Dalton Cumbrian Facility

Transcription

1 Dalton Cumbrian Facility Strategic Science Plan Purpose of this Document: This document gives a strategic description of the scientific programmes of the Dalton Cumbrian Facility (DCF) during its initiation period through 2015, i.e. it covers the totality of the joint 20 million investment. Cover Image: DCF on a sunny Cumbrian day.

2 Executive Summary The radiation sciences and nuclear engineering decommissioning programmes of the Dalton Cumbrian Facility have been initiated by the Dalton Nuclear Institute of the Faculty of Engineering and Physical Sciences of the University of Manchester with the support of the Nuclear Decommissioning Authority to perform research at the forefront of their respective fields, thereby to provide world-leading expertise to the nuclear power industry, especially in the areas of decontamination and decommissioning, and nuclear waste management treatment and storage. To be successful and to establish a viable future for the Dalton Cumbrian Facility, the science programmes have to make an impact in the nuclear industrial community, as well as in the general scientific community in the UK and world-wide. A multi-pronged approach employing lab and rig scale experiments, in conjunction with simulation and modelling, will be used to investigate the fundamental science and engineering that underlie many of the problems encountered by the Nuclear Decommissioning Authority in its stewardship of radioactive materials and the UK s nuclear legacy. The goal is to provide information for incorporation in whole system models for nuclear decommissioning, radioactive waste cleanup and management, nuclear power plant design and operation, and health physics. The physical consequence of the strategic science plan will be to grow the radiation sciences and engineering decommissioning capability to a resident team of at least 30 researchers by 2015, as well as supporting additional University of Manchester researchers from the Faculty of Engineering and Physical Sciences for extended periods. 2

3 Table of Contents Executive Summary Table of Contents List of Figures Mission Statement Introduction Background Research Staff and Facilities Radiation Science Team Nuclear Engineering Decommissioning Team Experimental Facilities Science Programmes Introduction Strategic Objectives Radiation Sciences Aim Introduction Research Program Chemical Degradation of Matter by Radiation. (Lead: Pimblott) Radiation-induced Dynamics in Heterogeneous Multi-phase Systems. (Lead: Koehler) Structural Effects of Radiation on Materials. (Lead: Jimenez-Melero) Other Research Areas Nuclear Engineering Decommissioning Aim Introduction Research themes

4 5.3.1 Contamination and Decontamination. (Lead: Sharrad) Waste Behaviour and Treatment. (Lead: Jones) Decommissioning Technologies. (Lead: Lennox/Stancu) Sustainability in Decommissioning, Policy, Practice and Decision Making. (Lead: Banford) Long-term Outputs...58 Appendix A. Dalton Cumbrian Facility Academic Staff

5 List of Figures Figure 2.1 The Dalton Nuclear Institute of the University of Manchester and its underlying research centres and facilities, including founding partner organisations... 9 Figure 2.2 DCF academic research staff and support team Figure 2.3 Schematic diagram of the 5 MV tandem ion accelerator system under construction by NEC and to be installed in the DCF Figure 2.4 DCF controlled atmosphere chamber constructed by M. Reid under the guidance of S. Koehler and currently located in the PSI Figure 2.5 Decommissioning Rig Facilities - NNL Workington Figure 2.6 Active Facilities - NNL Central Laboratory Figure 4.1 Degradation of polymeric materials Figure 4.2 Research programme on the degradation of alternative polymeric encapsulants Figure 4.3 Radiation chemistry of aqueous systems Figure 4.4 Evolution of programme on the radiation chemistry of water and the effects of different and mixed radiation fields Figure 4.5 Radiation-induced dynamics in heterogeneous systems Figure 4.6 Evolution of research on H 2 production and reaction in heterogeneous water-ceramic oxide systems Figure 4.7 Structural effects of radiation on materials Figure 5.1 Nuclear Engineering Decommissioning Research Themes Figure 5.2 Contamination and Decontamination Research Themes Figure 5.3 Contamination and Decontamination Research Progression Figure 5.4 Waste Behaviour and Treatment Research Themes Figure 5.5 Graphite Waste Behaviour Research Progression

6 Figure 5.6 Decommissioning Technologies Research Themes Figure 5.7 Decommissioning Technologies Research Progression Figure 5.8 Waste Management and Decommissioning Policy and Strategy Figure 5.9 WM&D Policy and Strategy Research Progression

7 1 Mission Statement The goal of the science programmes of the Dalton Cumbrian Facility (DCF) of the Dalton Nuclear Institute (DNI) of The University of Manchester (UoM) is to perform research at the forefront of the fields of radiation sciences and of engineering decommissioning, and thereby to provide world-leading expertise to the nuclear industry, especially in the areas of decontamination and decommissioning, and nuclear waste management treatment and storage. 7

8 2 Introduction 2.1 Background The radiation sciences and nuclear engineering decommissioning programmes of the DCF have been initiated by the DNIof the Faculty of Engineering and Physical Sciences of the UoM with the support of the Nuclear Decommissioning Authority (NDA) to embrace a wide range of experimental and modelling disciplines to address the needs of various nuclear stakeholders, especially those involved in the decommissioning of nuclear facilities within the UK. The DNI is the focus for all nuclear related research and higher learning activities within the university and oversees a wide variety on research centres and facilities including the DCF. This structure is summarised in Figure 2.1 To be successful and to establish a viable future for the DCF, the science programmes have to make an impact in the nuclear industrial community as well as in the general scientific community in the UK and world-wide. The DCF must be visible and present, producing high quality research output, and participating in national and international forums. These strategic tasks have to be performed in parallel to the physical development of DCF infrastructure the construction, commissioning, establishing, and operation of the experimental facility for nuclear decommissioning and radiation sciences at Westlakes Science and Technology Park in Cumbria. A multi-pronged approach employing experiments in conjunction with simulation and modelling will be used to investigate the fundamental science and engineering that underlie many of the problems encountered by the NDA in its stewardship of radioactive materials and the UK s nuclear legacy. The goal is to provide information for incorporation in whole system models for nuclear decommissioning, radioactive waste cleanup and management, nuclear power plant design and operation, and health physics. While this role does not extend to technology development, which lies under the auspices of the National Nuclear Laboratory (NNL), nuclear consultancies and the broader supply chain support organisations, an involvement in applied technology development being carried out by others, but based on our research 8

