South Africa 's state-owned power company said Tuesday it will suspend a unit at its nuclear power station near Cape Town because of higher-than-normal levels of radioactivity.

The radioactivity level in Koeberg Unit 1's primary coolant circuit is the result of one or more defective fuel rods in the reactor, Eskom Holdings Ltd. said in a statement.

The unit will shut down Sunday to find and replace the rod, resulting in an outage of about one month, it said.

Eskom generates and distributes almost 95% of the country's electricity, primarily from coal-fired power stations. It said the second unit at the Koeberg plant will operate at full capacity while the other unit is halted, but it said consumers should conserve electricity.

"There is no safety risk to the staff or the public arising from these higher than normal radioactivity levels," Eskom said, adding water is isolated from the environment.

Eskom is in the middle of a multi billion dollar expansion of its generating capacity to meet rising demand for electricity.