Catawba 1 cycle 1 HZP reactor physics model investigation

Following the startup of Duke Power Company's Catawba nuclear station, large disagreements were observed in the hot zero-power (HZP) reactor physics model when compared to the measured data. Errors of 15 to 20% were seen in the measured versus predicted power distribution in the form of an in-out tilt. This led to control rod worth errors of ∼ 20%. Comparisons of Duke predictions with the vendor at hot full power (HFP) and equilibrium xenon showed good agreement. These predictions were substantiated when Catawba reached these conditions. The reactor physics methodology used in the development of the Catawba 1 cycle 1 (C1C1) model had been proven with the startup and operation of both McGuire nuclear station units. This paper addresses possible causes as to why the C1C1 HZP model failed when the C1C1 HFP model and the McGuire HZP and HFP models gave good results