9 accomplishments, is envisaged given the expanded mandate of academia in the 21 st century. Nuclear Front-end 4.2m NWDA Rolls - Royce C-NET Nuclear UTC 8.2m DECC NAMRC DNI Research Facilities DCF RCRD 20m NDA 1.4m BNFL Underlying Science MPC BNFL CRR Nuclear Back-end Figure 2.1 The Dalton Nuclear Institute of the University of Manchester and its underlying research centres and facilities, including founding partner organisations. As stated in the collaboration agreement, in building the radiation sciences and engineering decommissioning capabilities of the DCF, it is the intention of the UoM and the NDA to locate the research activity of the DCF at Westlakes Science and Technology Park. When the DCF is operational, that facility will house the research activity of the Dalton Radiation Sciences (DaRS) and Nuclear Engineering Decommissioning (NED) groups, accepting that the academic staff will have UoM teaching and administrative responsibilities on the main campus in Manchester. It is expected that the research programmes based in Cumbria will also draw on existing staff based at Manchester when, and where appropriate. The objective of the strategic science plan is to grow the radiation sciences and engineering decommissioning capability to a resident team of at least 30 researchers by 2015, as well as supporting additional UoM researchers from the Faculty of 9

10 Engineering and Physical Sciences for extended periods. The research teams will be supported by technical and support staff. Core academic staff, postdoctoral research associates (PDRA) and graduate students (GS) will base their research work in West Cumbria and will be encouraged to locate themselves in the region. The DCF computer cluster will be located in Manchester, with remote access to the cluster for the researchers based in Cumbria. Establishing an active research community at the Westlakes Science and Technology Park, including a group of students, offers the opportunity for integration and direct interaction with key industrial personnel. Throughout the body of this document, all discussions about personnel, equipment and the location of staff and facilities should be taken as in accordance with the principles outlined in the collaboration agreement. 2.2 Research Staff and Facilities Research at DCF will fall into two areas: 1. Radiaton Science, and 2. Nuclear Engineering Decommissioning At the heart of the radiation science research programme is DCF s extensive irradiation facilities, which provide the opportunity to deliver fundamental research into radiation chemistry and radiation damage of materials, and which will be complemented by a wide range of high-end analytical and surface inspection equipment. The nuclear engineering decommissioning capability will incorporate both fundamental and applied research. Research will focus on developing and demonstrating innovative solutions that deliver benefits to the UK, as well as the international decommissioning and clean-up programmes. DCF will adopt a collaborative approach to the research programme, working closely with the NDA, the NNL, the Site License Companies and the industry supply chain. 10

11 The core research staff of the DCF envisaged under the cooperative agreement between the UoM and the NDA will provide a breadth of expertise to address the crucial challenges of radiation science and nuclear engineering decommissioning within the context of the UK s nuclear industry. The planned teams are comprised of six academics plus several supporting experimental officers, organised in the hierarchy shown in the following figure. The researchers are nominally divided into two teams supporting the two research programmes; however, cooperative interaction between the personnel is expected. Research Director Simon Pimblott Research Lead - Radiation Sciences Simon Pimblott Head of Facilities Charles Potter Research Lead - NED Barry Lennox Surface Science Sven Koehler Analytic Laboratory Ruth Edge Engineering Decommissioning Anthony Banford Radiation Damage Enrique Jimenez- Melero Ion Accelerator TBA Nuclear Graphite Abbie Jones Waste Streams & Reprocessing Clint Sharrad Remote Systems Engineering Alexandru Stancu Figure 2.2 DCF academic research staff and support team Radiation Science Team The Radiation Science team is currently made up of Professor Simon M. Pimblott (EPSRC Energy Research Chair in Radiation Chemistry, School of Chemistry) and Drs Sven Koehler (Dalton Fellow, School of Chemistry) and Enrique Jimenez-Melero (Dalton 11

12 Fellow, School of Materials). This team are part of the University s Research Centre for Radwaste and Decommissioning (RCRD) as well as the Centre for Nuclear Energy Technology (C-NET). These research centres operate under the auspices of the DNI Nuclear Engineering Decommissioning Team The core NED team comprises of: Professor Anthony Banford (Royal Academy of Engineering Visiting Professor of Nuclear Engineering, Chemical Engineering and Analytical Science), Professor Barry Lennox (School of Electrical and Electronic Engineering), Dr Clint Sharrad (School of Chemical Engineering and Analytical Science), Dr Abbie Jones (School of Mechanical Aerospace and Civil Engineering) and Dr Alexdru Stancu (School of Electrical and Electronic Engineering). This team are part of the RCRD and work closely with other university staff on specific research projects Experimental Facilities Development of the physical capability to address the significant challenges of the nuclear decommissioning industry at the DCF is the result of careful and planned investment. The irradiation facilities are at the heart of this investment. Two in-house radiation sources are being purchased: a 5 MV tandem van der Graaff accelerator capable of supplying 10 MeV protons and 15 MeV helium ions as well as a variety of partially stripped heavy (e.g. metal) ions, and a 60 Co gamma irradiator, as well as a controlled atmosphere chamber incorporating a low-energy electron gun. Figure 2.3 shows a schematic of the DCF tandem ion accelerator system, and the controlled atmosphere chamber employing laser rather than low energy electron radiation is shown in Figure

13 Figure 2.3 Schematic diagram of the 5 MV tandem ion accelerator system under construction by NEC and to be installed in the DCF. Figure 2.4 DCF controlled atmosphere chamber constructed by M. Reid under the guidance of S. Koehler and currently located in the PSI. The radiation sources will be complemented by an analytic and surface interrogation laboratory containing a variety of equipment for examination of irradiated systems. Analytic techniques to be employed include: gas chromatography for measuring gas production, ion chromatography for analyzing anions and cations in solution, 13

