Barré, who is also scientific advisor to French nuclear-technology group Areva, which was vying with Westinghouse, of the US, to build the latest version of its pressure water reactor (PWR) in South Africa, said that the PBMR's main draw-back was its "very low power density". This translated into a lower power output for the same material mass, as would be the case with the third-generation PWRs.

The PBMR, known generically as a high-temperature reactor, had a power density, according to Barré, of only 2 MW/m3, as compared to 100 MW/m3 for a conventional reactor, which also implied a far poorer investment-to-energy ratio.

This drawback could potentially be offset, however, if nuclear regulators took into account the PBMR's intrinsic safety, which would materially lower the capital expenditure associated with the intensive safeguards that are required when building any nuclear facility.

"So the regulator could say: ‘Given that a [core meltdown] cannot happen, we can eliminate the safeguards'," Barré argued, asserting that, should such an evolution occur, it would considerably improve the competitive position of the high-temperature reactor, which has been dubbed by some as a fourth-generation reactor.

He warned, though, that if the same standards were applied to PBMR, the technology would "probably not be competitive".

"So the question is still open, which is why it is important for a prototype to be operated so that there is more certainty. At present, it is simply paper studies and we cannot use these to make any economic assumptions," Barré elaborated, noting that he had had direct involvement with some of the early-generation high-temperature reactors, which he said could not be compared to the PBMR, which had been significantly advanced.

PROCESS HEAT POTENTIAL

Where Barré did see a potential niche for the high-temperature reactors, though, was in the production of synthetic fuels and cogeneration, particularly if it could reach temperatures as high as 1 000 degrees Celsius.

"Then the new applications are possible in hydrogen, synfuels and others. In that case, the PBMR will not be a competitor with a conventional reactor. But if it is only to make electricity, then you are in a competitive market and you will have to compete with the other technologies [on its cost per kilowatt hour]," he added.

But in the context of process heat and the production of synthetic fuels Barré was more optimistic, suggesting it could allow nuclear to play a far larger role in the production of transportation fuels, a position from which nuclear industry is currently absent.

Process heat is the high-temperature heat essential to permit many industrial processes and chemical processes and has, hitherto, mostly been generated using fossil fuels.

"In the world today, 97% of the energy used for transportation comes from oil. So any dent in this will be very valuable. For me, high-temperature reactors could be linked to cogeneration and synfuels," he asserted.

This niche has also not escaped the attention of the PBMR Company, which now had has a real chance of being demonstrated, in a process-heat application, in the US.

CEO Jaco Kriek revealed recently that it was at a point where it could potentially tender for a public-private partnership in North America, where the technology could be demonstrated for process heat.

However, he cautioned that PBMR would not be the only technology under consideration, with the US Department of Energy likely to probe various options.

The big thrust, however, was for the State-owned technology-development company to begin construction of a demonstration reactor alongside the existing Koeberg nuclear site in 2010. It hoped to load fuel in 2013 and begin reactor start-up in 2014.

The company was also hoping to bring on board new private-sector partners over the next few months as the National Treasury shows signs of funding fatigue - at present, the shareholders include the South African government, the State-owned Industrial Development Corporation, Eskom and Westinghouse.