Abstract
Control rod is an important fuel assembly which is responsible for power regulation and emergency shut-down to ensure the safe operation of nuclear reactor. Generally, the absorber material determines the control rod lifetime. Enriched boron carbide is a valuable absorber material for control rods, which has the advantages of strong neutron absorption capacity, good corrosion resistance and thermal stability. In this paper, a method for irradiation performance analysis of the cylindrical control rod composed of enriched boron carbide (B4C) absorber, stainless steel cladding and spring has been established, which was based on analyzing control rod behavior theoretically during irradiation. In order to accurately analyze the irradiation behavior of control rod in the reactor, the influence of thermal effect, stress-strain, fission gas release and rod internal pressure should be considered in the control rod performance code. Taking the cylindrical control rod used in small reactor as the object, the irradiation thermal-mechanical behavior of the control rod was simulated and analyzed under operating conditions. Therefore, the performance parameters such as absorber temperature, cladding temperature, control rod internal pressure, cladding stress and spring shear stress were calculated. The results show that the current design meets the mechanical integrity requirements of control rods, which verifies the applicability of the analysis method.
