In order to study the effects of 14 MeV neutron irradiation on materials used in the first walls of future fusion reactors, high-purity iron was ion-irradiated with and without helium in the JANNuS facility. Thin foils of high-purity iron were dual-beam irradiated in situ in a transmission electron microscope using 1 MeV Fe+ and 15 keV He+ ions. Several important results regarding dislocation loops and helium bubbles were obtained. For example, it was demonstrated that dislocation loops with a0 〈0 1 0〉 type Burgers vectors are glissile and can move and eliminate at the surface of the thin foil at 500 °C. A comparison of irradiations with and without helium showed that helium atoms reduce the mobility of dislocation loops in pure iron irradiated at 500 °C. Also, we demonstrated that the heterogeneous formation of bubbles inside dislocation loops found previously is also present for helium implantation rates of ∼80 atomic parts per million (appm) He/displacements per atom (dpa).