THE SOCIO-ECONOMIC, WASTE MANAGEMENT AND SECURITY OF
SUPPLY, HUMAN RESOURCE. DEVELOPMENT AS WELL AS SCIENCE. AND TECHNOLOGIAL
IMPLICATIONS OF NUCLEAR ENERGY IN SOUTH AFRICA
Paper submitted by Pebble Bed Modular Reactor (Pty) Ltd to the Portfolio Committee .on Environmental Affairs and Tourism as input for a Public Hearing held on 20 June 2007
Global energy demand, which is governed by population growth and increase in standards of living, is presently growing at about 2% per annum. The electricity component of demand is increasing more rapidly than the overall energy growth and is projected to increase by some 70% between 2000 and 2020, almost two-thirds of which will be from developing countries.
Currently, about 2 billion people have no access to electricity. Most electricity in the world is generated in coal-fired power stations (39%) followed by hydro (19%), nuclear (16%), gas (15%) and oil (10%). Apart from hydro-based power generation, renewable sources of electricity such as wind, solar, tidal, geothermal and biomass are intrinsically or economically not yet suitable or feasible for large-scale power generation where continuous, reliable supply is needed. These sources will have most appeal where demand is for small-scale, intermittent supply of electricity.
The World Nuclear Association lists 435 nuclear power plants in operation worldwide. About 30 more are under construction, over 60 power reactors with a total net capacity of nearly 70,000MWe are planned and over 150 more are proposed. Civil nuclear power has accumulated more than 11 000 reactor years of operational experience to date.
There is as much electricity generated by nuclear power today as from all sources worldwide in 1960. Nuclear power is increasingly being regarded as an important component of the energy mix in countries as part of their strategies to combat global warming and meet their Kyoto Protocol commitments for reduction in C02 emissions. The revival of nuclear power expectations is also reflected in the world uranium price, which increased from $10/lb in 2001 to the present $135/lb.
South Africa presently has approximately about 39 000 MWe local generating capacity, 87% of which is coal based and 5% nuclear. The projected future electricity demand indicates that this capacity will have to double over the next twenty years to keep up with growing demand. According to the South African Energy Policy and various statements by government, nuclear power must be retained as part of the energy mix and the relative contribution should even be increased.
Mention was further made of the planned establishment of a nuclear power export industry based on Pebble Bed Modular Reactor (PBMR) technology. Sustainable implementation of these expectations will require a review of, and coordinated RSA national strategy for, all the components of the nuclear fuel cycle, particularly in view of the major changes and downscaling within certain areas of the nuclear industry over the past 15 years.
The potential contribution of nuclear power to future electricity generation in South Africa should be viewed against the background of the sustainability of present plant as well as the anticipated growth in demand.
Assuming that the replacement of the existing 39 000 MWe does not include any additional nuclear plant, it can be seen that the stated objective of 4 000 MWe PBMR plant within 20 years (24 PBMR modules) would comprise only 5% of the anticipated 80000 MWe demand by then. This growth scenario would further allow all nuclear plants to be located at coastal sites, thus avoiding the high transmission premiums for delivering Highveld coal power to coastal regions.
This document presents information on the status and expected future developments in the various components of the fuel cycle in South Africa. It was generated as an input to the formulation of national strategy and policy making for the future deployment of additional nuclear power in South Africa.
The PBMR reactor is a helium-cooled, graphite moderated HTR which uses carbon and silicon carbide coated particles of enriched uranium enclosed in graphite to form a pebble or sphere as fuel. Helium is used both as the coolant and energy transfer medium. PBMR technology was initially developed in Germany, where two PBMR-type demonstration reactors operated successfully between 1965 and 1989. The PBMR project in South Africa was launched .in 1993 after Eskom acquired a licence from the German developers of the technology.
2.1. Plant Design
The DPP features a helium-cooled pebble bed reactor with a power output of 400 MWt coupled to a closed cycle gas turbine power conversion unit that consists of a power turbine driving a compressor on one shaft end, and the generator on the other as well as a recuperator, a pre-cooler and an intercooler. The main power system utilizes a recuperative Brayton cycle with helium as the working fluid. This differs from the German approach, which used a steam cycle. The rated power output of the DPP is 165 MWe. Reactor inlet and outlet temperatures are < 500 C and 900 C respectively. The DPP will be a single plant module, and PBMR power plants will subsequently be marketed as stand-alone or as multi-module plants, starting with four-module, 660 MWe units. The targeted levelized unit electricity cost for the four-module plant is < $40/MWt.
2.2. Fuel Management
A PBMR core contains nominally 452 000 fuel spheres, each with a diameter of 60 mm and a uranium content of 9 g. Loading of spheres is done online from the top, and spheres are extracted through de-fuelling chutes at the bottom. For initial loading, the core is filled with graphite spheres which are gradually replaced with LEU containing spheres until an equilibrium core, which operates with 9.6% enriched uranium containing spheres, is obtained. During operation, fuel spheres are continually extracted from the bottom and, depending on the burn-up achieved, either reloaded or transferred to the spent fuel tanks. Fuel spheres will traverse the core on average six times over some 900 days before attaining a target discharge burn-up of 92000 MWd/tU. An equilibrium core of a 400 MWt reactor will contain 4.068 t of 9.6% enriched uranium, while the annual requirement for fresh fuel (on average 489 spheres per day) will be 1.6 t of enriched uranium, which can be produced from 30 t to 40 t of natural uranium.
2.3. Safety Features
Several critical safety objectives which are normally achieved in existing commercial power reactors by means of custom engineered active safety systems are already passively and inherently present in PBMR reactors as result of its design, materials used and the physics involved. Some of the critical features include:
· the high radionuclide capability of the coated fuel particles even beyond operational temperatures;
· the large negative temperature coefficient of reactivity which will ensure prompt shutdown upon loss of coolant;
· the effective heat removal capability, which will prevent significant degradation of the fuel and the release of harmful quantities of radioactivity under loss of coolant conditions;
· the high heat capacity of the core.
