Papers in this volume: 8
1. Future plans for the Imperial College CONSORT research reactor
Author(s): Franklin S.J.
Page: 19
Keywords: Isotopes, NAA, Research & development, Research reactor, Research reactors
Abstract: The Imperial College (IC) research reactor was designed jointly by GEC and the IC Mechanical Engineering Department. It first went critical on 9 April 1965 and has been operating successfully for over 33 years. The reactor provides a service to both academia and industry for neutron activation analysis, reactor and applied nuclear physics training, neutron detector calibration, isotope production and irradiations. The reactor has strategic importance for the UK, as it is now the only remaining research reactor in the country. It is therefore important to put in place refurbishment programmes and to maintain and upgrade the safety case. This paper describes the current facilities, applications and users of the research reactor and outlines both the recent and the planned developments.
2. Analysis of seawater desalination with NHR-200
Author(s): Zhang, Y, Zhang D. and Dong D.
Page: 23
Keywords: China, Multi-effect distillation, Nuclear desalination, Nuclear heating reactor, Research reactors, Seawater desalination
Abstract: The NHR-200 is a nuclear heating reactor, with a thermal capacity of 200 MW, which has been developed by the Institute of Nuclear Energy Technology, Tsinghua University. The NHR-200 is a dual-vessel light-water reactor, having an integrated arrangement, full power natural circulation, self-pressurized design. This design ensures that, in the event of a loss of coolant accident, the reactor core remains covered by coolant, thus precluding the need for off-site emergency actions such as sheltering, evacuation, relocation and decontamination. The excellent performance of the NHR-200 indicates that it is suitable to be coupled with a seawater desalination plant, both from a technical and an economic viewpoint. Following systematic analysis and comparisons of economic, technological and safety factors, the designs for coupling the desalination plant with the NHR-200 have been selected. This paper discusses the options considered and looks at the factors which influence the final levelized water prices.
3. Modelling of advanced flowsheets using data from miniature contactor trials
Author(s): Wallwork A.L., Denniss I.S., Taylor R.J., Bothwell P., Birkett J.E. and Baker S.
Page: 33
Keywords: British Nuclear Fuels plc (BNFL), Centrifugal contactors, Nuclear fuel cycle, Process simulation, Purex, Reprocessing
Abstract: Advanced single-cycle flowsheets are being developed by BNFL to reduce the cost of reprocessing spent nuclear fuel. These flowsheets are being intensively investigated using experimental and computational methods together to minimize the amount of experimental work needed. This includes obtaining fundamental data such as reaction kinetics and distribution data, operating miniature contactor rigs and using the high level modelling language, SpeedUp, for simulation purposes. BNFL has considerable experience in flowsheet modelling. The models have progressed from early FORTRAN codes to SpeedUp models owing to the increased complexity of the simulations, the need for flexibility and quality assurance. Current models now provide BNFL with a powerful simulation tool with which to investigate flowsheet designs. An important aspect of modelling development is validation and data reconciliation so that the models can be used with confidence. Miniature contactor rigs at Sellafield were therefore commissioned, in part, to provide experimental data for this process. Some results of these trials are therefore provided. They are used to demonstrate the validation process and show the effectiveness and flexibility of BNFL models.
4. Development of BNFL's next generation of nuclear fuel cycle facilities
Author(s): Hanson B.C., Taylor R.J. and Parkes P.
Page: 39
Keywords: British Nuclear Fuels plc (BNFL), Nuclear fuel cycle, Reprocessing
Abstract: BNFL has recently started operation of its thermal oxide reprocessing plant (Thorp). Long lead times, however, mean that it is already developing options for Thorp's successor through its multimillion pound advanced reprocessing programme. As the future of nuclear power is uncertain, it is necessary to pursue a wide range of options, including those which involve novel technologies which are challenging to engineer but have the potential to realize substantial cost savings. Rather than employ a �scattergun� approach, engineering assessments are being carried out as early as practicable in order to eliminate candidates which are unlikely to realize sufficient cost reductions, or those which prove impractical to engineer at an industrial scale. The results of these design studies are being used to focus the main thrust of the development activities. Cost estimates including lifetime costs are continually being updated and refined as experimental data from the programme become available. Rather than construct large development rigs, the programme is also aiming to maintain flexibility by relying on the use of adaptable process and mathematical models. The use of these models allows the programme to concentrate on fundamental data which are faster and cheaper to collect. It is intended that these models, alongside the engineering and costing assessments, will form the basis of a technology demonstrator, backed up by physical demonstrators at appropriate scale where necessary to prove crucial processes. An �intelligent plant� concept is also being developed to give direction to the on-line analysis and control systems which must be developed to enable continuous plant operation. In parallel, alternative designs are being pursued at the outset to further reduce expected costs. Starting engineering assessments at this early stage has allowed the project to challenge some conventional nuclear design methodologies and produce some �radical� design proposals for comparison. This paper will describe the development strategy in more detail and give examples of progress in these areas to date.
