5-9 September 2016
Prague Congress Centre
Europe/Prague timezone

P2.131 Integration and mitigation aspects of the updated ITER ICH antenna shutdown dose rate analysis

6 Sep 2016, 14:20
1h 40m
Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Foyer 2A (2nd floor), 3A (3rd floor)

Prague Congress Centre

5. května 65, Prague, Czech Republic
Board: 131
Poster G. Vessel/In-Vessel Engineering and Remote Handling P2 Poster session

Speaker

Dieter Leichtle (Fusion for Energy)

Description

The Ion Cyclotron Heating and Current Drive system (ICH) is designed to launch RF power into the ITER plasma, and will reside in equatorial ports (EP) 13 and 15. Shutdown dose rates (SDDR) within the ICH port interspace are required to be ALARA and less than 100 μSv/h at 1066 seconds cooling, in locations where hands-on maintenance is required. The shielding performance of in-vessel, vessel and port systems are severely jeopardized by streaming paths such as the gaps between port frame and the ICH antenna. Recent design integration and assembly needs requested larger gaps to be compensated by streaming labyrinths. The impact on the SDDR levels due to these changes and further mitigation strategies have been studied in this work. An accurate description of in-vessel systems, consisting of blanket modules, manifolds and coils around the ICH port plug is needed and has been added to the previous MCNP model of the ICH antenna in the ITER torus sector reference model (C-lite). Several modified front shim designs of the gap dogleg labyrinths were trialed containing boron carbide to act as a neutron absorber. Initially average dose rates at 1066 seconds cooling were found to be on the order of 500 μSv/h, approximately doubled from previous analysis. However, this was primarily due to the effect of the fully open lower cryopump port, which in the previous model had been represented as a well-shielded diagnostic lower port. Replicating the shielded lower port environment in updated calculations resulted in dose rates of 235 μSv/h, a marginal reduction from the previous design. The attractive neutron attenuation capabilities by boron carbide shield elements in several locations of the ITER tokamak have been demonstrated. However, open lower ports potentially lead to significant radiation ‘cross-talk’ to the equatorial port interspace regions jeopardizing respective shielding design efforts.

Co-authors

Andrew Turner (UK Atomic Energy Authority (CCFE), Culham Science Centre,, Abingdon, Oxon, OX14 3DB, United Kingdom) Bertrand Beaumont (ITER Organization, Route de Vinon sur Verdon, 13067 Saint Paul Lez Durance, France) Dieter Leichtle (Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona, Spain) Michael Fleming (UK Atomic Energy Authority (CCFE), Culham Science Centre,, Abingdon, Oxon, OX14 3DB, United Kingdom) Philippe Lamalle (ITER Organization, Route de Vinon sur Verdon, 13067 Saint Paul Lez Durance, France) Roberta Sartori (Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona, Spain)

Presentation Materials

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