Unit 4 of Slovakia's Mochovce Nuclear Power Plant Delayed Grid Connection Due to Generator Testing Anomaly

en.Wedoany.com Reported - On October 13, Slovak power company Slovenské elektrárne announced that Unit 4 of the Mochovce Nuclear Power Plant postponed its first grid connection originally scheduled for that day due to a generator testing anomaly. The unit has an installed capacity of 471 MW. During the initial voltage test, an abnormal response occurred in the voltage measurement circuit of the non-nuclear equipment section. The operator decided to re-conduct part of the technical tests and expects to complete the first grid connection in the coming days.

Slovenské elektrárne spokesperson Lenka Šarláková stated that the repeated tests are mainly intended to confirm that the relevant equipment meets technical and quality requirements. The anomaly occurred in the power generation equipment section outside the nuclear island and does not affect nuclear safety. The operator also canceled the first grid connection press event originally scheduled for October 13. The unit is currently continuing its power ascension program and plans to synchronize the turbine generator with the Slovak national grid when reactor power reaches approximately 20%.

Unit 4 of the Mochovce Nuclear Power Plant uses VVER-440/V213 pressurized water reactor technology. On June 29, 2026, the unit began nuclear fuel loading and completed the loading of all 349 fuel assemblies on July 3. At 22:10 on August 6, the reactor reached criticality for the first time, and at 22:31 it reached minimum controlled power. At 15:33 on September 21, after obtaining approval from the Slovak nuclear regulatory authority, the unit entered the power ascension phase, began gradually increasing reactor output power, and conducted verification of system performance and safety functions at different power levels.

According to the commissioning schedule published by the operator, after the first grid connection, the unit will continue to increase power in stages, conduct operational tests on the reactor, turbine generator, and related auxiliary systems, and complete a 144-hour full-power test in the later stage of commissioning. Slovenské elektrárne plans to achieve full commercial operation of Unit 4 by the end of 2026, at which point the unit is expected to meet approximately 13% of Slovakia's electricity consumption demand.

Units 3 and 4 of the Mochovce Nuclear Power Plant belong to the same continuation project, with a total investment of approximately EUR 6.7 billion. Among them, Unit 3 was first connected to the grid on January 31, 2023. According to calculations published by the operator, after Unit 4 is put into operation, nuclear power is expected to cover approximately 77.5% of Slovakia's electricity consumption demand.