> Nobel Prize winner Glenn Seaborg, co-discoverer of plutonium and Chairman of the Atomic Energy Commission from 1961 to 1971, wrote that, “To our great surprise and dismay, it developed that Starfish added significantly to the electrons in the Van Allen belts. This result contravened all our predictions.
Nothing ever impacts the rate of radioactive decay. That's basic school physics.
This isn't radioactive products of the explosion itself (that is, gamma quants and beta particles produced by decay of fission products). They probably had no impact at all on any of the satellites (prompt radiation - neutrons produced in fission reaction itself - of course could and probably had some impact - but it lasts milliseconds to seconds).
What they are speaking is impact on Earth natural radiation belts with the electrons produced in the explosion. Electrons of course, do not decay at all. After that it was due to natural processes in the Earth's magnetic field to return things back to normal. This is a geophysical process that has nothing to do with the radioactive decay of any of the fission products produced.
You can see the official report here, it has a ton of detail and sources https://sgp.fas.org/othergov/doe/lanl/docs1/00322994.pdf
In it, J Van Allen (the one the belts are named after) is cited saying decay happened much more slowly at higher altitudes, from months to years.
Calling their work a “bad joke” is… interesting.