Speaker
Selanna Roccella
(FSN)
Description
The ITER operation program, as well as the DEMO operational, foresees for the vertical targets strike point region high steady state thermal fluxes that can be sustained only by components designed and manufactured accordingly. Their life-time is limited mainly by thermal fatigue caused by cyclic thermal loads inducing high mechanical stresses.The Plasma Facing components of the ITER divertor are made of a CuCrZr tube joined to tungsten drilled rectangular blocks (named monoblocks) provided of a complaint layer of pure copper (Cu-OFHC).In the framework of a EFDA contract (05-1249), ENEA manufactured six small mock-ups of the ITER divertor Inner Vertical Target plasma facing units that were tested to thermal fatigue loads at High Heat Flux (HHF) in the TSEFEY e-beam facility at the Efremov Institute. A comparison between FEM simulation and HHF test results has been presented in a previous work, where the lifetime estimated was less than that found during the experiments. A better estimation of the test results can be obtained by including in the calculation the residual stresses induced in the CuCrZr tube by the manufacturing process of the mock-ups.The reference manufacturing process used for the calculation is the Hot Radial Pressing (HRP). This process developed by ENEA and widely qualified is based on the radial diffusion bonding principle performed between the cooling tube and the armour blocks. The bonding is achieved by pressurizing internally the cooling tube while the joining interface is kept at the vacuum and temperature conditions.In the simulation, the joining process is considered and the residual stresses are the initial condition for the subsequent simulation of the HHF testing. Calculation of the mock-ups lifetime under high thermal loads fatigue is performed and the results are presented and again compared with the HHF test results.
Co-authors
Eliseo Visca
(FSN, ENEA, Frascati, Italy)
Fabio Crescenzi
(FSN, ENEA, Frascati, Italy)
Selanna Roccella
(FSN, ENEA, Frascati, Italy)
