Drop Impact Analysis of Control Rod Assembly for Sodium-Cooled Fast Reactor

Drop impact analysis of CRA with normal/abnormal drop condition was carried out to investigate the dynamic behavior and integrity evaluation. The results were as follows: The maximum stress was lower than yield strength and it was rapidly removed. Therefore, CRA maintained structural integrity and it is normally inserted into the flow hole of damper at abnormal condition. The purpose of primary control assemblies is two-fold: to provide neutronic start-up and shutdown, and control over the neutron population during normal operation. Secondary control assemblies are intended for rapid shut-down in emergency situations. Control assembly has a Control Rod Assembly with inner duct and control rod. Control rod assembly falls into a duct of control assembly due to gravity. Drop time and impact velocity of a control rod assembly are important parameters with respect to reactivity insertion time and the structural integrity of the Control Assembly. Drop time and velocity of Control Rod Assembly in normal condition were derived from CFD analysis. The objective of this study is to investigate the dynamic behavior and integrity evaluation of the Control Rod Assembly due to drop impact