Parliament - A British nuclear economist on Tuesday warned Parliament that the government was "ridiculously optimistic" about the potential cost of its nuclear power programme expansion.
"The government seems to have a history of assuming that things will go much better with nuclear power than they actually do," Stephen Thomas of Greenwich University told the standing committee on finance.
"The result is that South Africa has now embarked, this is the third time, on a nuclear programme on the basis of cost estimates that even before the programme has started appear ridiculously optimistic."
National Treasury has allocated R300bn for six new reactors to produce 9600 megawatt of nuclear power. The details of the plan are not known and experts are sceptical this sum will be sufficient.
Thomas said in the past decade the projected cost of nuclear construction had gone up sevenfold, to about 7000 US per kilowatt hour capacity of the plant.
"If a call for tenders is held next year I would be amazed if the figure that you receive is anything less than 7000 US per kilowatt."
Asked by MPs how this translated into the local currency, Thomas said it roughly meant building a nuclear reactor would cost at least R80bn.
He said this meant future generations would be saddled with debt with no clear provision to pay for it.
Thomas said the Integrated Resource Plan 10 made provision for new nuclear reactors with 92% reliability over time, but compared to international averages "that seems an inordinately optimistic assumption".
"Nuclear is the most risky option because in terms of its historic record very few nuclear plants are built to time and to cost, and a very large proportion of them don't operate as reliably as they are expected to."
Earthlife Africa project co-ordinator Tristen Taylor told MPs he would urge them not to approve financing for new nuclear plants without proper costing because it would violate the Constitution.
"Nobody knows what the nuclear programme will cost. It is simply an unknown factor. You have certain obligation in terms of the Constitution and the use of citizens' money. Essentially what it means is that Parliament cannot approve this expenditure."
Taylor said a nuclear tender process raised the spectre of large-scale corruption and proposed that if the government went ahead with it, tender documents be posted on the internet to ensure transparency.
In 2007, Eskom invited tenders for conventional light-water nuclear reactors, but following bids from Areva and Westinghouse, it shelved its plans for lack of funding.
The updated National Development Plan released in August called on the government to rethink its renewed plans to expand the nuclear fleet, warning it could prove too expensive and difficult to finance.