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Abstract The ITER Organization maintains neutronics reference models for nuclear analysis. The "lite" series of tokamak sector models has progressed over many years to the C-lite V1 model released at the end of 2013. Since then several model updates have been continuously implemented in various C-lite V2 models. The latest release, C-Model represents the 40° regular sector of the tokamak up to the bioshield with central upper, equatorial and lower ports, i.e. an even-port configuration. C-Model, as previous C-lite models, is based on a modular concept of model envelopes which fill all space of the torus sector. This envelope block structure has been adopted to facilitate model update management on the basis of single standalone models, which can be easily replaced in the model assembly. C-Model has been significantly improved with respect to C-lite in terms of specific system model design status and level of detail, focused on in-vessel and vessel components. The development of those updated system models was conducted according to the quality standards of ITER reference models. Modelling instructions, documentation and verification formed an essential part of the related activities. [ABSTRACT FROM AUTHOR]

Abstract Accurate measurement of the nuclear environment within a test tritium breeding-blanket module of a fusion reactor is crucial to determine tritium production rates which are relevant to self-sufficiency of tritium fuel supply, tritium accountancy and also to the evaluation of localised power levels produced in blankets. This requires evaluation of the time-dependent spectral neutron flux within the test tritium breeding-blanket module under harsh radiation and temperature environments. The application of an activation foil-based spectrometer system to determine neutron flux density using a pneumatic transfer system in ITER has been studied, deployed and tested on the Joint European Torus (JET) machine in a recent deuterium - deuterium campaign for a selection of high purity activation foils. Deployment of the spectrometer system has provided important functional and practical testing of the detector measurement system, associated hardware and post processing techniques for the analysis of large data sets produced through the use of list mode data collection. The testing is invaluable for the optimisation of systems for future planned testing in tritium - tritium and deuterium - tritium conditions. Analysis of the time and energy spectra collected to date and the status of the development of methods for post-processing are presented in this paper. [ABSTRACT FROM AUTHOR]

Shutdown dose rate calculations have been performed on an integrated ITER C-lite neutronics model with equatorial port 10. A ‘fully shielded’ configuration, optimised for a given set of diagnostic designs (i.e. shielding in all available space within the port plug drawers), results in a shutdown dose rate in the port interspace, from the activation of materials comprising equatorial port 10, in excess of 2000 μSv/h. Achieving dose rates of 100 μSv/h or less, as required in areas where hands-on maintenance can be performed, in the port interspace region will be challenging. A combination of methods will need to be implemented, such as reducing mass and/or the use of reduced activation steel in the port interspace, optimisation of the diagnostic designs and shielding of the port interspace floor. Further analysis is required to test these options and the ongoing design optimisation of the EP10 diagnostic systems. [ABSTRACT FROM AUTHOR]