Existing containment models for a loss of coolant accident at many nuclear power plants were created in the 1970s using older computer technology and thermal hydraulic models which were available at that time. While conservative, these models may not present the detail necessary to identify conditions which may be used to produce additional design margin for the plant. After exploring containment and critical flow modeling, the basis for the use of GOTHIC in this analysis was established. A GOTHIC model was then created to simulate the loss of coolant accident results shown in an Updated Final Safety Analysis Report analysis for the North Anna Power Station. This model was used to examine the effects of increased nodalization in a subcompartment on the existing containment model. It is shown that adding multidimensional sub-nodes to areas of interest can provide valuable detail which was absent in the UFSAR model. Simulations are able to show the localized pressure spike around a LOCA pipe break that quickly dissipates, leaving significantly lower pressures in what was once an averaged, single, lumped-parameter node. This suggests that additional design margin may exist depending on where the pipe break is assumed to occur. / Master of Science

A dynamic model was developed for the distillation mechanism of the Darlington Tritium Removal Facility. The model was created using the commercial software package MATLAB/Simulink. The goal was to use such a model to predict the system behaviour for use in control analysis. The distillation system was first divided into individual components including columns, condensers, controllers, heaters and the hydraulic network. Flow streams were then developed to transfer enthalpy, pressure and mass flow rate between the components. The model was able to perform various plant transients for validation and analysis purposes. A comparison of the different controllers was made with the introduction of various disturbances to the system. Also, the effect of the system disturbances when isolated from the transients was studied using the same controllers. Studying different plant transients and disturbances under each controller enabled a comparative analysis.

A dynamic model was developed for the distillation mechanism of the Darlington Tritium Removal Facility. The model was created using the commercial software package MATLAB/Simulink. The goal was to use such a model to predict the system behaviour for use in control analysis. The distillation system was first divided into individual components including columns, condensers, controllers, heaters and the hydraulic network. Flow streams were then developed to transfer enthalpy, pressure and mass flow rate between the components. The model was able to perform various plant transients for validation and analysis purposes. A comparison of the different controllers was made with the introduction of various disturbances to the system. Also, the effect of the system disturbances when isolated from the transients was studied using the same controllers. Studying different plant transients and disturbances under each controller enabled a comparative analysis.