New light on the Koeberg saga

As SA hobbles along in its darkness at noon, talk about problems at Koeberg is probably not what the country wanted to hear.

The power station’s unit 1 was shut down on September 3 to fix a problem with one of the control rod mechanisms.

The control rods, along with a “moderator” such as water or graphite rods, control the rate of fission in the reactor’s core and thus its output.

Lowering the rods into the core reduces the nuclear reaction; pulling them partly out allows the reactor to run hotter.

The rods are critical for “keeping the fission chain reaction active and preventing it from accelerating beyond control”, notes the Southern African Radiation Protection Association.

Eskom’s admission, then, of a problem with the mechanism was bound to put Koeberg in the spotlight again — something that the utility would likely rather avoid.

The plant, whose operating licence expires in July 2024, is in the middle of a controversial R20bn refurbishment — money that its detractors say could be better spent on renewable energy such as solar or wind.

At a briefing on the state of the system, Eskom CEO André de Ruyter pointed out that “this kind of issue” was quite common, following replacement of the control-rod drive mechanisms, which in unit 2’s case had been done during the recent maintenance outage.

Meanwhile, Eskom and Framatome, the original manufacturer, were analysing test data so that the reason for the problem could be “fully understood”.

Koeberg will never be Chernobyl. The Ukrainian power station had a different type of reactor that was also not protected by a 1m-thick concrete encasement as Koeberg’s is.

The only fallout from Koeberg is the controversy around keeping it going. Until the lights go off, of course.

*This article was amended on Saturday to reflect the difference between Koeberg and Chernobyl.