Na冷却高速炉におけるNa中での水素の存在形態に着目した挙動推定

• Published in: Journal of Computer Chemistry, Japan Vol. 21; no. 2; pp. 61 - 62
• Main Authors: 下山, 一仁, 加藤, 篤志, 宮本, 明, 山本, 智彦, 畠山, 望, 荒, 邦章, 三浦, 隆治, 宮本, 直人
• Format: Journal Article
• Language: Japanese
• Published: 日本コンピュータ化学会 2022
• Subjects: Hydrogen detection; Sodium-cooled fast reactor (SFR); Sodium-water reaction; Steam generator (SG); Ultra-accelerated quantum chemical molecular dynamics (UA-QCMD)
• ISSN: 1347-1767; 1347-3824
• DOI: 10.2477/jccj.2022-0026

In the cooling system of sodium-cooled fast reactors, it is required to identify and rapidly detect hydrogen explosively produced by the sodium-water reaction when a water leak occurs due to damage of a heat exchanger tube in a steam generator (SG), in contrast to low-concentration background hydrogen permeating through SG tubes during normal operation. In the present study, we focus on the difference between the background hydrogen and the hydrogen generated by the sodium-water reaction, and theoretically estimate the hydrogen behavior in liquid sodium by using computational chemistry methods. We find that dissolved H or NaH, rather than H2, is the predominant form of the background hydrogen in liquid sodium, and that hydrogen produced in large amounts by the sodium-water reaction can exist stably as fine bubbles with a NaH layer on their surface.