# Alternative RTG fuel

I heard that Pu238 has limited production capacity.
Apart from those widely discussed, I would be curious as of why these are rarely brought up:
• Pb210 is essentially Po210 with a longer half-life, which is more suitable for medium lifespan missions. How much Pb210 can be collected from a lead cooled reactor?
• Pu241 is essentially Am241, but it could give a slight power boost.
• Ac227 has a long decay chain which gives more (most?) power per atom. Any novel way for mass production?
• Cm242 is essentially Pu238, in addition to early power boost. Is it much harder to produce Pu238 this way?
• Pm147 has been discussed, but some sources give an unreasonably low power density (<1w/g) for its short half-life. Are they mistaken, or there is something I don't understand?

My assumption is:
1. spent fission fuel can be reprocessed promptly,
2. further decay of daughter isotopes contribute to total power output.

mfb
Mentor
238Pu has a high-energetic alpha decay to a long-living daughter isotope (which has the same features again), that makes radiation shielding easy. Most other isotopes have beta decays or high probabilities for gamma decays in their chains.

mheslep
Yeah, but 90Sr had been used and 241Am is being considered. I forgot to mention another assumption where anything close or less should be acceptable.

I believe the European Space Agency has announced they will be moving to Am-241 sources. They're less power dense, but with better RTG designs that is more than compensated for.

It's long lived, so it can support any interstellar mission. It alpha decays, so shielding is relatively easy. Production is, from what I've been told, fairly simple. I mean we produce it for smoke detectors as it is so I can't imagine up-scaling that process would be too difficult.

mfb
Mentor
It's long lived, so it can support any interstellar mission.
Any interplanetary missions. It is way too short-living to support interstellar missions unless you aim for something like Breakthrough Starshot with ~20% c.

It is produced in nuclear reactors. You cannot simply scale up the number of nuclear power plants in the world. You can extract more of this isotope out of their waste, however.