Reply To: Fusion Oil

[Aeronaut]

jamesr wrote:

Think we could do that in PWR fashion by pumping water through a beryllium anode and controlling the steam pressure with the cooling water pressure? I hear PWRs are making a comeback these days :shut:

There is no way a small beryllium electrode could withstand water pressurised to the 160bar or so needed to keep it liquid through the primary circuit, as they do in PWRs

As I understand it, the plan is to use helium gas as the primary coolant. What you then do as a secondary stage largely depends on how high a temperature you can let the helium outlet be. I am guessing no more than 480C. In which case a standard boiler & small forced cooling heat sink would be enough to dump 2MW. If you have several FF units together, the secondary circuits could be linked, and make it economical to put the steam through a turbine and recover 35% or so of the heat energy.

If the anode can cope with the helium temperature outlet being above 800C, then direct cycle options such as gas turbines become a possibility. But not probably worth it. High temperature gas turbines are being proposed and worked on for 4th Gen Fission reactors like the GT-MHR. However, even if you could operate at this temperature, I think the maximum pressure the anode can handle may be a limiting factor.

So much to learn, so little mind…

What kind of cooling channel wall thickness do you think we’d need to pump water at 160bar through a beryllium anode? I’m picturing 2 coaxial cooling tubes where cool source water flows up the outer layer and hot water returns down the anode’s centerline channel. I was going to ask required flow volume in L/sec until it dawned on me that we’re trying to cool a 10- to 30 nS heat impulse.

We can make the anode pretty much any diameter we please, as long as we don’t mind tradeoffs like required cathode diameters and cap bank size. Cap bank can be spread across many cores, so that’s not a huge issue. The payoff would be a drop-in boiler replacement that pays for itself in coal savings. I’d really like to target gas turbines, too, but that’s beginning to resemble another year.