③ Planned releases from nuclear facilities

What is a nuclear fuel reprocessing facility?

　Nuclear power plants use fuel rods containing uranium dioxide fuel pellets (equivalent to coal in thermal power plants) to evaporate water (boil water) using the heat energy emitted when uranium 235 fission occurs, and use the steam to turn a turbine to generate electricity.

火力発電thermal power generation　原子力発電nuclear power generation (of electricity)　燃料fuel　石炭coal　核燃料atomic fuel　熱エネルギー源Heat energy source　石炭を燃やすBurning coal　核分裂nuclear fission　電力源Power Source　お湯を沸かして発電タービンを回すBoils water and turns power turbine

　In nuclear power generation, fuel rods are replaced with new fuel rods when they are used up. Used fuel is called "spent fuel rods".Unlike thermal power generation, however, spent fuel rods contain a large amount of unburned plutonium, which is produced from unreacted uranium-235 and uranium-238. In other words, there is a considerable amount of unreacted uranium-235 and plutonium produced from uranium-238 in the spent fuel rods, so a "reprocessing plant" is a place to extract them and make fuel rods again.

＊For more information, please visit the Federation of Electric Power Companies of Japan HP：https://www.fepc.or.jp/nuclear/cycle/recycle/index.html

Why are radionuclides released from nuclear fuel reprocessing facilities?

　Spent nuclear fuel used in nuclear power generation is sheared and dissolved in a reprocessing plant, then separated and refined, and separated into nuclear fuel material and fission products. In this process, gases and liquid waste are generated. These wastes contain fission products (¹³⁷Cs, ⁹⁰Sr, etc.) and are released into the environment under the concept of keeping the dose to the surrounding public below the legal limit and as low as reasonably achievable (ALARA: as low as reasonably achievable), while managing them.

　The amount of emissions is determined by the facility's own control targets (limit values) in accordance with the laws of each country.

For more information, go to ATOMICA's Radiation from Reprocessing Facilities page.（https://atomica.jaea.go.jp/data/detail/dat_detail_09-01-02-06.html）

In Europe, nuclear fuel reprocessing facilities are in operation, and artificial radionuclides are being systematically (and controlled) released from these facilities.

The two reprocessing facilities are located in La Argues, France and Sellafield, England.

The figure below shows the annual releases (1970-1998) of a typical reprocessing plant in Europe (shown on the right).

　During this period, Sellafield released approximately 40 PBq of ¹³⁷Cs into the ocean. In 1976, the maximum amount reached 5.2 PBq/year (1.4 times higher than the direct leakage immediately after the Fukushima Daiichi Nuclear Power Plant accident), but this amount decreased to 0.008 PBq/year in 1998.

　The amount of ¹³⁷Cs released from La Argues is less than 3% of that from Sellafield when compared to the total amount of ¹³⁷Cs released, but this is also due to the difference in the amount of spent fuel processed annually.

セラフィールド、イギリスSellafield, United Kingdom

ラアーグ、フランスLa Argues, France

Below we show the year-to-year changes in the amount of radioactive cesium released from nuclear fuel reprocessing plants in Europe.

年間放出量Annual emission　福島第一原発事故直後の海洋への直接漏洩量Amount of direct leakage to the ocean immediately after the Fukushima Daiichi Nuclear Power Plant accident