2.4. Nuclear Material Safeguards
The inherent design and operational characteristics of the reactor also provide certain non-proliferation attributes to the reactor. These include closed system online fuelling and de-fuelling, the storage of all spent fuel in the facility, the sensitivity of the reactivity balance to the introduction of neutron-absorbing material into the core, and the unfavourable isotopic composition of the formed plutonium for the production of nuclear explosives.
2.5. Project status
Since its establishment in 1999, Pebble Bed Modular Reactor (Pty) Ltd has grown into the largest nuclear reactor design team in the world. In addition to the core team of some seven hundred people at the PBMR head-office in Centurion, more than a thousand people at universities, private companies and research institutes are involved with the project. Around the world, scientists and governments are looking to South Africa with great interest to see how the local nuclear reactor developments unfold.
The PBMR team is currently preparing for the building of a commercial scale power reactor project at Koeberg and a fuel plant at Pelindaba. The current schedule is to start construction in 2009 and for the first fuel to be loaded four years later. Construction of the fist commercial PBMR modules are planned to start three years after the first fuel has been loaded into the demonstration reactor.
2.6. Further Development
Further development objectives include the demonstration of PBMR technology for process heat application in the chemical, petrochemical and mineral industries as well as for hydrogen production.
While PBMR's research and development efforts were initially focused mainly on electricity generation, it has become increasingly apparent that the high-temperature, gas-cooled reactor technology will also enable access to markets that call for process heat applications. Next-generation high temperature reactors such as the PBMR can produce hydrogen for transportation or for upgrading coal and heavy crude oils into usable products, thereby relieving pressure on natural gas supply (the source of most hydrogen produced today).
They can also generate process heat for desalination, to extract oil from tar sands, and for many other industrial applications. Capable through its very high temperatures of 900 degrees C, the PBMR technology is ideally placed for these applications. To this end, Sasol is in discussion with PBMR to explore the possibility of replacing its coal-fired boilers with reactors. Sasol has also had preliminary discussions with Government about the potential for PBMR technology and how it can be used in the synfuels industry. It is not inconceivable that such a nuclear heat supply system could be operating by 2015.
In Canada there is interest from companies involved in the oil sands business to use the high temperatures created in PBMRs to create extremely super-heated steam to extract bitumen from oil sands instead of gas-fired plants currently in use.
PBMR is also a partner in a concept design contract with the US Department of Energy, to consider the PBMR technology as future source of hydrogen. The project is still in its pre-conceptual phase, but it could result in the construction of a South African-designed Pebble Bed Modular Reactor in the US before the end of the next decade.
The PBMR technology furthermore has desalination properties. To this end, the Department of Water Affairs has requested PBMR to work on a proposal for utilising the waste heat of the demonstration reactor at Koeberg for desalination purposes.
3. SUPPORTING INDUSTRIES
Deployment of new PBMR-based nuclear power capacity will be dependent on several supporting industries for the supply of materials and components. Whereas the demonstration plant will contain a fairly high percentage of imported materials and components, it is envisaged that the local content of the commercial PBMR reactors will be significantly higher due to the programme's strategy of promoting the establishment of local suppliers where thought economically feasible.
Supporting industries for the supply of enriched uranium for fuel production as well as material and components for reactors such as graphite and graphite structures, turbo machinery, pressure vessels, heat exchangers and main support systems (fuel handling, reactivity control, gas conditioning and inventory control), are of particular relevance. The programme would also require a nuclear waste disposal service for operational waste and spent fuel.
Local supporting industries for the programme will have many benefits, e.g. strategic (particularly with respect to nuclear material supply), job creation, skills development, upliftment of certain industrial sectors, import reduction and export opportunities. Local supply can, of course only be considered if it makes commercial sense. It may, in this respect, be prudent to revisit the reasons for the failure of South Africa's previous ventures into the field of local uranium enrichment and fuel production.
Uranium production in South Africa commenced in 1952 as result of the demand created by international nuclear weapons programmes. Production peaked in 1959 at 5 000 t p.a. U. After a 50% decrease in production, another peak, caused by the energy crisis of the 1970s, at more than 6 000 t p.a. U, followed in 1979. Since then, a sharp drop in demand and prices resulted in less than a 1000 t U currently being produced in South Africa.
More than 95% of the approximately 160 000 t U mined in South Africa thus far was obtained as a by-product of gold from the gold mines of the Witwatersrand-Klerksdorp-Free State area. Uranium production in South Africa is heavily dependent on the future of gold mining, which in turn is governed by prevailing gold prices, exchange rates and production costs. Gold production in South Africa is on the decline, and already fell from 580 t p.a. in 1994 to 342 t in 2004. Some uranium is also recovered from the mine tailings that have been generated over more than 100 years at the gold mines. Although previously associated with the gold mining industry, the Dominion mine near Klerksdorp is now regarded as a primary uranium mine with significant future potential.
There are at least two other uranium deposits of interest which are not associated with gold. One is the Phalaborwa Igneous Complex, from where about 5% of South Africa's total uranium production originated. Uranium production in this case is determined by the copper mining strategy of the mine where it is extracted as a by-product. Another potential area of interest is the Karoo sandstones which have not been mined thus far, but where uranium deposits have been explored in several areas. Results from drilling operations carried out during the 1970s indicated that the resource may contain approximately 100 000 t U in various cost categories.
