The design of systems important to the nuclear power plants (NPPs) safety must base on
compliance with regulatory documents' requirements and ensuring the object's reliable operation
throughout its entire life cycle. One of the aspects of increased requirements for the safe and dependable
operation of NPP instrumentation and control systems is perfecting human-operator information decision
support systems. In the paper, an approach is considered in which the operator support information system
kernel is a flexible modeling complex, which can be used as a digital twin. The paper also discusses methods
for assessing the proximity of a physical object and its digital twin based on a consistent and normalized
measure of dependence of random vectors.