Study on integrity of rod-bundle geometry caused by subcooled boiling induced vibration

2015 Fiscal Year Final Research Report

• Project/Area Number: 25289354
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Nuclear engineering
• Research Institution: Kyoto University
• Principal Investigator: Kunugi Tomoaki 京都大学, 工学(系)研究科(研究院), 教授 (40301832)
• Co-Investigator(Kenkyū-buntansha): YOKOMINE Takehiko 京都大学, 大学院工学研究科, 准教授 (40240204)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 軽水炉 / 沸騰 / 振動 / 安全性

Outline of Final Research Achievements

In order to investigate the fundamental phenomena of the SBIV (Subcooled Boiling induced Vibration) of the heater rod installed in the subcooled water, the experiments of subcooled pool boiling by the simplified experimental apparatus under atmospheric pressure were performed. In the experiments, influences by wall existence and due to wall configurations arranged in the three cases: "Single wall," "Parallel walls" and "Corner walls," are used. The important results obtained are as follows: 1) Existence of a wall nearby a heater rod encourages the growth of bubbles in the gap and such bubbles condense in the gap, which leads to larger acceleration of SBIV of the heater rod in the direction perpendicular to the wall; 2) Lower degree of subcooling leads to larger growth of vapor bubbles in the gap, and they move out from the gap to the open space, so this causes a vibration of the heater rod, i.e., the perturbation and condensation of the bubbles induce SBIV of the heater rod.

Free Research Field

熱工学