The second approach used by TEPCO to limit overflow into the sea was to plug a leak in a pit which was located near the unit 2 reactor basement and above the trench system.
The second approach used by TEPCO to limit overflow into the sea was to plug leaks into pits that were connected to the trenches. Discovered on 1 April, the leak in the unit 2 pit was located near the unit 2 reactor basement and above the trench system.