NUCLEAR-ENERGY IN SOUTH AFRICA
15 June 2007
(in response to an invitation to the public issued by the Portfolio Committee on Environmental Affairs and Tourism) By J. F. Siebert Pro Eng:Consulting Engineer (ex S. A. Atomic Energy Board, EsKom, and the National Nuclear Corp U.K.)
For the sake of brevity only a summary of the writer's views (the results of 1 5 years of association with the nuclear power industry) follows. Paragraph headings (except the first and last) are those contained in the invitation for submissions.
0.1 Prior to any discussion of the energy mix in
0.2.1 Given that an irreducible minimum of electrical generating capacity is necessary in the country the question remains as to what mix of generating modes (nuclear, coal, gas, solar, hydro etc) should be employed to achieve a minimum cost per
unit with due cognizance being taken of reliability considerations and other objectives and constraints as indicated above. A full multi-objective optimisation analysis is needed to provide an answer; in the meantime it remains essential to ensure the inclusion of all germane considerations in such a definitive study.
0.3 Even the above formulation of the problem is inadequate if one takes into account the fact that electricity is hardly the only form of exploitable energy; use of the former to provide heat is in fact thermodynamically inefficient and the direct use of nuclear energy in devices such as desalination plants, or urban district heating schemes must also be considered.
0.4 Africa is the least developed of the 5 continents and the opportunity (or duty!) exists for S Africa to guide it into a pattern of energy consumption appropriate to the novel lifestyles that (particularly) African populations will need to adopt in a century that will see critical shortages of fuels, water and other resources. Africa's greatest energy assets are its potential for hydro-electric generation and solar power (both renewable) and it would be unconscionable were these not fully exploited before turning to more problematic technologies (see Paras 2 and 3) especially in view of the limited capital available for energy investment.
0.5 Most fundamental to long-term energy-planning is an examination of the desirability (let alone possibility) of never-ending economic development and the holding out by politicians to voters of democratically constituted countries the prospect of U.S-style consumption patterns. Curtailment of these expectations and acceptance of more modest material circumstances (which do not imply less fulfilled lives) would radically influence energy forecasts.
1 SOCIO-ECONOMIC IMPLICATIONS OF NUCLEAR POWER
1.1 The socio-economic implications of nuclear-generated electrical power (to be specific) would clearly be conditioned by the extent of the 'roll-out' of any program and whether or not it was additional to, or a substitute for an alternative-program of coal-fired generating capacity possibly incorporating clean coal technology or C02 sequestration. Arguably employment opportunities would be unaffected, as (for example) a reduction in coal-mining activities supporting the latter would be offset by an expansion in uranium mining and processing. Indeed as an exporter of 'yellowcake' the possibility of S Africa's 'adding value' to raw U308 by establishing significant facilities for its conversion to gaseous form (UF6) , and even enrichment (see later) are not beyond the bounds of possibility. (Such a scenario was examined in the 1970's with the manufacture of fuel assemblies under license the final goal)
1.2 Historically the capital cost of a nuclear power station has been 30-40% higher than that of a coal-fired equivalent although how this relationship may change with the fitting of C02-reducing measures is unclear. Whether these will become mandatory under some successor to the Kyoto Treaty on greenhouse gases is open to question; certainly
1.3 In most countries where nuclear power is a real possibility, resistance to it appears to be diminishing, no doubt in the face of the perceived greater threat of global warming and the fact that no major nuclear incidents have occurred over the last 20 or so years. As the number of nuclear power plants world-wide increases and those now in operation age the chance of another major accident becomes statistically likely; with unpredictable effects on public opinion.
2. WASTE MANAGEMENT
2.1 Waste management remains the chief obstacle to the general acceptability of nuclear power by virtue of the malign properties of long-lived fission products produced in nuclear reactors. Consequent dangers are two-fold: (1) accidental discharge through natural processes-(eg"eaTthquake, diffusion processes) into potable water suppli~S"or the food chain; (2) dispersion ofthe waste into the environment by terrorist activity using various methods.
