An Adaptive Model for Decay Heat Estimation Using Scram Curves

This study introduces an adaptive model for estimating decay heat in nuclear reactors, particularly during transient scenarios with steadily reducing reactor power.Traditional approaches to decay heat calculation often rely on extensive nuclide tracking or standardized procedures.The former approach can be resource-intensive, requiring detailed tracking of a multitude of nuclides, while the latter often has limited applicability.The adaptive model proposed in this paper offers an alternative solution that circumvents these challenges by utilizing precalculated decay heat curves from scram scenarios.This methodology allows for on-the-fly decay heat calculation during simulation, adapting to varying power levels without the need for detailed nuclide tracking.The paper provides a description of the adaptive model, including its mathematical framework and operational procedure.The model's test case is developed using the IAEA benchmark exercise related to the loss of flow without scram test conducted at the Fast Flux Test Facility, a sodium-cooled fast reactor.The model is verified through single assembly calculations, where it demonstrates high accuracy in comparison to the depletion solver of the Monte Carlo code Serpent.This demonstrates the model's potential as a promising alternative for decay heat estimation in the analysis of accident scenarios.