  This paper reports the impact on confinement and power load of the high-shape
2.5MA ELMy H-mode scenario at JET of a change from an all carbon plasma facing
components to an all metal wall. In preparation to this change, systematic
studies of power load reduction and impact on confinement as a result of
fuelling in combination with nitrogen seeding were carried out in JET-C and are
compared to their counterpart in JET with a metallic wall. An unexpected and
significant change is reported on the decrease of the pedestal confinement but
is partially recovered with the injection of nitrogen.
