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Zablackaite, G.; 塩津 弘之; 城戸 健太朗; 杉山 智之
Nuclear Engineering and Technology, 56(2), p.536 - 545, 2024/02
被引用回数：0 パーセンタイル：0.08(Nuclear Science & Technology)Radioactive iodine is a representative fission product to be quantified for the safety assessment of nuclear facilities. In integral severe accident analysis codes, the iodine behavior is usually described by a multi-physical model of iodine chemistry in aqueous phase under radiation field and mass transfer through gas-liquid interface. The focus of studies on iodine source term evaluations using the combination approach is usually put on the chemical aspect, but each contribution to the iodine amount released to the environment has not been decomposed so far. In this study, we attempted the decomposition by revising the two-film theory of molecular-iodine mass transfer. The model involves an effective overall mass transfer coefficient to consider the iodine chemistry. The decomposition was performed by regarding the coefficient as a product of two functions of pH and the overall mass transfer coefficient for molecular iodine. The procedure was applied to the EPICUR experiment and suppression chamber in BWR.
南上 光太郎; 塩津 弘之; 丸山 結; 杉山 智之; 岡本 孝司*
Journal of Nuclear Science and Technology, 60(7), p.816 - 823, 2023/07
被引用回数：0 パーセンタイル：0.01(Nuclear Science & Technology)For proper source term evaluation, we constructed the theoretical model to estimate the mass transfer coefficient of gaseous iodine species under two-phase flow conditions, which complicates the direct experimental measurements. The mass transfer speed is determined by the product of the overall mass transfer coefficient and the interfacial area. By using the ratio of two gas components, the interfacial area, which is an important parameter that is difficult to measure, can be canceled out and the ratio of their overall mass transfer coefficients can be obtained. This ratio is expected to be equal to the ratio of their diffusion coefficients. Therefore, the unknown mass transfer coefficient such as iodine species can be estimated using the diffusion coefficients of two gas components and the reference mass transfer coefficient such as O
. We carried out the experiments using the bubble column to confirm this relationship. From the results in this study, we confirmed that the ratio of the overall mass transfer coefficient was in good agreement with the ratio of diffusion coefficient under the bubbly flow conditions. Using this relationship confirmed in this study, we estimated the mass transfer coefficient of I, one of the iodine species.
西沢 市王; 坂本 勉*; 勝山 和夫; 進士 義正; 三戸 規生; 松元 章
JAERI-M 9910, 37 Pages, 1982/01
3m
/hrの処理能力をもつ蒸気圧縮型蒸発処理装置を1978年3月に設置した。設置後、コ各種の試験を実施し装置の特性、最適運転条件を調べた。続いて実廃液の処理を実施し、さらにメンテナンスについても経験を積んできた。これらの経験から、(1)定格処理量は、設計条件である3m/hrが満足できた。また処理量を50%まで安全に制御して運転できた。さらに除染係数は10以上が得られた。(2)運転維持費に関係する蒸発比は、単効用蒸発処理装置と比較して14倍になった。したがって加熱源は1/14ですむ。(3)伝熱面に付着したスケールは、化学除染法でほぼ完全に除去できた。(4)主要機器の性能低下は、実廃液を約3,000m処理した時点においても見られない。 このことから、放射性廃液の処理に、蒸気圧縮式蒸発処理法も有力な処理手段であることが実証された。
Zablackaite, G.; 塩津 弘之; 城戸 健太朗; 杉山 智之
no journal, ,
To investigate the mass transfer effect on the overall iodine release to the environment, we propose a chemical-process-reduced mass transfer (CPR-MT) model for iodine that is based on two-film theory and includes an effective mass transfer coefficient (
). By formally decomposing into iodine chemistry and mass transfer contributions, we discuss their impact for a variety of severe accident conditions of nuclear power station.
Zablackaite, G.
no journal, ,
シビアアクシデント時の環境へのヨウ素放出に対して、プールスクラビングによる気液間の移行挙動を調査するために、境膜理論に基づき、有効物質移動係数をヨウ素化学による寄与と物理的な物質移行の寄与の積の形で分解することにより、各要素の寄与の重要性を定量的に評価する手法を考案した。pHによる両機構の寄与を定量的に解析し、低pH及び高質量移行係数の条件で物理的な寄与が高くなる傾向が示された。この評価手法は、事故条件に対する移行メカニズムの検討に有用である。
