MODELING AND SIMULATION OF ACTIVATION PRODUCT TRANSPORT IN HELIUM COOLING LOOPS

This study presents models to describe the mobilisation, mass transpor t and deposition mechanisms of active and non-active species in the co oling loop of helium-cooled fusion power plants. A simple nuclear sput tering model has been developed in order to determine the active sourc e term entering the coolant and the flux of sputtered particles ejecte d from the pipe surfaces. A time independent mass transfer model has b een formulated to determine the transport and deposition of nuclides a round the primary cooling circuit and the computer code HETRAN has bee n written to solve the mass transport of stable and active species at discrete locations around the cooling loop. The model describes the ma ss balance of each species accounting for the particle production and loss mechanisms in the coolant, the surface and the bulk solid. These models have been validated against experimental data and existing comp uter codes, where possible and found to be in good agreement with publ ished work. Example calculations are performed, to determine the coola nt, bulk solid and pipe surface atomic and activity concentrations for the primary circuit of the helium cooled SEAFP Plant Model 1. (C) 199 7 Elsevier Science S.A.