The electron cyclotron heating and current drive (EC H&CD) upper launcher (UL) is a component of the ITER tokamak machine devoted to inject localized high microwave power, in order to counteract plasma instabilities (MHD activity). The UL consists of an assembly of ex-vessel waveguides (with diamond windows and isolation valves) and an in-vessel port plug (PP). The PP, with length close to 6 m, is fixed by a support flange into the upper port of the vacuum vessel (VV) as a cantilevered structure and the nominal gap between PP and port is 25 mm only. During an earthquake, accelerations generated by seismic events cause oscillations of the PP which might be amplified in case of resonance with the natural frequencies. A seismic analysis is therefore required in order to check the response of the UL PP to earthquakes.
This paper shows the procedure used for the seismic analysis of the UL PP and results are given in terms of displacements and stresses. The ITER reference earthquake named SL-2 seismic event was considered. The response spectrum method was used in the analysis and floor response spectra (plots of acceleration versus frequency) provided by ITER/F4E at the upper level of the tokamak were applied to the supports as load. ... mehr