Design optimization of cylindrical burnable absorber inserted into annular fuel pellets for soluble-boron-free SMR

• Published in: Nuclear Engineering and Technology
• Main Authors: YuGwon Jo, Ho Cheol Shin
• Format: Article
• Language: English
• Published: Elsevier 2022-04-01
• Subjects: Burnable absorber; Spatial self-shielding effect; Annular fuel pellet; Soluble-boron-free; Small modular reactor
• Online Access: http://www.sciencedirect.com/science/article/pii/S1738573321005830

This paper presents a high performance burnable absorber named as CIMBA (Cylindrically Inserted and Mechanically Separated Burnable Absorber) for the soluble-boron-free SMR. The CIMBA is the cylindrical gadolinia inserted into the annular fuel pellets. Although the CIMBA utilizes the spatial self-shielding effect of the fuel material, a large reactivity upswing occurs when the gadolinia is depleted. To minimize the reactivity swing of the CIMBA-loaded FA, two approaches were investigated. One is controlling the spatial self-shielding effect of the CIMBA as burnup proceeds by a multi-layered structure of the CIMBA (ML-CIMBA) and the other is the mixed-loading of two different types of CIMBA (MIX-CIMBA). Both approaches show promising performances to minimize the reactivity swing, where the MIX-CIMBA is more preferable due to its simpler fabrication process. In conclusion, the MIX-CIMBA is expected to accelerate the commercialization of the CIMBA and can be used to achieve an optimal soluble-boron-free SMR core design.