Kripke Platek set theory has collection instead of replacement, and it is a weakening of KP if one has replacement instead of collection. Call KP minus colection plus replacement KF for *Kripke Fraenkel*. Is KF weaker than KP in that some transfinite recursion can be done by KP which cannot be done by KF? If so, is that a difference inherited by strengthened theories as $\Sigma _{n} KP$ and $\Sigma _{n} KF$ for $n>1$?