About the major leakage of highly contaminated water, Tepco published the assessment of the environmental influence.
The leaking reservoirs are 880 m from the sea. About Sr-90 and Tritium, Tepco estimated it takes 10 ~ 100 years for the nuclides to penetrate underground to reach sea.
Because they don’t even know the ground water level, they simulated the speed based on the two assumptions that the ground water level was O.P.+30m, and it was 20m. (O.P. = Onahama peil)