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A methodology to evaluate the neutron activation, categorize as radwaste, generate radiological checklists, and optimize the packaging for disposal of activated components according to French regulations is presented. The methodology obtains results like specific activity, dose rates and radwaste relevant parameters in a fine 3D mesh superimposed over the geometry of interest and can handle the typically complex models common in the nuclear fusion analyses like those of the ITER project. State-of-the-art radiation transport and activation codes are used along with a purposefully developed Python tool (F4E-radwaste), which performs the post-processing of the large amount of data generated and includes a graphical user interface. The 3D nature of the results allows the organization of packages of activated materials in a way that minimizes the amount of mass classified with higher radwaste levels and is subject to more stringent regulations and expensive disposals. An application case study of the methodology is presented for the In-Vessel Viewing System (IVVS) ITER system. The IVVS is especially suited as an example for this type of analysis as its elongated shape pointing towards the plasma results in a significant gradient of neutron flux and activation levels, and therefore radwaste categories. It is demonstrated how the methodology enables the reduction of the total higher radwaste level mass by optimizing the packaging of the IVVS radwaste., This work has been funded with support from F4E. This publication reflects the views only of the authors, and F4E cannot be held responsible for any use which may be made of the information contained herein., Peer Reviewed, Postprint (author's final draft)

The In Vessel Viewing System (IVVS) will be one of the essential machine diagnostic systems at ITER to provide information about the status of in-vessel and plasma facing components and to evaluate the dust inside the Vacuum Vessel. The current design consists of six scanning probes and their deployment systems, which are placed in dedicated ports at the divertor level. These units are located in resident guiding tubes 10 m long, which allow the IVVS probes to go from their storage location to the scanning position by means of a simple straight translation. Moreover, each resident tube is supported inside the corresponding Vacuum Vessel and Cryostat port extensions, which are part of the primary confinement barrier. As the Vacuum Vessel and the Cryostat will move with respect to each other during operation (especially during baking) and during incidents and accidents (disruptions, vertical displacement events, seismic events), the structural integrity of the resident tube and the surrounding vacuum boundaries would be compromised if the required flexibility and supports are not appropriately assured. This paper focuses on the integration of the present design of the IVVS into the Vacuum Vessel and Cryostat environment. It presents the adopted strategy to withstand all the main interfacing loads without damaging the confinement barriers and the corresponding analysis supporting it.

The In Vessel Viewing System (IVVS) will be one of the essential machine diagnostic systems at ITER to provide information about the status of in-vessel and plasma facing components and to evaluate the dust inside the Vacuum Vessel. The current design consists of six scanning probes and their deployment systems, which are placed in dedicated ports at the divertor level. These units are located in resident guiding tubes 10 m long, which allow the IVVS probes to go from their storage location to the scanning position by means of a simple straight translation. Moreover, each resident tube is supported inside the corresponding Vacuum Vessel and Cryostat port extensions, which are part of the primary confinement barrier. As the Vacuum Vessel and the Cryostat will move with respect to each other during operation (especially during baking) and during incidents and accidents (disruptions, vertical displacement events, seismic events), the structural integrity of the resident tube and the surrounding vacuum boundaries would be compromised if the required flexibility and supports are not appropriately assured. This paper focuses on the integration of the present design of the IVVS into the Vacuum Vessel and Cryostat environment. It presents the adopted strategy to withstand all the main interfacing loads without damaging the confinement barriers and the corresponding analysis supporting it.