3 ms·

> ITER, as of 2006, was supposed to be followed almost immediately by DEMO, a power plant capable of producing electricity in 2033. This is not true. DEMO will

by jnxx 6y ago

> ITER, as of 2006, was supposed to be followed almost immediately by DEMO, a power plant capable of producing electricity in 2033. This is not true. DEMO will not be able to breed Tritium. Without tritium breeding, there will be no self-suffiency in term of fuel. You can't filter Tritium from sea water because it is not there - it is unstable. There is no fusion experiment which could achieve a Deuterium-Deuterium fusion within the next decades, the required densities are many orders of magnitudes away. You can generate Deuterium by electrolysis and isotope separation of water, but to day, Tritium can only be produced in heavy-water generators. Which exist only a few in the world, and which are powered by uranium. In theory, yes, it could be possible to breed tritium within a fusion reactor. But this is as theoretical as somebody in the 17th century saying that you could adapt a steam engine to flap wings and make it just a bit lighter to get a flying machine which could carry a few hundred people with near speed of sound across the Atlantic, at once.

willis936 6y ago
Of course a DEMO will have tritium breeding. One of ITER’s tasks is testing lithium breeder blankets. Reactor studies have included the calculations of necessary thickness of lithium blankets to make sufficient tritium and not increase the minor radius by an unacceptably high amount.
pfdietz 6y ago
> This is not true. DEMO will not be able to breed Tritium. DEMO not only will breed tritium, it will not be feasible without tritium breeding. Otherwise, it would not be able to operate, as it will run out of DT fuel. Even getting enough tritium to start DEMO operations will be difficult, as there will be little left after ITER is done. The primary source of tritium, heavy water power reactors, will not long survive, and even all of those would not provide enough tritium for DEMO operation without DEMO being able to make its own tritium. The need for breeding to work at DEMO means there's going to have to be an intermediate reactor, a Fusion Nuclear Science Facility, between ITER and DEMO to firm up blanket engineering. I don't think this gets talked about much because, frankly, those in power in the fusion community will be retired by then.

by jnxx 6y ago

willis936 6y ago

Of course a DEMO will have tritium breeding. One of ITER’s tasks is testing lithium breeder blankets. Reactor studies have included the calculations of necessary thickness of lithium blankets to make sufficient tritium and not increase the minor radius by an unacceptably high amount.

pfdietz 6y ago

> This is not true. DEMO will not be able to breed Tritium. DEMO not only will breed tritium, it will not be feasible without tritium breeding. Otherwise, it would not be able to operate, as it will run out of DT fuel. Even getting enough tritium to start DEMO operations will be difficult, as there will be little left after ITER is done. The primary source of tritium, heavy water power reactors, will not long survive, and even all of those would not provide enough tritium for DEMO operation without DEMO being able to make its own tritium. The need for breeding to work at DEMO means there's going to have to be an intermediate reactor, a Fusion Nuclear Science Facility, between ITER and DEMO to firm up blanket engineering. I don't think this gets talked about much because, frankly, those in power in the fusion community will be retired by then.