Mochovce power output to grow from 942 to 1000 megawatts

Mochovce power output to grow from 942 to 1000 megawatts
Efficiency projects at Unit 1 and 2 should increase production by 450 gigawatt-hours per year, without higher fuel or personnel costs.

On 15 August, Slovenské elektrárne shut down one of the two turbine generators at Mochovce NPP Unit 2, and after it cooled down, the Company started to dismantle the high-pressure and low-pressure parts of the turbine on Monday, 17 August. This kicked off the most important part of the large and demanding modernization project to increase the nuclear power plant units’ efficiency.

The work shall result in approximately seven percent increase in the electrical power of both operating Mochovce NPP units – from 471 MWe to 500 MWe. Combined, the output will grow from 942 to 1000 MWe.

First, Slovenské elektrárne will increase the output of Mochovce 2, which shall supply more electricity to the grid from November. In the spring of 2021, the project will also be completed at the Mochovce 1.

Extensive modernization

Complete high-pressure part and flow sections of low-pressure parts will be replaced at both turbines at Mochovce 2 with modified and more efficient ones. Turbine oil regulation and control will also be changed due to the electronic turbine regulator replacement.

This will be related to the overhaul of valves, fittings, flaps around turbines, replacement of moisture separators upstream of turbines and feedwater nozzles, replacement of current and 15.75 kV voltage converters behind generators. The replacement will continue with 400 kV unit transformers and other works in electric and I&C system.

Similar modifications were done by Slovenske elektrarne at the Bohunice V2 Nuclear Power Plant, where electrical output was increased in 2010. Completion of the efficiency increase project at both Mochovce units should bring up to 450 GWh generated annually, without risen fuel costs, personnel costs and with reduced maintenance costs in coming years.

„The turbine's output at a cooling water temperature of 21.5 ºC will be 250.72 MWe, but the current technology enables even further increase in the unit's efficiency. Once the turbines are modernised, we will perform warranty measurements, which will show us potential reserves for further possible increase in the output of the secondary circuit equipment – particularly separators, high-pressure and low-pressure heaters. Service life of the turbines after their modernization will be 40 years.“

Martin Mráz
Mochovce NPP Director