency of converting heat to work (in the case of nuclear plants, efficiency of the steam turbine). This is pretty much independent of the size of the reactor.
(Why liquid water? One huge reason is neutronics (the nuclear part): a very high density of hydrogen nuclei (H in H2O) is useful for scattering neutrons, which slows them down to speeds where they get absorbed by heavy nuclei (reactor fuel) and start fission reactions. [This isn't necessary: in fact "fast reactors" work with neutrons flying at relativistic speeds. But it's much easier.])
300 ºC is actually pretty cool; the steam from coal power plants gets up to around 600 ºC [1], and internal-combustion gas turbines can reach temperatures of even 1,600 ºC [2]. Water-cooled reactors are held back in efficiency by the need to keep water liquid at core temperatures. Conceptually they can get a bit further by pressurizing water to supercritical conditions [3], at about 510-550 ºC/25 MPa; these aren't being built. (These are fast reactors; the density of this supercritical water is very low, about 0.1 kg/L, so it's a weaker moderator).
There's enormous value in having 60 years of data on the neutron irradiation properties and mechanical failure modes of a material. An "obsolete" design is also a well-understood one, and you can't afford to fail fast and often in the nuclear industry.
Heat engines are significantly more energy efficient at 600 degrees Fahrenheit than 300C (572F). Especially when you want to use a 2 stage system and limit how much your irradiating your turbines.
PS: There are actually a lot of reactor designs out there, but overall most designed are based on a small number vary old basic designs and a large number of tradeoffs. For example many people love Pebble bed reactor's, but they are gas cooled and use a lot of graphite at high temperatures which will burn with just a little oxygen at which point you lose your moderator and things can go vary badly.
I wonder what this means for nuclear engineering's future, because I'm looking at Transatomic Power's team and I'm seeing a lot of influence from academia. Both members of the actual management team are PhD candidates, and all three members of the advisory board are professors. Granted this is one sample, but it seems like the barriers to entry for energy startups in general, but especially those dealing with nuclear power, are too steep at the moment for anything to move forward without help from academia.
It's also a meaningless statement from the sidelines. Just where are all of these outlandish reactor designs coming from, anyways? Oh, right. Academia. This isn't a case of a hidebound academia and a fantastically innovative private sector. Really, the opposite is true.
And why we have to use steel piping at 153atm and 300C?
The fact is that we are using a design that is totally obsolete and designed for creating nuclear bombs, not for giving us energy.
The good thing about startups is that they could think different, use creativity to innovate and invent new methods. Einstein was not very intelligent a la Von Newman, contrary to popular belief, but he was super creative.
Creativity is destroyed in academia.