Hacker News Reader

Comment by shaqbert | Hacker News Reader

Nobody designs new boiling water reactors these days. Reactors efficiency increase with temperature, that is why pressurized water is the name of the game - as it can have a much higher boiling point.

The higher temperature = better reasoning is also the reason why there is such a hype train going for reactor designs based on molten salts.

Needless to say a higher temperature also puts more strain on any material and makes safe operation generally harder.

View on HN

One of the things that I don't get is that there a lot of cool fission designs that are arguably only hampered by the state of the art in molten-salt plumbing, but the only fusion design with mainstream support requires molten lithium plumbing for breeding tritium and heat exchange, along with a few other things that are still a touch experimental. Hash out the molten salt plumbing for the fission reactors since it appears strictly a subset of the fusion problems.

No, its not a subset of fusion problems. Very different problems:

Molten salt fission problem = dealing with vast quantities of a highly chemically active salt touching our plumbing directly over 40 to 60 years.

Fusion problem = containment of a small quantity by a magnetic field.

Fusion also has the "dealing with vast quantities of a highly chemically active salt touching our plumbing directly over 40 to 60 years." Nobody talks about it because the magnetic containment problem is harder.

You can't use water like most fission designs?

Some fusion designs in theory would burn deuterium-tritium. Typical way to produce tritium is from lithium. When lithium absorbs a neutron it fissions into tritium + helium. Potential designs for fusion reactors then have a way of exposing lithium to the neutron flux from the reactor.

These smaller modules would be ideal for that. As the plumbing wears out, replace the module, and recycle the old module, make another one.

Smooths the scaling, production process outlays, gives opportunity for continuous improvement in the module manufacture and efficiency

Reply on news.ycombinator.com