South Africa’s sole nuclear power station Koeberg, which is located in the Western Cape, marks a major operations milestone today, April 4, which is the thirtieth anniversary of Unit 1 having been connected to the grid.

Eskom, which operates the two-unit plant, calculates that Koeberg has produced 332 490 GWh since April 4, 1984, the equivalent of a yearly supply for about 924 000 middle households, consuming around 1 000 kWh a month.

Construction of the 1 800 MW facility started on July 1, 1976, with Unit 2 eventually entering commercial operations in November of 1985.

But Koeberg’s development also took place during a far different – and much less transparent – era in South Africa’s history, arguably epitomised by the fact that the Dutch-Swiss consortium that was initially selected to build the power station to a boiling water reactor design was unable to close the transaction, owing to growing political opposition to apartheid.

South Africa subsequently turned to the German and the French short-listed tenderers, which had offered pressurised water reactor (PWR) designs. The French consortium of Framatome, Alstom, Spie Batignolles and later Framateg was eventually selected to build a power station based of the PWR technology.

Eskom was, in fact, not the initial driver of the project, with the then Atomic Energy Board having initiated formal investigations into economic aspects of nuclear power in South Africa in 1965, at the request of the then Minister of Mines. The studies were premised on meeting the future electrical demands of an increasingly industrialised Western Cape province.

However, by 1969, it was decided that Eskom should lead the development, since it was already in the business of building and operating power stations.

The State-owned utility stresses that there was never a link between the construction, commissioning and operations of nuclear plant and the development of Pelindaba and South Africa’s nuclear weapons programme. It also says the decision to build an enrichment plant at Pelindaba and beneficiate South Africa’s uranium was also taken before any decisions were made regarding Koeberg.

NATURAL TARGET

Nevertheless, the plant became a natural target for the anti-apartheid movement and, in December 1982, four limpet mines were detonated on what was still then a construction site.

The African National Congress’s armed wing Umkhonto we Sizwe claimed responsibility for the attack, and in 1995, the Mail & Guardian carried a report on how Rodney Wilkinson and his girlfriend, Heather Gray, had carried out the attack. However former Eskom CEO Dr Ian McRae said its investigations also showed up a link to German terror group Baader-Meinhof.

Security was stepped up after the 1982 event and threat assessments continue to be performed by the State Security Agency, with the security plan regularly audited and adjusted.

Following the ‘9/11’ attack on the World Trade Center, in New York, in 2001, Koeberg performed engineering studies to determine the vulnerability of the plant from an airborne attack and Eskom reports that Koeberg is designed to take account of external hazards, “one of which was an aircraft flying into the containment building”.

Still, in 2002, Greenpeace activists penetrated the sea-facing perimeter of the station by entering into the “stilling basin” and climbing up the walls and on to the pump house, which resulted in a further upgrade of the security systems.

SAFETY & WASTE

From a safety perspective, Koeberg, which employs some 1 200 people, has been aligned to the equivalent French nuclear power plants and Eskom says its systems and protocols are currently at a level that the International Atomic Energy Agency recommends for new nuclear power stations.

“Post the Fukushima accident, Eskom undertook a full safety reassessment of Koeberg with respect to the impact of external events and submitted the results to the National Nuclear Regulator (NNR). The NNR concluded that the plant design is sufficiently robust to withstand a similar event to the Fukushima accident.”

But emergency procedures and the emergency preparedness were upgraded and additional mitigating equipment procured. “As part of this process, Eskom is also undertaking a longer-term project to upgrade the plant to further improve the capability to withstand as yet unidentified events.”

Koeberg’s used fuel is another key area of focus. About 2 120 used-fuel elements have been taken out of the reactors and stored in the spent fuel pools at Koeberg.

Low- and intermediate-level radioactive waste, meanwhile, is placed in metal drums and concrete containers, respectively, and disposed of by burial at the Vaalputs National Radioactive Waste Repository, in the Northern Cape.

On loading into the reactor, each fuel element contains about 464 kg of uranium dioxide (UO2), meaning that, over the past three decades, Koeberg has used about 984 t of UO2.

But Eskom stresses that only about 5% of the uranium is actually used, with the remainder left over in the used-fuel element. An equivalent-sized coal-fired power station, it highlights, requires about 15 000 t to 20 000 t of coal daily.

Between 1988 and 1996, uranium conversion, uranium enrichment and fuel fabrication was performed locally by the then Atomic Energy Corporation. But during this period, only one reactor was supplied with locally produced fuel, with the balance fabricated in France.

After the lifting of economic sanctions in the 1990s, a decision was made to close the higher cost domestic fuel production facilities and Eskom currently sources its nuclear fuel from the international market. Enriched uranium is sourced from all three of the world’s major uranium enrichment suppliers, while the fabricated nuclear fuel elements are currently sourced from Areva and Westinghouse.

CURRENT OUTAGE

The plant’s Unit 2 is currently undergoing it twentieth refueling, maintenance and inspection outage, which started on March 24 and is expected to be completed by the second week of May. Eskom says the primary purpose of the outage is to refuel of the reactor, with few modifications planned.

Following the infamous ‘bolt incident’ of 2005, Koeberg has reportedly implemented strict procedures that carefully control the tools and consumables, including bolts, taken into each work area during maintenance activities. “Strict quality control and awareness training for artisans, technicians and supervisors, as well as implementation of the work procedures, are part of the measures taken to avoid repeat events.”

Koeberg’s operational milestone also coincides with what appear to be intensifying efforts around South Africa’s proposed new nuclear build programme, to which President Jacob Zuma again referred in his February State of the Nation address.

Should the procurement eventually proceed, South Africa is likely to again invest in the PWR technology, with the reactors at Koeberg classified as ‘Generation II’ technology and the technology being assessed typically described as ‘Generation III or Generation III+’ technology.

Eskom, which will be the owner operator of any nuclear fleet, says a number of Koeberg lessons will be incorporated into the build programme. “The most important lesson is the development and inculcation of a nuclear safety and security culture,” the utility says.

The critical question facing South Africa, however, is whether to pursue another round of mega-scale power generation projects in light of the troubles faced at Medupi and Kusile, or whether another more incremental approach could have lower engineering and financial risks.

But given South Africa’s climate change commitments and the prospect of Eskom having to retire coal-fired stations in the middle of the next decade there are also strong arguments for new nuclear assets.

Should a decision be made to proceed, the financial package, together with disciplined implementation, will become critical success factors. That said, the experience gained from Koeberg’s 30 years of safe operations, together with the nuclear skills that period of operations has yielded, could prove invaluable.