Treated Water Portal Site

April 2017

ABOUT

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 treated water while also showing how we have removed the radioactive substances from contaminated water and reduced risks.

information
  • 2019.7.29
    Water amount and storage capacity of tanks for the Units 1-4 was changed as the calculating method which had been different for each tank area was unified.
  • 2019.3.27
    The transfer of treated water from the Advanced Liquid Processing System (ALPS) stored in bolted flange tanks to welded tanks was completed.
    Click here for details
  • 2019.2.28
    Available for smartphones
  • 2019.1.21
    English version launched
Amount of treated water stored in tanks
  • Amount of treated water being stored (as of August 22,2019)

    *Amount of water between the bottom of a tank and the lower measuring limit of the water gauge

At the Fukushima Daiichi Nuclear Power Station, the radioactive substances in contaminated water are removed using a multi-nuclide removal equipment (ALPS) and the resulting treated water is stored in tanks on site along with Cesium/Strontium-treated water. There are 977 tanks on site. 834 storage tanks are being used for water treated with ALPS, 129 storage tanks are being used for Cesium/Strontium-treated water, 12 storage tanks are being used for fresh water treated with RO facility and 2 tanks are being used for concentrated seawater (as of August 22, 2019).
※In accordance with construction plans, the total tank capacity will be approximately 1.37 million m³ built by the end of 2020.

ALPS etc. treated water

Cesium/Strontium-treated water

tank
Storage Amounts and Radioactive Concentration of ALPS etc. treated water
  • Amount of ALPS etc. treated water being stored (as of June 30, 2019)

    *Only completely filled tanks were used to calculate the amount, so this amount may differ from the entire amount of stored water.

At current time, water treated with multi-nuclide removal equipment (ALPS) 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.

More detail at the radioactive concentrations of each storage tank area
More detailat treated water data from the ALPS outlet
Increase from the previous data (March 31, 2019)

Cesium/Strontium-treated water

タンク
円グラフ
Contaminated Water Treatment History

The Japanese government’s standard for storing treated water 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 do.se 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

    • Issues Addressed

      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.

    • Treatment Plan

      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.

    • Achievements

      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 that required by were exceeded.

      ※1 Percentage of times that of the concentrations required by law was exceeded based on the number of samples and broken down for each radionuclide.
      ※2 Total amount treated by existing ALPS, additionally installed ALPS, high-performance ALPS

  • FY2016

    • Issues Addressed

      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.

    • Treatment Plan

      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.

    • Achievements

      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.

      ※1 Percentage of times that of the concentrations required by law was exceeded based on the number of samples and broken down for each radionuclide.
      ※2 Total amount treated by existing ALPS, additionally installed ALPS, high-performance ALPS

  • FY2017~

    • Issues Addressed

      Water being stored in bolt-tightened flanged tanks, which pose a high risk of leaking, will be treated as quickly as possible.

    • Treatment Plan

      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.

    • Achievements

      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 Cesium/Strontium-treated 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 public noticewere exceeded increased compared to FY2016.
      Additionally, transfer of all ALPS-treated water stored in flanged tanks to welded tanks was completed in March, 2019.

      ※1 Percentage of times that of the concentrations required by law was exceeded based on the number of samples and broken down for each radionuclide.
      ※2 Total amount treated by existing ALPS, additionally installed ALPS, high-performance ALPS

Q&A
Question and Answer

Let us answer your questions.

  • What is the “contaminated water” being generated at the Fukushima Daiichi Nuclear Power Station?
    “Contaminated water” refers to water that contains highly concentrated radioactive substances that has been generated as a result of the Fukushima Daiichi Nuclear Power Station accident.

    Inside the reactors of Fukushima Daiichi Nuclear Power Station Units 1~3, there is fuel that melted and solidified during the accident (fuel debris). This fuel debris is being kept cool by continuously spraying it with water, but when this water comes in contact with the fuel debris it is exposed to the highly concentrated radioactive substances and becomes “contaminated water.” This “contaminated water” that contains highly concentrated radioactive substances accumulates inside the reactor buildings and when it mixes with groundwater or rainwater flowing into the buildings even more “contaminated water” is produced.
    This “contaminated water” is being treated/purified to reduce the concentrations of radioactive substances using multiple types of equipment. After risk has been sufficiently reduced in this manner , it is stored in tanks on site as “treatead water”.

    Click here for information on contaminated water countermeasures

  • Can Multi-nuclide removal equipment (ALPS) remove all of the radionuclides contained in contaminated water generated at the Fukushima Daiichi Nuclear Power Station?
    Multi-nuclide removal equipment (ALPS) can remove the most of radionuclides contained in contaminated water with the exception of tritium.

    The ALPS is one of the pieces of equipment used to purify contaminated water at the Fukushima Daiichi Nuclear Power Station. Radioactive substances are removed by passing the contaminated water through adsorption towers that are filled with adsorbents thereby enabling this equipment to remove the most of radionuclides with the exception of tritium.
    The government has stipulated two different regulatory standards for contaminated water. The first are regulations for contaminated water if it is to be stored in tanks. And, the second are regulations for contaminated water if it is to be discharged into the environment. Preventing impact on the surrounding environment has been our first priority, so contaminated water has been purified/treated using the ALPS etc. while adhering to the regulations for storing contaminated water in tanks. Therefore, at current time, all of the water that has been processed with the ALPS meets the regulations for tank storage, however more than 80% of it does not yet meet the regulations for environmental discharge.
    If TEPCO decides to dispose of the water treated with the ALPS by discharging it into the environment the water will first be purified again (secondary treatment) in order to reduce the amount of radioactive substances in the water as much as possible (with the exception of tritium) and ensure that it meets the regulations for environmental discharge.

    Click here for more information on the history of contaminated water treatment

  • What is “tritium?”
    Tritium is a radionuclide that is a relative of hydrogen.
    It exists naturally and is present in water vapor in the atmosphere as well as rainwater and tap water.

    Tritium is hydrogen with two extra neutrons (hydrogen-3) and it has the same characteristics as hydrogen.
    Tritium is a radionuclide that emits beta radiation but the amount of energy emitted is weak and can be blocked with a sheet of paper.
    Tritium is generated when cosmic radiation from space mixes with the Earth’s atmosphere. In the atmosphere the tritium bonds with oxygen instead of hydrogen which is why it exists in the form of water in the water vapor and rain in the atmosphere, as well as in the oceans, etc. We ingest tritium through the water we drink in our daily lives but our metabolism prevents it from accumulating/concentrating in our bodies and it is immediately excreted.
    Tritium is generated through the process of nuclear fission in nuclear power facilities both in Japan and overseas (nuclear power stations and reprocessing facilities), and each country has regulations for discharging tritium into the oceans and atmosphere in a controlled manner.

    Click here for more information on tritium
    (special content from the Agency of Natural Resources and Energy)