Performance of low smeared density sodium-cooled fast reactor metal fuel

Abstract

An experiment was performed in the Experimental Breeder Rector-II (EBR-II) in the 1990s to show that metallic fast reactor fuel could be used in reactors with a single, once-through core. To prove the long duration, high burnup, high neutron exposure capability an experiment where the fuel pin was designed with a very large fission gas plenum and very low fuel smeared density (SD). The experiment, X496, operated to only 8.3 at. % burnup because the EBR-II reactor was scheduled for shut-down at that time. Many of the examinations of the fuel pins only funded recently with the resurgence of reactor designs using very high-burnup fuel. The results showed that, despite the low smeared density of 59% the fuel swelled radially to contact the cladding, fission gas release appeared to be slightly higher than demonstrated in conventional 75%SD fuel tests and axial growth was about the same as 75% SD fuel. There were axial positions in some of the fuel pins which showed evidence of fuel restructuring and an absence of fission products with low melting points and gaseous precursors (Cs and Rb). A model to investigate whether these areas may have overheated due to a loss of bond sodium indicates that it is a possible explanation for the fuel restructuring and something to be considered for fuel performance modeling of low SD fuel.

Baseline Postirradiation Examination of the AFC-3C, AFC-3D, and AFC-4A Experiments

“…The radiographs of 3D R2 and 3D R3 show some asymmetric behavior. This sort of behavior was also seen in solid, low smear density pins in AFC-3A/B [9] and in EBR-II irradiations [20]. However, the axial growth in 3D R3 (U-10Mo) is significantly greater than in R2 (U-10Zr).…”

“…AFC-3C R3, 3C R4, and 3D R1 all have fairly high fission gas release. Low smear density fuel like AFC-3C R3 has historically had high fission gas release [20], but the fission gas release for solid low smear density fuel in AFC-3B was lower or near 70% [9]. Also, the fission gas release for AFC-3D R2 is in the historical fission gas release band of 70±10%.…”

Integrating Advanced Modeling and Accelerated Testing for a Modernized Fuel Qualification Paradigm

“…In general, the strategy has been to reduce the SD of the fuel cross section following two main routes: solid fuel with low SD or annular fuel (with or without bond sodium). Solid, sodium-bonded fuel with lower SD (<75%) has been tested in both the EBR-II, reaching burnup of 8.3%FIMA during the X496 experiment 41 and annular (He bonded), and solid low SD within AFC experiment series 3 in the Advanced Test Reactor (ATR) (AFC-3) reaching low burnup of ~2-4%FIMA (Refs. 37 and 42).…”

Automatic information extraction from neutron radiography imaging to estimate axial fuel expansion in EBR-II

“…The EBR-II dataset is comprehensive, as it combines a great range of experiments with different fuel alloys, cladding types, and geometric characteristics leading to the qualification of sodium-bonded U-10Zr fuel in EBR-II, and provides data that could be used for other metal fuel designs for advanced SFRs. Some publications show data analysis from a few of the SFR fuel experiments [4][5][6][7][8][9][10], but much of the data has not been reported, analyzed, or even segregated into a usable form.…”