Nuclear / Waterhammer Solutions and Testing

Waterhammer Solutions and Testing

Waterhammer Solutions - Background

When water flow is started or stopped faster than the system can respond acoustically, a pressure surge commonly referred to as a waterhammer event will occur. This same principle is also applicable when the flowing medium is steam rather than water. In the case of steam, the pressure surge is known as a steam hammer event. Both water and steam hammer events have the potential to cause catastrophic damage.

Waterhammer events are transmitted through the system at the speed of sound of the water-pipe combination. For water in a steel pipe, this is essentially the speed of sound in water (~4600 ft/s or 1400 m/s which is close to 1 mile/s). With this high transmission velocity, pipe segments are loaded in a highly transient manner causing them to shake. As a consequence, significant dynamic loads can be transmitted to the piping supports as well as the system components, i.e. valves, instrumentation, etc.

Waterhammer Solutions - Benefits & Expertise

A structured approach to addressing waterhammer solutions provides an efficient and cost effective and safe solution to address your waterhammer issues. 

Our expert team of engineers has extensive experience addressing and resolving various types of waterhammer issues utilizing the following: 

  • Analysis using key industry recognized transient analysis software including GOTHIC, owned by EPRI (Electric Power Research Institute, Inc.) and RELAP5 , a product of Idaho National Laboratories and FAI developed GW2
  • Experimental testing simulating waterhammer events
  • Training on how to mitigate or resolve future waterhammer issues

  Representative Pressure Trace for Waterhammer Event

Waterhammer Testing - Background

Our experimental facilities are designed to conduct noncondensable gas-water or steam-water waterhammer tests simulating conditions of interest in plants including those situations where a noncondensable gas volume is formed in the pump discharge piping. Waterhammer pressures are measured during the experiments and translated to plant conditions. This data can be used to set the limits of acceptable gas accumulation. Tests are conducted in an extended length piping configuration of the plant system and most importantly, the tests are run for a range of initial void sizes in the piping high point.

Waterhammer Testing - Benefits & Expertise

Our experts have experience testing multiple components at our facilities including:

  • Different piping high point configurations in terms of riser, downcomer and high point lengths
  • Influence of a check valve and mini-flowline
  • Multiple void distribution
  • System rigidity, and flow visualization (as an aid in model development) through transparent PVC piping

 Waterhammer Test Facility Schematic