3-D Montecarlo analysis of the NET shielding system

During the first phase of the physics program, NET should be operated with an extended plasma size maintaining, however, the NET-DN basic dimensions for the magnet and for the vacuum vessel shielding system. This means that a reduced space is available for the blanket. Moreover, as less stringent technological conditions are desirable in this phase, a more reliable solution has been foreseen for the blanket which has been designed to fulfill only shielding and heat removal requirements and is mainly composed of water cooled stainless. Within the frame of the European Task in shielding design studies (N2), a detailed 3-D neutronicanalysis has been carried out for this configuration using the MCNP Monte Carlo code. The analysis has been mainly oriented to access the shielding performances related to the radiation limits on the superconducting coils. An overall characterization of the neutron and photon field in the whole system has also been done. Typical selected results are reported in this paper. (author). 8 refs.; 3 figs.; 3 tabs;