14 liquid chromatography for measuring polymers and other organics, mass spectrometry for isotopic analysis, UV/visible/NIR absorption and transmission spectroscopy for analysis of liquid samples, fluorescence and phosphorescence spectroscopy of liquids diffuse and specula reflectance spectroscopy for examining surfaces and powders, BET measurement for surface absorption characterisation, Fourier transform infra-red spectrometry for examining surfaces, Fourier transform Raman spectroscopy and Raman microscopy with multiple laser excitation (1064, 782, 633 and 532 nm) for examining surfaces, and scanning electron microscopy in vacuum and under environmental conditions. The radiation science facilities available at the DCF when it is fully operational in 2012 will be unrivalled in the UK and amongst the best worldwide. The NED research team will have access to state of the art facilities based in West Cumbria, notably the DCF, the NNL Central Laboratory and the NNL Workington Facility, in addition to other University facilities. The DCF will be utilised to support legacy waste and decommissioning research, notably to consider the performance of materials and wasteforms in radiation environments. NNL Workington will be used as a base for non-active, rig and remote engineering research. This facility allows researchers to build and operate engineering scale apparatus to underpin their research. The facility (illustrated below, Figure 2.5) has the capacity to simulate pond and silo type conditions using the deep pit and to build mock up cells/caves to simulate plant and the space to carry out tests of remote engineering systems. The facility has already been used effectively to test remote 14

15 devices developed at the University and other university researchers will soon start work on the NNL molten salt facilities as part of a research council funded critical mass grant collaboration. Figure 2.5 Decommissioning Rig Facilities - NNL Workington The NNL Central Laboratory will be used for research which requires experimentation using radioactive materials. This facility provides unique infrastructure within the United Kingdom for research with high specific activity radionuclides. The Central Lab is well equipped for the characterisation of radioactive materials and solutions with access to numerous spectroscopic and analytical techniques including UV-vis-NIR absorption, Raman, IR-ATR and luminescence (TRLIFS) spectroscopies, electrochemical methods (e.g. cyclic voltammetry, bulk electrolysis), scanning electron microscopy and powder X-ray diffraction. The facility is able to safely conduct research on active materials with the use of active laboratories, plutonium-active gloveboxes and a rig hall. The NED research team is the first academic group to successfully gain access to these facilities for postgraduate students, through the third-party access agreement, and indeed research is already underway with University of Manchester researchers currently in the laboratory. 15

16 Figure 2.6 Active Facilities - NNL Central Laboratory. Images of the Radiation Sciences and Nuclear Engineering Decommissioning team members and the principal research facilities are included in Appendix A. 16

17 3 Science Programmes 3.1 Introduction Establishment of the science programmes of the DCF is based on a major investment in human and physical capabilities by the UoM and the NDA. The primary focus of this initiative is the development of the experimental facility at the Westlakes Science and Technology Park in Cumbria. Ultimately, this facility will provide frontline scientific support for nuclear challenges. As the Westlakes Science and Technology Park facility will not be fully operational until September 2012, preliminary experimental radiation science studies are being performed using irradiation facilities available in the School of Pharmacy at UoM and at the University of Notre Dame Radiation Laboratory (ND Rad Lab), United States of America (USA), as well as in laboratory space at the UoM main campus. In addition, early access to the Central Laboratory of the NNL has been initiated and two PhD research projects from the NED programme are underway. 3.2 Strategic Objectives The strategic goals of the DCF programmes are to: build a world leading intellectual and experimental capability in radiation effects of nuclear systems and the engineering decommissioning of nuclear legacy materials and facilities, create awareness of, and to brand, the Dalton Cumbrian Facility, build cooperative research networks, produce stakeholder benefits, and demonstrate the value of the UoM and NDA investment. 17

18 4 Radiation Sciences 4.1 Aim To develop a mechanistic understanding of radiation-induced effects and chemical processes to allow a predictive description of degradation of materials performance. 4.2 Introduction Development of the experimental capabilities and the research programme at DCF to achieve optimum performance, relevance and sustainability requires investment of time and effort in experimental equipment specification, and in consulting and communicating with interested nuclear industry stakeholders and academic institutions. Extensive discussions have been initiated with industry stakeholders and academic institutions with the goal of developing communication and research partnerships. These discussions have revealed real research needs and opportunities for academia in seven areas: (i) decommissioning and clean-up, (ii) waste remediation, storage and management, (iii) geological disposal, (iv) spent fuel reprocessing, (v) continued generation, (vi) next generation nuclear new-build, and (vii) advanced nuclear energy systems with scientific challenges spread across the fields of radiation chemistry, radiation physics, and radiation effects on materials. 4.3 Research Program Long term sustainability of the DCF at Westlakes needs (i) a strong research portfolio, based on needs of nuclear stakeholders, underpinned by (ii) a well-supported academic research programme addressing fundamental phenomena in radiation, nuclear and 18

19 engineering sciences. Investigations in three broad interdisciplinary fields are planned as the basis of the long-term DCF based experimental programme. These fields are: and 1. the chemical degradation of matter by radiation (Lead: Pimblott), degradation of polymeric materials radiation chemistry of aqueous systems 2. the radiation-induced dynamics in heterogeneous multi-phase systems (Lead: Koehler), radiolysis of water-metal oxide mixed-phase systems 3. the structural effects of radiation on bulk materials (Lead: Enrique Jinenez Melero). mechanistic understanding of irradiation induced changes in mechanical properties. Each research field is coordinated by one of the DaRS team members; however, the research team works in a coordinated and interdisciplinary way to focus relevant expertise on projects and to bring the maximum benefit to each and every research study. Within each of the three research fields, a variety of projects will focus upon aspects of scientific and technological interest in the seven critical areas listed earlier. Comparison of the results from the first two fields will differentiate the effects of radiation on bulk homogeneous materials from those on mixed-phase systems, and thereby elucidate the role of interfacial processes and the influence of the transport of energy, of charge and of matter across interfaces on observable radiation-induced materials degradation and deterioration. Understanding chemistry at interfaces is a fundamental grand challenge. 19

