Control rod drop transient analysis and incident recognition

A control rod drop incident is a relatively frequent transient over the lifetime of a pressurized water reactor. In order to distinguish this particular incident from other similar depressurized events, the transient nuclear and thermal hydraulic characteristics are identified so that the operator can immediately recognize and effectively confirm the incident. The results of this investigation can be used in operator training programs to identify various anticipated transients and, therefore, take proper actions to mitigate the consequences. The investigation of this incident uses the RETRAN system analysis computer code for the Nuclear Project Nos. 1 and 4 currently being constructed by the Washington Public Power Supply System. The dropped control rod transient is simulated by initiating a reactivity reduction at 0.001 seconds after steady-state initialization. A comparison of the transient parameters among a number of similar depressurized incidents is also included