Results of Radioactive Material Analysis in the Vicinity of the Fukushima Daiichi Nuclear Power Station

Results of radioactive material analysis at each collection point (for February 2023)

Air

Air at power station site

Radionuclide analysis is conducted of air collected inside the power station site.

Seawater

Radionuclide analysis is conducted of seawater collected along the coast of the power station and near the water intakes of Units 1 to 4.

Sampling PlaceEnglish form
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*Results of radionuclide analysis of seawater near power station and near water intakes of Units 1 to 4

Starting April 2, 2019, a change was made to where the seawater radionuclide analysis results are archived for the power station coastline and near the Unit 1 to 4 water intakes. Please see here. (Pages showing seawater analysis results in PDF files archived in the section headed “Monitoring on east side of Unit 1 to 4 turbine buildings and bay” )
Note that graphs and detailed analysis results from remeasuring, and analysis results for other collection points, continue to be archived as in the past.

Results of radionuclide analysis of seawater near south discharge outlets of Units 1 to 4

As of September 2018, a change was made to where the radionuclide analysis results are archived for seawater sampled near the south discharge outlets of Units 1 to 4. Please see here. (Pages showing seawater analysis results in PDF files archived in the section headed “Monitoring on east side of Unit 1 to 4 turbine buildings and bay”)

Seawater at bay entrance (measured by radioactivity monitors)

Starting October 1, 2016, data indicating the latest status in 10-minute intervals is made available in real time.

Subdrain water

Radionuclide analysis is conducted of radioactive materials in water collected from subdrains, etc. near the turbine buildings of Units 1 to 6 and the subdrain near the central waste treatment facility.

Subdrain water near turbine building	English form
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Subdrain water near the centralized waste treatment facility	English form
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Subdrain and groundwater drain sampling

Groundwater near buildings is pumped up before it can enter the buildings (measure to minimize increase in contaminated water). Moreover, groundwater flowing toward the sea that has been dammed up by installing an ocean-side impermeable wall (measure to prevent contaminated water from leaking) is pumped up, cleaned, and checked for water quality before being discharged into the ocean, in a water treatment facility for subdrain, etc. that went into operation in September 2015. Groundwater that has been pumped up is stored in temporary storage tanks, radioactivity levels are measured, and confirmation is made that it is within operational targets.
To ensure objectivity of the analysis results, radiation level analysis is also conducted by third-party agencies.

	Cesium-134	Cesium-137	All beta	Strontium	Tritium
Operational targets for temporary storage tanks	1Bq/l	1Bq/l	3Bq/l	-	1500Bq/l
(For reference) Regulatory limits	60Bq/l	90Bq/l	-	30Bq/l	60000Bq/l
WHO guidelines for drinking-water quality	10Bq/l	10Bq/l	-	10Bq/l	10000Bq/l

An overview of subdrain initiatives and implementation status is given here.

Temporary storage tank and water collection tank analysis results	English form
12468101214161819212323 (Detail)252628

Weighted average sample analysis results
23 (As of December, 2022)23 (In the third quarter of FY 2022) Note:Analysis is conducted on water collected before discharge after mixing in the same ratio as that of discharged water each time to all discharged water for that month.

Analysis results for discharged water	English form
The most recent data is from December 21, 2022.

Transfer tank analysis results : The most recent data is from June 14, 2016. (English form)

Groundwater bypass-related sampling

As a measure for minimizing the increase in contaminated water, a groundwater bypass went into operation in May 2014, by which groundwater on the mountain side is pumped up before it can enter buildings and its water quality is confirmed before it is discharged into the ocean. Groundwater that has been pumped up is stored in temporary storage tanks, radiation levels are measured, and confirmation is made that it is within operational targets.
To ensure objectivity of the analysis results, radiation level analysis is also conducted by third-party agencies.

	Cesium-134	Cesium-137	All beta	Strontium	Tritium
Operational targets for temporary storage tanks	1Bq/l	1Bq/l	5Bq/l	-	1500Bq/l
(For reference) Regulatory limits	60Bq/l	90Bq/l	-	30Bq/l	60000Bq/l
WHO guidelines for drinking-water quality	10Bq/l	10Bq/l	-	10Bq/l	10000Bq/l

An overview of the groundwater bypass initiative and implementation status is given here, along with related materials.

