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At the Fukushima Daiichi Nuclear Power Station we are enlisting the cooperation
of a great many people in order to move forward with countermeasures for contaminated
water that was generated in conjunction with the accident and contained high
concentrations of radioactive substances.
Through this portal site we shall explain the current situation and give you
data/information on ALPS treated water, etc. while also showing how we have removed the
radioactive substances from contaminated water and reduced risks.
Note on “Water treated with multi-nuclide removal equipment, etc.” is notated. (revised in April, 2021)
Water treated with multi-nuclide removal equipment (ALPS) so that the concentrations
of radioactive materials other than tritium sufficiently satisfy regulatory standards
for safety (sum of ratios of legally required concentrations, excluding tritium, is
less than 1) shall be referred to as, “ALPS treated water.” Water that has been
purified with multi-nuclide removal equipment (ALPS), but for which the concentrations
of radioactive materials do not meet regulatory standards for safety (sum of ratios of
legally required concentrations, excluding tritium, is 1 or higher) shall be referred
to as, "Treated water to be re-purified." The term “ALPS treated water, etc.” shall be
used when referring collectively to both types of water.
*The terms used in past documents shall remain unedited. Hence, the definitions differ
slightly from the terms used after the March 11, 2020 revision of said terms.
ALPS treated water, etc.
ALPS treated water
％（m³）
Water to be re-purified
％（m³）
Sr removed water
%
Sr removed water
At current time,
ALPS treated water, etc. is being
stored in tanks after removing most radionuclides, with the exception of tritium. ALPS
has the ability to remove radionuclides (with the exception of tritium) to levels
below
“concentrations required by law,”
which is the Japanese government’s regulatory standard used when
discharging contaminated water/treated water* into the environment.
However, as a result of malfunctionsthat occurred when the equipment was put
into operation and differing operating objectives that have changed with time, the
amount of water being stored at current time is as shown in the diagram on the right
that breaks down the amounts by
the sums of the ratios of the concentrations required by law.
ALPS treated water, etc. is being stored in tanks on site. On December 11, 2020, the
construction of tanks with a capacity of approximately 1.37 million m³ was completed.
However, the amount stored in tanks is expected to reach the planned capacity by the
summer of 2022. (Tank Construction Progress Status)
We have to examine how to utilize the entire site as work progresses in order to
construct of facilities needed for decommissioning (tanks for continuous storage,
temporary storage facilities for spent fuel and fuel debris, etc.) amidst site space
restrictions.
*On December 11, 2020, the installation of approximately 1.37 million m3 of tanks was completed.
Current utilization of the Fukushima Daiichi Nuclear Power Station site
※Buildings drawn with a dotted line indicate facilities that will be built in the
future
※As of October, 2019
We have to examine how to utilize the entire site as work progress in order to construct facilities needed for decommissioning.
The Japanese government’s standard for storing ALPS treated water, etc. at the
Fukushima Daiichi Nuclear Power Station stipulates that
“the effective dose at site borders must be under 1mSv/year.”Since FY2013 we have been purifying contaminated water with multi-nuclide removal
equipment (ALPS) and as of the end of FY2015 had achieved our goal of reducing the
effective dose rate at site borders to below 1mSv/year. After achieving this goal,
ALPS continued to be operated with the intention of reducing risks at the power
station
FY2013~FY2015
The site border dose rate during 2013, when highly radioactive contaminated water from which only cesium had been removed was being stored in tanks on site, was 9.76mSv/year, thereby greatly exceeding the “effective dose at site borders of 1mSv/year or less,” which was the standard stipulated by the government.
The multi-nuclide removal equipment (ALPS) was put into operation in 2013 and equipment operation rate was increased to purify contaminated water and quickly reach the objective of reducing effective dose rates at site borders to below 1 mSv/year.
As a result of purifying contaminated water with the ALPS, the effective dose rates at site borders was reduced to below 1 mSv/year by the end of FY2015. However, due to nonconformances with the ALPS equipment, concentrations of radionuclides require by law were exceeded.