4.2 Resource estimates
South Africa's uranium resources which can be recovered at a production cost of < $130/kg have been estimated at 298 000 t. That places South Africa's reserves amongst the top four to five countries in the world. Some 60% of these resources are associated with and dependent on gold mining, while the bulk of the rest is in the Karoo sandstones. This figure must, however, be treated with caution, since the published resource estimate of 298 000 t U for 2002 has apparently not been adjusted for increases in production costs for many years.
4.3 Future needs
Uranium production in South Africa is inextricably linked to and determined by the world uranium market prices and the local production of gold. The present upswing in world demand and prices seems sustainable and will most likely stimulate increased production. Total local uranium demand for a South African nuclear energy programme consisting of the Koeberg power station and 30 PBMR reactors would be at most 1 500 t p.a U. This is modest compared to the extraction and processing facilities which have been retained by many mines in operational or mothballed status from times when production was more than 6 000 t p.a.
It seems reasonable to assume that the present level of international uranium prices, which escalated dramatically over the last two years, will result in sufficient South African production to supply the potential future need. A drop in international uranium prices could reduce South African production to below local needs. Low prices, on the other hand, would imply that uranium will be readily available on international markets and therefore also to South Africa.
When considering the security of future local uranium supply to a South African nuclear programme, the relevant question would be whether uranium reserves, in the long term, would be sufficient to guarantee commercially competitive recovery of sufficient uranium for the programme. This is, under present conditions, totally dependent on the future of gold production in the country.
As mentioned above, gold production is on the decline, and the closure of more mines over the next 20 to 30 years seems inevitable. It would, therefore, in the interest of long-term security of supply, be important to find and develop alternative uranium sources which are. not so dependent on gold or other co-products. The Karoo sandstones probably present the most promising area for further exploration and possible future uranium mines. The new focus on the mining of uranium as primary product in the Klerksdorp area by SXR Uranium One as well as uranium recovery from tailings may further contribute towards uranium production which will be less dependent on gold. It is further also important that the uranium resource estimate be updated to allow for production cost increases for the past 10 years.
5. URANIUM CONVERSION
A conversion plant for the production of UF6, the feed material to enrichment plants, from Ammonium Diuranate (ADU) which was supplied by South African mines, was operated by Necsa between 1986 and 2000 as part of its nuclear fuel production programme. The plant had a nameplate capacity of 1 200 t p.a. U as UF6, but production was < 50% of the capacity for most of the operating period. A production rate of 850 t p.a. U was achieved after technical modifications in 1995. Approximately one-third of the almost 6 000 t U as UF6 produced by the plant was used as feed material for uranium enrichment in South Africa, while the rest was exported. The Necsa plant, which included distillation of UF6 as the final purification step, was internationally highly regarded for the purity of its product.
After Necsa terminated its fuel production programme for Koeberg, an attempt was made to retain the conversion plant for the production of UF6 for export. This was not successful due to the high operational cost, and the plant was closed in 2000. The plant is scheduled for decommissioning in future. Certain critical components were already badly corroded at that stage, and are no longer fit for plant use. The main reason for the poor economic performance was the low capacity of the plant. International experience has shown that a commercial plant should have a capacity of at least five times the nameplate capacity of the Pelindaba plant.
The conversion process required facilities for the production of HF (from locally mined CaF2, fluorspar) and F2 gas. The HF plant with a capacity of 4 500 t p.a. HF is still operational, and supplies HF to Necsa's commercial fluorochemical programme for local industry and also for export. F2 is also still being produced at Necsa for its fluorochemical business.
5.2. Future conversion requirements
Local production of fuel for 30 PBMR reactors would require a UF6 production capacity of approximately 750 t p.a. U as UF6. Even if all of Koeberg's fuel were produced from locally converted uranium, a total local conversion capacity of approximately 1 000 t p.a. U as UF6 would be required.
The establishment of an economically viable conversion plant in South Africa could therefore only be considered if the bulk of production were exported as UF6, enriched uranium or reactor fuel, if such plants of economic capacity were available locally. The transport penalty of exporting UF6 instead of .uranium oxides should be further noted. Global demand for commercial conversion services (52 000 t U as UF6 for 2005) is presently met by the five major commercial producers. It seems likely that some existing producers (Areva, for example) will expand their capacities to meet the expected growth in demand in future.
5.3. Future strategies
South Africa's future needs for enriched uranium will largely be determined by the requirements of the Light Water and PBMR power reactors. Enrichment levels of approximately 5% will be required for Light Water Reactors and 9.6% for PBMR reactors. Assuming a scenario where the nuclear power component of Eskom gradually increases to 14.5% in 2030 when 5 000 MWe will be generated by Light Water Reactors and a further 4 950 MWe by PBMR reactors, an enrichment capacity of almost 1 500 000 SWU p.a. would be required to fuel the reactors.
There are three broad approaches which can be considered for meeting the SWU deand:
Firstly, the construction of an independent indigenous enrichment facility in South Africa under fulllAEA safeguards can be considered. This would, in all probability, be based on centrifuge technology, which should provide the best and lowest risk opportunity for establishing commercially competitive enrichment technology in South Africa. Recent statements by South African researchers that an improvement of the old vortex tube technology can be expected to lower the power requirement for uranium enrichment would still require confirmation by an extensive and costly Research and Development (R&D) programme before any view on the competitiveness of the improved technology for uranium can be formulated. Unfortunately most of the other unfavourable characteristics of the process, such as the use of hydrogen as carrier gas, will also still apply. The option of a local plant may possibly be seen as providing maximum assurance of supply, but it suffers from serious disadvantages such as the availability of mature competitive technology, very high capital investment and low economy of scale, particularly matching of the enrichment plant capacity to the growing product requirement over time. The approach of constructing an independent plant in South Africa would certainly result in the highest cost of enrichment services for Eskom.
