Regulatory Review of Test Features of the Digital Plant Protection System for Ulchin Nuclear Power Plant Units 5 and 6

摘要

Computer based systems play the key role in the I&C system important to safety of nuclear power plant, which are being applied in safety critical systems as well as non-safety systems. In this context, the evaluation of their test features provided to keep the safety and operability of digital protection systems is very important in the regulating senses. This paper presents the evaluation result and regulatory approach of the test features and methods of digital plant protection system (DPPS) for Ulchin nuclear power plant units 5 and 6. Firstly, the issues associated with the hardware design classification of test facility, MTP, of DPPS are presented. Secondly, regulatory approaches are presented on the ITP cross-channel data link of DPPS and the design concept of trip channel bypass for periodic surveillance testing for bistable function.