Monitoring of the ALPS treated water

The ALPS treated water is discharged under strict control, including measuring the concentration of radioactive materials contained in the water before the discharge and confirming that the concentration is below the regulatory standard.
Therefore, there will be no food safety issues for fish living in the vicinity and other food products.

Analysis results of ALPS treated water

Previous Batch*

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TEPCO and a third-party laboratory, JAEA, analyzed the ALPS treated water prior to discharge and confirmed the water satisfy the discharge limit

* ALPS treated water sampled on February 29, 2024 (K4-C tank group)

* Discharge limit:The sum of ratios to the regulatory concentrations limits of nuclides other than tritium is less than 1.

Previous Batch*

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TEPCO and a third-party laboratory, JAEA, analyzed the ALPS treated water prior to discharge and confirmed the water satisfy the discharge limit

* ALPS treated water sampled on March 25, 2024 (K4-A tank group)

* Discharge limit:The sum of ratios to the regulatory concentrations limits of nuclides other than tritium is less than 1.

For detailed analysis results, click the buttons below.

Monitoring results of the sea area near TEPCO Fukushima Daiichi Nuclear Power Station. (Tritium in seawater and fish)

Current Status*

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CLEAR

* Based on the latest analysis by each laboratory

Legend

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CLEAR: Not exceeding Discharge Suspension level (Inspection is needed for facility operation status and others if the concentration is above this level)

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WATCH: Exceeds Discharge Suspension level

* Discharge Suspension level:

700 Bq/L in the vicinity of the discharge outlet

30 Bq/L outside the vicinity of the discharge outlet

Even if the sea water concentration exceeded these discharge suspension level, the tritium concentration in the surrounding sea area will be well below the discharge limit of 60,000 Bq/L and the WHO standards for drinking water of 10,000 Bq/L. The surrounding sea area is safe.

For detailed monitoring results of the sea area tritium and other nuclides,
click the buttons below.

Confirmation of the safety of the water to be discharged

Confirmation* that radioactive materials in ALPS treated water are below the discharge limit before the discharge into the sea.
Not only TEPCO but also JAEA, as a third party with expertise, will analyze and confirm the water.

Purification process

purification process
STEP1
Reliable purification of nuclides other than tritium below the discharge limit.
STEP2
Tritium is further diluted more than 100 times with seawater to fully satisfy the discharge limit.
  • ・Tritium concentration below 1500 Bq/L**
  • ・Nuclides other than tritium are below 1/100 of the discharge limit.
STEP3
Only ALPS treated water, which is far below regulatory standards, is discharged into the sea.
After the discharge, tritium concentrations in the sea area and marine products are confirmed by monitoring.
  • * For each stage of measurement, third-party laboratories such as the IAEA also take measurements to ensure objectivity.
  • ** 1/40 of the discharge limit, about 1/7 of WHO drinking water standard.
  • ** Same as standard for the concentration of the sub-drainage water being discharged to the sea since 2015.

Results of the monitoring in a larger sea area

As a result of TEPCO's assessment of the impact of the discharge, the range of estimated tritium concentrations (1-2 Bq/L) higher than the current tritium concentrations (0.1-1 Bq/L) in seawater are only limited in the vicinity area within 2-3 km around the FDNPS, however you can also check the results of monitoring in a larger sea area.

Plans for monitoring by the national government, local governments, and TEPCO.