Quasistatic reactivity balance equation to meet inherent safety requirements

The three inherent safety shutdown requirements previously developed and proved from the fast reactor systems and LMRs have been used to check if the fast reactors can go critical depending on these requirements without any external reactivity intervention such as control rod or shutdown systems. In this paper, the same requirements and procedures were used to check if the thermal reactors satisfy these requirements using data from Yonggwang unit 7 as a reference. For various power level, the value of the three inherent safety shutdown requirements were evaluated where positive reactivity, ρext, is inserted by control rod ejection incident. Even though typical PWRs do not satisfy these requirements and cannot be stabilized at equilibrium power, fast Doppler feedback and subsequent drop of control rods shutdown the reactors. We have fuel temperature and moderator temperature coefficients where the moderator temperature coefficient is affected by the boron concentration and the fuel temperature coefficient is affected by fuel burnup then these values could be more or less positive or negative reactivity insertion depending on those variables