OK guys,
Physics lesson here so bear with me. ALL things nuclear start off with a fission trigger. If it is a boosted weapon, i.e. has a tritium packet, the fission trigger heats the tritium so it boosts the yield with a fusion reaction.
IT makes NO difference if the yield is 1kt or 100kt - the amount of radiation released will be the same, just with a varied dispersal depending on the FISSION yield, because of having the use the same amount of fissile material to start a chain reaction in the first place. (Usually on order of 7kg of PU-238 - not many U-235 guntype bombs hanging around).
Enhanced Radiation Weapons (Neutron bombs) were actually the cleanest weapons - and the historical irony is the TSAR BOMBA, the 51 MT black coc-k of death was, by yield - the cleanest explosion every attempted on earth.
P.S. On a side note - if you were able to create the same conditions to heat the fusion packet up which the fission trigger does, but without using the fission trigger - you'd have perhaps a frightening paradigm of a fusion weapon without the harmful long lived transuranics.
Wolf