1. Produktentwicklung und Maschinenelemente
Fachbereichs Maschinenbau
Technische und Wirtschaftswissenschaftliche Universität Budapest
Concept design for the scaling and optimization of diagnostic components located in vacuum vessel
Process optimization system
Judit Szalai
Introduction
The ITER’s (International Thermonuclear Experimental Reactor) mission is to demonstrate the feasibility of fusion power and prove that the tokamak type of magnetic confinement device can work without negative impact .
The final ITER design with the diagnostic cable ducts on the vacuum vessel wall shown in Figure 1.
The diagnostic cable ducts with the mineral insulated cables (MI cables) at the vacuum vessel shown in Figure 2. The MI cables will be used throughout the vacuum vessel environment to convey electrical signals to and from magnetic coils, bolometers, vacuum vessel instrumentations and thermocouples. These stainless steel sheathed cables vary in diameter from 1,5 mm to 4,8 mm.
The diagnostic cable ducts are located on the vessel wall, made from pure extruded aluminum insert plates and lodged between each layer of cables, culminating with a sub-base plate and linking the loom to the vessel inner surface.
The diagnostic cable ducts with the mineral insulated cables can be treated with a distributed as a network, and we need a thermal model that describes the intended behavior of the thermal component. The temperature variation (ΔT) of the diagnostic cable ducts must not exceed 10 K. In this case the thermal conductivity is an effective method of aim the heat transfer in the vacuum environment. In this locations need to ensure the strong contacts between the inner surfaces of the diagnostic cable ducts and the surface of MI cables, and also need to ensure the strong contacts on the internal surface of diagnostic cable ducts between the vessel wall.
1.2. Process optimization of diagnostic system using 3-D model
and transient thermomechanical simulation
Firstly the plasma heat flux on the plasma facing surfaces secondly, the volumetric heat generation caused by neutron irradiation and finally the coolant temperature of the vacuum vessel surface. In the thermal boundary conditions are the coolant temperatures calculated as an average of inlet and outlet temperatures and heat transfer coefficient between the cooling vacuum vessel wall and the diagnostic cable ducts. The contacts are bonded in the 3D-model.
The electromagnetic loads occurring during disruptions shall result in significant mechanical moments and forces on the diagnostic cable ducts and be joining constructions. The materials and design must ensure that the structure is able to withstand the loads on operating temperature. The force and torque components from acting on the diagnostic cable ducts are shown in Figure 3.
Introduction
The highest heat charge to be taken into account when composing the structural design affecting in the course of the fusion process the vacuum vessel and the shielding blocks amounts to 360 °C. In this case of the shielding blocks from the side of the plasma less than 150 °C on the contact surface between the vacuum wall and the outer surface of the diagnostic cable ducts. In the MI cables and the diagnostic cable ducts of the diagnostic system heat progression in the internal volume stemming from neutron and gamma radiation will take up a value between 0,024-0,12 W/cm3.
The effect of heat loads was simulated with FEM (Y.Nakasone, S. Yoshimoto, T. A. Stolarski: 2008) and results helped to optimize the geometry of diagnostic cable ducts.
1.3. Process optimization system for the new structure of the diagnostic cable ducts
Based on thermal-mechanical calculations, the numbers and locations of the anchor points can be optimized. As a result of the optimization of the bond, the stresses were lower with this solution of the structure of the diagnostic cable ducts. The block diagram of the optimization algorithm is shown on Figure 4 .
The algorithm uses graphical interface for the calculation of exerted forces in the construction of the diagnostic cable ducts. The user interface contains input fields where each material, condition and geometry variable can be specified for the calculation's equations.
2. Conclusion
Based on thermal-mechanical calculations, welding, in this case, were
successfully replaceable with the anchor element, and the new concept allows to deform the structure of diagnostic cable ducts. As a result of the optimization of the diagnostic cable ducts, the stresses were lower with this solutions.
References
Plasma Physics and Fusion Energy: Jeffrey P. Freidberg 2007
Y. Nakasone, S. Yoshimoto, T. A. Stolarski: Engineering analysis with ANSYS software, Elsevier, Oxford, 2008
Design Description Document: DDD 11 ITER_D_22HV5L v2.2 Magnet Section 1. Engineering Description (2006). Retrieved June 10th, 2017
EN 10302:2008, Summary of Material Data For Structural Analysis of the ITER Vacuum Vessel Supports3 VTZHT_v1.0 . Retrieved June 10th , 2017
E. Onate: Structural Analysis with the Finite Element Method Linear Statics, Springer, Dordrecht 2013
Figure 1.: The final ITER design with the diagnostic cable ducts on the vacuum
vessel wall
Figure 3.: Force and torque components from acting on the diagnostic cable ducts
Figure 2: The final ITER design with the diagnostic cable ducts on the vacuum vessel wall
Figure 4.: The algorithm calculates and shows the numeric results of the exerted forces in the structure of the diagnostic cable ducts