Secondly, procurement of-enrichment services on international markets is of course an option. Uranium at enrichment levels of up to 5% is readily available from various suppliers as part of an extensive international trade network. Security of future supply should be very high, particularly for countries that forego the building of their own enrichment facilities. There is, however, no diversity of supply for 9.6% enriched uranium for PBMR reactors. The initial limited demand for this level of enrichment will also not stimulate diversity of supply, and the programme may be dependent on a single supplier with the associated risk. When Generation IV nuclear reactors come into commercial production, there may be a growing demand for higher enrichment fuel for future High-temperature Gas-cooled Reactors (HTGRs). This may lead to a diversity of suppliers entering this market, resulting in an assurance of supply situation similar to that in the current up to 5% services market. It should, however, be noted that the bulk (91.4%) of the separative work required for the production of 9.6% enriched uranium is required for taking it up to 5%. If, therefore, 5% enriched uranium is procured on the normal market and a single enricher (or more) is contracted to upgrade it from 5% to 9.6% (8.6% of the total-separative work), it would not be too serious to even pay a significant premium for this last step. A centrifuge facility required to do the upgrading for 20 PBMR reactors would hardly be more than a laboratory scale facility.
Thirdly, joint ownership in facilities either in the country of the technology holder or in South Africa is an option. The plant will be financed, managed and staffed on a multinational basis and partners of the technology holder will not gain access to sensitive technology. Details of this type of arrangement are still being developed, but it can be accepted that it would result in adequate assurance of non-proliferation as well as assurance of supply. Economy of scale would be an advantage of such a jointly owned facility. It would also require a more manageable investment for each member state than building an indigenous national facility. In addition, it would be suitable for enrichment levels up to 9.6% or more.
Another possibility for the procurement of 9.6% enriched uranium which may be worth exploring is linked to the down-blending of HEU from Russian and American nuclear warheads. Dow-blended HEU from both sources is presently being used in USA power reactors. The question arises whether 9.6% enriched uranium could be obtained from the USA or Russia for the interim period until such time as this level of enrichment becomes generally available as a result of future demand by High-temperature Reactors (HTRs).
In conclusion, the PBMR requirement for fuel enriched to 9.6% may well turn out to be the determining factor in deciding on a procurement strategy. It is important that a feasible and economically acceptable strategy for the procurement of the 9.6% enriched fuel be found and agreed with a reliable producer in good time.
The supply of 20% enriched uranium for SAFARI-1 fuel is not addressed in this document, since it involves very small quantities of material for which international supply lines are well developed and secure.
6. FUEL FABRICATION
South Africa-is nuclear fuel requirements for the foreseeable future will be determined by the needs of the Koeberg Nuclear Power Station, the SAFARI-1 reactor and the PBMR programme.
Koeberg procured all its fuel requirements from Framatome (now Arera) since commissioning of the two reactors in 1984/1985 until 1988, after which Necsa provided the fuel until the closure of the Beva plant in 1996. The Beva plant had a production capacity of approximately 200 fuel assemblies per annum while the Koeberg requirement was approximately 70. The plant was closed due to cost considerations as result of the low throughput and the negative expectations of future growth in local demand, as well as the inability to find export opportunities. Eskom has since procured its fuel on the open market and recently entered into a long-term contract with Areva for fuel production, and with Russia for the supply of the enriched uranium.
Highly Enriched Uranium (HEU) fuel for the SAFARI-1 reactor was procured from the USA from commissioning of the reactor in 1965 until 1977, when the USA terminated the agreement. Since 1982, SAFARI-1 fuel has been produced by Necsa -in the Materials Test Reactor (MTR) fuel fabrication facility after locally produced HEU became available. The South African inventory of HEU is presently used to fuel the reactor, as well as for target plates for the commercial production of radioisotopes. The fuel consumption of the reactor, on average 40 fuel elements containing 300 g U-235 each, is largely determined by the isotope production programme.
Following the licence agreement between Eskom and the German PBMR technology holder, a laboratory was established at Pelindaba, where PBMR fuel production
technology has been demonstrated on laboratory scale. Fuel spheres for irradiation testing will be available from the laboratory by the end of 2007. The design and licensing of a Pilot Fuel Plant (PFP) is at an advanced stage.
6.2. Future strategies
Koeberg will continue its practice of procuring fuel production and enriched uranium on the open market. Should uranium conversion and enrichment be resumed in South Africa, it can be expected that preference for locally enriched uranium will be considered for the production of Koeberg fuel. It is unlikely that local PWR fuel production will be considered in South Africa again, as a fuel production plant would face the same obstacles as the Beva plant. Koeberg will continue to strive for higher burn-up of fuel and would thus require fuel with higher enrichment levels (up to 4.95%). The introduction of MOX fuel could also be considered in future.
The SAFARI-1 reactor will, as part of the worldwide trend, convert to operation with Low Enriched Uranium (LEU) fuel. LEU fuel implies a technology changeover for the MTR fuel plant, and it is likely that future fuel production will be a mix of imported and locally manufactured components. The optimum mix will have to be determined. LEU will have to be imported in any case. That would result in the existing HEU inventory possibly becoming available for the production of isotope production targets only. SAFARI-1 may consider upgrading to 30 MW in future, which would result in 30% higher fuel consumption.
PBMR fuel spheres from the laboratory facility will be irradiated in foreign facilities as part of the fuel qualification programme. Construction of a PFP will commence by the middle of 2007 and production will start by the end of 2009. Sufficient fuel (450 000 fuel spheres) must be available for loading the Demonstration Power Plant (DPP) by the end of 2010. The PFP will have an initial capacity of 270 000 fuel spheres per annum. It will be upgraded gradually to 540 000 fuel spheres per annum and later on to even higher capacity. The present PBMR strategy would require a fuel production capacity of at least 900 000 fuel spheres per annum to service the equilibrium cores of PBMR reactors by 2015. A commercial fuel plant with a capacity of at least 3.6 million fuel spheres per annum would be required to service the equilibrium cores of six four-pack power plants for Eskom as envisaged in the PBMR strategy. Development of a next generation PBMR fuel will be initiated in future. It would be necessary for a fuel development laboratory to be maintained at Pelindaba, for SAFARI-1 to be equipped for test irradiations, and for a Post-irradiation Examination (PIE) capability to be established at Necsa.
