Tritium Concentration and Diffusion in Seawater Discharged from Tokai Reprocessing Plant

Nakano, Michio; Kokubun, Yoshihiro; Takeishi, Minoru

doi:10.5453/jhps.44.60

Cited by 4 publications

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“…The distribution from the both to the 3 H concentration in seawater was estimated to be about 0.1 Bq/L in 2000. 2) Normalized 3 H discharge amount (in GBq/GWa) defines 3 H discharge amount per generated electric energy by the reprocessed spent fuel. Normalized 3 H discharge amount of the TRP was 5.6 x 10 5 (GBq/GWa) at maximum, which was approximately equal to those of the La Hague reprocessing plant in France and of the Sellafield one in United Kingdom.…”

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confidence: 99%

Tritium Concentration and Diffusion in Seawater Discharged from Tokai Reprocessing Plant

Kokubun

Fujita

Nakano

et al. 2011

Progress in Nuclear Science and Technology

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The Tokai Reprocessing Plant has reprocessed the total amount of 1,140 tons of spent fuels since 1977 to the end of fiscal year 2008. During the operation, radioactive liquid effluent has been discharged into the sea from the outlet of the pipeline after the discharge approval. The amount of 3 H discharged to the sea was 4.5 PBq in total. Therefore, since 1978, JAEA has sampled seawater around the outlet every month. Tritium concentrations in seawater were analyzed and measured using a liquid scintillation counter. All data were used to calculate the dilution factor which means the ratio of the 3 H concentration in seawater to that in liquid effluent. The number of 3 H samples with concentrations below the detection limit was 9,079 (82.0 %) and the number of those from the limit to 40 Bq/L (as quantification limit) was 1,964 (17.7 %). The maximum concentration was 1,700 Bq/L at the point just above the outlet in 1979. Moreover, the dilution factors were ranged between 240 and 6,500,000. All 3 H concentrations in water were confirmed to be below 60,000 Bq/L that was specified by the law and there has been no concern about environmental safety risk.

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Section: Introduction *mentioning

confidence: 99%

Tritium Concentration and Diffusion in Seawater Discharged from Tokai Reprocessing Plant

Kokubun

Fujita

Nakano

et al. 2011

Progress in Nuclear Science and Technology

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Estimation of temporal variation of tritium inventory discharged from the port of Fukushima Dai-ichi Nuclear Power Plant:analysis of the temporal variation and comparison with released tritium inventories from Japan and world major nuclear facilities

Machida

Iwata

Yamada

et al. 2022

Journal of Nuclear Science and Technology

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Estimation of Temporal Variation of Discharged Tritium from Port of Fukushima Dai-ichi Nuclear Power Plant: Analysis of the Temporal Variation and Comparison with released Tritium from Japan and Major Nuclear Facilities Worldwide

Machida

Iwata

Yamada

et al. 2022

Transactions of the Atomic Energy Society of Japan

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We estimate the monthly discharge inventory of tritium from the port of Fukushima Daiichi Nuclear Power Plant (1F) from Jun. 2013 to Mar. 2020 using the Voronoi tessellation scheme, following the tritium monitoring inside the port that started in Jun. 2013. As for the missing period from the initial month, Apr. 2011 to May 2013, we calculate the tritium discharge by utilizing the ratio of tritium concentration to 137 Cs concentration in stagnant contaminant water during the initial direct runoff period to Jun. 2011 and the discharge inventory correlation between tritium and 137 Cs for the nextunknown continuous-discharge period up to May 2013. From all the estimated results over 9 years, we found that the monthly discharge inventory sharply dropped immediately after closing the seaside impermeable wall in Oct. 2015 and subsequently coincided well with the sum of those of drainage and subdrain etc. By comparing the estimated results with those in the normal operation period before the accident, we point out that the discharge inventory from the 1F port after the accident is not very large. Even the estimation for the year 2011 is found to be comparable to the maximum of operating pressurized water reactors releasing relatively large inventories in the number of digits. In the national level, the total domestic release inventory in Japan significantly decreased after the accident owing to the operational shutdown of most plants. Furthermore, 1F and even the total Japanese discharge inventory are found to be minor compared with those of nuclear reprocessing plants and heavy-water reactors on a worldwide level. From the above, we suggest that various scenarios can be 1 (国研) 日本原子力研究開発機構システム計算科学センター 2 東京大学大気海洋研究所 3 (国研) 日本原子力研究開発機構原子力基礎工学研究センター 4 ㈱アトックス 5 (国研) 水産研究・教育機構水産資源研究所＊ Corresponding author, E-mail: machida.masahiko＠jaea.go.jp 論文(町田，他) 日本原子力学会和文論文誌( 2022) , Advance Publication by J-stage openly discussed regarding the management of tritium stored inside 1F with the help of the present estimated data and its comparison with the past discharge inventory.

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Tritium Concentration and Diffusion in Seawater Discharged from Tokai Reprocessing Plant

Cited by 4 publications

References 1 publication

Tritium Concentration and Diffusion in Seawater Discharged from Tokai Reprocessing Plant

Tritium Concentration and Diffusion in Seawater Discharged from Tokai Reprocessing Plant

Estimation of temporal variation of tritium inventory discharged from the port of Fukushima Dai-ichi Nuclear Power Plant:analysis of the temporal variation and comparison with released tritium inventories from Japan and world major nuclear facilities

Estimation of Temporal Variation of Discharged Tritium from Port of Fukushima Dai-ichi Nuclear Power Plant: Analysis of the Temporal Variation and Comparison with released Tritium from Japan and Major Nuclear Facilities Worldwide

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