Analytic estimation of the impact pressure in a beam-tube due to water-hammer effect

Generated neutrons are transferred through the beam-tubes of a research reactor. When a beam-tube rupture occurs inside the pool, the pool water enters quickly into the tube, and hits the flange foil at the other end. Unless the foil endures the impact pressure, a multiple beam-tube-rupture accident will occur. Therefore, to determine the thickness of the end flange foil, the impact pressure has to be estimated. In this study, the maximum impact pressure is estimated analytically by considering the water hammer phenomenon. The result is then validated with computational fluid dynamic (CFD) simulations. For the simulations, a commercially available CFD code, ANSYS CFX, is used. The analytic solutions show good agreement with the CFD results.