During plasma disruptions in JET, the thermal energy (10MJ) and magnetic energy (20MJ) are lost in the form of heat to the Plasma-Facing Components (PFC) on time scales of less than 1ms and 20ms, respectively. The thermal energy Wth stored in the plasma is dissipated initially in the Thermal Quench (TQ), followed by the magnetic energy dissipation in the Current Quench (CQ). During the thermal quench phase of the unmitigated disruptions the main part of the thermal energy is lost by convection to the first wall and only a small part (0.2¥Wth) by radiation. The energy deposition is distributed non-uniformly over the first wall surfaces and it may significantly contribute to the local power loads onto PFCs.