Application of AFT Fathom code to steady-state thermal-hydraulics analysis of ITER Primary Heat Transfer Systems

The ITER Tokamak Cooling Water System (TCWS) is comprised of four (3) primary heat transfer systems and their supporting sub-systems; these primary heat transfer systems include First Wall Blanket and Divertor PHTS, Neutral Beam Injector PHTS, Vacuum Vessel PHTS. The TCWS provides the cooling water to ITER tokamak client systems for heat removal during plasma operations and provides the primary confinement barrier for the radioactive substances (Activated Corrosion Products (ACPs) and tritium) that become entrained in the cooling water. The TCWS PHTSs have specific functional design criteria for meeting the thermal-hydraulic parameters for heat removal, pressure, and temperature at the supply and return headers and at the tokamak in-vessel components. These parameters need to be carefully assessed in order to select key components that comprise the physical system including pumps, heat exchangers, valves, pipe and balancing orifices. AFT FathomTM code is a graphical platform for modeling incompressible flow in pipe networks. The main features of the code include the modeling network flow, pressure, and temperature at all node points in the system based on the Process Flow Diagram (PFD) and the input data (Workspace Window) and provide the analysis results (Visual Report Window) in a graphical form. FATHOMTM permits the definition of geometric properties of the circuit and includes pipe length, fittings, and components elevations. These characteristics are utilized to verify the correspondence of physical the geometry of the model with the analog PFD and hence provide a good approximation of the actual hydraulic circuit. The various models of the PHTSs performed using FATHOMTM permits the prediction of the various thermal-hydraulics characteristics during the steady-state performance of the TCWS.