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Comment by npo9 | Hacker News Reader

I disagree. The biggest (technical) disadvantage of fission is the creation and use of radioactive materials.

Fusion solves this problem in large part because it uses and produces significantly less radioactive materials... materials that wouldn’t count as a security concern.

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Fusion reactors turn themselves into radioactive waste. Neutron radiation is inherent to nuclear fusion and when previously stable non-radioactive substances are subjected to neutron radiation, they may absorb some of those neutrons and become radioactive. (This is called neutron activation.) Some materials are less prone to this than others and that would be considered during the construction of a production fusion reactor, but even so components of the reactor would likely become so radioactive that the only way to perform maintenance on the reactor would be robotics. And when the reactor eventually needs to be decommissioned, it needs to be treated accordingly.

I wasn't aware of these issues. Did some searching and found this article that covers them (and others) in detail: https://thebulletin.org/2017/04/fusion-reactors-not-what-the...

This talk from the MIT fusion lab lays out some approaches they have for solving problems in current fusion reactor design, in particular dealing with the radiation problem in a cost-effective manner. https://youtu.be/KkpqA8yG9T4

The ARC reactor is still unacceptably large and expensive. Its volumetric power density is still a factor of 40 worse than a PWR primary reactor vessel.

> And when the reactor eventually needs to be decommissioned, it needs to be treated accordingly.

by that time putting it on a Starship, and sending it to the Sun might become a feasible option.

No, that's clearly wrong.

Make fission 10x cleaner or 10x safer and people still wouldn't build them.

Make existing reactors 10x cheaper, but no safer or cleaner, and they'd be selling like hotcakes.

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