Editing Openai/691a2d9f-c044-8012-bccf-942bfce6334d (section)

=== Assistant: 17-11-25 02:12 ===
17-11-25 02:12
GPT-5.1

Right. This is the uncomfortable point where the romantic idea collapses into thermodynamics and nuclear physics reality.

If you need continuous power for ~100,000+ years, the question becomes:

: 

Short answer:
* Most practical reactor fuels do not have half-lives anywhere near 100,000 years if you want high power output per kg.
* Isotopes with very long half-lives have extremely low specific power, meaning you would need absurd quantities of them.
* For real energy at spacecraft-scale, you need fission breeders or fusion, not static isotope decay.