Contact Dose Rates And Relevant Radioactive Inventory In ITER TBM Systems

The determination of the radioactive inventory and of the contact dose rates in the different ITER Test Blanket Modules systems is carried out, both for Helium-Cooled Lithium–Lead (HCLL) concept and the Helium-Cooled Pebble-Bed (HCPB) concept. The evaluations have been carried out by means of the MICROSHIELD code, starting from the data on the neutron-induced radioactivity in the blanket materials, already available for both the blanket modules. The possible sources of radioactive material in all the systems have been individuated and their contributes estimated

ITER Développement des procédures de fabrication pour les sous composants en acier 9 % Cr de la couverture tritigene Helium Cooled Lithium Lead (HCLL)

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Radioactive Safety Estimates for ITER TBM Systems

The determination of the radioactive inventory and of the contact dose rates in the different ITER Test Blanket Modules systems is carried out, both for Helium-Cooled Lithium-Lead (HCLL) concept and the Helium-Cooled Pebble-Bed (HCPB) concept. The evaluations have been carried out by means of the MICROSHIELD code, starting from the data on the neutron-induced radioactivity in the blanket materials, completely available for both the blanket modules. The possible sources of radioactive material in all the systems have been individuated and their contributes estimated. In general, for both HCLL and HCPB systems, radioactivity inventory and contact dose rates turn out to be quite moderate. No particular radioactive safety concern should arise for the examined component

Radioactive Safety Estimates for ITER TBM Systems

The determination of the radioactive inventory and of the contact dose rates in the different ITER Test Blanket Modules systems is carried out, both for Helium-Cooled Lithium-Lead (HCLL) concept and the Helium-Cooled Pebble-Bed (HCPB) concept. The evaluations have been carried out by means of the MICROSHIELD code, starting from the data on the neutron-induced radioactivity in the blanket materials, completely available for both the blanket modules. The possible sources of radioactive material in all the systems have been individuated and their contributes estimated. In general, for both HCLL and HCPB systems, radioactivity inventory and contact dose rates turn out to be quite moderate. No particular radioactive safety concern should arise for the examined components

Assessment of HCLL-TBM optimum welding sequence scenario to minimize welding distortions

International audienceThe ITER HCLL-TBM (Helium Cooled Lithium Lead Test Blanket Module) box assembly development implies the welding development of the following components the Box and the Stiffening Grid (SG) made of vertical and horizontal Stiffening Plates (noted respectively v-SP and h-SP). This multi-chamber box structure in EUROFER97 steel is made of plates cooled by multiple meandering channels where circulates pressurized helium. For the assembly of these components, characterized by numerous multipass welds, Gas Tungsten Arc Welding (GTAW) is envisaged as reference process. Moreover, the TBM has large dimensions and thin plates which makes it very sensitive to welding distortions and is problematic regarding the assembly feasibility and compliance with geometric tolerances. This paper presents the numerical simulation and experimental work performed to optimize the v-SP to box assembly sequence, which is the most critical assembly regarding distortions, in order to minimize welding distortions.One of the technical lock of this study is high calculation times needed for this large component which implies to set up a simplified welding simulation method. The study is composed of three main phases an experimental-numerical study of a T-joint fillet mock-up GTAW used to develop the preliminary welding procedure and to validate a simplified simulation method, a numerical optimization of the v-SP to box welding sequence via the simplified method, and the experimental application of the optimized v-SP to Box welding sequence on the TBM mock-up. The calculation and comparison of four different v-SP to box welding sequences allowed to identify the best sequence regarding welding distortions and to apply it experimentally

The European ITER Test Blanket Modules: Assessment of manufacturing technologies for HCLL

International audienceThe HCLL-TBM (Helium Cooled Lithium Lead Test Blanket Module) is one of the two European TBMs chosen tobe tested in ITER. HCLL TBM structure is constituted by a box, made of two Side Caps (SCs) and a First Wall (FW),stiffened by horizontal and vertical Stiffening Plates (SP) and closed on its back by several back plates (BPs). All structuresubcomponents are internally cooled by Helium circulating in meandering squared section channels. This paper describesmanufacturing technologies developed and implemented to assembly the SPs into the box.It presents the preliminary manufacturing procedure developed and applied for the assembly of the SPs into the box byTungsten Inert Gas (TIG). Several mock ups have been manufactured from laboratory to feasibility mock ups (scale 1:1)on which non-destructive and destructive tests have been carried-out to identify the preliminary manufacturing procedure.Due to TBM specificities (namely complex welding trajectories, heavy and big components, plates with channels, spaceconstraints, ...) a specific welding facility including a custom welding torch and an automated bench has been achievedand is also described in the paper.We detail the adopted manufacturing strategies, as the optimization of welding sequence to minimize distortions and thecustomization of welding parameters, to compensate machining tolerances and welding gaps. Results such as weldedjoints quality and microstructure, internal cooling channel deformation and structure distortions are reported. Thesedevelopments have been performed following a standardized procedure complying with professional codes and standards(RCC-MRx)

The European ITER Test Blanket Modules: EUROFER97 material and TBM’s fabrication technologies development and qualification

The paper overviews activities focused on qualification of EUROFER97 structural material, introduced under a probationary phase in the nuclear components design and construction code RCC-MRx, and identification/analyses of gaps in the respective material database to be filled in. Additionally the available design rules in the code are reviewed to verify their applicability to the specificities of EUROFER97 steel and to the TBM design and fabrication. Progress achieved in development of fabrication technologies and procedures applied for manufacturing of the TBM sub-components, like, HCLL and HCPB cooling plates, stiffening plates, first wall and side caps, and for TBM structure sub-assembly is described. The used technologies are based on fusion (laser and TIG) and diffusion (HIP) welding techniques taking into account specificities of the EUROFER97 steel. With help of the agreed notified body, an appropriate approach/methodology for qualification of the developed, TBMs-related preliminary welding procedure specifications has been identified and future steps established