system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why were scientists able to make the fusion H-bomb in the 1950's but have not yet created a working nuclear fusion reactor? What are the major challenges of the second that don't appear in the first?

ELI5: Why were scientists able to make the fusion H-bomb in the 1950's but have not yet created a working nuclear fusion reactor? What are the major challenges of the second that don't appear in the first?
gpt
> What are the major challenges of the second that don't appear in the first?

1. Detonating a 50 kiloton fission first stage to pump a deuterium fusion stage is generally considered to be unfavorable as a method to jumpstart a commercial fusion reactor due to the tendency of this technology to fucking turn the town into a crater.

2. A thermonuclear device only needs to work for a fraction of a second. Sustaining the reaction indefinitely is way harder, though less exciting-looking.