Experimental studies on metallic fuel relocation in a single-pin core structure of a sodium-cooled fast reactor

• Published in: Nuclear engineering and design Vol. 322; no. C; pp. 204 - 214
• Main Authors: Kim, Taeil, Harbaruk, Dzmitry, Gerardi, Craig, Farmer, Mitchell, Chang, Yoon Il
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2017; Elsevier BV; Elsevier
• Subjects: Boiling; Cladding; Eutectic Formation; Experiments; Fast nuclear reactors; Fragmentation; HCDA; Metal Fuel; Nuclear fuels; Reactors; Relocation; SFR; Sodium; Sodium cooled reactors; SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; Temperature; Uranium; HCDA; Metal fuel; Eutectic formation; Relocation; SFR; Fragmentation
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2017.06.049

•Experiments dropping molten uranium into test sections of single fuel pin geometry filled with sodium were conducted.•Fuel cladding was failed due to eutectic formation between uranium and HT-9M.•Voids formed by boiling of sodium in coolant channel were observed.•Numerous fragments of the relocated fuel were found. Experiments dropping molten uranium into test sections of single fuel pin geometry filled with sodium were conducted to investigate relocation behavior of metallic fuel in the core structures of sodium-cooled fast reactors during a hypothetical core disruptive accident. Metallic uranium was used as a fuel material and HT-9M was used as a fuel cladding material in the experiment in order to accurately mock-up the thermo-physical behavior of the relocation. The fuel cladding failed due to eutectic formation between the uranium and HT-9M for all experiments. The extent of the eutectic formation increased with increasing molten uranium temperature. Voids in the relocated fuel were observed for all experiments and were likely formed by sodium boiling in contact with the fuel. In one experiment, numerous fragments of the relocated fuel were found. It could be concluded that the injected metallic uranium fuel was fragmented and dispersed in the narrow coolant channel by sodium boiling.