South African power utility Eskom has signed ZAR200m ($15.6m) deal with Holtec International for the supply of seven new nuclear waste storage casks for its 2x900MW Koeberg nuclear power plant located about 35km from Cape Town.

The deal forms the first phase of the planned three-phase spent fuel storage upgrade project to support the operations of the Koeberg facility beyond 2018, reported Reuters.

The facility’s existing spent-fuel pools where fuel assemblies containing uranium and plutonium, are stored for decade-long cooling under water, are 70% full.

Eskom spokesman said: "Additional space will be created by moving spent fuel from spent-fuel pools into dry spent-fuel storage casks."

Under the second phase, the company will buy additional 30 to 40 dry storage casks, following which an on-site transient interim storage facility (TISF) will be developed by 2019, in the final phase.

Eskom is palming to transport the dry storage casks from the TISF to the off-site central interim storage facility, which is planned to be developed by 2025.

The Koeberg station, which is estimated to generate about 32t of spent fuel annually, is said to be the only commercial nuclear power plant in Africa.

South Africa intends to have 9,600MW of additional nuclear power generation capacity by 2030, to meet its raising electricity demand.

As part of this effort, the country is seeking final storage options such as recycling high-level waste or storing it deep underground, for the spent fuel.