Tritium distribution between the primary circuit and associated systems of a VVER NPP power unit

Abstract

The present paper considers the simulated distribution of tritium in the primary circuit of an NPP with a VVER reactor and its auxiliary systems. The activity of tritium in the coolant and auxiliary reactor systems varies during power operation, passing through a maximum. The results of calculations for different flow rates of uncontrolled leakage and drain waters are compared with experimental data on tritium activity in the systems of operating VVER NPPs. Calculation results satisfactorily agree with more than 300 points of experimental data, given the value spread of approximately two orders of magnitude. The study assesses the tritium activity of the spray pond and compare calculated tritium emissions with measurement results. As in the case of the primary circuit, calculations are satisfactorily consistent with experimental data. Thus, the calculation method predicts reliable values of tritium activity in liquid media of VVER reactor units.