Minor Actinide Burning in Thermal Reactors [electronic resource]: A Report by the Working Party on Scientific Issues of Reactor Systems /
Organisation for Economic Co-operation and Development.
Organisation for Economic Co-operation and DevelopmentContributor
Organisation for Economic Co-operation and DevelopmentContent Provider
Paris : OECD Publishing,
2014.
A modern light water reactor (LWR) of 1 GWe capacity will typically discharge about 20-25 tonnes of irradiated fuel (spent fuel) per year of operation. Despite the low content of about 0.1-0.2% of minor actinides in spent fuel, these actinides can nonetheless contribute significantly to decay heat loading and neutron output, as well as to the overall radiotoxic hazard of spent fuel. For this reason, there has long been an interest in transmuting minor actinides to reduce their impact on the back end of the fuel cycle. Fast reactors are needed to effectively transmute transuranics (TRUs), including minor actinides. However, recent studies have demonstrated that TRU transmutation rates can also be achieved in thermal reactors, although with certain limitations due to the accumulation of transuranics through recycling and their impact on the safety of power plants. The transmutation of TRUs could potentially be implemented in a substantial number of thermal reactors operating today, while waiting for a similar programme in fast reactors to allow for commercial-scale operations in 20 to 30 years or more. This publication provides an introduction to minor actinide nuclear properties and discusses some of the arguments in favour of minor actinide recycling, as well as the potential role of thermal reactors in this regard. Various technical issues and challenges are examined from the fuel cycle, operations, fuel designs, core management and safety/dynamics responses to safety and economics. The focus of this report is on the general conclusions of recent research that could be applied to thermal reactors. Further research and development needs are also considered, with summaries of findings and recommendations for the direction of future R&amp;D efforts.
1. Introduction 9 -1.1 Neptunium, americium and curium nuclear properties 9 -1.2 Rationale for minor actinide transmutation 13 -1.2.1 Radiotoxicity reduction 13 -1.2.2 Decay heat reduction 15 -1.3 Minor actinide transmutation strategies 15 -1.3.1 Homogeneous/heterogeneous recycling 15 -1.3.2 Single/multiple recycling 16 -1.3.3 Storage 17 -1.3.4 Minor actinide recycling in thermal reactors versus fast reactors 17 -1.3.5 Minor actinide recycling in thermal reactors as a technology demonstrator 18 2. Potential role and objectives of minor actinide recycling in thermal reactors 21 -2.1 Light water reactor (LWR) studies 21 -2.2 Heavy water reactor (HWR) studies 22 -2.3 High-temperature reactor (HTR) studies&nbsp; 23 -2.4 Survey of experimental studies 24 3. Issues associated with utilisation of MA-TRU fuels 29 -3.1 Recycling modes – homogeneous and heterogeneous 29 -3.2 Reprocessing 30 -3.3 Separation technologies 31 -3.4 Fuel manufacturing 33 -3.5 Fresh fuel transport and handling 34 -3.6 Irradiation testing&nbsp; 34 -3.7 Licensing 35 -3.8 Irradiated fuel 35 -3.9 Waste 36 -3.10 Impact on geological disposal&nbsp; 36 -3.11 Overall timescales 36 -3.12 Non-technical considerations 36 4. Fuel cycle issues 39 -4.1 Source terms&nbsp; 39 -4.2 Fuel fabrication 42 -4.3 Transport&nbsp; 42 -4.4 Utilisation rates&nbsp; 43 -4.5 Irradiated fuel inventories&nbsp; 44 -4.6 Radiotoxicity and environmental impact 44 5. Fuel and core design 45 -5.1 Fuel design&nbsp; 45 -5.2 Core design&nbsp; 45 -5.2.1 Equilibrium UO 2 core 46 -5.2.2 Equilibrium Am-Cm core 46 -5.2.3 Nuclear design parameters&nbsp; 47 -5.3 Material balance 51 -5.4 Fuel matrices 52 6. Operations, safety and licensing 55 -6.1 Initial fissile loading 55 -6.2 Impact on plant operations 56 -6.2.1 Fresh fuel receipt 56 -6.2.2 Core loading 56 -6.2.3 Core operation 57 -6.3 Code validation 57 -6.4 Licensing timescales&nbsp; 57 7. Economics&nbsp; 59 -7.1 Costs and benefits 59 -7.2 Cost impact&nbsp; 60 -7.2.1 Separation 60 -7.2.2 Transport 61 -7.2.3 Fresh fuel receipt and storage 61 -7.2.4 Core reactivity effect 61 -7.2.5 Licensing 62 -7.2.6 Discharge, storage and transport of spent MA-TRU fuels&nbsp; 62 -7.2.7 Spent fuel management 62 -7.2.8 Overall cost impact 62 -7.3 Economic benefits&nbsp; 62 -7.3.1 Repository cost savings 62 -7.3.2 Avoidance of radiological doses&nbsp; 63 -7.4 Subsidisation mechanisms&nbsp; 63 8. Research and development needs 65 -8.1 Separations 65 -8.2 Fuel fabrication 65 -8.3 Fuel transport&nbsp; 65 -8.4 Fuel design 66 -8.5 Core design 66 -8.6 Spent fuel characterisation 66 -8.7 Fuel cycle assessment 66 -8.8 Overall timescales&nbsp; 67 9. Summary and recommendations 69 References&nbsp; 71 List of bibliographic references related to the Report on Minor Actinide Burning in Thermal Reactors 73  
A modern light water reactor (LWR) of 1 GWe capacity will typically discharge about 20-25 tonnes of irradiated fuel (spent fuel) per year of operation. Despite the low content of about 0.1-0.2% of minor actinides in spent fuel, these actinides can nonetheless contribute significantly to decay heat loading and neutron output, as well as to the overall radiotoxic hazard of spent fuel. For this reason, there has long been an interest in transmuting minor actinides to reduce their impact on the back end of the fuel cycle. Fast reactors are needed to effectively transmute transuranics (TRUs), including minor actinides. However, recent studies have demonstrated that TRU transmutation rates can also be achieved in thermal reactors, although with certain limitations due to the accumulation of transuranics through recycling and their impact on the safety of power plants. The transmutation of TRUs could potentially be implemented in a substantial number of thermal reactors operating today, while waiting for a similar programme in fast reactors to allow for commercial-scale operations in 20 to 30 years or more. This publication provides an introduction to minor actinide nuclear properties and discusses some of the arguments in favour of minor actinide recycling, as well as the potential role of thermal reactors in this regard. Various technical issues and challenges are examined from the fuel cycle, operations, fuel designs, core management and safety/dynamics responses to safety and economics. The focus of this report is on the general conclusions of recent research that could be applied to thermal reactors. Further research and development needs are also considered, with summaries of findings and recommendations for the direction of future R&amp;D efforts.
Bibliographic Level Mode of Issuance: Monograph
Nuclear Energy
Mechanical Engineering
Engineering & Applied Sciences
Nuclear Engineering