In the nuclear power engineering, methods of detection faults and diagnostics, as well as systems of information support of human-operators in order to increase the safety and reliability of the operation play the increasing role One of tasks solved within the information support is the task of calculating technical and economical indexes. The problem of calculation of technical and economical indexes and its place in the make-up of the application software of the unit level control system of the automated process control system of the nuclear power plant “Kudankulam” is considered.