At the Rostov NPP, engineer Sergey Kudrevatykh proposed changing the turbine unit repair technology — and reducing one of the complex operations from 36–60 days to 12. The new method was applied at power unit No. 3 during scheduled preventive maintenance.
The problem arose due to the gradual subsidence of the turbine unit's foundation. The position of the equipment is also affected by temperature and vibration loads. As a result, the axial clearances of the turbine's flow path change. The permissible deviation is only ±1 mm.
The idea of using a compensating insert came to me, but we implemented it together with colleagues from the centralized repair shop.
If the clearance goes beyond the norm, rotating parts can touch stationary elements during start-up or shutdown of the power unit. Previously, restoration required up to two months, and at the Rostov NPP, they wanted to meet the standard 30-day scheduled preventive maintenance.
Engineers proposed installing a compensating insert with extended fasteners between the flanges. This allowed the shaft line to be returned to its design position without modifying the turbine casing.
As a result, the operation took 12 days — three times less than the minimum previous period. At the same time, labor intensity decreased by 9 times, and the power unit's scheduled preventive maintenance was completed ahead of schedule.