Mechanistic critical heat flux prediction for in-vessel retention conditions

Md Abdur Rafiq Akand, Tatsuya Matsumoto, Wei Liu, Koji Morita

研究成果: ジャーナルへの寄稿学術誌査読


In-vessel retention (IVR) is considered a feasible technique to keep reactor pressure vessel (RPV) integrity in a severe reactor accident. For light water reactor (LWR), the effectiveness of this strategy relies soundly on the critical heat flux (CHF) distribution over the external surface of the lower plenum of RPV, whose orientation varies gradually from downward-facing horizontal to vertical. The CHF prediction capability of the liquid sublayer dryout model is efficient for high mass flux in vertical flow boiling conditions. This paper focuses on how to adapt the model to the changed orientation of the heating surface. Bubble departure diameter (dB) and net vapor generation point (NVG), the starting point for the void fraction developing in a heating channel, is one of the important key points in the CHF prediction. Therefore, to assess the predictive potential of CHF under IVR, experimental research was performed to measure bubble departure diameter and NVG for a changing heating surface orientation from downward-facing horizontal to vertical with a mechanistic model basing on the force balance. A modified liquid sublayer dryout model was then proposed where the channel orientation effect is considered to measure the bubble departure diameter (vapor blanket diameter) using the improved force balance model. The NVG is modified according to the departure diameter. The predicted departure diameter and subcooling at NVG show good consistency with the experimental data, and the modified liquid sublayer dryout model can predict the CHF data with an average relative error of 18.36% in IVR.

ジャーナルNuclear Engineering and Design
出版ステータス出版済み - 12月 1 2021

!!!All Science Journal Classification (ASJC) codes

  • 核物理学および高エネルギー物理学
  • 原子力エネルギーおよび原子力工学
  • 材料科学(全般)
  • 安全性、リスク、信頼性、品質管理
  • 廃棄物管理と処理
  • 機械工学


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