Method to determine and evaluate the emergency shut down margin of a nuclear pressurized water reactor

摘要

Method for determining and evaluating the emergency shutdown margin of a pressurised water nuclear reactor, characterised in that consists in calculating a shutdown margin by the application of the general formula: Mar = DELTA Pg + DELTA Pp - DELTA Pr, in which Mar is the required shutdown margin, DELTA Pg is the antireactivity attributed to the control rod assembly of the reactor when this assembly moves from zero insertion to full insertion, DELTA Pp is the reactivity introduced by changing from nominal power to a zero power, DELTA Pr is the antireactivity already consumed for bringing the reactor into the situation which it occupies at the instant being considered and is calculated from the antireactivity which stems from the measured position of the power control clusters (20), using the measured axial power distribution (C1 to C6) and the previously defined core exhaustion, from a term evaluating the reactivty input obtained by the drop in power between the nominal power and the existing situation of the reactor and from a scale constant. …IMAGE…