Shielding proposal to mitigate the PFC #2 heating due to 16N decay photon radiation from the activated cooling water

Abstract

In this work, the total heating of the ITER superconducting Poloidal Field Coil #2 (PFC #2) has been calculated due to 16N decay photon radiation emitted from the activated water in the Blanket Manifolds, the Chimney pipes and the Tokamak Cooling Water System (TCWS) manifolds. In order to reduce the total nuclear heating of the PFC #2, shielding measures have been proposed; a set of conceptual stainless-steel shields has been designed and inserted into the computational model of the ITER machine covering the Upper Port Stub (UPS) Chimney and the UPS Chimneybox. The results have shown a 42% reduction of the PFC #2 heating, i.e. from 275 W down to 160 W, when 10 cm thick plates have been placed on the mentioned UP structures. At the same time, the maximum specific heating of the PFC #2 has been decreased by 63%, from 40 W/m3 down to 15 W/m3. A recommendation has been given for further reduction of the PFC #2 heating by improving the on-going design of the TCWS duct.