Monitoring by sampling

Results of radioactive nuclide analysis are published by sampling below items on the premises and the surrounding area of Fukushima Daiichi NPS.

• Prompt Report of Analysis Results
• Definite Results of Analysis
• Analysis Results at Water Treatment Facility
• Analysis Results of Fish and Shellfish (the ocean area within 20km radius of Fukushima Daiichi NPS)

The subdrain and groundwater drain systems started operations from September 2015. The subdrain system (a measure to prevent the increase of contaminated water) pumps up groundwater from around the reactor buildings before it flows into them. The groundwater drain system (a measure to prevent the leakage of contaminated water) pumps up groundwater held back by the installed seaside impermeable wall before it flows into the port area. The water pumped by either system is purified, tested, and then discharged into the port area.
It is then stored in temporary storage tanks and the radioactive concentration is measured to confirm that the water quality does not surpass the upper limits set by TEPCO.
Third-party organizations also analyze the radioactive concentration to ensure the objectivity of the analysis results.

	Cesium 134	Cesium 137	Gross β	Strontium	Tritium
TEPCO's upper limit of radioactive concentration for temporary storage tanks	1Bq/l	1Bq/l	3Bq/l	-	1500Bq/l
Regulatory Notification Limit (for reference)	60Bq/l	90Bq/l	-	30Bq/l	60000Bq/l
WHO Guideline for Drinking Water	10Bq/l	10Bq/l	-	10Bq/l	10000Bq/l

Analysis Results of Relay Tanks

English form

The newest data is on June 14, 2016.

Analysis Results of Temporary Storage Tanks and Water Collecting Tanks

English form

• Jul 1
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• Jul 7(detail)
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• Jul 31

Analysis Results of Weighted Average Sampling

*The analysis of the water sampled before being discharged, which is mixed at the rate of each amount out of the whole amount of discharged water in a month.

• Jul 7(As of May)

Analysis Results Regarding Discharge

English form

• Jul 12

As a measure to prevent contaminated water from accumulating, the groundwater bypass has begun its operation since May 2014, which pumps up groundwater on the mountain side before flowing into the buildings and drains the water into the ocean after checking its purity. The pumped up groundwater is once stored in temporary storage tanks, and then its radioactive material concentration is mesured to confirm that its quality meets the operation target.
The third-party organization also analyzes the radioactive material concentration to ensure the objectivity of the analysis result.

	Cesium 134	Cesium 137	Gross β	Strontium	Tritium
Operation Target	1Bq/l	1Bq/l	5Bq/l	-	1500Bq/l
Notification Level Limit (Reference)	60Bq/l	90Bq/l	-	30Bq/l	60000Bq/l
WHO Drinking Water Guideline	10Bq/l	10Bq/l	-	10Bq/l	10000Bq/l

Analysis Results of Pump Well

English form

• Jul 2
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• Jul 20(2)
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• Jul 30

Analysis Results of Temporary Storage Tanks

English form

• Jul 4
• Jul 4(detail)
• Jul 11
• Jul 18
• Jul 25

Analysis Results of Weighted Average Sampling

English form

*The analysis of the water sampled before being discharged, which is mixed at the rate of each amount out of the whole amount of discharged water in a month.

• Jul 4(As of May, 2016)

Analysis Results Regarding Discharge

English form

• Jul 7

 

The sampling near the South Water Outlet, at the Drainage Channel, and around tanks in the H4 area has been continued in order to monitor the impact of several leakage accidents such as the leakage from the bottom flange of the No.5 tank in the H4 area I group happened in August, 2013, the dripping from the top plate of the B-A5 tank in the B south area happened in October, 2013, and the leakage from the top plate flange of the C1 tank in the H6 area happened in February, 2014.

South Water Outlet, Drainage Channel

English form

• Jul 1
• Jul 1(2)
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• Jul 15(2)
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• Jul 29(2)
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• Jul 31

Observation Hole around H4 Area

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Observation Hole around H6 Area

English form

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The rainwater accumulated inside the dike in the tank area has been sprinkled on the premises of Fukushima Daiichi NPS since May, 2014 after being purified by the desalination system (reverse osmosis membrane) etc.

English form

The newest data is on June 14, 2016.

Results of radioactive nuclide analysis for groundwater at the east side of Unit 1-4 Turbine Buildings and seawater at the port in order to monitor the source, the extent, and the effect of the radioactive materials in the groundwater toward the ocean.

English form

• Jul 1
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• Jul 31

Radioactive materials were detected from the accumulated water inside the pits as a result of purification test at wells (subdrain pits), which is adjacent to Unit 1-4 Buildings at Fukushima Daiichi NPS. Since there is a possibility of being affected by fallout, we installed new observation well around Unit 1-4 Buildings in order to assess the impact of fallout.

The newest data is on October 1, 2014.

The analysis results of the major 3 nuclides (I-131, Cs-134, Cs-137) are updated daily as a prompt report above.
Here, the reevaluation of the major 3 nuclides and analysis results of other γ nuclides are posted as a definite report.

English form

July 27, 2016	Definite Results of Nuclides Analysis at Fukushima Daiichi Nuclear Power Station (Announced on June 16 - 30, 2016) [Definite Report] Nuclides Analysis Results of the Radioactive Materials in the Air at the Opening of Buildings at Fukushima Daiichi NPS
July 6, 2016	Definite Results of Nuclides Analysis at Fukushima Daiichi Nuclear Power Station (Announced on June 1 - 15, 2016)

English form

The newest data is on June 14, 2016.

July 22, 2016	Nuclide Analysis Results of Fish <Port Area of Fukushima Daiichi Nuclear Power Station> Nuclide Analysis Results of Fish and Shellfish (Ocean Area Within 20km Radius of Fukushima Daiichi Nuclear Power Station) (excluding the Port Area)