The problem: Cooling water is exiting reactor 2 and leaking in this maintenance pit down-system, finding its way into the ocean
The plan: Simple - fill the maintenance pit with concrete to stop the leak
The fail: 1 Sievert/hour ++ water is now draining out of a different location; access to maintenance pit now blocked with 2 tons of cement.
No happy ending yet, and judging from the location and volume of water exiting this wall, it ain't gonna be easy to plug. Please excuse the sarcasm, it's hard to resist.