241-Americium with a Beryllium moderator is probably used as a source for epithermal neutrons.
3-H Tritium is a beta emitter, present in huge amounts of radioactive methane flared after Project Gasbuggy, 1967.
60-Cobalt and 137-Cesium are positron/gamma emitters.
Using depleted 238-Uranium sinker bars near moderated epithermal neutron sources allows fertile 238-U to neutron capture, thereby eventually creating 239-Pu.
Other radionucleotides probably are also generated, but of these, 239-Pu is among the most toxic and carcinogenic.