Final test for Koeberg unit 1 before being returned to service

Eskom will be performing a full load rejection test on unit 1 of Koeberg nuclear power station on Saturday. 

The unit, which generates 920MW, has been out of commission since December last year for maintenance. The outage was expected to be for six months. 

Initially, Eskom had promised the unit would be synchronised to the grid by the end of October. 

“The purpose of the full load rejection test is to verify and demonstrate the ability of the unit to supply its auxiliary load and return to steady state conditions after a sudden disconnection from the national grid,” the power utility said. 

This was the final test that needed to be performed after the installation of the new steam generators. 

Eskom said the South African Grid Code (SAGC) required units be tested if modifications were made that could affect their capability to meet the grid code requirements.

“As part of the steam generator replacement project, significant changes (modifications) were made on numerous plant components, including control systems.

“Therefore, in line with SAGC, the response of the unit to a full load rejection incident needs to be tested and verified.” 

Before and in preparation of the full load rejection test, various commissioning tests were performed successfully.

“As a result, Eskom is confident this test will be a success.” 

It said in the unlikely event of the test failing and resulting in a unit trip, the Koeberg team is ready to respond and will work towards safely returning the unit to service as soon as possible. 

Unit 2’s three steam generators are scheduled for replacement during its planned outage, which will start once unit 1’s recommissioning is completed.

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