Comment by jacobn
5 hours ago
Are there any nuclear alternatives that don't include strapping low grade bombs to the reactor core (PRW/BWR: water separation -> hydrogen + oxygen -> boom, like happened @ Fukushima) or using coolants that instantly start violently combusting when exposed to air or moisture (sodium)?
I love the promise of nuclear energy, and I understand that every single engineering decision has tradeoffs, but these tradeoffs just seem so bad? Are there really no better options?
There have been some sodium cooled designs that have used a closed cycle gas turbine using nitrogen as the working fluid for the secondary circuit, in order to avoid any issues with sodium-water reactions with a traditional steam Rankine secondary circuit.
There are also fast reactor designs using lead as the coolant rather than sodium. These are interesting, but less mature than sodium cooling. Sodium is better from a cooling and pumping perspective though.
Lead-bismuth eutectic.
A eutectic is an alloy that has a lower melting point than any of its components.
Lead-bismuth eutectic or LBE is a eutectic alloy of lead (44.5 at%) and bismuth (55.5 at%) used as a coolant in some nuclear reactors, and is a proposed coolant for the lead-cooled fast reactor, part of the Generation IV reactor initiative. It has a melting point of 123.5 °C/254.3 °F (pure lead melts at 327 °C/621 °F, pure bismuth at 271 °C/520 °F) and a boiling point of 1,670 °C/3,038 °F.
https://en.wikipedia.org/wiki/Lead-bismuth_eutectic
I was also curious. Claude answers: https://claude.ai/share/244fc2f5-1c4d-4e52-b316-e9cc34c8b98b I would be interested in a real expert's critique/commentary of this answer.
I like the pebble-bed design because it seems the most intrinsically safe of the three.
Pebble beds are very safe but also very fuel inefficient.
The improvement is more on the fuel cladding for classic pwr or pebble bed reactors... But even without all this, nuclear is one of the safest sources of power on the planet, because we made it so
The AGRs are advanced reactors that use an inert coolant, CO2. In fact they have been designed to cool down quicker than any credible loss of coolant. And have been in service since the 70s, with some slated to go on until 2030.
I mean the LWR fleet has proven to be incredibly safe by any objective measure with deaths per TWhr as good or better than wind/solar. The very incident you mentioned had a direct death count of 0 or 1 depending on who you ask. Industrial shit blows up all the time, you just don't hear about it because it's normal and accepted.
What needs to improve about nuclear is our ability to deliver it on time and on budget. Safety is already more than adequate.
That is never going to happen until we are building more of a consistent design. I think every LWR is use today is a custom bespoke piece of equipment.
China has a liquid uranium in the vein of the lftr design allegedly operating.
That I believe is the safest design, but I'm not a nuclear engineer.