Operator Tepco has published a video taken inside the Fukushima Daiichi unit 2 primary containment vessel which suggests that the level of water in the PCV is below the level of the grate. The actual water height was not seen. The actual water level in the unit 2 PCV is significant because the unit 2 wetwell was assumed to be cracked and leaking, an assumption made after booming noises were heard coming from the unit in the first few days of the crisis.
An attached thermocouple gave support to current temperature readings; although its readings were slightly higher (in the worst case, 45.7°C vs 42.6°C), the maximum difference was just over 3°C. The internal wall of the PCV was shown covered with rust-coloured deposits.
The video was taken by a borescope small-diameter camera with light source inserted in a penetration prepared by installing two protective plates that were then drilled through to create a space for the borescope to pass. It was also inserted with a thermocouple wire that measured temperature.
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