Heating in a reactor fuel element rod under transient conditions. Part II. DINO. Temperatures during a loss of coolant accident

A computer programme to calculate the temperatures in a fuel rod subject to a loss of coolant accident is described. The programme requires descrete information of the coolant channel hydraulic history stored on an external storage device, magnetic tape or data cards. The temperature response of the fuel rod is described in a finite difference formulation.

The solution of the finite difference scheme is performed by the alternating directional implicite method, which is always stable and well suited to handle large equation systems. The programme determines the heat transfer coefficients along the channel based upon the hydraulic history and several heat transfer correlations in the programme.

The heat fluxes are computed through all internal and external surfaces. The decay of power in the fuel rod during the blow down is input to the programme. The programme is written in Algol for the Risø Borroughs B6700 computer. Plotter procedures are widely used to finish the output and lineprint output is minimized.

The problem size, i.e. the number of nodes, is independent of the programme, only determined by the user. The ratio procestime/real time for a 500 node problem is 100:1.