7. NUCLEAR WASTE MANAGEMENT AND DECOMMISSIONING
The following categories of nuclear waste are formed during the generation of nuclear power:
· The production of fuel for nuclear reactors creates radioactive waste containing un-irradiated natural and enriched uranium from conversion, enrichment and fuel production processes;
· During reactor operations, small quantities of fission products from the fuel and neutron activation products from construction materials are recovered during decontamination of liquid and gaseous effluent streams. This type of radioactive waste, together with redundant components, is classified as Short-lived Low and Intermediate Level Waste (LlLW-SL) and consists predominantly of radionuclides with half-lives of < 31 years.
· Spent fuel assemblies contain uranium and other actinides with long half-lives formed from uranium as well as a broad range of fission products. This waste is classified as High-level Waste (HLW).
7.2. Strategies for South African radioactive waste
7.2.1. Koeberg Nuclear Power Station
The Koeberg Nuclear Power Station consists of two PWRs with a total capacity of 1 840 MWe. The reactors are of French origin and were commissioned in 1984/1985. Fuel containing 4.4% enriched uranium is presently supplied by Areva. Fuel burn-up of 52000 MWd/t is being achieved. On average, 35 t of enriched uranium in 75 fuel assemblies is required annually. The natural uranium. requirement to fuel the power station is approximately 350 t per annum. Fuel for the reactors was supplied by Necsa for a period of 10 years before the Beva fuel plant was closed. The present life expectancy of the reactors is 40 years.
The extension of the reactor lifetimes to 50 or even 60 years and the possible introduction of MOX fuel is being investigated. The enrichment level of fuel will be increased to 4.95% in future. All spent fuel generated during the 40-year operation period can be accumulated in the spent fuel storage pools, but more dry storage capacity would be required for longer periods of operation.
Koeberg's solidified operational waste classified as LlLW-SL is disposed of in shallow (10m) trenches at the Vaalputs radioactive waste repository. This is likely to continue for the remaining life of the two Koeberg reactors.
Except for some fuel assemblies in four dry storage casks, all spent fuel at Koeberg is stored in the spent fuel storage pools, which would be able to accommodate the rest of the spent fuel for the full expected 40-year lifetimes of the two reactors. Should the operational period of the two reactors be extended to 50 years, however, the dry storage capacity of Koeberg would have to be expC!nded to make provision for a total of almost 4 000 spent fuel assemblies. For the likely scenario where another 40 years of dry storage, preferably at the eventual disposal site, would be necessary after the closure of the reactors, more .storage casks (probably a mixture of the existing Castor casks as well as Nuhoms casks) would be required before the spent fuel would be encapsulated for final disposal.
In the event that the reprocessing option for Koeberg spent fuel is chosen, the removal of spent fuel from the storage pool for reprocessing could be scheduled such that no additional dry storage casks would be required for storage, since the waste received from the re-processor would already be contained for storage. It should, however, be noted that both the direct disposal as well as the reprocessing routes would eventually require a deep disposal facility as well as a dry storage facility at the disposal site.
The above scenario for the management of Koeberg spent fuel would imply that a deep disposal facility should be ready for final encapsulation and disposal by about 2070.
7.2.2 PBMR Programme
Operational waste generated by the demonstration PBMR on the Koeberg site will generally be in the category LlLW-SL. It will be handled similarly to operational waste from the existing reactors and disposed of at Vaalputs.
Two options for dealing with spent PBMR fuel are being considered at present:
· The first option involves the direct disposal route. This implies on-site storage of the spent fuel for another 40 years after the closure of the reactor, after which it can be transferred to shipping casks for storage and disposal at the HLW repository. A multi-model plant producing 1 000 MWe will require 14 shipments per annum in standard PWR spent fuel casks.
The second option involves reduction of the HLW volume
by removing the matrix and outer pyrolytic graphite of the coated particles at
an on-site facility. The coated particles are then fed into storage casks. It
is further aimed to remove the C-14 isotope from the graphite and to reuse the
cleaned graphite for the production of fresh fuel. This option could reduce the
volume of HLW to 4% of that of the first option. The viability of the volume
reduction process has not yet been demonstrated and-development work would be
required before decisions can be made.
Radioactive waste at the Pelindaba site originated from:
a. Process development and production of fuel for the Koeberg reactors as well as HEU for the military programme. This waste is primarily in the category un-irradiated uranium and most of it is stored in drums in the Pelstore facility.
b. Waste associated with the operation of SAFARI-1, particularly fuel production and spent fuel.
c. R&D and radioisotope production programmes, which are mostly short-lived isotopes in the category LILW-SL.
Before 1996, some un-irradiated uranium contaminated waste as well as short-lived isotope waste was buried in shallow trenches at Thabana. Since then, Thabana has only been used as a waste storage site. Spent fuel from SAFARI-1 is stored in the reactor pool and also in a dry storage facility at Thabana.
