To assess the suitability for ITER of operation during the low activation phase in ELMing H-mode helium plasmas and to investigate in detail areas in which the underlying physics differs from operation with hydrogenic isotopes as the main plasma species, pure He discharges have been explored in JET during a three week period at the end of first experimental campaign in 2001. As many as possible of the principal operating regimes in D (e.g. L and H-mode and OS plasmas) have been explored with the aim of improving understanding in confinement, the L-H transition, ELMs and edge physics. With regard to the latter, particular topics of interest include atomic physics and impurity production and their influence on divertor radiation, detachment and density limits.