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FY2016
The multi-nuclide removal equipment (ALPS) enabled much progress to be made with contaminated water treatment thereby causing the amount of treated water to exceed the storage capacity of constructed tanks and we started to run out of tanks to store treated water.
In addition to accelerating the construction of tanks to store the treated water, the purification capacity of ALPS was leveraged and equipment operated while keeping in mind the concentrations required by law for each type of radionuclide.
As a result of leveraging ALPS purification capacity, in comparison to FY2013~FY2015, the percentage of cases where the concentrations of radionuclides required by law were exceeded decreased.
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FY2017~
![フェーズ.3 [2017～]](images/top/circumstances/title03.png)
Water being stored in bolt-tightened flanged tanks, which pose a high risk of leaking, will be treated as quickly as possible.
All water stored in flanged tanks shall be treated with the multi-nuclide removal equipment (ALPS) by the end of FY2018 while maintaining effective dose rates at site borders at below 1 mSv/year and increasing the operation rate of ALPS in an effort to reduce risk.
The operation rate of ALPS was increased while keep in mind the objective of reducing risks associated with water stored in flanged tanks. As a result, while the treatment of all the Sr removed water (water that had yet to be treated with ALPS) stored in flanged tanks was completed in November 2018, the percentage of cases where the concentrations of radionuclides required by law were exceeded increased compared to FY2016.Transfer of all ALPS-treated water stored in bolted flange tanks to welded tanks was completed in March, 2019.
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The Future Handling of ALPS treated water, etc.
One of the systems used to purify contaminated water that has been generated at the Fukushima
Daiichi Nuclear Power Station. With the exception of tritium, this equipment can remove most of
the radionuclides present in contaminated water.
Click here for details
Contaminated water from the Fukushima Daiichi Nuclear Power Station that has been purified and
is being stored in tanks at the power station site. There are two types of treated water. “Sr
removed water” is water from which cesium (Cs) and strontium (Sr) have been removed, and “ALPS
treated water, etc.” is Sr removed water from which most radionuclides, except for tritium, have
been removed.
Click here for details
Water from which most radionuclides, with the exception of tritium, have been removed using the
multi-nuclide removal equipment (ALPS), which is equipment used for purifying contaminated water
generated at the Fukushima Daiichi Nuclear Power Station.
Click here for more details on the ALPS
National laws and regulations※ that stipulate the radioactive concentration limits for each radionuclide if radioactive substances from the Fukushima Daiichi Nuclear Power Station are to be discharged into the environment.
※Public Notification of Requirements for the Safety of the TEPCO Fukushima Daiichi Nuclear Power Station and the Protection of Specific Nuclear Fuel Material
ALPS treated water, etc. currently being stored in tanks shall be handled while strictly
complying with the government’s “Basic Policy on handling of ALPS treated water at the Tokyo
Electric Power Company Holdings’ Fukushima Daiichi Nuclear Power Station” that was made official
on April 13. In releasing ALPS treated water into the sea, we will ensure that the discharged
water is safe by conforming to safety standards based on laws, and relevant international laws
and practices, while conducting radiation impacts assessments on people and the environment*.
Thus we will secure the safety of the public, the surrounding environment, and of agricultural,
foresty and fishery products.
If ALPS treated water, etc. is to be disposed of through discharge into the environment, the
water will be re-purified using multi-nuclide removal equipment until the concentrations of
radioactive substances, excluding tritium, satisfy the government’s regulatory standards for
safety (sum of ratios of legally required concentrations is less than 1).
Prior to discharge the water shall be sufficiently diluted with seawater. In the near term,
discharge amounts will be within the threshold of 22 trillion Bq/year which is the target
discharge management value for Fukushima Daiichi Nuclear Power Station before the accident. This
amount will be reviewed as needed based on progress made in decommissioning.
*Including the potential impact on the marine environment
The Nuclear Regulation Authority requires that additional doses (additional doses newly given off by the power station facility that exclude naturally occurring radiation) posed on site borders from rubble and contaminated water stored at the power station site must be under 1mSv/year. This “effective dose at site borders” is used as a safety management standard when storing ALPS treated water, etc. in tanks on site.
