3D thermal-hydraulic analysis of two irregular field joints for the ITER vacuum vessel

In ITER, so-called "Irregular" Field Joints (IFJs) are foreseen at the interface between irregular sectors of the Vacuum Vessel (VV), which is located inside the cryostat and houses the in-vessel components. In the IFIs, a peculiar design of the equatorial port, with respect to that adopted in the Regular Field Joints (RFIs), accommodates the irregularities of the adjacent VV sectors. The IFJs are subject to nuclear heating and actively cooled by sub-cooled pressurized water flowing in a dedicated hydraulic loop, which includes the space left open by the borated In-Wall Shielding (IWS). Here we perform the 3D steady state thermal-hydraulic analysis of two different IFIs using the Computational Fluid Dynamics (CFD) software ANSYS-FLUENT (R). The water flow field, the pressure drop and the temperature maps are computed. The thermal performance of the IFJs in nominal operation is compared to that of an RFJ and it is shown that also in this case enough cooling capability is available to avoid hot spots above the design limits, while the pressure drop remains acceptably low. (C) 2015 Elsevier B.V. All rights reserved.