e-Article
Performance of different absorber materials and move-in/out strategies for the control rod in small rod-controlled pressurized water reactor: A study based on KLT-40 model
Document Type
Article
Author
Source
Nuclear Engineering and Technology, 56(7), pp.2756-2766 Jul, 2024
Subject
Language
English
ISSN
2234-358X
1738-5733
1738-5733
Abstract
Small rod-controlled pressurized water reactors (PWR) are the ideal energy source for vessel propulsion, benefiting from their high reactivity control efficiency. Since the control rods (CRs) increase the complexity of reactivity control, this paper seeks to study the performance of CRs in small rod-controlled PWRs to extend the lifetime and reduce power offset due to CRs. This study investigates CR grouping, move-in/out strategies, and axially non-uniform design effects on core neutron physics metrics. These metrics include axial offset (AO), core lifetime (CL), fuel utilization (FU), and radial power peaking factor (R-PPF). To simulate the movement of the CRs, a "Critical-CR-burnup" function was developed in OpenMC. In CR designs, the CRs are grouped into three banks to study the simultaneous and prioritized move-in/out strategies. The results show CL extension from 590 effective full power days (EFPDs) to 638–698 EFPDs. A lower-worth prioritized strategy minimizes AO and the extremum values decrease from 0.69 and + 0.81 to 0.28 and + 0.51. Although an axially non-uniform CR design can improve AO at the beginning of cycle (BOC), considering the overall CR worth change is crucial, as a significant decrease can adversely impact axial power distribution during the middle of cycle (MOC).