Speaker
Davide Flammini
(Department of Fusion and Nuclear Safety Technology)
Description
The ITER In-Vessel Viewing System (IVVS) consists of six identical units located at the B1 level of the Tokamak complex, at lower ports 3, 5, 9, 11, 15 and 17. They can be deployed to perform in-vessel inspections between plasma pulses or during a shutdown. When not in use, each unit is housed inside a dedicated port extending from the Vacuum Vessel (VV) outer wall to the port cell (PC), locked by a primary closure plate and equipped with a guide tube, shield blocks and a feedthrough for various services.
In this work relevant nuclear quantities in the PC have been calculated by means of the MCNP-5 Monte Carlo code in a full 3-D geometry, including the IVVS and its shielding blocks geometry.
A comprehensive MCNP model of the PC has been developed including a detailed description of the Bioshield plug, pipes, penetrations, cask rails and PC door. The neutron and gamma sources needed to perform the nuclear analyses have been defined taking into account both the contribution from the radiation streaming through the Lower Port and the gammas locally emitted by activated water circulating in the cooling pipes.
Monte Carlo calculations have been performed to assess the radiation field inside the PC through neutrons and gamma maps. Absorbed dose during the ITER lifetime on sensitive components have been estimated in the PC area, in order to estimate the nuclear loads that the installed equipment have to withstand. Furthermore, the impact of the gamma-rays emitted by neutron-activated water circulating in the Primary Heat Transfer System have been evaluated on the PC environment: 3-D maps of the gamma flux, absorbed and biological dose rates during plasma operation are provided.
Co-authors
Adrian Puiu
(Fusion for Energy, Calle Josep Pla 2,Torres Diagonal Litoral B3, Spain)
Anton Travleev
(INR, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D 76344 Eggenstein-Leopoldshafen, Germany)
Davide Flammini
(Department of Fusion and Nuclear Safety Technology, ENEA, Frascati, Italy)
Fabio Moro
(Department of Fusion and Nuclear Safety Technology, ENEA, Frascati, Italy)
Raul Pampin
(Fusion for Energy, Calle Josep Pla 2,Torres Diagonal Litoral B3, Spain)
Roger Reichle
(ITER Organization, Route de Vinon sur Verdon,Saint Paul Lez Durance, France)
Rosaria Villari
(Department of Fusion and Nuclear Safety Technology, ENEA, Frascati, Italy)
Ulrich Fischer
(INR, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D 76344 Eggenstein-Leopoldshafen, Germany)
Yuefeng Qiu
(INR, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D 76344 Eggenstein-Leopoldshafen, Germany)
