Water Hammer

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Analysis Division

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Water Hammer

Peak Axial Load Associated with a 100 in3 Void
The potential for water hammer loads is an important consideration in the design and operation of nuclear power plant piping systems. Water hammer occurs when there is a pressure surge or wave in a piping system caused by a fluid (gas or liquid) in motion that is forced to stop or change direction suddenly. Potential causes of water hammer include, but are not limited to, rapid valve closing, pump failure, voids in normally water-filled lines, entrainment of water in steam-filled lines, and steam condensation in lines containing both steam and water. The large hydraulic loads from water hammer events can cause damage to pipes and structures. By predicting the occurrence and magnitude of potential water hammer effects the proper design and operating procedures can be implemented.

GOTHIC™ is capable of effectively modeling complex interconnected subsystems under various plant operating conditions. The GOTHIC code has been sufficiently verified and validated with respect to gas transport in combination with liquid, water hammer, and degassing. GOTHIC offers considerable flexibility in modeling the three-dimensional flow of gases and liquids and has been qualified against several gas and water flow experiments, including the Westinghouse Purdue tests performed specifically for Generic Letter 2008-01 and a Millstone Unit 3 test performed in response to GL 2008-01. Each plant and their distinctive scenario can be uniquely created and evaluated within a GOTHIC model.

Analysis Division Experience with Water Hammer

The Analysis Division has performed various water hammer analyses for nuclear power plants. We also maintain a strong experience base in nuclear plant operations and safety analysis requirements. We are exceptionally and uniquely qualified to complete water hammer analyses given our experience, as follows:
GOTHIC Noding Diagram of RHR pump Discharge
Analysis Support

For more information on our ability to analyze water hammer, and how this ability can be applied to your plant, please contact Anita Gates or Steve Winter. The Analysis Division contact list is here, including phone numbers.