5. A regulator's viewpoint - regulatory approach to judging the adequacy of nuclear safety-related civil engineering design
Author(s): Bradford P., McNair I. and McNulty A.
Page: 43
Keywords: Civil engineering, Health and Safety Executive (HSE), Licence conditions, Nuclear operations and safety, Regulatory issues, Safety cases, Safety functions
Abstract: The objectives of this paper are to explain the legal framework within which the nuclear industry and the Nuclear Installations Inspectorate (NII) operate; clarify the basis from which the NII assesses civil structures; reinforce the approach the NII expects the nuclear industry to follow to demonstrate that its structures are safe enough; and to argue that what is sought is not �overdesign� but adequate design against clearly identified safety functional requirements, using appropriate design standards.
6. Building life and life extension - experience at Sellafield
Author(s): Riding J.
Page: 49
Keywords: British Nuclear Fuels plc (BNFL), Civil engineering, Decommissioning, Nuclear fuel cycle
Abstract: BNFL's Sellafield site has developed significantly since the 1950s, and continues to develop with the current major construction projects in progress. There exists therefore a wide range of buildings and infrastructure facilities of various age and construction style. It is the experience at Sellafield that where life extension is required, it is to achieve two fundamental objectives%3A to extend the period of safe operations, or to extend serviceable life in order to support decommissioning programmes. Integrated multi-discipline teams are usually established for Sellafield projects. This is especially appropriate for life extension projects which present more restrictions and interfaces than �new build� projects. It has been demonstrated that project teams which include operators, designers, safety personnel, and constructors, are required to establish achievable life extension/decommissioning strategies. Further advantages are gained if these teams of appropriate skills and experience are maintained throughout the project as it progresses through safety case preparation, design, installation and commissioning. A critical aspect of life extension projects concerns the restrictions imposed by the nature, the operational demands, and the immediate environment of the existing facility. These restrictions will influence the scope and complexity of the project and will necessitate effective teamwork at all stages, from initial strategies through to commissioning.
7. Decommissioning - a contractor's experience
Author(s): Ingham E.L.
Page: 55
Keywords: Radioactive waste management - transport and disposal, Sodium, United Kingdom Atomic Energy Authority (UKAEA), Waste Management, Waste management & disposal
Abstract: The last decade has seen, arguably, the most significant changes in the nuclear industry since its beginnings almost 50 years ago. The major new construction projects of the 1980s have been supplanted by liabilities management, and along with that change comes a very different range of engineering challenges. This paper discusses the implementation of decommissioning programmes from a contractor's viewpoint, citing specific project examples to illustrate the variable physical and radiological conditions and the range of risks which can be encountered.
8. The SGHWR decommissioning project - waste strategy
Author(s): Graham G. and Napper M.
Page: 61
Keywords: Radioactive waste management - transport and disposal, Steam generating heavy water reactor (SGHWR), Steam generating heavy water reactors (SGHWR), United Kingdom Atomic Energy Authority (UKAEA), Waste Management, Waste management & disposal
Abstract: Every facility must reach a stage in the decommissioning process where low-level waste (LLW) becomes the major factor in the decommissioning costs, therefore a cost-effective strategy for dealing with the waste must be sought. This paper describes the waste management strategy process that was carried out at the steam generating heavy water reactor (SGHWR) at Winfrith in Dorset. Obviously, each facility will have its own specific radiological problems, with its own unique fingerprint, which will have to be addressed, and, therefore, the optimum waste management strategy will differ for each facility. However, from the work done at SGHWR, it can be seen that it is possible to formulate a structured approach for dealing with LLW which meets the requirements of all stakeholders, is safe, technically acceptable, cost-effective, and, furthermore, is equally applicable to other plants.