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

• Published in: Nuclear engineering and design 2020-08, Vol.365, p.110719, Article 110719
• Main Authors: Kim, Taeil, Harbaruk, Dzmitry, Lisowski, Darius, Bremer, Nathan, Farmer, Mitchell, Grandy, Christopher, Chang, Yoon Il
• Format: Article
• Language: English
• Subjects: Bundling; Drop tests; Eutectic Formation; Eutectics; Fast nuclear reactors; Freezing; Freezing point; Impact tests; Mathematical analysis; Melting points; Metal fuels; Metallic Fuel; Nuclear engineering; Nuclear fuels; Nuclear safety; Pore size; Porosity; Pressure; Pressure drop; Reactors; Relocation; SFR; Sodium; Sodium cooled reactors; SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; Uranium
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2020.110719

•Experiments dropping uranium into sodium filled pin bundle geometry were conducted.•Post-test radiographic images were used to confirm how the uranium was relocated.•Pressure drop was measured to evaluate the blockage of the sodium coolant channel.•The more formation of the eutectics could lead to more dispersion and less blockage. Understanding the relocation behavior of metallic fuel in severe accident scenarios is one of the most important factors in the safety assessment of sodium-cooled fast reactors (SFRs). In the present study, the relocation behavior of uranium metallic fuel was investigated by conducting metallic fuel relocation experiments using 19-pin bundle test sections in the Argonne’s Metallic Uranium Safety Experiment (MUSE) facility. Post-test radiographic images were taken to characterize the uranium fuel relocation within the pin bundle test section. In addition, the pressure drop in the test sections was measured after the relocation experiments to evaluate the blockage of the sodium coolant channel. The pressure drop in the pin bundle test sections was also analytically calculated by varying the porosity and the pore size of the relocated fuel. The porosity and pore size of the relocated fuel in the pin bundle test sections were estimated by comparing those calculated pressure drop values with the measured pressure drop values from the pressure drop tests. The experimental results showed that the more formation of the eutectics could lead to more fuel dispersion and less blockage due to the lower freezing point of the eutectics.