Remote Operated Vehicle Mock-Up Test
Even though McGuire Nuclear Power Plant is located on the shores of Lake Norman, it relies on cooling water from a separate service water pond. Duke Energy, operators of the plant, wanted to investigate the conditions of the service pipeline that connects the service pond to the plant. They elected to use a robotic underwater vehicle attached to a tether. However, because the service water line connecting the pond to the plant is an important safety function, the retraction tension on the robotic underwater vehicle needed to be validated before the vehicle was deployed using a mock-up test.
Mock-up testing would determine if the tether would remain within the tether failure tension after the vehicle has advanced past several turns and more than several hundred feet into the pipeline. The main sources of tension on the tether are the turns in the pipeline.
Alden worked with Hibbard Inshore to set up a model of the pipeline bends with limited straight pipe lengths between them to correctly simulate the tether friction during a retraction. In addition, the mock-up test demonstrated to the plant the ability to identify various pipeline characteristics of interest that could be encountered during the real inspection. The mock-up also provided a similar level of water visibility to ensure the rover inspection would still be successful under turbid water conditions.
Contact us for more information on mock-up testing.
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Hydraulic Structure Engineering DesignRelated Projects
An existing roof vent arrangement was allowing rainwater to enter the Pot Room. Alden supported efforts to develop a roof vent geometry to eliminate the intrusion of rain water. The purpose of the CFD study was to ensure that the roof vent modification did not increase pot room temperature levels beyond specified limits for workers in the plant.
To evaluate the existing and proposed Pot Room arrangements, thermal and fluid flow profiles in the immediate vicinity of the pots were determined based on air flows through the plant floor and wall mounted vents. The detailed CFD model was developed from plant drawings to include all major basement, pot room and roof venting geometries. The surrounding ambient environment was included with quiescent atmospheric conditions and average ambient temperature. Thermal losses form the pots to the pot room air and from the pot room to the environment were included in the analysis. The results of the CFD modeling showed that the proposed modification to the roof venting arrangement was acceptable and would not increase the temperature in the worker-occupied spaces by more than 2 degrees F.
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Civil Infrastructure
Smelter Pot Room Roof Ventilation System
Read how a CFD study ensured that a roof vent modification did not increase pot room temperature levels beyond safe levels
Plant McDonough, owned and operated by Southern Company, has experienced excessive siltation at the makeup water intake. The intake uses cylindrical wedgewire screening within an intake originally designed for much larger, once-through cooling water flows. Flow modeling was performed to provide a viable passive solution to reducing the sediment accumulation at the intake. To model the geometric details of the system accurately, a field survey was performed prior to the flow modeling efforts. The flow study included both CFD modeling and scale physical modeling.
For this investigation, Alden developed a 1:20 scale live bed physical model. This model was extremely well tuned to reproduce the behavior of bed load sediment. Even with the very fine crushed walnut shell particles, however, it was challenging to reproduce the behavior of suspended load. The use of a high fidelity CFD model, therefore, proved extremely useful for this project, in that suspended load is generally very accurately tracked with CFD models, which are not well validated for bed load simulation. By using the two together, the two extremes of sediment transport are captured, and developing a solution that covers this range has a high likelihood of success.
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Civil Infrastructure | Hydrology Hydraulics and Fluids
Plant McDonough Intake Modification
CFD and physical model study to assist in the evaluation of a solution to reduce the sediment accumulation.