Behavior of Lead-Bismuth eutectic (LBE) expansion caused by phase transition in response to heat treatment

• Published in: Nuclear engineering and design Vol. 365; p. 110714
• Main Authors: Odaira, Naoya, Fujiwara, Takuma, Arita, Yuji
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2020; Elsevier BV
• Subjects: Bismuth; Cooling rate; Density; Expansion; Heat treatment; Heat treatments; LBE; Lead bismuth eutectic; Liquid metals; Nuclear engineering; Nuclear reactors; Nuclear safety; Phase transition; Phase transitions; Rate equation; Reactors; Solidification; Expansion; LBE; Lead bismuth eutectic; Rate equation; Phase transition
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2020.110714

•Changes in LBE volume was obtained an experiment based on Archimedes principle.•The results indicates volume change clearly indicates it is induced by phase transition of ε phase to α-Bi phase.•Phase fraction was determined with the density of each phase. Obtained phase fraction data were fit to rate equation. Lead-bismuth eutectic (LBE) is liquid metal coolant candidate for fast reactors, and especially accelerator-driven systems. Further, freeze sealed valves had been proposed to contribute passive safety to fast reactors. LBE is known to expands after solidification, the stress to coolant pipes induced by the expansion should be determined quantitatively. LBE had widely been studied in nuclear field, but little information exists on changes in LBE volume. We therefore measured changes in LBE density over 1,000 h for five LBE samples cooled at various cooling rates. The volume change of LBE is caused by a phase transition. It was found that the rate equation is consistent with our experimental data on slowly cooled LBE. Changes in LBE density, expansion behavior, and phase transitions in response to heat treatment were described in this study.