ABSTRACT

Non-premixed combustion of hydrogen jets containing sodium vapor and mist reduces threats to reactor containment integrity in sodium-cooled fast reactors (SFRs) because it gradually consumes hydrogen gas generated mainly by a reaction between sodium and concrete. Previous studies have been limited to experimentally determining ignition thresholds on the jet temperature and the sodium concentration under specific gas concentrations. In this study, ignition experiments on hydrogen jets containing sodium mist were carried out at a specific jet temperature and sodium concentration under various gas concentration conditions (1–15 vol% hydrogen and 3–21 vol% oxygen). As a result, a stable sodium flame was observed in the jet and then formed a lifted hydrogen flame from a fuel nozzle outlet. An attached hydrogen flame on the outlet was also formed under high hydrogen concentration conditions. These flame structures seemed to be attributed to hydrogen flame propagation, which depends on the hydrogen concentration, jet temperature, and jet velocity. Additionally, the experimental results revealed ignition thresholds on the gas concentration and indicated a flammable region where the hydrogen-sodium jet combustion was more advantageous than an explosive premixed hydrogen combustion. Our study will enable the advancement of safety assessment technology in SRFs.

摘要

含有钠蒸气和雾的氢气射流的非预混燃烧减少了对钠冷快堆 (SFR) 中反应堆安全壳完整性的威胁，因为它逐渐消耗主要由钠和混凝土之间的反应产生的氢气。以前的研究仅限于通过实验确定特定气体浓度下喷射温度和钠浓度的点火阈值。在这项研究中，在不同气体浓度条件（1-15 vol% 氢气和 3-21 vol% 氧气）下，在特定的射流温度和钠浓度下对含有钠雾的氢气射流进行了点火实验。结果，在射流中观察到稳定的钠火焰，然后从燃料喷嘴出口形成升氢火焰。在高氢气浓度条件下，出口处也形成了附着的氢气火焰。这些火焰结构似乎归因于氢火焰传播，这取决于氢浓度、射流温度和射流速度。此外，实验结果揭示了气体浓度的点火阈值，并表明氢钠喷射燃烧比爆炸性预混氢燃烧更有利的易燃区域。我们的研究将推动 SRF 安全评估技术的进步。实验结果揭示了气体浓度的点火阈值，并指出了一个易燃区域，在该区域中氢-钠喷射燃烧比爆炸性预混氢燃烧更有利。我们的研究将推动 SRF 安全评估技术的进步。实验结果揭示了气体浓度的点火阈值，并指出了一个易燃区域，在该区域中氢-钠喷射燃烧比爆炸性预混氢燃烧更有利。我们的研究将推动 SRF 安全评估技术的进步。