No radioactive waste from Necsa has thus far been transferred to Vaalputs. It is envisaged that all waste meeting the Vaalputs Waste Acceptance Criteria (LILW-SL at present) will in future be disposed of there. A signifiCant portion of the un-irradiated uranium contaminated waste (LILW-LL) is not within the Vaalputs Waste Acceptance Criteria at present. It is important that a decision be obtained on the future acceptability of this category of waste at Vaalputs, possibly in retrievable storage containers at depths of more than 10m. A decision must be made on whether the existing waste in the Thabana trenches would have to be recovered or whether it will be managed as disposed-of radioactive waste on a permanent basis. The volume of SAFARI-1 spent fuel is extremely low compared to that of Koeberg and the most effective disposal method would be to follow the Koeberg approach. Provision for long-term management and storage of radioactive waste at Pelindaba will be necessary for waste which cannot be accepted at Vaalputs.
According to the draft document on the Radioactive Waste Management Policy and Strategy for South Africa, reprocessing of spent fuel should not be excluded as an option which, if selected, would probably have to be contracted out to other countries in view of the high cost and limited expected local demand. Reprocessing technology for PBMR spent fuel is not yet available and it would probably be prudent to postpone a possible decision on the reprocessing of Koeberg spent fuel until more information is available on the future of PBMR technology in South Africa, and on the associated reprocessing requirements (if any) to ensure a holistic national strategy for the management of spent fuel.
South Africa already gained some 10 years' experience in the decommissioning of uranium contaminated plants through the ongoing Decontamination and Decommissioning (D&D) programme at Pelindaba. Necsa also developed a long-term plan and cost estimate for the D&D of its historical and some other facilities over the next 30 years, the bulk of which will be funded by government. Eskom is making financial provision for the decommissioning of the Koeberg reactors, and is already planning the decommissioning process after the closure of the reactors, probably in 2025. The present plan envisages completion of the decommissioning process by about 2055. PBMR (Pty) Ltd is providing guidelines for the decommissioning of the demonstration unit and other PBMR units. It is envisaged that decommissioning will be carried out with spent fuel stored in the spent fuel tanks to gain maximum decay advantage.
Some key guiding principles for the planning process in all cases include the following: ensure the maximum radioactive decay time practically possible before commencing operations; plan the D&D processes to be followed, and estimate as far as possible the quantities of materials and types as well as levels of contamination which must be handled; develop a funding plan; and ensure that facilities will be available to deal with all waste streams and to manage the resulting radioactive waste.
8. RESEARCH AND DEVELOPMENT
The PBMR programme is presently the main focus and strategic driver of all fuel cycle related work in South Africa, and its direct and indirect needs should therefore be a major consideration in setting the national R&D agenda in this field. Combined with technological requirements by SAFARI-1 and all South Africa's nuclear waste activities, R&D planning objectives should aim to address requirements in the following broad areas:
· A survey of resources and technology agreements to ensure the future availability of enriched uranium for fuel fabrication;
· The effective establishment and operation of the demonstration reactor and pilot fuel plant;
· The development and demonstration of next generation technologies including maximization of South African content in the supply of PBMR reactors and fuel in the medium and long term;
· Cost-effective and environmentally sensitive management of spent fuel and other radioactive waste according to national policy and strategy;
· The establishment and maintenance of R&D facilities and well-trained teams of engineers and scientists in South Africa to execute the objectives and capabilities for managing R&D projects which may have to be done in cooperation with foreign countries.
8.1. Uranium resources
Information on South Africa's uranium resources in the various cost categories should be updated and the future impact of uranium producers and initiatives in uranium mining on the resource estimates should be evaluated. More information should be obtained on the Karoo Sandstone uranium deposits, particularly the resources in various cost categories.
Strategies and planning on conversion technology should be taken against the background that all commercial suppliers, including South Africa's former conversion plant, apply the same proven technology for the conversion of uranium. Conversion adds only approximately 4% to the total cost of nuclear fuel in the fuel cycle, and there is limited incentive for development work on cost reduction.
A study of cost structures (minimum commercial plant capacities, global trends, markets) in the conversion business should be undertaken and a position regarding the future of conversion in South Africa should be formulated. A strategy to retain fluorine technology in South Africa should be considered.
8.3 Enrichment technology
It is, as was already discussed earlier in this document, unlikely that South Africa will embark again on the establishment of an indigenous enrichment plant. The only mechanism whereby enrichment technology could be re-established in South Africa would be through a joint undertaking with an established technology partner, most probably centrifuge technology, in which case the. South African technological contribution would be limited to the provision of non-sensitive components, UF6 handling facilities, supporting services, etc. Negotiations on the implementation of a joint undertaking would require a core of knowledgeable people in the field.
A strategy for the supply of 9.6% enriched uranium should also be formulated and the approach chosen should be negotiated with prospective suppliers/partners.
8.4. Fuel Technology
R&D in fuel technology should be focused on the production of high-quality and cost-effective first generation PBMR fuel, and also on improving the integrity of next generation fuel (higher burn-up and corrosion resistance as well as reduced diffusion of fission products through the coating) as would be required for PBMR reactors of increased efficiency and for higher temperature New Generation Nuclear Plant (NGNP) application such as hydrogen production.
8.5. Reactor technology
In order to maintain the competitive edge achieved by the PBMR design relative to the norms set for the next generation nuclear reactors, technological development will be required in several areas, including the following:
· Improvement of reactor efficiency by developing tools for plant design optimization and conditioning technology to improve graphite radiation resistance;
· Minimization of radioactive waste generation and personnel exposure to radiation by limiting the transfer of radionuclides to the power conversion system;
· Improvement of the inherent characteristics and applicability of the reactor for New Generation Nuclear Plant (NGNP) applications.
