Radioactive Concentration measured by Seawater Radiation Monitor near Fukushima Daiichi Nuclear Power Station The following are radioactive concentrations in seawater measured by the seawater radiation monitor installed at the port entrance of Fukushima Daiichi Nuclear Power Station.

Monitoring points Expansion Radiation concentration Expansion



※Data is not displayed on the graph when the measurement results are below the detection limits.

Detection limits:

・Cesium 134 : 0.02 Bq/L

・Cesium 137 : 0.05 Bq/L

・Gross β : 8.7 Bq/L





※The measurement results from the seawater radiation monitor may vary due to the effects caused by natural

Potassium 40 (β nuclide) being contained in seabed sand and seawater when they are stirred up by rough seas.





※After cleaning the equipment, Cesium concentration readings fall due to removal of radioactive material adhered to the detection tank.





※For reference:

The following are the regulatory notification limits set according to the rules for security of nuclear facilities and

protection of specific nuclear fuel at Fukushima Daiichi Nuclear Power Station:

・Cesium 134 : 60 Bq/L

・Cesium 137 : 90 Bq/L



○Announcement

・Equipment was cleaned on March 24, 2020. *Data may be missing due to equipment failure, cleaning, or regular inspections.



