Improved lumped analysis of transient heat conduction in a nuclear fuel rod

Transient heat conduction in a nuclear fuel rod is analysed by an improved lumped parameter approach. The circunferential symmetry is assumed with the heat transfer through the gap modelled by a heat transfer coefficient. Hermite approximation for integration is used to obtain the average temperature and heat flux in the radial direction. Significant improvement over the classical lumped parameter formulation has been achieved. The proposed fuel rod heat conduction model can be used in stability analysis of BWR, simplified model of PWR or real-time simulator of nuclear power plants.