Effects of noncondensable gas on passive cooling systems in Fukushima Daiichi and advanced reactors

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H06483
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Nuclear engineering
• Research Institution: Hokkaido University
• Principal Investigator: YAMAMOTO Yasunori 北海道大学, 工学研究院, 助教 (10800906)
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: 非常用復水器 / 凝縮熱伝達 / 非凝縮性ガス / 自然循環

Outline of Final Research Achievements

Isolation condenser (IC) is one of the passive core cooling system that can be used even when loss of power accident occurs. Experiments simulating IC were carried out to evaluate the cooling capability, where various parameters such as steam flow rate, temperature distribution in a heat transfer tube and pressure were measured. In order to evaluate effect of non-condensable gas on cooling capability of IC, injection section of helium gas to natural circulation loop was constructed. Pressure in the loop increased and steam flow rate decreased due to the reduction of driving force of natural circulation when helium was injected under quasi-steady state conditions.

Free Research Field

原子炉熱流動

Academic Significance and Societal Importance of the Research Achievements

福島原発事故を経験し、全交流電源喪失に備えた対策の重要性が再認識されており、ICのような静的炉心冷却系は有力な安全対策の１つである。事故の条件を含めてICの活用を考えた場合、福島第一原発1号機で問題となった水素の影響が懸念される。ICのシステム全体を模擬して水素影響を評価した実験データの公開文献はほとんどなく、本研究で得られたデータは、ICの水素ロバスト性を評価するための重要な知見となることが期待される。