Efficient critical safety analysis model for PWR fuel assembly under transport accidents by neutron worth iteration

Criticality safety analysis is essential for fuel assembly transport, as it ensures subcriticality under all potential accident scenarios. Traditional methods are computationally expensive, requiring hundreds of input cases. The Neutron Worth Iteration method was developed to efficiently determine conservative k ∞ envelopes for PWR fuel assemblies under transport impacts. By iteratively adjusting the configuration of fuel rods according to the neutron worth distribution within a fuel assembly, the method optimizes rod positioning to maximize k ∞ . This method significantly reduces computational effort while maintaining a slight k ∞ deviation of less than 2.62 ‰ . This approach enables rapid yet rigorous criticality safety assessments. • Derives neutron worth-pitch linear relation for PWR fuel assemblies. • Proposes Neutron Worth Iteration Method, cutting computation files sharply. • Ensures minor k1 deviation and conservatism via k1 revision.