Event Selection for Safety Analysis

For the safety analysis, the abnormal transients and accidents are taken from each category as the reactivity abnormality, pressure abnormality, reactor coolant flow abnormality, and inadvertent start or malfunction of core cooling system in Table 6.4 except the CR assembly misalignment and drop transient, and the depressurization of core cooling system transient. They are shown in Table 6.5. 

The CR assembly misalignment and drop is representative of the radial power distribution abnormality. However, it cannot be analyzed because only the single channel model and point kinetics are used here. The change of the radial power distribution is expected to affect the cladding temperature distribution as it affects the departure from nucleate boiling ratio distribution of PWRs. The depressurization of core cooling system transient is not analyzed because it will be almost the same as the pressure control system failure transient It should be remembered that reactor depressurization does not threaten the Super LWR safety as is described in Sect 6.3. 

The waste gas decay tank rupture accident and the improper fuel assembly insertion or drop accident are not considered in this book. 

Decrease in core coolant flow rate Partial loss of reactor coolant flow Loss of offsite power Abnormality in reactor pressure Loss of turbine load Isolation of main steam line Pressure control system failure Abnormality in reactivity Loss of feedwater heating Inadvertent startup of AFS Reactor coolant flow control system failure Uncontrolled CR withdrawal at normal operation Uncontrolled CR withdrawal at startup 

Decrease in core coolant flow rate Total loss of reactor coolant flow Reactor coolant pump seizure Abnormality in reactivity CR ejection at full power CR ejection at hot standby LOCA 

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