Speaker
Rafael Enparantza
(Design)
Description
The Normal Heat Flux (NHF) First Wall (FW) panels are designed to withstand the heat flux from the plasma inside ITER. These components are made of beryllium tiles bonded to a copper alloy and 316L (N) stainless steel heat sink. A NHF FW panel consists of several fingers as elementary plasma facing units. This this paper presents the experimental stress and deformations measured on a 10-fingers mock-up representative of the first stainless steel to CuCrZr joint. The scope of this work covered only this initial stage and is not representative of the final shape of the panel.
Specifically, this paper reports on the monitoring of surface stresses at different steps in the manufacturing process of a simplified 10-fingers prototype of a NHF FW panel: 1) after the HIP process 2) after the solution annealing treatment and precipitation hardening of the CuCrZr layer and 3) continuous surface stress measurement during the cutting of the fingers by EDM. For this, a bespoke extensometry system has been developed.. Results show that surface stress values after HIP are low, in the range of 150 MPa (Von Mises), with infrequent peaks of 300 MPa. Results also show that solution and precipitation hardening do not affect in general these values, although a slight increase in some points was observed sometimes. During the cutting operation important changes of the surface stress have been observed (average above 400 MPa), which eventually lead to visible deformations in the part.
Results show that deformation is due to the release of internal stresses as new free surfaces are created. No relationship should be expected between the finger manufacturing sequence and stress. The stress release is general and affects the whole geometry of the part. Research concludes that internal stresses should be measured after the HIP process to verify the conclusions.
Co-authors
Fernando Samaniego
(Fundación Leading Innova (CT-Innova), C/ Isabel Torres 1, Santander, Cantabria 39011 , Spain)
Ignacio Cobo
(CT Innova, Barrio La Agüera s/n, San Felices de Buelna 39409, Cantabria, Spain)
Jesus Alonso
(Design, Manufacturing and Assembly, IK4-TEKNIKER, Eibar, Spain)
Josu Eguia
(Design, Manufacturing and Assembly, IK4-TEKNIKER, Eibar, Spain)
Rafael Enparantza
(Design, Manufacturing and Assembly, IK4-TEKNIKER, Eibar, Spain)
Steffano Banetta
(Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019, Barcelona, Spain)
Tindaro Cicero
(Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019, Barcelona, Spain)
