Simplified Calculations of Different Dragon Power Transfer Functions. Dragon Project Report

The control rod oscillator method is useful to calibrate control rods and to determine the prompt neutron lifetime at zero reactor power, and to determine heat conduction and heat transfer coefficients at power. The difference between the zero power and power transfer functions is due to temperature coefficients associated with the different zones of the reactor. The subject of this paper is to describe equations for the dynamic behaviour of the reactor and to study the influence of the assumed heat conduction models of the fuel elements on the power transfer function. The fundamental terms of the sinusoidal temperature variations effecting the temperature feed back, on the transfer function are calculated with the heat diffusion equation for cylindrical geometry. The corresponding thermal stresses (plane strain) are calculated for a homogeneous cylindrical fuel element, with isotropic. heat and elasticity properties. The derived equations exclude heat radiation and refer to a time independent mean axial coolant temperature. (author)