My particle physicist's answer would be No, not for fuel, not in existing reactor designs. The necessary technical methods would be such that a small part of the energy available would end up as heat and useful energy as in the fission type reactors, it will not be cost effective.
Consider that the antiprotons will have to exist in a plasma with positrons suspended in a magnetic field. Plasma is not very dense, orders of magnitude less dense than uranium. It has to impinge on ordinary matter in a controlled manner and the products of the annihilation will have to travel some distance. The products are on the average 5 pions, 1/3 of which are pi0 which decay practically immediately into two high energy gammas.
The charged pions decay in ~10^-8 seconds into a muon and a neutrino, neutrinos will leave without interacting and muons will interact minimally electromagnetically,without depositing much energy. The energy that can be trapped is the electromagnetic ionization that the pions and muons leave in whatever material is used for the trapping of the energy. One would need detailed calculations to establish what type of material would trap most of the energy , but it will have to be a new design, from scratch. The difference lies in the kinetic energies of the products of the interaction: in fission they are low and the products can be trapped in ordinary matter because further decays are improbable. In an antiproton on matter reactor the kinetic energies are large and the charged products have to be trapped before the decay, while a new design is needed for the gammas of the pi0.
clarification after comment: Fission reactors have developed specific methods of turning the kinetic energy of the fission products into heat, this means specific materials suitable for this purpose. Fission works with energies of particles of the order of MeV, and a small part of that is kinetic energy. These heavy slow moving fragments can be stopped by ordinary materials, their kinetic energy absorbed by them.
The energy of the antimatter matter annihilation is almost 2 GeV with the average multiplicity of 5 pions it means that each pion gets on average 400 MeV. This energy is mainly kinetic, they are very light particles moving fast and different materials and methods would have to be used than the ones in a fission reaction.
In this bubble chamber picture we see lots of charged pions ( the chamber is transparent to the gammas of pi0) from the annihilation ,and the decay to a muon and an appropriate neutrino for one of them. The medium , probably liquid hydrogen, is not dense enough to contain the energy of the interaction. The objective for a reactor would be to absorb all the kinetic energy of the pions before their decay in 10^-8 seconds. Maybe magnetic fields would be necessary to trap them in suitable dense material so that their kinetic energy turns into ionization energy and finally heat. New technology is needed, is all I am saying, and maybe so expensive that the output would not be cost effective.