Design and performance of 2D and 3D-shuffled breed-and-burn cores

3D in-core fuel management optimization for breed-and-burn reactors

“…It can be seen that k∞ increases rapidly with burnup before it reaches 1.0 and the change slows down in the vicinity of its maximum value. Figure 14 k∞ evolution with burnup of metallic DU fuel [11].…”

“…This section introduces the perceived design of the fuel rods and fuel assemblies to facilitate the 3D shuffling. In the original solution [11], assembly segments are axially connected with upper and lower connecting grapplers to form a full-length assembly, while the segment at the bottom of the core is connected to a shielding and flow orificing block that is designed to remain in a fixed location in the reactor for the lifetime of the core. This design was later carefully evaluated and modified especially for the connecting mechanism to ensure the core stability under all operating conditions and the reliability when moving fuel assembles in the sodium coolant.…”

“…(1) maximum core pressure drop across core: 0.9 MPa, [11] (2) maximum sodium velocity across the core: 12 m/s, [33] (3) maximum fuel-cladding interface temperature: 650 • C, [34] and (4) maximum peak fuel temperature: 1000 • C. [35] 3 Shuffling Pattern Optimization Using Simulated Annealing Method…”

“…The implementation of the 3D fuel shuffling strategy considered in the previous section will require significantly longer refueling time, more complicated refuelling machine and, possibly, two separate refueling machines to cut down the total refueling time, [11] and larger workspace above the core to disassemble and reassemble the fuel assemblies relative to 2D fuel shuffling. Therefore, a number of design approaches for 3D shuffling simplifications were examined and their effect on the core performance improvements 36 relative to 2D fuel shuffling was quantified.…”

“…[10] [11] That preliminary study concluded that the optimal 3D shuffling pattern (SP) offers an approximately 30% reduction in the peak radiation damage while increasing the fuel utilization relative to a 2D shuffling.…”