An example of a limited scope INPRO sustainability assessment of an innovative nuclear energy system used the BN-1200 fast reactor as a case study. The INPRO assessment was performed at the full-depth criteria level and helped to identify actions for sustainable long term deployment of sodium cooled fast reactors. The publication describes the application of the INPRO sustainability assessment method to the innovative nuclear energy system based on BN-1200 fast reactors in the areas of economics and safety of nuclear reactors. The case study is intended to verify readiness of the updated INPRO Methodology for assessment of the sodium cooled fast reactors and to develop recommendations for further improvements to the INPRO assessment method.