Nuclear Energy ~ The 'Pro' Position
Author: Ayanda Myoli - CEO, Nuclear Industry Association of South Africa (NIASA)
( Article Type: Opinion )
It was all much simpler forty years ago. If more power was needed, Eskom contacted the mining organisations, located a coalfield containing half a billion tons of coal or rather more, and built another power station. South Africa enjoyed the cheapest electricity in the world.
The situation has rapidly become more complicated. It is no longer acceptable to plan to burn hundreds of millions of tons of coal. The Department of Energy, having assumed the planning role, must now choose between a range of generation technologies, none of them without its own specific challenges. Burning oil and gas is somewhat less objectionable environmentally than burning coal, but only somewhat. Oil and gas are in any case finite resources that will become progressively more expensive. Viewed through the eyes of our descendants, they are too valuable as chemical feedstock to burn.
South Africa has minimal domestic hydro power but does have the long-term possibility of importing from countries to the north, politics permitting. Wind and solar power are developing quickly elsewhere and are expected to make a substantial contribution to South Africa’s energy mix. The fact that both are intermittent does, however, justify backup support from other suitable base-load sources. Nuclear power is a suitable base-load source, and is well established having provided up to 17% of world electricity for more than twenty-five years. Geothermal energy and energy derived from biomass may be feasible but are unlikely to become major players. Power derived in various ways from the ocean is conceivable but the various technologies are in their infancy.
Despite the complexity, the initial planning work has been done and the electrical energy plan for South Africa has been determined by the Department of Energy in the ‘Integrated Resource Plan 2010’ gazetted in May 2011. The Plan envisages that, despite essential efforts to economise, electricity consumption will rise from 260 TWh (terrawatthours) in 2010 to 454 TWh in 2030. The envisaged energy mix in terms of installed capacity and share of energy generated by 2030 will then be as follows:
Energy source Installed capacity, MW Share of energy
generated
Coal 41 071 65%
Open circuit gas turbine 7 330 <1%
Combined cycle gas turbine 2 370 1%
Pumped storage 2 912
Nuclear 11 400 20%
Hydropower 4 759 5%
Wind 9 200
Concentrated solar power 1 200 9% combined
Photovoltaic solar power 8 400
Other 890 Not stated
IRP2010 is to be revisited every two years and doubtless revised as the world energy scene unfolds. The debate concerning the optimal energy mix will continue. The nuclear component of 11 400 MWe (1800 MWe existing at Koeberg and 9 600 MWe new nuclear capacity),
appears to be the maximum that the IRP Committee believes can be installed by 2030. The 9 600 MWe of new nuclear capacity represents between six and nine reactors (depending on the type selected) on three or four nuclear sites. The case for maintaining this figure (if not increasing it), is the Case for Nuclear Energy, which is based on the following:
• Demand for energy, especially electrical energy, will rise. The country will need all the environmentally acceptable and affordably priced energy that is available.
• Burning fossil fuels will become increasingly costly and politically unacceptable and must be minimised.
• Renewable energy is intermittent and must be backed by conventional base-load power sources.
• Nuclear generation is internationally well-proven and can in principle provide all the electrical energy needed.
• Nuclear safety, waste disposal and other issues associated with nuclear generation are manageable.
• Nuclear generation is still at an early stage of development and can potentially provide power for thousands of years.
NUCLEAR GENERATION WELL PROVEN
Significant nuclear electricity was first generated when the EBR-1 (Experimental Breeder Reactor 1) famously lit up four light bulbs in Idaho in 1951. The Russians followed with 5 MW from the prototype RBMK reactor at Obninsk in 1954. Britain followed two years after that with the first of four 50 MW reactors at Calder Hall and then America in 1957, with the 60 MW shore-based naval reactor at Shippingport. It is convenient to define these earliest reactors as Generation I designs. Generation II designs, such as the two pressurised water reactors at Koeberg, evolved from them and now constitute approximately 80% of some 430 ‘workhorse’ reactors generating 14% of the world’s electricity. Many of the Generation II reactors in operation, including the two reactors at Koeberg, have over the years been upgraded to keep their designs aligned to modern safety standards and thus are now closer to Generation III designs. Generation III reactors are now operating in Japan and Generation III+ units with more passive safety (as opposed to engineered safety) features built in are under construction in Finland, France and China. Generation IV reactors may well look radically different and will embody major improvements in efficient fuel utilisation, inherent safety, proliferation resistance and waste minimisation. Such reactors are being developed for deployment in about 2030. The world’s nuclear fleet is working well. Nuclear generation can be considered well proven, well able to meet the South African IRP2010 requirement, and having great scope for development far into the future.
NUCLEAR SAFETY
Organisations such as the Paul Scherer Institute in Switzerland document the numbers of deaths associated with accidents in the different forms of energy generation. They make it clear that over the past few decades nuclear generation has been by far the safest technology, Chernobyl data (OECD/NEA Report 978-92-64-99122-4). Since then we have experienced Fukushima. Three men on site were killed by the tsunami. There were no deaths attributable to radiation. Some recovery workers were exposed to radiation which may increase their risk of developing cancer in later life. Nuclear technology is evolving and is still in the early stages. Three Mile Island 2 was an early Generation II reactor. No one, either on or off-site was harmed, but the accident taught numerous lessons concerning plant design, the analysis of potential accidents, operator training and emergency response. These lessons were incorporated into Generation II reactors now operating, the Generation III reactors already operating in Japan and into post-Chernobyl reactors of the so-called Generation III+ designs which are now being built in Finland, France and China. Fukushima has taught further lessons, not least the importance of protection against flooding and of absolutely secure back-up power supplies. Where necessary, appropriate modifications will be back-fitted into existing operating reactors and incorporated into Generation III+ and Generation IV systems now on the drawing board.
