The paper overviews the requirements of international standards on application of diversity in safety-critical NPP instrumentation and control (I&C) systems. The NUREG 7007 classification of version redundancy and the method for diversity assessment are described. The paper presents results from the analysis of instruments and design tools for FPGA-based embedded digital devices from leading manufacturers of programmable logics using the Xilinx and Altera (Intel) chips, which are used in NPP I&C systems, as an example. The most effective integrated development environments are analyzed and the results of comparing the functions and capabilities of using the Xilinx and Altera (Intel) tools are described. The analysis of single failures and fault tolerance using diversity in chip designs based on the SRAM technology is presented. The results from assessment of diversity metrics for RadICS platform-based multi-version I&C systems are discussed.