Analysis of operating data related to power and flow distribution in a PWR

Abstract

The analysis of the effects of the uncertainties associated with temperature and power measurements in the Connecticut Yankee Reactor leads to the evaluation of the uncertainty associated with the effective flow factor. The effective flow factor is defined as the normalized ratio of the average assembly power to the coolant temperature use in each instrumented fuel assembly. Analysis of operating data indicates that the effective flow factor is a measure of the quality of agreement between the reactor physics and the thermal hydraulic analysis of the core. The methods given are also used for the evaluation of the uncertainties associated with the peaking factors, including the results of a sensitivity analysis developed with the code INCORE. Flow calculations have been performed with the code COBRA III C. The original version of the code COBRA III C has been expanded and a method is given to easily handle any further change in the code. A sensitivity a! nalysis, using the code COBRA III C shows the weak sensitivity of the exit conditions of the coolant on most input parameters and on the inlet flow distribution of the coolant selected for the calculation. This low sensitivity indicates that the information obtained from the assembly exit thermocouple cannot be used for the determination of the cross flow pattern between the fuel assemblies.