Papers in this volume: 6
1. Determining BPEO for discharge of residual 99Tc from the Sellafield site
Author(s): Dunlop P. and Clough M.E.J.
Page: 43
Keywords: British Nuclear Fuels plc (BNFL), Environment, Political issues, Radiological discharges, Regulatory system, Reviews
Abstract: Discharges of technetium-99 (a long-lived, anthropogenic radionuclide, formed by the fission processes that occur in nuclear reactors) from the Sellafield site into the Irish Sea have received a high political profile. As part of the Environment Agency's (EA) full re-examination of Sellafield's discharge Authorisations under the Radioactive Substances Act 1993 (RSA93), technetium-99 (99Tc) has warranted specific attention and has been subject to a period of public consultation. A Decision Document has recently been issued by the EA (currently awaiting the attention of the Minister), recommending that British Nuclear Fuels plc (BNFL) pursue further abatement of 99Tc by implementing a scheme to route the major discharge stream to vitrification (solid waste). To support the 99Tc review, BNFL was asked, by the EA, to undertake a best practicable environmental option (BPEO) study. A streamlined methodology was developed to meet the tight time-scales and agreed with the EA. From the qualitative assessment of seven final options against seven criteria, the `continue current operations' option was identified as the BPEO. It should be noted that the BPEO study concentrates on residual discharges of 99Tc, since current operations on the Sellafield site route greater than 90% of 99Tc to vitrification. Recognising that the selection of a BPEO should be subject to review, BNFL asked NRG (Dutch consultants to the nuclear sector) to provide an independent peer review. In conclusion, the NRG review concurred that current operations represent BPEO, as identified in the BNFL study, but made some observations regarding the approach of the study and the methodology.The EA produced an Explanatory Document to assist the public consultation and included the BNFL BPEO study and the NRG review in the consultation documents. A further review has also been undertaken by National Economic Research Associates (NERA) who reviewed the previous documentation and also applied a more formal multi-criteria analysis following guidance from the Department of the Environment, Transport and the Regions (DETR). NERA arrived at the same conclusion, namely that the BPEO, on present evidence, was continuation of the present processes until the end of Magnox effluent reprocessing.The 99Tc issue raises some significant points in terms of the effectiveness of BPEO assessments for radioactive discharges and the role that they play in informing the final decision as part of Authorisation reviews. There is a need for practitioners to better understand how to undertake, present and interpret BPEO while conceding that identifying the BPEO may not be enough.
2. The implications of LC36 on a mixed site - Devonport Management Limited
Author(s): Clark A.
Page: 47
Keywords: Licence conditions, Management, Regulatory issues, Regulatory system
Abstract: DML owns and operates Devonport Royal Dockyard, the largest marine support complex in Western Europe. The company's primary business is refitting and refuelling nuclear submarines, modernising and refitting warships and updating and overhauling naval weapons systems, as well as providing a wide range of design and management services. Consequently, DML's nuclear and non-nuclear activities coexist on the same site and its location, business diversity and history make it unique within the nuclear industry. Within this setting, Licence Condition 36 (LC36) compliance has presented specific management challenges. This paper outlines the company's approach to living with LC36 within a fast-changing, dual-regulated environment.
3. Nuclear power in Finland
Author(s): Paavola M.