2.2 While in principle the waste management problem may be solvable through rigorous administrative controls supervised by bodies such as the IAEA , their effective implementation would be highly vulnerable to the well-known tendency of the taxpaying public to be unsympathetic to long-term government spending on projects with little tangible benefit. This phenomenon is already evident in
2.3 Waste management difficulties are magnified enormously if mixed oxide fuel is used in reactors. The manufacture of the fuel containing a mixture of plutonium and uranium oxides involves the 'reprocessing" of spent uranium fuel assemblies and is a notoriously 'dirty' operation giving rise to copious quantities of high-level waste. Yet in the light of a potential shortage of natural uranium it is often seen as desirable by energy economists, and even a partial solution of the waste management problem.
2.4 The decommissioning of obsolete nuclear power stations which may be seen as another aspect of waste management represents a further often neglected and unknown nuclear power cost.
3 SECURITY OF SUPPLY
3.1 Natural uranium (U308) is widely available (
the total uranium content; since most power reactors operate using a U235 concentration of about 2% or more, 'enrichment' of natural uranium to that level is required. This process (in any of its various forms) is energy intensive, and politically contentious in view of its place in the chain leading to the manufacture of nuclear weaponry. Security of supply of uranium fuel for possible S. African nuclear power stations therefore hinges on the further development of the Nuclear Non-Proliferation Treaty and whatever international regime may be constructed to deal with the enrichment requirements of individual countries. Prospects are not hopeful in a world in which disruption of energy supplies is now a standard diplomatic ploy.
4. HUMAN RESOURCE DEVELOPMENT
4.1 While nuclear power exemplifies high technology, this is mainly in the design and fabrication of critical components (pressure vessels, reactor internals etc) Such activities (in the case of large 'Koeberg-type stations) would more likely than not be performed outside of S Africa by non~South African engineers. Even in the case of the Pebble-bed Reactor (PMBR) only a small cadre of South Africans need be directly involved in view of the international nature of the project (but see Para 5) and the global nature of any engineering contractor competent enough to undertake sophisticated metallurgical and forming processes. On the other hand it is possible that in view of its foundational role in PMBR technology South Africa could in the event of the technology being widely adopted become the specialist supplier of certain components (as has already happened to some extent in the aerospace and automotive sectors)
4.2 At the moment there are (to the writer's knowledge) no South African tertiary institutions offering courses on nuclear power. This is an omission that under any circumstances should be rectified on an appropriate scale. As things are a worldwide shortage of engineering skills is proving to be a constraint in the expansion of all forms of energy infrastructure.
5 SCIENCE AND TECHNOLOGICAL IMPLICATIONS
There is no doubt that the announcement of a program of nuclear expansion including some PBMR-driven generating capacity would be a major stimulant to scientific research and development in S Africa; less so if the program were exclusively based on large 'Koeberg-type' PWR reactors of 900 Mwe or so, purchased 'off the shelf' from overseas vendors. The R+D necessary to develop a small but efficient 'African' PMBR could mesh well with S African capabilities (but see 4.2)
Nuclear power should not be adopted on a massive scale until the full potential of hydro-and solar-generation in the subcontinent (taking into account climate change) has been explored, and utilized. Tax concessions etc should be immediately introduced to encourage the use of the latter especially for purposes such as space and water heating. Two 'Koeberg-type' nuclear stations (900 Mwe per reactor) should be ordered by EsKom , as well as two PBMR stations of 250Mwe each, financed by international capital. These would have the effect of both providing power to the national grid as well as cultivating a core of relevant expertise. Methods of using the waste heat from such stations should be explored. Demand-side management should be used (for example the introduction of off-peak domestic tariffs) to limit peak power offtake,
To cover any shortfall between this figure (plus some minimum reserve capacity) and total available generating capacity (including the nuclear, hydro and solar components mentioned above) a number of coal-fired and/or high-efficiency combined cycle stations should be also be included in EsKom expansion plans