In 2009-2011 so-called ITER-like wall was installed on JET tokamak, with beryllium limiters and tungsten divertor. Change of the plasma facing materials from carbon to metallic had a significant effect on plasma operations and confinement. Achieving steady plasma performance has become more challenging due to impurity accumulation [1], which has put additional constraints on the available operational space. Confinement in scenarios with low Ploss/PLH<2 was found to be worse with respect to similar scenarios in JET C-wall, due to degraded confinement in the pedestal [2].