Friday, 20 October 2023: Over the past few days many residents close to Koeberg Power Station might have noticed steam rising from the power station on some occasions. For the workers at Koeberg this is good news as it is an indication that the outage for Unit 1 is almost over. The steam generators on Unit 1 have been successfully replaced and the unit is expected to be synchronised to the grid by the end of October 2023. Thereafter, the unit will start supplying electricity to the national grid, however the output will be ramped up to full power over a period of two weeks, while commissioning tests are performed. This marks another milestone on the Eskom’s Generation Operational Recovery Plan which is aimed at sustainably improving generation performance by improving the energy availability factor to an average of 65% by March 2024.
Although it experienced some delays, the process of returning Unit 1 to service is intentionally thorough, as it is essential to ensure all the safety systems are functioning correctly and that the unit is ready to operate reliably for the duration of the upcoming cycle. Currently the water in the reactor circuit, which includes the three steam generators, has been increased to its operating pressure and temperature (155bar and 300degrees Celsius). The process required numerous tests of the safety systems, with more tests still to be performed before and after the start-up of the nuclear reaction. The completion of the commissioning tests will end a long but safe, steam generator replacement journey and signal the return of Unit 1 to commercial operation.
The three steam generators on Unit 2 are scheduled for replacement in the upcoming Unit 2 outage, which will start once the Unit 1 commissioning is complete. Although this outage start date has been shifted to mid-November 2023, the Koeberg team together with the main contractor and their sub-contractors are using the experience gained from the installation on Unit 1 to reduce the outage period required to replace the steam generators on Unit 2.
The replacement of the steam generators was identified in the licence application for long term operation of Koeberg that was submitted to the National Nuclear Regulator (NNR), as being a prerequisite for the station to operate safely beyond its original licenced operating period of 40 years (beyond 2024). The completion of this long and challenging outage on Unit 1 through the commitment, sacrifice and hard work of all the Eskom employees, contractors, partners, and suppliers is a huge milestone in the process of extending the life of Koeberg and a positive development in the execution of Eskom’s Generation Operational Recovery Programme. Hopefully, should the NNR award the licences to Koeberg to operate beyond 2024, the station will continue to operate safely and reliably for another 20 years, as it has been the case for the last 39 years. This is recently demonstrated by Unit 2 good performance while Unit 1 was on long outage.