8.6. Radioactive waste and decommissioning technology
R&D needs for the effective long-term management of existing Low and Intermediate Level Waste (LlLW) in South Africa are low. Technology for the processing and disposal of short-lived LlLW (LlLW-SL) is well established and is dealt with on a routine basis. Processing technology for un-irradiated uranium containing waste in the category LlLW-LL is also well established, but no disposal methodology has been licensed as yet. Finalization of this matter would require the design, safety assessment and licensing of a facility at a suitable site, probably Vaalputs. Management of radioactive waste arising from the PBMR programme will, due to its uniqueness and special requirements, however, require the development of special technologies. High-level Waste (HLW), predominantly spent fuel from the Koeberg power station and SAFARI-1, would use internationally developed best practices whether being directly put into final storage, or being reprocessed.
8.6.1. PBMR Radioactive Waste
Waste minimization and reuse of certain materials are the main drivers of technology development for PBMR radioactive waste. This would imply the separation of coated particles from spent fuel spheres and the reclamation of matrix graphite. HLW originating from the PBMR programme will be dealt with similarly from a. policy perspective to other HLW in South Africa.
8.6.2. High-level Waste
There is as yet no HLW disposal methodology or facility for dealing with this category of waste from Koeberg, Necsa or the PBMR. Planning of R&D work on the preparation of HLW for final disposal must await finalization of the national policy and strategy on radioactive waste, particularly with regard to reprocessing. The draft policy and strategy document does, however, indicate that investigations for the establishment of a deep geological facility must go ahead in the interim. This directive would imply that work be initiated on the selection of a suitable site (which could be Vaalputs), the conceptual design of a repository, as well as geological modelling and associated studies to support the safety assessment and licensing of the facility.
International knowledge and experience of radioactive waste technologies, particularly HLW, are generally readily accessible through the IAEA and other international forums. Inputs from such sources are most valuable and should be fully exploited in support of local activities. The key would be to establish and maintain a group of experts who would be able to absorb the international information and apply it locally.
Decommissioning and the associated decontamination technology of non-irradiated uranium contaminated equipment is well established in South Africa and hardly merits supporting R&D. Present work in this field presents an ongoing learning experience in the optimal synchronization and costing of the full chain of activities, as well as the estimation of the full nuclear liability associated with plants and equipment.
Decommissioning experience of equipment contaminated with actinides and fission products, as found in nuclear reactors, is limited in South Africa. International experience in this field is growing rapidly and technical information is generally shared widely between countries. It can realistically be assumed that with the aid of existing D&D experience in South Africa as well as information from international sources, it should be possible to plan and execute an effective D&D programme if reactor personnel with operational experience and knowledge of plant hazards are involved in the project.
9. CAPACITY BUILDING
An extensive and high-level human resource capability in nuclear science and technology was established in South Africa in the past as part of a broad range of R&D programmes and nuclear services, as well as fabrication and production facilities. The most notable of these are the following:
The activities at Necsa, where people gained
experience in research reactor operation and applications; isotope production
and applications; radiation applications; various scientific and technological
R&D programmes; uranium conversion and enrichment as well as nuclear fuel
production; decontamination of nuclear facilities; nuclear waste management and
disposal; nuclear component design and manufacturing technology; and nuclear
regulation and safety. -
· iThemba Labs, which provide experience in accelerator construction, operation, maintenance and application for nuclear particle physics research, isotope production and particle therapy of patients.
· Operation and maintenance experience of PWRs at Koeberg.
· Regulatory experience of nuclear facilities and mines at the National Nuclear Regulator (NNR).
· Various universities, hospitals and clinics which provide experience and training in nuclear sciences as part of academic curricula, accelerator applications, medical applications of isotopes and radiation, and radiation protection training.
· More recently, the launch of the PBMR programme created an exciting and demanding new earning opportunity for the South African nuclear sector. Significant experience has been gained with high-temperature power reactor design, as well as laboratory scale fuel fabrication. An extensive international technological support network with the associated skills transfer opportunities has also been established.
Apart from a number of facilities which were closed
down at Necsa, all the other activities referred to above are still an ongoing
part of the national nuclear Science and Technology (S&T) human resource
capability. The rapid growth in the human resource requirements of the PBMR
programme as well as the need for transformation in existing institutions have,
however, created a high demand for suitably qualified persons which are presently
just not available in the nuclear sector. The existing training capability is
further insufficient to meet the demand and several actions aimed at rectifying
the situation have been initiated in the recent past.
9.2. Future Strategy
The following existing and planned training opportunities will be available for addressing the shortage of skilled workers in the nuclear sector.
9.2.1. Existing Nuclear Focused Postgraduate Qualifications at Universities
- North-West University (Mafikeng)
The Centre for Applied Radiation Science and Technology (CARST) presents a two-year MSc degree in radiation sciences and technology. The first year is fulltime study at the university followed by a year at a nuclear institution during which experimental work is done for a dissertation.
- North-West University (Potchefstroom)
Two Masters' programmes in nuclear engineering for candidates holding BEng and BHons degrees are offered on a distance contact basis (including one lecture week per course) which enables full-time workers to participate. Courses are presented by local and international experts. The university is a member of the World Nuclear University. The engineering faculty developed and operates a physical model of the PBMR power conversion unit, which also serves as a useful tool for postgraduate training. (Refer to Appendix I for more information.)
- Masters in Accelerator and Nuclear Sciences
The two-year course is presented jointly by the universities of Zululand and the Western-Cape together with iThemba LABS. The first year is full-time study at the universities for an Honours degree followed by a year at a nuclear institution where experimental work is done for a dissertation. Students can specialize either in accelerator science (MANUS) or material science (MA TSCI). (Refer to Appendix I for more information.)
- Witwatersrand University
The university offers two postgraduate courses. A course on radiation protection and safety follows the syllabus of the IAEA on this subject. It is an 18-week fulltime course. The other course on physics, engineering and safety of nuclear power reactors is normally given at Koeberg and requires full-time study of about 22 weeks. Industrial visits to SAFARI-1, the micro-model of the PBMR power conversion unit and the PBMR fuel development laboratory are included. (Refer to Appendix I for more information.)
