Prolongation of the operation life of reactor

housings and 1st circuit equipment

  Prolongation of the operation life of reactor shells, equipment and pipelines of the first and second contours after the expiration of the project lifetime based on a complex of works on revision of design bases and a reassessment of the safety of power units.

  Works include:

  • compilation and analysis of technical documentation (design documentation, documentation of the manufacturer, the passport to the elements of equipment and pipelines)

  • analysis of operating conditions

  • state of the metal inspection results analysis (Pre-operational, periodic and top priority);

  • Identification and analysis of failure modes, causes and mechanisms of failure appearance and development;

  • Establishment of the causes and mechanisms of aging.

  • Establishment of parameters and criteria of technical conditions;

  • Development and approving of Work programs for technical condition evaluation (TCE) and justification of the lifetime prolongation possibility (JLP).

  • technical conditions examinations and additional tests of elements material and processing of the results;

  • thermo-hydraulic parameters calculation at transient processes and real loading cycles analysis with the forming of calculation modes;

  • Static, brittle and cyclic strength calculations and seismic vibrations analysis for considered elements of the reactor taking into account their real geometry, loading parameters, including the calculated forces from the connected pipings and thermo-hydraulic parameters at transient processes.

  • estimation of the technical conditions of the equipment elements and pipelines;

  • recommendations development for aging management to ensure safety and reliable operation at beyond design operational period;

  • justification of the lifetime prolongation possibility and establishment of the new reassignment operation period.

 Computational justification of the safe operation is based on thermo-hydraulic and probabilistic calculations, static, cyclic, brittle and seismic strength calculations.

 

  Thermo-hydraulic and probabilistic calculations were performed in order to obtain boundary conditions for the reactor parts strength calculations. These calculations are required for estimation of the safe operation period of the reactor parts to ensure their integrity in terms of resistance to brittle failure (deterministic and probabilistic estimations) and cyclic loads analysis (deterministic calculations).

 Works were performed for the following equipment:

  • main circuit pipelines, main circuit valves, injection and breathing pipelines of Pressurizer, reactor coolant pumps and steam generators of the Unit 1 of South Ukraine NPP;

  • reactor structures (RPV, PVI, reactor supports, upper block with reactor cover) of Unit 2 of South Ukraine NPP and Units 1 and 2 of Zaporizhia NPP;

  • main circuit pipelines, tanks and pipelines of ECCS, pipelines of Pressurizer, bubbling tank, reactor coolant pumps and steam generators of the Units 1 and 2 of Zaporizhia NPP;

  • reactor structures (RPV, PVI, upper block with reactor cover) of Units 3 and 4 of Zaporizhia NPP;

  • main circuit pipelines, tanks and pipelines of ECCS, pipelines of Pressurizer, bubbling tank, reactor coolant pumps and steam generators of the Unit 1 of Khmelnitskiy NPP.

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