RADIOACTIVE WASTE
The nuclear reactors of Koeberg (and similar) power stations consist of 157 uranium fuel assemblies. About fifty highly radioactive used fuel assemblies are discharged from each reactor every eighteen months or so. After storage under water for around four years, these used fuel assemblies can be stored indefinitely in dry casks either at the power station site or in special facilities. Their heat generation continues at a gradually diminishing rate for forty or fifty years before they can be compacted and finally disposed of as waste. Other than for public relations reasons there is no need to rush to locate spent fuel disposal sites. The French propose to commission their first high level waste repository in 2025, the British in 2029.
Each used fuel assembly contains several kilograms of plutonium, itself a highly valuable source of energy, as well as unused uranium. Several countries including the UK, France, Russia and Japan are now chemically ‘reprocessing’ used fuel to recover this material. The residual radioactive waste is ‘vitrified’, i.e. mixed with molten glass which then solidifies, and sealed inside corrosion resistant containers, before being placed into tunnels in carefully selected rock formations, or in clay or salt deposits. These containers of radioactive waste would be retrievable should the need arise. There will be no threat to future generations. Radioactivity diminishes with time, in contrast to the toxicity of poisonous materials produced by industry in great quantities every day. Similarly, the transport of low and intermediate waste to Vaalputs in the Namaqualand and its disposal there constitute no threat whatsoever to the local population.
RADIOACTIVE EFFLUENTS
A point is reached at which it makes no sense to further reduce the radioactive content of effluent routinely discharged into the ocean and into the atmosphere. Accordingly, minute carefully controlled quantities of radioactive materials are released by nuclear power stations and other facilities. The resultant exposure of the surrounding population is too small to measure and must be calculated from the known effluent releases. At Koeberg, the maximum calculated exposure has always been less than 25 microsieverts per year (μSv/y). This should be compared with the agreed internationally allowed limit for the general public of 1000 μSv/y, the South African limit of 250 μSv/y and our inescapable natural background level of about 2400 μSv/y.
From time to time, anti-nuclear organisations announce the discovery of ‘clusters’ of cancer or, more often, childhood leukaemia around and linked to nuclear power stations. These announcements are systematically repudiated by local or national health authorities but with no fanfare and often after a long delay. Clusters are believed to be viral in origin and due to the invasion of rural communities by large numbers of industrial personnel. Recent investigations of thirteen nuclear sites in the UK by the Committee on Medical Aspects of Radiation in the Environment (COMARE) and a similar study in Switzerland have shown no statistically credible evidence of clusters associated with nuclear power stations.
NUCLEAR WEAPONS PROLIFERATION
The nuclear industry takes the proliferation issue very seriously. There are several ways of making weapons-grade fissile material that have no connection with nuclear reactors. The problem therefore extends beyond the nuclear power industry. Government authorities must insist that all countries give IAEA inspectors the right to inspect all facilities. They must then be prepared to take resolute action if any country is considered to be breaking the rules. With reference to nuclear power, the low-enrichment fuel for today’s nuclear power reactors is useless for weapons purposes both as new fuel and after its four years in the reactor. Furthermore, the existence of a civil nuclear programme in a country opens that country to nuclear inspectors and makes the operation of a clandestine nuclear weapons programme less likely.
Safeguarding of plutonium stocks will continue in the nuclear industry. Fuel cycles that ensure that plutonium produced by reprocessing is never refined to weapons grade are under investigation as are fuel cycles involving thorium rather than uranium - since plutonium does not figure in the thorium fuel cycle.
NUCLEAR GENERATION FOR THE FUTURE
Nuclear generation is sometimes presented as a stopgap, and means of bridging the gap between the current reliance on fossil fuels and the second coming of renewables. However, nuclear technology is proven technology which is no mere stopgap. It has the potential to meet all our electrical energy needs for a very long time. French reactors provide over 75% of domestic electricity needs and export to surrounding countries. A standard 1000 MWe reactor needs approximately 200 tons per year of as-mined natural uranium. A 2009 MIT study of the future of nuclear power looked at estimates of world uranium and concluded that there is sufficient readily recoverable uranium for the lifetimes of 1000 such reactors. On the same basis South Africa has enough uranium for at least fifty reactor lifetimes.
Further, breeder reactors have been operating in several countries since EBR-1 lit up its four light bulbs in 1951. Breeder technology can be used to extract sixty times more energy from a given mass of uranium than can the standard fission reactors considered by MIT. More than this, thorium can be converted into fissile uranium 233 and thorium is at least three times more abundant in the Earth’s crust than uranium. Man is an ingenious animal. Breeder reactors based on uranium and thorium will provide fission energy, if we need it, for thousands of years. Meanwhile, research on nuclear fusion continues apace.
With the inclusion of 9 600 MW of nuclear in the country’s electricity plan in terms of IRP2010 the SA government has given its support and commitment to nuclear power, taking into account the lessons learned from Fukushima, as a viable option for low carbon, base-load electricity generation. The SA nuclear program will be one of the largest energy programs ever undertaken in this country, and the government has clearly indicated the importance of industrialization and localization of certain nuclear capabilities. Localization of our nuclear program will have spin-off effects which will include economic development, scientific & industrial development, cost reduction especially for a fleet approach, job creation, R&D etc. The local industry is gearing itself up for the challenge.