Page: 51
Keywords: Carbon dioxide, Energy, Finland, Fossil fuels, Global warming, Nuclear industry (civil), Nuclear power, Nuclear power plant (NPP), Power stations (non-fossil fuel), Renewable energy sources
Abstract: Energy plays a vital role in the country's economy and welfare. Due to Finland's cold climate, long transportation distances and energy-intensive industries, Finland's own energy resources are very limited. More than 70% of the primary energy demand in Finland is imported and more than half of that from one country only Russia. Total energy consumption has stabilised in Finland but electricity consumption has grown steadily and it is forecast that this growth will continue into the future. Electricity generation is diversified and is based on the use of several fuels. The share of nuclear electricity is 27%. Operational experience of the four Finnish nuclear reactors has been very good. Production has been reliable; for example, at Olkiluoto the average capacity factor over the past ten years is about 94%. The high utilisation rate coupled with low fuel costs proves that nuclear electricity has been very competitive in the deregulated electricity market and safety of production has not been compromised.With regard to the management of nuclear waste, Finland has resolved this problem. The law demands that spent nuclear fuel, and only Finnish spent fuel, shall be finally disposed of in the Finnish bedrock. The Finnish government has given approval in principle for the plans and parliament ratified them in the spring of 2001. The final repository will be located close to the existing power plant units at Olkiluoto at several hundred metres depth in two-billion-year-old bedrock. Safety authorities and the local municipality have approved the plans and the location for the repository.Studies show that nuclear generation costs in Finland are lower than those for coal and gas. Based on spring 2001 price levels, the studies indicate that nuclear electricity maintains its position even when the interest rate is varied by up to 10% per year. Teollisuuden Voima Oy (TVO) power company has submitted an application to the Finnish government for construction of an additional nuclear reactor in Finland. The main argument for the application is the need to produce safer, more economical and more environmentally friendly electricity without CO2 emissions. New plant would increase the security of electricity supply, decrease the dependence on electricity imports, replace old fossil-fuel-based production capacity and offer, together with renewables, the most effective and economic way to meet greenhouse gas reduction targets. The application is for construction of one light-water reactor with proposed capacity ranges of between 1000 and 1600MW. Location would be one of the existing sites, either Loviisa or Olkiluoto.
4. French experience on o.d. IGA/SCC and fouling of SG tubes
Author(s): Stutzmann A., Viricel L., Dijoux M. and Lemaire P.
Page: 59
Keywords: Chemical processes, Chemical processes (including corrosion), France, Power plant components, Secondary-side corrosion of SG tubes, Steam generators
Abstract: The secondary side corrosion of steam generator (SG) tubes represents the main degradation of components in operating power plants, strongly impacted by chemistry. Accordingly, Electricit de France (EDF) has made extensive studies of the chemical parameters in its fleet of 57 PWRs to determine which factors might influence corrosion development and has implemented an optimised secondary system chemistry to control corrosion phenomena and mitigate intergranular attack/stress corrosion cracking (IGA/SCC) at low cost. This paper describes the studies carried out on materials, chemistry during operation, and hideout returns during shutdown and maintenance, leading to preventive or remedial actions. Secondary fouling of SG tubes is also becoming a major concern because it leads to a pressure loss on some units. Remedies are studied to eliminate these deposits to recover heat transfer exchange.
5. Managing nuclear graphite ageing
Author(s): Marsden B.J.
Page: 67
Keywords: Advanced gas-cooled reactors (AGRs), Chemical processes (including corrosion), Magnox reactors, Materials, Power plant components, Research & development, Stress analysis
Abstract: Diverse designs of graphite-moderated reactors have been developed since the start of nuclear power production in the late 1940s. These reactors have in common large graphite cores (up to 2000t) whose properties and dimensions change with age, leading to graphite component deformations and stresses which are reflected in the whole core deformation. The graphite cannot be practically removed from the cores therefore the life of the graphite may well determine the life of the reactor. In some cases the behaviour of the graphite used in particular reactor systems was not fully understood when the reactors were designed. This has led to core behaviour which has differed from the original design intent. The graphite integrity in a reactor is important as it provides channels for the coolant flow and control rod entry. Therefore to ensure that the optimum safe core life is obtained, the graphite ageing mechanisms must be understood, monitored and managed. The nuclear graphite technology that has been developed since the 1940s has been used to demonstrate an understanding of the in-reactor graphite component and core ageing process. This technology is now being used to predict and manage future core behaviour in the UK and overseas graphite reactor systems.
6. Development of innovative reactors and fuel cycles: the IAEA role
Author(s): Mourogov V.
Page: 80
Keywords: Innovative technologies, International Atomic Energy Agency (IAEA), International Collaboration, Nuclear fuel cycle, Nuclear industry, Nuclear industry (civil), Nuclear power plant (NPP)
Abstract: Over the last 15 years, nuclear power's share of new capacity additions worldwide has not kept pace with either its share of electricity generated or its share of installed capacity. Unfortunately, it is a trend that is projected to continue. IAEA forecasts show nuclear's share of global capacity dropping to between 6% and 8% by 2020 and its share of electricity generation dropping to between 9% and 12% . This paper discusses the major challenges that must be dealt with successfully if nuclear power is to measure up to some of the more bullish long-term projections. It goes on to describe the work being done by INPRO (International Project on Innovative Nuclear Reactors and Fuel Cycles) and GIF (Generation IV International Forum) to help meet nuclear's challenges for the twenty-first century.