A three-dimensional PWR-core pin-by-pin analysis code NECP-Bamboo2.0

A PWR-core pin-by-pin fuel management calculation code system named NECP-Bamboo2.0 has been developed, including the two-dimensional lattice calculation code Bamboo-Lattice2.0 and the three-dimensional steady-state whole-core pin-by-pin calculation code Bamboo-Core2.0. Pin-cell homogenized few-group constants are handled in an optimized least-square fitting form. A tightly coupled calculation strategy is employed for multi-physics coupling iterative process. A three-dimensional whole-core spatial parallel algorithm based on the unified domain decomposition is established to decrease both computing time and storage. (1) Compared with the traditional two-step method, the pin-by-pin calculation can ensure the accuracy of reactor reactivity, can reduce the average error of pin-power calculation from 2% to 1% for large commercial PWR core, can reduce the error of pin-power from 11% to 3% for the small PWR core. (2) NECP-Bamboo2.0 can directly provide pin-resolved distributions, including coolant temperature, fuel temperature, burnup and so on. The corresponding accuracy is comparable with one-step high-fidelity results.