Measures against Contaminated Water

Water contaminated with radioactive materials has been treated based on the following three basic policies.

< Basic Policy 1: Removing contaminant sources >

< Basic Policy 2: Isolating water from contaminant sources >

Pump up groundwater on the mountain side of the buildings to suppress inflow of groundwater around the buildings
Pump up groundwater using the well near the buildings (subdrain) to lower the groundwater level, thereby suppressing inflow of groundwater into the buildings
Construct a frozen soil wall around the buildings to suppress inflow of groundwater into the buildings
Suppress infiltration of rainwater into soil by paving the surface (facing)

< Basic Policy 3: Preventing leakage of contaminated water >

Construct a sea-side impermeable wall made of steel pipes to reduce outflow of groundwater containing radioactive materials into the sea
Construct a groundwater drain in the area between the sea-side impermeable wall and the land-side impermeable wall and pump up groundwater to reduce the outflow of groundwater into the sea
In order to ensure safe storage of water after purification using ALPS and other equipment, promote storage in welded tanks with lower leakage risks

These efforts have brought about the following outcomes:

The amount of newly generated contaminated water decreased from approx. 540 m³/day in May 2014 to approx. 130 m³/day in FY2021, and the goal of approx. 150 m³/day set in the Mid- and Long-term Roadmap has been achieved.
Treatment of the accumulated water in the buildings, except for reactor buildings, etc. for Unit 1 to Unit 3, was completed and the goal set in the Mid- and Long-term Roadmap has been achieved.
Concentrations of radioactive materials in the port decreased significantly.