There's a lot of really difficult issues with this one that they seem to be politely sweeping under the rug.
First of all, they have to pre-heat this reactor core material to get it into liquid form. If the core is mostly made of lead, with a melting point of around 600 K or 330 C, then that takes a heck of a lot of heat. It's also pretty dangerous and difficult to contain that within a huge ensemble of actuating pistons. I'm not really sure how they plan on containing it so nicely, but it's not going to be a piece of cake.
Second of all, they plan on compressing this liquid core with mechanical pistons? This is pretty incredible. Water, for example, is generally assumed to be incompressible, because it is so difficult to get it to decrease its volume under pressure. I could be mistaken, but I would assume that lead is also practically incompressible. So if they are relying on liquid lead compression, then their pistons will have to be enormously powerful and well balanced. That's no doubt why they seek to use so many pistons, but still it seems like it will be a massive engineering difficulty.
It could be that they don't rely on compressing the liquid lead, and instead, they are just using the lead as a vehicle to transmit the acoustic compression wave. However, that's still pretty damn difficult because the lead is so dense and heavy and the pistons will have to move so fast that it will still act locally incompressible, to some degree. This is more speculation on my part, here.
Finally, they also need to spin up all this reactor liquid metal, which seems like it will also be extremely difficult. There's no easy way to spin up some massive spherical tank of 600 K, heavy as hell metal, surrounded by a huge number of actuating pistons. Maybe they plan on using something clever like spinning the liquid up through some electrodynamic interaction, but this definitely won't be trivial, either.
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There's a lot of really difficult issues with this one that they seem to be politely sweeping under the rug. First of all, they have to pre-heat this reactor core material to get it into liquid form. If the core is mostly made of lead, with a melting point of around 600 K or 330 C, then that takes a heck of a lot of heat. It's also pretty dangerous and difficult to contain that within a huge ensemble of actuating pistons. I'm not really sure how they plan on containing it so nicely, but it's not going to be a piece of cake. Second of all, they plan on compressing this liquid core with mechanical pistons? This is pretty incredible. Water, for example, is generally assumed to be incompressible, because it is so difficult to get it to decrease its volume under pressure. I could be mistaken, but I would assume that lead is also practically incompressible. So if they are relying on liquid lead compression, then their pistons will have to be enormously powerful and well balanced. That's no doubt why they seek to use so many pistons, but still it seems like it will be a massive engineering difficulty. It could be that they don't rely on compressing the liquid lead, and instead, they are just using the lead as a vehicle to transmit the acoustic compression wave. However, that's still pretty damn difficult because the lead is so dense and heavy and the pistons will have to move so fast that it will still act locally incompressible, to some degree. This is more speculation on my part, here. Finally, they also need to spin up all this reactor liquid metal, which seems like it will also be extremely difficult. There's no easy way to spin up some massive spherical tank of 600 K, heavy as hell metal, surrounded by a huge number of actuating pistons. Maybe they plan on using something clever like spinning the liquid up through some electrodynamic interaction, but this definitely won't be trivial, either.