20 4.3.1 Chemical Degradation of Matter by Radiation (Lead: Pimblott) Degradation of polymeric materials Organic materials are frequently found in association with nuclear reactor infrastructure or waste materials in the form of polymers, solvents, or waste oils. In addition, polymers have been proposed as alternative encapsulants for nuclear wastes containing reactive metals. The radiolysis of Figure 4.1 Degradation of polymeric materials. these materials can lead to structural failure or hazardous H 2 or CH 4 gas formation. The production and properties of a wide range of radiation-induced species in hydrocarbons and other low permittivity media have been investigated in experiments yields of stable gaseous molecular products, like H 2 ; however, only limited data are available on the yields of other products. A detailed mechanistic understanding of the physical and chemical processes occurring in radiolysis is not available except on the most empirical level. The lack of a detailed mechanistic model makes it difficult to speculate on product yields for different types of radiation or to predict the effects of radiation on uninvestigated materials. Current research on the degradation of polymeric materials focuses on: Effects of radiation on PVC. The polymer PVC is encountered in many environments throughout the nuclear waste management portfolio. There are concerns about its degradation and about the production of potentially explosive and corrosive gases such as H 2 and HCl. Radiation-induced degradation of PVC has been shown to depend upon the radiation type (,, or n) and on the environment (e.g. the presence of over-gases, humidity, hydrocarbons, ceramic particulates, etc). In addition, production of HCl has been found to continue for an extended period (days) post irradiation. This 20

21 work complements NDA supported and Sellafield Ltd overseen experiments at the NNL-Central Laboratory involving Pu-contaminated PVC. A new research project will be initiated in the near future: Radiation effects on alternative encapsulants. The principal packaging method for ILW is immobilization in cement; however, for some wastes other packaging systems are desirable. This project will provide information to challenge/demonstrate the viability of the use of polymeric materials for the encapsulation of radioactive wastes containing reactive metals. Several types of polymer system are currently under consideration as packaging materials for these materials. This project will focus on silicon rubbers obtained by the cross-linking of silicone systems resulting from the hydrolysing silanes. The initial focus will be on well-characterised systems of wellknown composition before moving on to uncharacterised commercial/proprietory polymers. The performance of the polymers will be studied in isolation and when in contact with water at neutral and highly alkaline ph. This wide range of conditions will offer information relevant to the likely environments in short-term storage as well as long term disposal in the GDF. Figure 4.2 shows the progression of the research programme currently associated with understanding radiation effects on polymeric encapsulants for wastes containing reactive metals, highlighting the funding sources for the research performed. 21

22 Figure 4.2 Research programme on the degradation of alternative polymeric encapsulants. Future research will address: Production of non-aqueous liquids by degradation of organics and hydrocarbon polymers. It has been suggested that solid organic materials decompose in an irradiation field to form liquids which can then act as a transport medium for radionuclides and provide a route to the biosphere. This is a problem of particular significance in calculating risks associated with waste disposal Radiation chemistry of aqueous systems Understanding the radiation chemistry of water is central to most of the critical challenges of the nuclear industry, ranging from the control of coolant chemistry in water cooled reactors to groundwater chemistry in a GDF to the Figure 4.3 Radiation chemistry of aqueous systems. 22

23 safe storage of reprocessed plutonium and of spent fuel. The current research efforts in this area focus on: Production of H 2 from water. Water is a common coolant and shield material, and adsorbed water is ubiquitous on surfaces in the storage of radioactive materials. Water radiolysis produces H 2 ; however, the effects of small amounts of organics, of colloids, of metal surfaces and impurities, including other atmospheres, on hydrogen production are poorly characterized. The main objective of this research project is to gain an understanding of the early steps in the radiolysis of water, in particular to determine the main source of H atom and its yield depending on the system and energy applied. To achieve these aims, radiation chemical experiments combined with stochastic track chemistry calculations were used to investigate the formation of H atom in the irradiation of water and aqueous solutions. This research is being performed in cooperation with the US Department of Energy (DOE) ND Rad Lab and the NNL. Effects of different and mixed radiation fields. Radiation effects due to the neutron fields of nuclear reactors or the self-radiolysis by -particles from transuranic waste materials are driven by fundamental chemical processes. The interplay between these processes depends on the type of radiation, and damage initiated by neutrons and heavy ions is very different from that induced by -rays and fast electrons. Data on the effects of high-let radiations (such as alpha particles and accelerated light and heavy ions) are scarce, but the available data reveal a significant effect of particle type and energy, which reflects the competition between intra-track reaction of the radiation-induced radicals, diffusion, and scavenging. This competition is modified by changes in the ion track structure. As a complement to a systematic experimental investigation, we are developing realistic models for track physics and chemistry to predict radiation effects in complicated practical applications and where experiments cannot be performed. The planned progression of this research programme is outlined in Figure

24 Figure 4.4 Evolution of programme on the radiation chemistry of water and the effects of different and mixed radiation fields. Future activities already funded will include experiments and modelling on: Radiation chemistry of nitrate and nitric acid systems. The standard method for the extraction of actinides from fission products, used to return plutonium and uranium in used fuel rods back to the beginning of the nuclear fuel cycle, involves a liquid extraction process in which the actinides are extracted into an organic phase leaving the fission products in an aqueous acidic phase, of 6M nitric acid. A number of factors are thought to affect the processes efficiency and safety of operation. Most important is the degradation of complexes in the organic phase via reaction with radicals produced through water and nitrate radiolysis, and the radiolytic formation of potentially explosive H 2 gas. In this study, experiments in conjunction with simulation and modelling will be used to investigate the chemical reactions of nitrate and nitric acid that occur in the PUREX process due to exposure to radiation. This NDA supported 24

25 research program follows on from earlier mechanistic studies on the production of H 2 in simpler aqueous systems, mentioned earlier Radiation-induced Dynamics in Heterogeneous Multi-phase Systems. (Lead: Koehler) Understanding the effects of radiation at interfaces and on the transport of charge and energy across an interface is relevant to many practical problems in the nuclear industry. Heterogeneous environments are frequently encountered in the management of radioactive waste materials, in the storage of plutonium Figure 4.5 Radiation-induced dynamics in heterogeneous systems. from reprocessing and spent nuclear fuel, and in nuclear power plant infrastructure. Examples include sludge and slurries in storage facilities, and porous oxide coatings on the metal surfaces of the primary circuit in a nuclear reactor. Deposition of a significant quantity of energy near a phase boundary is a pathway for wholesale exchange of reactive intermediates between the two phases. For instance, radiation chemical studies on aqueous dispersions of silica and of zirconia have shown that electrons can cross from both oxides to water. Other experiments have shown that the radiation-induced production of H 2 from water adsorbed on various ceramic oxide particles can significantly exceed the expected amount produced from direct energy deposition in the water; and the yield of H 2 depends critically on the oxide. There is an apparent separation of the reducing (e - aq and H 2 ) and oxidizing equivalents at the ceramic oxide interface. Possible explanations include (i) the trapping of the hole within the oxide particle through a change in the oxidation state of an ion in the lattice of the oxide particle, (ii) the trapping of a hole at the surface of the oxide particle followed by dissolution or modification of the surface, or (iii) the formation of reactive oxygen species adsorbed on the surface of the particle. The formation of defects in silica and other ceramic oxides by irradiation is well known, but a correlation 25

