It's weird that the products of the U235 chain reaction seem noticably less horrible than what you get when you forcibly split U238 with a fast neutron from hyd

It's weird that the products of the U235 chain reaction seem noticably less horrible than what you get when you forcibly split U238 with a fast neutron from hydrogen fusion. It seems like you get way worse fallout from an H-bomb than from an A-bomb even accounting for yield. Unless you do what the Soviets did in the Tsar Bomba test and replace the U238 with lead.