Advanced SearchSearch Tips
CFD Analysis to Estimate Drop Time and Impact Velocity of a Control Rod Assembly in the Sodium Cooled Faster Reactor
facebook(new window)  Pirnt(new window) E-mail(new window) Excel Download
 Title & Authors
CFD Analysis to Estimate Drop Time and Impact Velocity of a Control Rod Assembly in the Sodium Cooled Faster Reactor
Kim, JaeYong; Yoon, KyungHo; Oh, Se-Hong; Ko, SungHo;
  PDF(new window)
In a pressurized water reactor (PWR), control rod assembly (CRA) falls into the guide tubes of a fuel assembly due to gravity for scram. Various theoretical approaches and numerical analyses have been performed because its shape is simple and its design was completely developed several decades ago. A control rod assembly for a sodium-cooled faster reactor (SFR) which is geometrically more complicated is being actively developed in Korea nowadays. Drop time and impact velocity of a CRA are important parameters with respect to reactivity insertion time and the mechanical robustness of a CRA and a guide duct. In this paper, computational method considering simultaneously the equation of motion for rigid body and the Navier-Stokes equations for fluid is suggested and verified by comparison with theoretical analysis results. Through this valuable CFD analysis method, drop time and impact velocity of initially designed SFR CRA are evaluated before performing scram tests with it.
Control Rod Assembly;Drop Time;Impact Velocity;Scram;Sodium-cooled Fast Reactor;
 Cited by
Kim, K. R., Jang, K. J., Park, J. S., and Lee, W. J., 2010, "Drop time evaluation for SMART control rod assembly", Proceeding of KFMA2010.

Choi, K. S., and Kim, I. K., 1994, "Development of A computer program for drop time and impact velocity of the rod cluster control assembly", Nuclear Engineering and Technology, Vol. 26, No. 2, pp. 197-204.

Andriambololona, H., Bosselut, D., and Massin, P., 2007, "Methodology for a numerical simulation of an insertion or a drop of the rod cluster control assembly in a PWR," Nuclear Engineering and Design, Vol. 237, No. 6, pp. 600-606. crossref(new window)

Donis, J. M., and Goller, H., 1972, "A mathematical model of a control rod drop", Nuclear Engineering and Design," Vol. 23, No. 1, pp. 107-120. crossref(new window)

Yoon, K. H., Kim, J. Y., Lee, K. H., Lee, Y. H., and Kim, H. K., 2009, "Control rod drop analysis by finite element method using fluid-structure interaction for a pressurized water reactor power plant, Nuclear Engineering and Design", Vol. 239, No. 10, pp. 1857-1861. crossref(new window)

CFX manual, 2014, "ANSYS CFX Ver. 15," ANSYS Inc.

Morrison, F. A., 2013, "Data correlation for drag coefficient for sphere", Department of Chemical Engineering, Michigan Technological University, Houghton, MI (

Schlichting, H., 1995, Boundary Layer Theory, McGraw-Hill, New York.

White, F. M., 2006, Fluid Mechanics 6th edition, McGraw-Hill, New York.

Kikuchi, K., Konno, T., Ichikawa, S., Kubota, Y., and Mochizuki, O., 2013, "Unsteady Drag Coefficient of a Falling Sphere in Water", JSME, Vol. 79, No. 798, pp. 151-163.