AbstractDust mobilization and air ingress characteristics in a fusion reactor during a loss-of-vacuum accident (LOVA) event were analyzed numerically using a newly developed thermal-hydraulic analysis code under the conditions of a compressible flow and three-dimensional cylindrical coordinates. Some physical models on the motion of dust were considered to resolve the dust mobilization characteristics. Air ingress behavior through breaches was calculated by using the compressible Navier–Stokes equations. It was clarified quantitatively from the present numerical results that the predicted average pressures in a vacuum vessel (VV) agree well with the experimental results within an error of 10% for different breach diameters and the dust mobilization depends on the flow configurations of the buoyancy-driven exchange flows through breaches and the dust density, and the rate of dust released from the VV through the breaches to the outside depends on the breach positions on the VV, and furthermore, the present numerical approach is very effective to estimate the thermal-hydraulic phenomena inside the VV after the LOVA event occurs.
真空喪失事故（LOVA）事象時における核融合炉内のダスト巻き上げおよび空気侵入特性を、圧縮性流れおよび三次元円筒座標系の条件下で新たに開発した熱流動解析コードを用いて数値解析した。ダストの運動に関するいくつかの物理モデルを考慮し、ダスト巻き上げ特性を明らかにした。破口を通じた空気侵入挙動は、圧縮性ナビエ・ストークス方程式を用いて計算した。本数値解析結果から、異なる破口径に対する真空容器（VV）内の平均圧力の予測値が実験結果と誤差10%以内で良好に一致すること、ダスト巻き上げは破口を通じた浮力駆動交換流の流動形態とダスト密度に依存すること、VVから破口を通じて外部へ放出されるダストの放出率はVV上の破口位置に依存すること、さらに本数値解析手法がLOVA事象発生後のVV内の熱流動現象を評価する上で非常に有効であることが定量的に明らかにされた。