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• An alternative procedure to obtain a realistic thermal field for the central outboard blanket (COB) segment of the DEMO WCLL has been set-up and investigated. • A set of polynomial functions of the radial and toroidal variables has been obtained to reproduce the thermal field calculated in the COB equatorial region. • A comparison of the calculated and interpolated thermal field and of the corresponding secondary stress fields has been carried out. • To assess the applicability of the interpolation procedure to coarser mesh, a mesh independence study has been performed. • The polynomial functions have been applied to the whole COB segment to assess its thermomechanical response. In the frame of the EUROfusion research activities devoted to the design of the DEMO breeding blanket (BB), the Water-Cooled Lithium-Lead BB (WCLL) concept is one of the candidates currently assessed in EU. To this end, an intense research campaign is ongoing to develop a robust geometric configuration for the WCLL BB Central Outboard Segment (COB). Since the current reference design of the WCLL COB segment is not mature enough to allow a full thermal-hydraulic assessment, an alternative procedure aimed at obtaining a thermal field for the whole segment without performing its complete thermal-hydraulic analysis is presented and applied in this work. The scope of the work is to obtain a thermal field for the whole WCLL COB segment detailed enough to ensure a reliable prediction of the secondary stress spatial distribution, which is pivotal for the segment structural analysis. The procedure is articulated in three steps. Firstly, a thermal analysis of the equatorial region of the WCLL COB is performed, in order to calculate the thermal field in the most loaded region of the segment. Then, a multi-region interpolation is carried out in order to obtain a set of polynomial functions of the radial and toroidal variable, accurately representing the thermal field of the assessed equatorial BB slice. Finally, the calculated functions are applied to the whole COB to impose a realistic thermal field to the segment for the prediction of the stress, strain and displacement fields. Since the mesh for the analysis of the whole segment is expected to be coarser than that used for the assessment of its equatorial region, in this paper a mesh independence assessment of the interpolating functions is reported. In particular, their predictive power both in terms of temperature and secondary stress (i. e. thermal-induced stress) is assessed taking into account a decreasing level of detail of the adopted spatial discretization grid. The obtained results, widely reported and discussed hereafter together with the models and the adopted assumptions, show a great predictive power of the adopted polynomial functions, with a good mesh independence of the calculated temperature and stress values. [ABSTRACT FROM AUTHOR]

Abstract: The In-wall shielding (IWS) located between two shells of the vacuum vessel is part of the vacuum vessel of ITER. The function of the IWS is to provide neutron shielding and to reduce toroidal field ripple. The IWS plates are fastened using M30 bolts to hold them securely and the IWS blocks are mounted to the support ribs using the brackets and M20 bolts. The paper presents a structural finite element analysis of one sample IWS block carried out using ANSYS* to establish the benchmark analysis procedure of the IWS blocks. Boundary conditions are set taking into account the assembly procedure of the IWS blocks. The analysis is carried out in three load steps (1). Pretension on M30 (2). Pretension on M30 and M20 and (3) pretension on M30 and M20 plus Electromagnetic forces, dynamic forces, Seismic forces, etc. The stresses and displacements of individual IWS components are evaluated against their allowable stress limits as per an ASME guideline. The ITER-India’s results of analysis are compared with the ITER-IO’s results for the worst category 3-load step 3 and they are found comparable. This establishes the analysis procedure to be used for all of the IWS blocks. [Copyright &y& Elsevier]