26 with radiolytic effects of a liquid phase has not been observed. A number of studies identifying reactive oxygen radicals on various ceramic oxide surfaces have been made. A fundamental understanding of the radiation-induced chemistry of heterogeneous water-oxide systems that can be used for risk assessment purposes in the transportation and storage of nuclear wastes and PuO 2 will require not only the elucidation of the effects of radiation on the constituent media, but also a description of the physical and chemical processes occurring at the interface, and of the possibly significant role of low-energy electrons in the transport of charge and energy across the interface. The current headline research topic in this area is: Radiolysis of water-metal oxide mixed-phase systems. Recent studies have shown significant radiation-induced chemistry between oxide particulates and adsorbed water and hydrocarbons. This chemistry is a complicating factor for (long-term) nuclear waste storage. Specific questions include why there is apparently no energy transfer from PuO 2 to adsorbed water, in contrast to UO 2 and CeO 2, and why the yield of H 2 yield from moist PuO 2 increases approximately exponentially with added water above a threshold level. This work is being carried out in cooperation with NNL under the auspices of the EPSRC DIAMOND research consortium and underpins Sellafield SLC supported work in NNL-CL on hydrogen production from water-puo 2. 26

27 Research Progression Behaviour of Water-Ceramic Oxide Systems Sellafield DOE Bechtel Bettis EPSRC H 2 production from aqueous slurries H 2 production from adsorbed water on oxide surfaces H 2 /O 2 chemistry over oxide surfaces PuO 2 storage & disposition H 2 formation in Hanford waste tanks H 2 production from aqueous systems Current 2011 Future Figure 4.6 Evolution of research on H 2 production and reaction in heterogeneous water-ceramic oxide systems. In addition a new project is about to be initiated on: Understanding the radiation stability of alternative phosphate cement systems. Empirical experiments have shown that ionising radiation may lead to radiolysis of entrained water in phosphate cements, but the effect on wasteform integrity and durability is unknown. In collaboration with the Immobilisation Science Laboratory at the University of Sheffield, we are investigating of the radiation stability of phosphate cement systems developed for radioactive waste immobilisation. The objectives are to determine the dose and dose rate dependence of cement water radiolysis, the stability of cementing phases and their decomposition products, e.g. evolved gas, and radiation induced changes in dimensional stability and mechanical properties. This knowledge will support a predictive model for the long term radiation stability of these materials. Future planned research activities will include: Radiation effects of water-cement systems. Grouting of radioactive wastes is the generally accepted immobilization and packaging method, but a number of 27

28 complicating questions remain. Is there energy transfer from the solid matrix to water? How do pure cement/silica grouts compare with cement? What is the effect of reducing agents on yields? What is the effect of nitrate wastes? What is the effect of long term irradiation on e.g. water removal, nitrate to nitrite conversion? What is the product of radiolysis of nitrite wastes? This research is a natural extension of studies described above in this and the preceding sections. Mechanistic understanding of radiation-induced corrosion. The role of radiolysis in the corrosion of metals is central to problems across the nuclear power portfolio, from plant operation to the long term storage of wastes. A mechanistic understanding of radiation-assisted corrosion chemistry, important for predicting long term safety, is not available Structural Effects of Radiation on Materials (Lead: Jimenez-Melero) A detailed knowledge of the effect of radiation damage on structural and fuel cladding materials is fundamental to predicting the behaviour of components in nuclear infrastructures ranging from reactors (both during and after service) to Figure 4.7 Structural effects of radiation on materials. facilities for waste storage to plant employed in waste processing operations. Of particular concern is the expectation that the neutron fluxes components receive in-service may cause changes to the dimensions, microstructure, microchemistry and hence to the mechanical, corrosion and fracture properties of the materials of which they are comprised. Currently, there are no material test reactors for material irradiation within the UK and there is only very limited access to particle accelerators suitable for such studies. The aim of the DCF is to create a world-class facility for investigating materials response to irradiation in applications that span the whole of nuclear fuel cycle. 28

29 Radiation damage is defined as micro-structural and micro-chemical changes induced in materials by exposure to fluxes of energetic neutrons, or other fast particles (i.e. electrons, protons, alpha particles, and heavy ions). From the viewpoint of reactor structural materials, the most important damaging particles are fast and thermal neutrons. The key features of how neutron irradiation modifies a material s properties are displacement of atoms and the transmutation of specific alloy constituents. The most deleterious transmutation products for structural materials are He and H. A major determining feature is the level of radiation damage (usually quoted in terms of displacements per atom (dpa)), and the operating temperature of the component. Changes in bulk properties are a result of modification of the material at the nearatomic scale. The exact property change depends critically on the material and the environment. The research programme has two thrusts, (i) research to underpin lifetime extension of operating reactors of all classes, and (ii) the development of novel radiation tolerant materials. In the former, not only is it necessary to demonstrate that the irradiation induced changes in dimensional and mechanical properties do not compromise the function of the component, but also that the modification of the material do not lead to issues in subsequent storage and reprocessing. While in the latter, the ultimate research goal is to predict behaviour and/or develop radiation resistant structural alloys or steels. Understanding of the underlying mechanisms is important, but not sufficient in itself. It is necessary to relate mechanisms to bulk materials behaviour for engineering applications. It is not possible to cover all the scientific needs with the available resources for DCF. The initial scientific focus of the radiation damage efforts will be on mechanistic understanding of: atomic-scale damage mechanisms in metals and their impact on microstructural development, corrosion of irradiated metallic in-core components, and 29

