Fig. 1 Concept of a passive reactor shutdown device More

Fig. 2 Outline of axial arrangement in driver fuel pin, device fuel pin, and preheating pin More

Fig. 3 Example of arrangement of 16 device subassemblies in the core (arrows: device subassembly positions) More

Fig. 4 Schematic views of pin arrangement across the device subassembly (right) and vertical material arrangement in each type of pin (left) More

Fig. 5 Relationship between the device fuel power sharing and reactivity worth of 16 device subassemblies based on a single device subassembly More

Fig. 6 Variation in the power, flow, and P / F over time for ULOF without device operation: ( a ) conventional homogeneous core and ( b ) low sodium void reactivity core More

Fig. 7 Variation in the flow and P / F over time for ULOF without device operation: ( a ) conventional homogeneous core and ( b ) low sodium void reactivity core More

Fig. 8 Variations in the power, flow, and P / F over time for ULOF with device operation: ( a ) conventional homogeneous core and ( b ) low sodium void reactivity core More

Fig. 9 Variation in the coolant temperature over time in a fuel subassembly with a relatively higher P / F (low sodium void reactivity core) More

Fig. 10 Variations in the power, flow, and P / F over time for ULOF with U-Fe device operation: ( a ) conventional homogeneous core and ( b ) low sodium void reactivity core More

Fig. 11 Effect of asynchronous device operation on variation in the power, flow, and P / F over time in conventional homogeneous core: ( a ) device reactivity of −$1.86 and ( b ) device reactivity of −$2.40 More

Fig. 1 ATHENA main vessel layout and primary coolant flow path More

Fig. 2 Solution 1 BT conceptual scheme (CIRCE-HERO like) [ 21 ] More

Fig. 3 Active length for the 3 solutions (91 BTs cases) More

Fig. 4 Active length of Solution 2 (61 versus 91 BTs cases) More