Discharge History

FY2024 Sea Area Monitoring Results
(concentrations of tritium in seawater)

Tritium concentrations obtained sea area monitoring within a 3km of the power station are well below our operational index (discharge suspension level: 700Bq/L).
[Click here for details of operational indices]

Results of quick tritium measurement*
Round Within a 3km of the power station Within a 10km square
in front of the power station
1st Max. 29 Bq/liter Below the detection limit
2nd Max. 7.7 Bq/liter Below the detection limit
3rd Max. 18 Bq/liter Below the detection limit

*Measurement performed with a detection limit of approx. 10Bq/liter in order to obtain the results quickly.

Comparison of concentration of tritium in seawater

*1: This standard has been stipulated based on the calculation that if a person were to drink approximately 2L of the water coming out of the discharge outlet of a nuclear facility every day for one year, his/her exposure would be 1mSv.

*2: Source: Environmental Radioactivity and Radiation in Japan (Period: April 2019 to March 2022)

FY 2024 Discharge History

(as of July. 16, 2024)

Annual accumulated ALPS treated water discharge volume

00,000

Total accumulated ALPS treated water
discharge volume since the commencement
of discharge in August 24,2023:
00,000,000

Annual accumulated tritium discharge volume

Approx.0trillion Bq

Total accumulated tritium discharge volume
since the commencement of discharge
in August 24,2023:
Approx.00trillion Bq

Annual discharge limit of tritium:
22 trillion Bq

Discharge history for each discharge

Analysis results of ALPS treated water prior to dilution ALPS treated water discharge history
Round Analysis date
at the
measurement/
confirmation facility
Tritium
concentration
The sum of the ratios of the concentration of each radionucide to the regulatory concentration,
excluding tritium
Discharge period Tritium concentrations after dilution* Amount of ALPS treated water Amount of tritium
1st Apr. 17,
2024
19×104
Bq/liter
0.31
<
Regulatory standards
1
Apr. 19, 2024
~
May. 7, 2024
Max. 266 Bq/liter 7,851 Approx. 1.5 trillion
Bq
2nd May. 15,
2024
17×104
Bq/liter
0.17
<
Regulatory standards
1
May. 17, 2024
~
Jun. 4, 2024
Max. 234 Bq/liter 7,892 Approx. 1.3 trillion
Bq
3rd Jun. 26,
2024
17×104
Bq/liter
0.18
<
Regulatory standards
1
Jun. 28, 2024
~
Jul. 16, 2024
Max. 276 Bq/liter 7,846 Approx. 1.3 trillion
Bq
1st Jun. 22,
2023
14×104
Bq/liter
0.28
<
Regulatory standards
1
Aug. 24, 2023
~
Sep. 11, 2023
Max. 220 Bq/liter 7,788 Approx. 1.1 trillion
Bq
2nd Sep. 21,
2023
14×104
Bq/liter
0.25
<
Regulatory standards
1
Oct. 5, 2023
~
Oct. 23, 2023
Max. 189 Bq/liter 7,810 Approx. 1.1 trillion
Bq
3rd Oct. 19,
2023
13×104
Bq/liter
0.25
<
Regulatory standards
1
Nov. 2, 2023
~
Nov. 20, 2023
Max. 200 Bq/liter 7,753 Approx. 1.0 trillion
Bq
4th Feb. 26,
2024
17×104
Bq/liter
0.34
<
Regulatory standards
1
Feb. 28, 2024
~
Mar. 17, 2024
Max. 230 Bq/liter 7,794 Approx. 1.3 trillion
Bq
num mm. dd
20yy
n万
Bq/liter
0.55
<
Regulatory standards
1
mm. 2, 2023
~
mm. 2, 2023
Max. n Bq/liter 0 Approx. 0 trillion
Bq

* Tritium concentrations in the water sampled at seawater pipe (including “uncertainty,” the accuracy of analysis)

FY2024 Discharge Plan

Round Discharge period Amount of
ALPS treated water
Tritium concentration*1 Amount of tritium
1st Apr.~May. 2024 Approx. 7,800㎥ 18~20×104 Bq/liter*2 1.5 trillion Bq
2nd May.~Jun. 2024 Approx. 7,800㎥ 17~19×104 Bq/liter*2 1.4 trillion Bq
3rd Jun.~Jul. 2024 Approx. 7,800㎥ 16~18×104 Bq/liter*2 1.3 trillion Bq
4th Jul.~Aug. 2024 Approx. 7,800㎥ 16~31×104 Bq/liter*2 1.7 trillion Bq
5th Aug.~Sep. 2024 Approx. 7,800㎥ 30~35×104 Bq/liter*2 2.4 trillion Bq
6th Sep.~Oct. 2024 Approx. 7,800㎥ 34~35×104 Bq/liter*2 2.7 trillion Bq
7th Feb.~Mar. 2025 Approx. 7,800㎥ 34~40×104 Bq/liter*2 3.0 trillion Bq

*1 Tritium concentrations will be less than 1,500Bq/liter by dilution more than 700 times with seawater

*2 Average value of the tank group that was assessed taking into account the radioactive decay until April 1, 2024

Discharge History