Impact of W monoblock damage on EAST operations in recent campaigns

Highlights: • Statistics analysis on the disruptivity due to W monoblock damage have been performed for each EAST campaign from 2017 to 2019. • After the 2017 campaign, the main contribution to impurity-induced disruption is W due to divertor damage. • The disruptivity due to W monoblock damage increases with the increase of the auxiliary heating power. • Normal discharges can be promptly recovered after disruptions due to W monoblock damage. • The W divertor damage is currently tolerable for the overall EAST operations. The upper divertor of EAST has been upgraded to ITER-like tungsten plasma-facing components since 2014. The impact of tungsten monoblock damage on plasma operations in recent EAST campaigns was studied. Various damage on the divertor tiles such as melting, cracking and arcing was found. Statistics analysis on the disruptivity due to W monoblock damage have been performed. W impurity produced from W divertor damage becomes the main impurity that leads to disruption during 2018, 2019a and 2019b campaigns compared to other impurities. With increasing auxiliary heating power, the W divertor damage becomes more and more serious. The current divertor damage is still tolerable for the overall EAST operations. Such studies can provide good references for the future fusion devices with W monoblocks, such as ITER.