The PBMR Human Capital Research and Innovation Frontier (PHRIF) Programme was initiated by the Department of Science and Technology (DST) in conjunction with the nuclear industry in 2004. Although the programme is primarily focused on the human resources needs of the PBMR programme, it is evident from the list of projects that the whole nuclear industry will benefit from it.
The projects include support to grade 10, 11 and 12 pupils from disadvantaged areas to study science and mathematics; bursary support to undergraduate, masters, doctoral and postdoctoral students; the sponsoring of eight research chairs in PBMR-related technologies at South African universities; sponsoring of conferences; and networking for communities of practice in the nuclear sector. Programme funding for the next 10 years will amount to a total of R230 million. Although the research chairs will be focused on topics of particular interest to the PBMR programme, several of these will also be of interest to the broader nuclear industry. (Refer to Appendix I for more information.)
- Other Courses
Local capacity building can further benefit by a broad range of IAEA-sponsored initiatives such as:
· The fellowship scheme, whereby fellows from South Africa can receive on-the-job training at foreign institutions for periods of up to one year.
· AFRA workshops in South Africa or elsewhere in Africa where workshops, normally lasting one to two weeks, on various topics such as nuclear waste, and research reactor, medical and agricultural applications, are presented by recognized international experts.
10. INDUSTRIALIZATION AND LOCALIZATION
The decision of the South African Government to support and finance the development of the Pebble Bed Modular Reactor (PBMR) was partially based on the economic and developmental advantages to South Africa - in addition to the provision of electric power. The future local and international sales provide a significant industrial and skills development opportunity for South Africa. PBMR (Pty) Ltd has consequently embarked upon an aggressive industrialization and localization drive in order to maximize the economic and technological opportunities for South Africa.
10.2. Supply chain
a. Following the successful completion of the demonstration unit, PBMR intends supplying pebble bed reactors to the local and international market.
b. The first 'commercial' units are scheduled for delivery to Eskom in 2018, and can thereafter be supplied at a rate of three per annum;
c. To support this programme and. the export market potential, PBMR must:
i. Establish a secure an internationally competitive supply chain capable of delivering six pebble bed reactors per annum;
ii Maximize South African local content which is economically justifiable and-sustainable,-and-technically-achievable
10.3 Localization initiative
10.3.1. Objective of Localization Initiative The objectives of the localization initiative are:
1. Active participation in the establishment of an economically viable and sustainable nuclear industry in South Africa.
2. Skills development, job creation and Black Economic Empowerment (BEE) through the nuclear industry.
3. Export promotion of capital goods and value-added products.
4. Promotion of local industrial capacity and capability and the support of Small, Medium and Micro Enterprises (SMMEs) where possible. The promotion of manufacturing improvements and R&D- in order to remain internationally competitive.
5. Promotion of technology transfer, joint ventures, new trading partners and foreign investment.
10.3.2. National Industrial Participation Programme
The National Industrial Participation Programme (NIPP) of the Department of Trade and Industry (DTI) constitutes an important mechanism whereby international suppliers will be obliged to formulate programmes which would benefit the South African economy.
10.3.3. Steps to establish a South African support industry for PBMR
The following steps have been identified in a localization initiative to establish a South African support industry for PBMR:
a. Industrial development
- Recapitalization of the heavy industry capability in South Africa.
-New industrial development for capabilities that do not currently exist.
- Industrial upgrade of existing industries that could potentially deliver components to PBMR.
- Significant NIPP opportunities.
- Production technology R&D.
- Competitiveness and cost reduction strategies.
- Optimized logistics and consolidation.
- International benchmarking.
b. Skills development
- Must be linked to other skills development programmes to support all the capital projects in the country.
- University and technikoneducation
- Artisans - especially in welding and machining.
- Learnership Programmes.
- Mentoring Programmes.
- Project-specific Training Programmes.
- International Exchange Programmes.
c. Scientific and technological development
- Technology transfer (important NIPP opportunity).
- Establishment of Centres of Excellence at universities as well as the identification of networks of expertise countrywide.
- Local R&D.
- Contracted R&D.
- Optimum utilization of existing facilities, i.e. Necsa, CSIR.
d. Quality assurance
- Re-establishment of quality assurance programmes and disciplines with the required procedures and documentation.
- Reskilling of manufacturers.
- Promotion of safety culture.
- Training f<?r manufacturers and inspectors.
- ASME and other international certification suitable for the nuclear industry.
e. Corporate structures
- Adequate corporate structures for large and technically advanced local manufacture.
- Viable corporate structures that will be able to support the long-term strategic goals of PBMR.
- Partnerships and joint ventures.
- Local and foreign direct investment.
f. Black economic empowerment
- Many equity opportunities in local manufacture.
- BEE procurement.
- Training and educational initiatives.
g. SMME development
- Many support services.
- Support of local communities during construction.
- Long-term relationship with local communities during operation and maintenance of plants.
h. Appropriate financial structures
- Investment finance through the Industrial Development Corporation (IDC) and other financial institutions.
- Strategic investments.
- World Bank and International Development Banks.
- Cost of finance - especially in the face of financial support provided by other governments to their industries.
- Export credit guarantees.
i. Government support mechanisms
The government, through DTI, has instituted various support mechanisms for industrial development such as:
- strategic-Investment Programme-(SIP)
- Support Programme for Industrial Innovation (SPII).
- Technology and Human Resources for Industry Programme (THRIP).
- Competitiveness Fund.
- Support for quality assurance upgrades.
- Customs relief for capital imports.
- Export incentives.
- Industrial Development Zones (IDZs).
ii. These programmes may have to be revised in order to support the PBMR requirements, and some entirely new programmes may have to be defined and agreed