Execution period 2002 - 2004
Contractor Kozloduy NPP Plc.


The purpose of the task is the development of a technical design for the decrease of the level of vibrations in the foundation of the Turbine Generator 9, as well as measurement and analysis of the vibrations of the foundation of the Turbine Generator 10.

A complex study has been performed on the dynamic behavior, functionality and the strength capacity of the foundations of 1000 MW turbines of Units 5 and 6 of Kozloduy NPP.

The actual condition of the turbine foundation civil structure has been ascertained at the Stage 1. The field data obtained and the conclusions made are used at the next stage in the theoretical (numerical analysis) of the dynamic behavior of the structure.

Field dynamic tests have been performed at the Stage 2 under normal operation conditions and during a transient mode, dynamic and static analysis of the turbine foundation structure, by taking into consideration the results of the examination carried out at the Stage 1. Three types of analyses have been carried out in the analytical study of the turbine foundation:

  • Modal analysis - for determination of the natural frequencies and forms of the structure, and determination of the resonance frequencies of the structure.
  • Dynamic analysis with a harmonic input effect – for determination of the theoretical values of the amplitudes of the vibrations in the places of the bearings of the shaft. Sinusoidal signals with frequencies equal to the resonance ones for the structure have been used as an input effect. The results obtained analytically are compared with the displacement values measured at the field dynamic tests of the turbine foundation.
  • Static analysis - for determination of the structure deformations at temperature impacts, and tensions and exertions in the basic parts of the structure, which are necessary for the strength checks. The displacements obtained by the analytical method have been compared with the data of the geodetic monitoring, which has been carried out in the period of turbine operation.

Based on the conclusions made within the Stages 1 and 2, in the Stage 3, projects have been developed for the following:

1) rehabilitation of the foundation’s firmness;

2) monitoring of the building structure;

3) improvement of the geodetic monitoring;

4) Improvement of the ventilation in the Turbine Hall.

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