30 irradiation induced changes in mechanical and fracture properties. Studies of the mechanisms of atomic scale damage are relatively easy to undertake and are an essential part of a national capability, and understanding the mechanisms underlying corrosion and mechanical and fracture properties plays to existing strengths within the UoM. Potential initiation projects are: Mechanistic understanding of corrosion of irradiated in-core components. It is important to understand the corrosion of the cladding (of high burn-up fuel) in wet and dry storage conditions; however, testing of irradiated cladding is difficult. An innovative approach is to simulate neutron irradiation-induced sensitisation by proton irradiation, building on previous work achieved through international collaboration between UoM and the University of Michigan. This project will investigate the use of proton-irradiated stainless steels to develop cladding-specific corrosion monitors for use in wet and dry conditions. The research will link with ongoing studies in the MPC at Manchester and at NNL and Sellafield (Dr. Guy Whillock). Corrosion mechanisms in Zr alloys in a gamma flux. It is well established that zirconium alloys display a pre-transition, i.e. slow corrosion rate followed by a fast corrosion rate. It has been found empirically that the point of transition varies with alloy composition, which has led to the development of more advanced Nb containing zirconium alloys. However, the lack of mechanistic understanding a) represents a major obstacle to development of mechanistic life predictions and therefore the exploitation of these alloys, and b) hinders further development of new alloys which can sustain substantially higher burn-up fuels than the current generation of cladding material. It is believed that the transition from slow to fast corrosion is related to a phase transformation in the oxide layer (tetragonal (meta-stable) to monoclinic (stable) ZrO 2 ), which would result in a volume expansion and explain the cracks commonly observed in the oxide layer. This project on corrosion mechanisms in Zr-alloys will focus on the effect of irradiation on the stability of the tetragonal phase. 30

31 Mechanistic understanding of irradiation induced changes in mechanical properties. Optical image correlation techniques developed within the UoM Materials Performance Centre will be applied to the study of creep in surface grains of proton irradiated material. Novel use of synchrotron radiation will enable the 3D study of yielding grains in textured microstructures (diffraction contrast tomography), and the measurement of inter-granular strains and change of deformation mechanisms (advanced high energy x-ray diffraction), which have an impact on stress corrosion initiation and irradiation creep. It is likely that future activities will include studies of: Mechanistic understanding of atomic scale damage mechanisms and their impact on micro-structural development. A fundamental understanding of damage mechanisms in irradiated graphite is central to continued operation of the UK s fleet of AGRs. This understanding lies at the heart of dimensional change, creep and mechanical property changes. This project will address point defect clustering in high energy cascades and factors controlling the early stages of dislocation loop formation. Such insight is critical in modelling macroscopic changes in graphite properties as a result of irradiation (e.g. dimensional change) and understanding factors associated with Wigner energy release. The latter is particularly important for long term storage of legacy graphite wastes. Irradiation-induced changes in composition adjacent to the grain boundary. This type of radiation-induced modification frequently makes a material susceptible to corrosion. This project will characterize the influence of irradiation on grain boundary composition to investigate the key factors that influence irradiation-induced segregation to (and from) internal micro-structural boundaries in structural materials, such as stainless steel fuel cladding. Previous work has shown that this is influenced by grain boundary structure, which is sensitive to prior thermo-mechanical processing history. This work will aim to identify microstructures (e.g. welds or cold/warm worked regions) with greater sensitivity to this form of degradation. 31

32 4.3.4 Other Research Areas The radiation science capabilities developed in the DCF under the collaboration agreement between the UoM and the NDA will focus on the grand challenges faced in decommissioning, site reclamation and restoration, waste management and disposal, continued generation and nuclear plant operation, including reprocessing. However, a part of the extended plan for the long-term viability of the facility is to develop capabilities and to undertake science benefiting the whole nuclear portfolio, including new reactor and advanced nuclear energy systems. There will be scientific overlap and leverage between these two areas and current work. Including reactor and advanced nuclear fuels research in the scope of the DCF also enhances its long term sustainability, a driver for both the UoM and the NDA. Research programmes addressing challenges in renewable energy technologies, and life and medical sciences are also envisaged. These new research avenues are outside the remit of the NDA, and the funding and gearing of such programs will be kept distinct. One current research topic outside the current core mission considers: Impact of radiation fluxes on microbial cells: a metabolomic approach. This BBSRC funded project utilises the facilities and expertise of the Williamson Research Centre for Molecular Environmental Science, MIB, School of Chemistry, and the National Nuclear Lab (CASE sponsor) to determine the impact of radiation fluxes on a range of microbial cells. High radiation fluxes have been shown to be tolerated by a few specialist organisms with very active DNA repair mechanisms such as Deinococcus, although exciting new data suggest that radiation can have unexpected beneficial impacts on microbes such as fungi, which may be able to convert ionising radiation into biochemical energy via pigments such as melanin. This project uses state of the art metabolomic techniques to address the physiological adaptations to high radiation fluxes of key microorganisms (including carefully selected fungi, algae and bacteria) relevant to the bioremediation of radionuclides and the geological disposal of nuclear waste. This research will provide fundamental information on microbial detoxification and novel energy generating systems. 32

33 A planned research project now under development will address: Antioxidants for disease prevention. The effects of ionising radiation on biological compounds are best investigated using flash radiolysis. Free radicals are agents in a wide variety of diseases, such as, atherosclerosis, diabetes, multiple sclerosis, rheumatoid arthritis and cancer. Indeed, the International Atomic Energy Agency has recently called for unified action to fight the cancer epidemic in developing countries. Interest in antioxidants for disease prevention has been the focus of many research studies involving natural and diet-derived antioxidants and both pulse radiolysis and laser flash photolysis are particularly suitable techniques to understand the molecular basis for their mechanism of action. In collaboration with the Gray Institute for Radiation Oncology and Biology (Dr Boris Vojnovic) in Oxford, a 6 MeV elinac will be used for radiolysis pump-probe experiments of biological compounds. The elinac has pulse lengths of between 50 ns and 4 s. Transient species will be detected using an optical system to measure either light absorption or fluorescence. For all of the above research areas, proposals for work will be developed in collaboration with external stakeholders, ensuring that research activities are aligned with actual issues faced in current technological, medical and societal challenges. In taking this approach, the aim is to carry out high quality research that addresses realworld issues, providing a fundamental understanding of problems that stakeholders can build upon. A complete list of current research projects within the Dalton Radiation Science Group is given in Table 4.1 and future research projects under development in Table

