R&D of a strain monitoring system for the EAST tungsten divertor

Abstract

The tungsten divertor of the Experimental Advanced Superconducting Tokamak (EAST) device operates at varying temperatures and strong electromagnetic fields during plasma operation. In order to monitor the thermomechanical and electromagnetic responses of the structural components, a strain sensor system has been proposed to be applied in the EAST device. To develop this technology, two initial experiments on the thermal strain measurement of a tungsten divertor module of the EAST have been carried out using electrical strain gages and optical strain sensors. However, some engineering issues were exposed during the experiments. Under this condition, all these issues are summarized and discussed this time. Moreover, a comparison between the two techniques has been made when applied in the tungsten divertor. To make them more suitable for the application in the tungsten divertor of the EAST, several activities including a thermomechanical simulation, the welding technologies for the sensors’ installation and a thermal stability test on the optical strain sensors were conducted. Based on these progresses, it is expected that the strain monitoring system will be established in the EAST device in the near future. Keywords: Tungsten divertor, Strain monitoring, Electrical strain gage, Fiber Bragg Grating, EAST