Pumping well analysis results	English Form See here for maximum values.
14681113151820222527

Temporary storage tank analysis results	English Form
7142121 (Detail)

Weighted average sample analysis results	English Form
21 (as of December, 2022)

Analysis results for discharged water	English Form
The most recent data is from December 21, 2022.

Monitoring for tank leakage

In response to leakage from a bottom flange of Tank No. 5 in the I group of the H4 tank area discovered in August 2013, dripping from an upper top plate of a B south area tank (B-A5) occurring in October 2013, and leakage from a flange of an upper top plate of the C1 tank in the H6 tank area occurring in February 2014, ongoing sampling has been implemented to monitor the effects of such leakage. This sampling is conducted near the south discharge outlets of the Fukushima Daiichi Nuclear Power Station, the discharge channels on the site premises, and around the H4 area tanks.

Observation holes around the H4 tank area	English Form See here for maximum values.
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Observation holes around the H6 tank area	English Form See here for maximum values.
291623

South discharge outlets and discharge channels

Note:Starting September 2018, a change was made to where the analysis results are archived for the south discharge outlets and discharge channels.
See here for the analysis results for the south discharge outlets. See here for the analysis results for the discharge channels.

Monitoring on east side of Unit 1 to 4 turbine buildings and bay

Radionuclide analysis is conducted of groundwater on the east side of Unit 1 to 4 turbine buildings and of seawater in the bay, for confirming sources of radioactive materials in groundwater and their diffusion status, and for monitoring impact on the ocean.

English Form See here for maximum values.
1234 (See Highest Dose)56789101112131415161718192021 (See Highest Dose)22232425262728 (See Highest Dose)

Sampling data from discharge channels on the premises of the Fukushima Daiichi Nuclear Power Station

Monitoring of each of the discharge channels continues, since rainwater flows into the channels after falling on the turbine building roofs, which were contaminated by fallout at the time of the accident.

English Form See here for maximum values.
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Analysis results for underground reservoirs

In response to the external leaking of water stored in an underground reservoir, occurring in April 2013, impact on the surroundings is being monitored, analyzing groundwater at leak detection holes installed next to the reservoirs and observation holes around them.
Note that the amount of underground reservoir leakage was thereafter assessed to be around 20 to 30 liters.

Other

Sampling of sprinkled water that has been treated in rainwater treatment equipment after being dammed in tank area

Rainwater dammed in the tank area, after being treated using the reverse osmosis (RO) desalination and other systems, since May 2014 has been sprinkled on the premises of the Fukushima Daiichi Nuclear Power Station. To confirm the impact of this sprinkling, levels of radioactive materials in the treated water (sprinkled water) and in the air at the sprinkling locations, and the surrounding air dose rates, are analyzed.
The most recent data is from June 14, 2016. (English Form)

Detailed analysis results of groundwater around Unit 1 to 4 buildings

In purification testing of wells (subdrain pits) adjacent to Unit 1 to 4 buildings, radioactive materials were detected in water accumulated in the pits. Given the possibility that the source of this radiation is from fallout, new observation pits were installed near Unit 1 to 4 buildings, and fallout is being monitored.
The most recent data is from October 1, 2014.

Water Treatment Equipment Analysis Results

English Form
17

Fish, Shellfish and Seaweed Analysis Results
(waters within 20 km of Fukushima Daiichi Nuclear Power Station)

At the time of the accident, highly concentrated contamination in the basement of the turbine building flowed into the port through underground trenches. Therefore, we analyze fish and shellfish sampled within a 20 km radius around the power station in order to check the effects of cesium on fish and shellfish and the trends.
In accordance with the government‘s policy on the water treated with multi-nuclide removal equipment etc., we have strengthened monitoring of fish and seaweed since April 2022 in order to continuously check the diffusion status centered around tritium into the sea and the conditions of marine organisms. We have increased the number of locations, targets and frequency for measurement, and set detection limits (lower detection limits) to be in line with national targets. Please click here for details.

Sampling Place
27 Analysis Results of Fish <Sampled within a 20km Radius of the Fukushima Daiichi Nuclear Power Station> 21 Analysis Results of Fish <Sampled within a 20km Radius of the Fukushima Daiichi Nuclear Power Station> Analysis Results of Fish <Sampled from the Port Area of the Fukushima Daiichi Nuclear Power Station> Analysis Results of Seaweed <Fukushima Daiichi Nuclear Power Station>