34 Table 4.1 Current research projects in Radiation Science. Research: DCF Staff Facility Sponsor Decommissioning and Disposal PhD studentship: Radiolytic Pimblott DCF, NDRL DCF & USDOE degradation of PVC Contract: Radiolytic degradation of silicones Pimblott DCF, NDRL NDA-DRP & UKAEA Waste Remediation and Management PhD studentship: Radiolytic off-gassing of organics in Pimblott DCF, NDRL DCF, USDOE & USNSF aqueous environments PhD studentship: Koehler DCF, PSI DCF Photodissociation Dynamics at Surfaces PhD studentship: Radiationinduced Koehler DCF, PSI DCF, USDOE desorption of H 2 from water on metal oxide surfaces Aqueous radiation chemistry of U(IV) Pimblott DCF EPSRC, CEA, & USDOE Deep Geological Disposal PDRA: Radiation damage to biopolymers and biosystems Pimblott DCF, PSI, NDRL DCF, USDOE & USNIH PhD studentship: Irradiation Pimblott DCF, Sheffield- NDA Bursary damage in phosphate cements ISL PhD studentship: Impact of radiation on microbial cells Pimblott DCF, SEAES, Pharmacy, NDRL BBSRC & NDA- RWMD Continued Generation and New Nuclear Build PhD studentship: H 2 production Pimblott DCF, NDRL EPSRC & USDOE in the irradiation of water in contact with oxide particles Effects of mixed radiation fields Pimblott DCF, NDRL EPSRC & USDOE funded PhD studentship: Radiolysis of water in zeolites Pimblott DCF, Laserlab EPSRC, CEA & EU-Laserlab Spent Fuel Reprocessing PDRA & PhD studentship: Radiation effects on reprocessing materials Sharrad, Pimblott DCF, NDRL, NNL- CL EPSRC Advanced Reactors and Fuel cycles Undergraduate: Radiation chemistry of water and aqueous systems at elevated temperatures Pimblott DCF EPSRC, Nuffield Foundation 34

35 Table 4.1 Current research projects in Radiation Science (cont). Research: DCF Staff Facility Sponsor Other Topics PhD studentship: Optical fibrebased, non-destructive spectroscopic techniques for in situ analysis of uranium / polymer interfacial regions Pimblott DCF, PSI, AWE Aldermaston AWE Table 4.2 Future research projects in Radiation Science. Research: DCF Staff Facility Potential sponsor Decommissioning and Disposal Radiolysis of novel polymeric encapsulants Pimblott DCF, NDRL DCF & NDA- RWMD Waste Remediation and Management PhD studentship: Radiation catalysed reaction of gases over oxide surfaces Pimblott DCF EPSRC & Sellafield Ltd * Irradiation of hydrocarbons and polymers in contact with oxide particles Deep Geological Disposal Radiations chemistry of extremely alkaline systems Production of NAPL in GDF wastes Pimblott DCF EPSRC & Sellafield Ltd Pimblott DCF, NNL-CL DCF, EPSRC & NDA-RWMD Pimblott, DCF, NNL- NDA-RWMD Koehler Harwell Continued Generation and New Nuclear Build Radiation initiated corrosion in Pimblott DCF Serco, Rollsmetals, steels & nuclear alloys Royce & MoD Irradiation effects on flow Pimblott, DCF, MPC EPSRC, BARC localisation in zirconium alloys Preuss India PhD studentship: Radiolysis of Pimblott DCF, Laserlab EPSRC, CEA & water in zeolites EU-Laserlab Spent Fuel Reprocessing Radiations chemistry of nitric Pimblott DCF, NNL-CL EPSRC & NDA* acid and nitrate containing systems The radiolytic steady state and factors controlling H 2 production * Already funded Pimblott DCF EPSRC & Sellafield Ltd* 35

36 5 Nuclear Engineering Decommissioning 5.1 Aim To develop an enhanced understanding of the behaviour and properties of radioactive waste which allows significant improvements to be made to its treatment and handling during decommissioning and its ultimate disposal. 5.2 Introduction The nuclear engineering research programmes based out of the DCF represent only one component of the University s efforts in this field and deployment of UoM expertise within the DCF will not be limited to the DCF based staff. This science plan focuses on the four key research themes identified in Figure 5.1. Figure 5.1 Nuclear Engineering Decommissioning Research Themes 36

37 5.3 Research themes Descriptions of each of the nuclear engineering decommissioning research themes and challenges are provided in the following sub-sections. The extensive ongoing projects are detailed in tables in the appendices, in addition to tables listing potential future research proposals Contamination and Decontamination (Lead: Sharrad) Contamination of pipes, vessels and buildings represent a unique challenge for decommissioning of nuclear facilities at the end of their operational lives. Research at the DCF in this area will initially target developing an improved understanding of the contamination processes, in order to focus future efforts Figure 5.2 Contamination and Decontamination Research Themes on the development of effective decontamination systems. Further research will address effluent treatment/decontamination to reduce discharges from waste management activities. Each of these areas is underpinned by an understanding of the range of engineering disciplines including chemical and environmental engineering, radiochemistry and materials behaviour Contamination mechanisms This theme will study the physical and chemical aspects of the interactions between soluble or colloidal radionuclide species found in relevant solution conditions with solid materials. The materials to be studied will include those that are used to house or transfer active liquors (e.g. concrete, steel, etc...), solids generated by corrosion or decomposition (e.g. brucite from the corrosion of Magnox fuel rods), and materials found in and around geological repository environments (e.g. clay). This work will generate a comprehensive understanding of the pertinent radionuclide behaviour in 37

