Position Papers

Nuclear fission technology is generally considered to be at a mature stage of development. However, there are still many advances in science and technology being made right across the fuel cycle. These developments will help meet the challenges of future energy demands and security of supply. They will help make improvements in efficiency and safety of nuclear operations and clean-up. And they will also help in securing long term waste management solutions including disposal and in the area of radiological-nuclear threat reduction.   

NNL has many years experience of the nuclear fuel cycle and associated science and technology and is in an ideal position to advise decision makers on key topics which are important when considering the UK's ability to meet these nuclear challenges.

NNL's view on these topics is being set out as a series of Position Papers. These papers reflect our independent and authoritative view and are supported by underpinning studies.

  • Thermal Processes for Immobilising Intermediate Level Wastes

    Thermal Processes for Immobilising Intermediate Level Wastes

    The UK has gained experience of a number of processes for the immobilisation of radioactive waste over several decades. This experience comprises development of product formulations, immobilisation processes, as well as commissioning, operating and optimising immobilisation plants and includes innovations that have been adopted internationally.

    Since 1991, high level liquid waste from reprocessing has been vitrified using a French process for inductive heating of calcined liquid waste, whilst most operational intermediate level wastes have been directly encapsulated in cement. Although substantial progress has also been made in the vitrification of high level wastes produced before 1991, there remain a number of legacy intermediate level wastes from these earlier days of reprocessing for which decisions on immobilisation have yet to be made.

    Thermal processes have the potential to provide high quality glass and ceramic based waste products and may offer significant savings on operational and disposal costs of these wastes due to the potential for reduced volume in comparison with cementation. A wide range of thermal processes exist worldwide that could be used for immobilisation of some of these UK legacy wastes.

    This paper discusses the potential benefits of thermal processes as well as the challenges that would need to be overcome to implement thermal processes for intermediate level wastes. The UK’s track record in operating Waste Vitrification Plant is discussed along with a range of other technologies which could be applied for ILW.

    Thermal Treatment Position Paper

  • Advanced Reprocessing

    Advanced Reprocessing

    "Advanced Reprocessing - Research and Development Needs" looks at the requirements to support options to close the fuel cycle in the 21st century. 

    The expected growth of nuclear energy in the UK and globally, as part of the mix of safe, secure and low carbon energy supply needed by 2050, will result in substantial quantities of used nuclear fuel in storage. Disposal of used fuel in a Geological Disposal Facility (GDF) towards the end of the 21st century, or even later, is a feasible route for this used fuel, the so-called ‘open’ or once-through nuclear fuel cycle.

    Advanced Reprocessing Position Paper

  • Minor Actinides Transmutation

    Minor Actinides Transmutation

    For many years there has been a sustained international interest in partitioning and transmutation of the minor actinides neptunium, americium and curium produced by fission reactors. Although these three elements are produced in relatively small quantities in fission reactors, they are major contributors to the decay heat, neutron output and radiotoxicity of spent nuclear fuel.

    Implementation of minor actinide transmutation on a commercial scale will require major research and development effort sustained over many years and is not likely to be available for at least twenty years. This position paper sets out the view of the UK National Nuclear Laboratory's (NNL) of the potential role of minor actinide transmutation in the context of nuclear waste management in the UK.

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  • Boiling Water Reactors Position Paper

    Boiling Water Reactors Position Paper

    The purpose of this paper is therefore to give a description of BWR technology and to set out the basic design and operating principles of the BWR, with a more in-depth look into Hitachi-GE's ABWR. The evolution of the BWR is discussed, followed by a global overview of BWR deployment. The reactor core and nuclear fuel are then described, with particular emphasis on the differences and similarities between BWRs and PWRs (of which the UK has in-depth knowledge via Sizewell 'B' PWR).

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  • Proliferation Resistance and Physical Protection

    Proliferation Resistance and Physical Protection

    Assessing the inherent Proliferation Resistance and Physical Protection (PRPP) characteristics of nuclear systems is an area that is becoming increasingly important internationally. International efforts to stimulate the development of advanced nuclear systems, such as the Generation IV International Forum (GIF) and the IAEA International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) project, have identified the need to strengthen features that provide inherent PRPP. The UK National Nuclear Laboratory (NNL) has been proactive in developing a PRPP assessment methodology in support of UK requirements in this area. Although PRPP assessment methods were developed primarily to guide decision making on advanced reactor and fuel cycle R&D, they can also be applied in other contexts, such as the management of historic UK liabilities. This position paper explains the issues involved in PRPP assessments and highlights why NNL decided to develop its own methodology and why the new method is suited for real world application not just in the UK, but internationally. 

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  • Fuel Cycle R&D Safeguard Advanced Ceramic Fuel Skills

    Fuel Cycle R&D to Safeguard Advanced Ceramic Fuel Skills

    Nuclear energy is a mature, reliable and low-carbon technology and is viewed by many as an essential contributor to a sustainable energy mix. In many countries, policy concerning the back end of the fuel cycle has yet to be resolved and many have yet to finalise their plans for geological disposal. Decisions on open vs closed fuel cycles will be dependent on the speed at which new fuels and reactor technologies are developed and on ultimate power generation requirements. As such, advanced reactor and fuel cycle research has an important role to play in setting out the most appropriate scenarios for nuclear energy deployment for the remainder of this century.

    This paper sets out the rationale for a fuel manufacturing R&D programme together with the skills and expertise required to implement it.

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  • Thorium Fuel Cycle

    Thorium Fuel Cycle

    In recent years, interest in the thorium fuel cycle has grown notably, with several commercial and research organisations looking to undertake assessments of thorium fuels for a variety of reasons. This paper provides an independent review of the thorium fuel cycle by the UK National Nuclear Laboratory (NNL), highlighting the strengths and weaknesses of thorium, not just in the UK context, but globally.

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  • UK Nuclear Horizons

    UK Nuclear Horizons

    Conditions for a nuclear renaissance are falling into place in many countries. New nuclear build is recognised as having a clear role as part of the future energy mix. Our latest position paper sets out our assessment of the key areas that need to be considered and addressed in order to implement a workable strategy for our future energy supply.The thorium fuel cycle presents an alternative option to the usual uraniumplutonium fuel cycle that has long been advocated and researched, but which has yet to be adopted on a commercial scale. 

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  • Small Modular Reactors

    Small Modular Reactors

    With the growth of nuclear energy world-wide, there has been a resurgence of interest in new reactor designs. These include a substantial number of Small Modular Reactor (SMR) concepts for a range of applications including electricity production, district heating, desalination and plutonium management.

    NNL's latest position paper introduces some of the potential SMR designs and technologies and provides an insight into the benefits and potential role of SMRs in the UK. The paper only considers land-based SMRs, although there is potential for their use in maritime propulsion.

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