Multi-nuclide removal equipment (ALPS) etc. treated water is stored in tanks on site. In order to reduce the risks associated with leaks, bolt-tightened flanged tanks are being gradually replaced with welded tanks. Transfer of all ALPS-treated water stored in bolted flange tanks to welded tanks was completed in March, 2019. Furthermore, double layers of dikes has been erected around the tank areas to prevent water from leaking outside of the area in the event that a tank does leak. The tank areas are also patrolled and water levels continually monitored in order to prepare for risks associated with leaks.
Upon realizing the necessity to not only examine scientific safety, but also deliberate methods for disposing of multi-nuclide removal equipment (ALPS) etc. treated water* that take into consideration social impact, the government established the Subcommittee on the Handling of ALPS etc. treated water. The subcommittee comprises experts from various fields that comprehensively discuss not only technical issues, but also social impact, such as damage to reputation.
The Japanese government has two regulatory standards for contaminated water:
1.Standards for water that is to be stored in tanks
(effective dose rate at site borders)
2.Standards for discharging water into the environment
(concentrations required by law)
Japanese laws and regulations stipulate the radioactive concentration limits for each radionuclide (concentrations required by law) if radioactive substances are to be discharged into the environment. Since the concentrations required by law differ for each radionuclide, when discharging multiple radioactive substances the ratios of the concentrations required by law are calculated for each radionuclide and the total is referred to as the "sum of the rations of the concentrations required by law”
※Public notice of Requirements for the Safety of the TEPCO Fukushima Daiichi Nuclear Power Station and the Protection of Specific Nuclear Fuel Material
ALPS treated water, etc. is now stored in welded tanks, which have larger storage capacity and
are less likely to leak.
Double dikes constructed around tanks prevent water from flowing beyond a certain point in the
event of a leak.
Tank area are patrolled and water levels continuously monitored in order to be able to quickly
respond to leak risks.
We considered using other types of tanks such as
“large-capacity tanks,” “underground tanks,” and “Floating shore tank,”
but ultimately decided to store the ALPS treated water, etc. in welded tanks.
※These images are for illustrative purposes only.
*On December 11, 2020, the installation of approximately 1.37 million m3 of tanks was completed.
We will be carefully designing various facilities to enable smooth decommissioning work.
We will also deliberate the construction of other facilities that become necessary in the course
of decommissioning.
| Required point in time | Facility | Purpose |
|---|---|---|
| First half of the 2020’s |
Analysis facility for various samples |
To improve analysis capabilities |
| Storage facility for fuel debris removal equipment |
For maintenance of fuel debris removal equipment |
|
| Mock-up facility for fuel debris removal |
For prior checks of fuel debris removal equipment |
|
| Training facility for fuel debris removal |
For training before fuel debris removal |
|
| Storage facility for accident response equipment |
For storing equipment used during the accident |
|
| Second half of the 2020’s |
Fuel debris and radioactive waste research facility |
To study the knowledge obtained from full-scale fuel debris removal |
| Waste recycling facility | To reduce the volume of, and reuse, waste |
|
| Temporary waste storage area | For storing waste a decade from now and beyond |
We estimate that “temporary storage facilities for spent fuel and fuel debris” will require 81,000 ㎡ of land.
Water treated with multi-nuclide removal equipment (ALPS) so that the concentrations of
radioactive materials other than tritium sufficiently satisfy regulatory standards for safety
(sum of ratios of legally required concentrations, excluding tritium, is less than 1) shall be
referred to as, “ALPS treated water.”
Water that has been purified with multi-nuclide removal equipment (ALPS), but for which the
concentrations of radioactive materials do not meet regulatory standards for safety (sum of
ratios of legally required concentrations, excluding tritium, is 1 or higher) shall be referred
to as, "Treated water to be re-purified."
The term “ALPS treated water, etc.” shall be used when referring collectively to both types of
water.