Advancements in reactor designs enable new operational concepts for nuclear power plants that alter the work of control room operators and can influence their performance in different ways. The performance implications of these changes in longer time frames (i.e. days, weeks, and months) remain largely unexplored. In this documentary research, we identify main changes to characteristics of operators’ work in a multi-unit SMR operational concept compared to conventional plant operations. The multi-unit concept is found to indicate increases in cognitive demands, higher potential for role conflict and work over-/underload, increased access to information and tools, reduced skill and task variety, and reduced social support. We discuss their potential effects on performance within the Job Demands-Resources framework.