The PHV-1000 steam generator is one of the main heat exchangers in the primary circuit of the power unit of nuclear power plants with a WWER-1000 reactor. The efficiency of its operation directly affects the thermal power and overall electricity generation of the power unit. The reliability of the heat exchange tubes forming the main heat exchange area is critical not only for thermal performance but also for the safety characteristics of the steam generator. As a result of damage and tube plugging, the active heat-exchange surface decreases, directly affecting the steam generator's operation. The paper investigates the impact of heat-exchange tube degradation and plugging in the PHV-1000 steam generator on its thermal parameters, particularly steam productivity. The importance of limiting the number of plugged heat exchange tubes within the regulated norms (up to 2% of tubes) is emphasized, and the possible consequences of exceeding this threshold for the thermal efficiency and resource of the power unit are substantiated. Methods for monitoring the condition of heat-exchange tubes are analyzed, particularly, the eddy-current non-destructive method and the modern welded method ZOK–PG 08 for tube plugging is considered.
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