Project for optimization of maintenance and repairs of systems important to safety, based on risk-informed management of NPP configuration

The installed capacity utilization factor (ICUF) of power units is one of the key indicators of NPP operational efficiency. According to the results of 2019 the average ICUF indicator at power units of NNEGC “Energoatom” is 73%.

Optimization of annual preventive maintenance (outage) will reduce the time of power unit shutdown and increase the volume of electricity generation. Modern risk-informed approaches can reduce the period of annual outages and increase ICUF.

The average current ICUF at US nuclear power plants is 94%.

At power unit No. 2 of ZNPP, NT-Engineering, in collaboration with NNEGC “Energoatom”, is completing a pilot project for optimization of maintenance and repairs of systems important to safety based on risk-informed management of nuclear power units’ configuration. The project is implemented on the basis of consolidated experience of American NPPs with the support of the US Department of Energy (DoE) and the Argonne National Laboratory (ANL).

The purpose of the pilot Project is to increase the installed capacity utilization factor (ICUF) due to:

  • optimization of outages;
  • execution of separate repair works, tests during reactor facility operation at power;
  • introduction of risk-informed approaches to maintenance and repair optimization.

The Project was performed in three directions, which were implemented in parallel and interconnected:

  • regulatory aspects;
  • probabilistic safety analysis;
  • regulations and repairs.

According to the analysis performed by NT-Engineering specialists, for outage-2019 at power unit No. 2 of ZNPP, it is possible to reduce the duration of repair work by 22 days by postponing part of repair work from the period of outage to the period of operation at power. Reducing the duration of outage by 22 days allows increasing the annual volume of electricity generation and, accordingly, increasing the ICUF of power unit.

The implementation of the pilot Project and industrial application of its results allows to increase the economic indicators of the power unit without reducing the achieved safety level, to obtain information on the current risk level based on the current values of CDF (core damage frequency) and LERF (large early release frequency) safety indicators, to immediately assess the impact of decisions on safety, as well as optimally plan repair work.

The materials of the Project have been developed in full, in due time and in accordance with the current requirements of nuclear and radiation safety of Ukraine, which is confirmed by the Customer’s positive response.

Customer’s positive response