Principles of I and C replacement in VVER-1000 NPPS

Existing information and instrumentation and control systems in Ukrainian nuclear power plants with VVER-1000 reactor (types V-302 and V-338) which were brought into operation prior to 1989, have certain peculiarities which make their replacement and modernization advisable. To limit these peculiarities the following steps should be followed: - An analysis is required to determine the degree of compliance with international standards; based on the results corrective measures can be proposed. - Due consideration must be given to the procurement of spare parts and the replacement of components belonging to the I and C systems and the plant computer, as these procedures will be based on finding adequate alternatives. - It should be remembered that the technology and design of modern I and C systems have certain advantages over those systems installed in the plants in question. The former are more realizable,require less maintenance and have fewer equipment items, which means improved plant availability, fewer non-scheduled outages and shorter scheduled outages. (Author)