Investor Presentaiton

Purification of radionuclides other than tritium The existence of radionuclides itself is not an issue. What matter is the total radiation impact from all kinds of radioactive materials in the water. The radiation level will be maintained below the regulatory standards to ensure the safety of people and the environment. ➤ Regardless of the type of the facility (accident plants or operational reactors), the regulatory standards are set to control the type of the total radiological impact of all the nuclides. (It is not a matter of nuclides or number of nuclides, but the total radiological impact to human should be considered). Before 2018, purified water contains radionuclides of the water which exceed the regulatory limit due to operational condition (around 70% of all the tanks at the FDNPS (around 0. 87 M tons/1. 30M tons)). After 2019, all of the water falls under the category i). These radionuclides other than tritium will be re-purified to below the regulatory standard by using ALPS again before the discharge. i) 30%: Purified below the regulatory standards except for tritium ii) 70%: Radioactive materials in addition to tritium exist more than regulatory standard values* Nuclides other than tritium Nuclides also found in water from operating NPPS *All of the water purified after 2019 falls under the category i). Ref. The results of re-purification performance test (TEPCO, 2020) Ratio to each regulatory standard value Before Re-purify After Re-purify Cobalt, Manganese, etc. Type of nuclides Nuclides found in water from accident plants (or reprocessing plants) Cobalt-60 Cesium, Strontium, lodine, etc. Cesium-137 Strontium-90 lodine-129 Sum of the all All of the above nuclides including nuclides found only in accident plants will be re-purified to meet the regulatory standards other than tritium. Furthermore, it will be diluted more than 100 times before discharge. nuclides other than tritium 0.18 0.0017 6.7 0.0021 2155 0.0012 3.3 0.13 2406 0.35 To be diluted more than 100 times further: ~0.0035 15

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