Photograph 2: Damage at the mid-lower section. The refractory layers between turns were damaged (magenta arrow). A punctured hole was found on turn-14 (white arrow).

Photograph 2: Damage at the mid-lower section. The refractory layers between turns were damaged (magenta arrow). A punctured hole was found on turn-14 (white arrow).

Photograph 2: Damage at the mid-lower section. The refractory layers between turns were damaged (magenta arrow). A punctured hole was found on turn-14 (white arrow).