38 both the solution phase and in the solid state, with the focus on probing the sorption behaviour of radionuclide species onto solid surfaces. The influence of radiolytically damaged surfaces to radionuclide sorption mechanisms will also be investigated. A range of techniques (e.g. XPS, SEM, XAS) will be applied to characterise the surface species that have formed and, where appropriate, depth profile analyses will be conducted to determine the level of intrusion of radionuclides into these materials. Thermodynamic and kinetic parameters (e.g. binding constants and rates of sorption) determined from these studies can be used to develop predictive models for radionuclide distribution. These approaches can assist in ascertaining radionuclide transport behaviour at the process scale and assist to develop methods for the effective removal of radionuclides from contaminated solid materials Decontamination techniques Techniques will be developed in order to reduce the contamination of plant facilities to lower radiation dose rates that will allow man access to facilitate plant decommissioning and/or to re-categorise waste. Contamination can either be mobile (liquid, dusts and powders), or fixed onto surfaces (e.g. steel, concrete) which will require different decontamination methodologies. In some cases, these methods will need to be utilized in plants/facilities with convoluted geometries and restricted access. In the case of mobile contamination, methods will focus on the technology for collecting active material while minimizing the spread of contamination. For fixed contamination, technology will be developed to disrupt or dissolve the surface contamination which will most likely require strong chemical complexants that can be treated or directly converted to a wasteform Effluent treatment The major liquid effluent streams arising from the Sellafield site are from purged storage pond water and fuel reprocessing. However, as decommissioning and waste retrievals commence on all sites further effluents will be generated during these processes. Potentially these streams contain significant levels of activity and must be treated before discharge. Currently, there are two major processes used for cleaning 38

39 the liquid streams - ion-exchange and a chemical flocculation process. These two processes have been responsible for massively reducing the levels of radioactivity released in liquid effluents whilst concentrating the radionuclides contained within the waste into the smallest practicable volume for treatment and encapsulation. Research in this area will investigate the compatibility of current treatment methods for the removal of radionuclides from different effluent streams (e.g. POCO liquors), engineering addendums to current treatment plant designs in order to efficiently meet regulatory requirements and developing novel approaches for the removal of targeted radionuclides (e.g. Tc, Am) from effluents that have proven to be problematic. The engineering design approaches of process integration and intensification also will be considered Radiochemistry Molecular scale understanding of the solution and colloidal behaviour of radionuclides in effluent and decontamination conditions can underpin the knowledge required to fully comprehend contamination mechanisms and the outcomes of decontamination and effluent treatment processes. The focus of this effort will be to provide relevant information using the radionuclides of interest (e.g. actinides and fission products), in realistic conditions (such as radiation environments), restricting work with inactive analogues to technique development. This work requires appropriate infrastructure for active experimental work, such as active fume-hoods, glove boxes and characterisation techniques, which is available to the DCF through the Access Agreement with the National Nuclear Laboratory Central Laboratory Ongoing Research Dr Sharrad has a well established track record in radionuclide containing effluent chemistry research that is relevant in decommissioning scenarios. This capability was originally developed through interests in areas other than nuclear decontamination and effluent treatment (e.g. fundamental science, environmental transport, reprocessing). Many of the skills and knowledge acquired in these research areas will be transferred to decontamination studies. 39

40 Research Progression A list of projects in progress in the field of Decontamination is included in the table below. One example illustrating the transfer of already established skills and knowledge to decontamination research is presented below. The skill base was initially developed from research into the fundamental chemical behaviour of actinides in aqueous environments, specifically alkaline conditions found in fuel storage ponds. The research area has progressed to studies of transuranics in pond conditions funded by a NDA student bursary. This project provided the opportunity for the postgraduate student, Tamara Griffiths, to access the active facilities at NNL-Central Laboratory via the third party access agreement. The radiochemistry skill set developed from this work will be combined with chemical engineering expertise to establish applied research in effluent treatment techniques and projects in this area have recently received funding. Input will also be obtained from industrial partners such as NNL and Sellafield Ltd. These effluent treatment projects will use active facilities, established from previous work (i.e. NNL CL), and will look to incorporate facilities such as DCF (e.g. radiation stability) and NNL Workington Laboratory (e.g. process scale up) into the research programme. We believe this work can evolve into a large research consortium developing engineering decontamination processes to be funded by both industry and research councils, with the ultimate aim of enhancing methods for decontamination. 40

41 Research Progression Decontamination NDA EPSRC NNL SLC Industry EPSRC TSB Decontamination engineering processes Industry EU FP8 EPSRC Enhanced decontam BNFL CRR Student placement in NNL-CL Current 2011 Future Figure 5.3 Contamination and Decontamination Research Progression Potential Future Research Projects. The initial focus will be on developing a core team utilising DCF, Central Laboratory and Workington facilities researching decontamination and effluent treatment issues relevant to the Sellafield and Magnox sites. Indeed, this work will start shortly with three doctoral projects, the first a UoM DTA studentship, the second an NNLadministered CASE studentship and the third an industrially funded Eng.D. researcher. Subsequently a research council critical mass grant application will be submitted to build on this industry funding. A list of potential research projects currently under consideration for development in the field of Decontamination is given in Table following: 41

42 Table Current research projects in Contamination and Decontamination. Research DCF Staff Facility Sponsor PhD studentship: Actinide Sharrad NNL-CL, Idaho NDA speciation in Sellafield ponds National Lab. PhD studentship and PDRA: MBase: Molecular Basis for Advanced Separations research consortium Sharrad, Pimblott, Koehler DCF, NNL-CL, Idaho National Lab. EPSRC Development of solid materials for the selective removal of radionuclides from liquid effluents generated in the nuclear fuel cycle PDRA: Explorative study of the nuclear industry and government requirements for the treatment of plutoniumcontaining effluent and decontamination issues PhD studentship: Actinide colloids and nano-particles: Relevance to legacy waste, clean up and geological disposal Amino acids for minor actinide separations PhD studentship: Electronic properties of actinide extractants Sharrad, Banford Sharrad Heath / Sharrad Sharrad Sharrad NNL-CL, DCF NNL-CL, Sellafield Ltd DCF / UoM DCF, UoM, Idaho National Lab UoM, NNL- Central EPSRC EPSRC Knowledge transfer account NDA LDRD (DoE) EPSRC Doctoral Training Centre Table Future Research Projects: Contamination and Decontamination. Research DCF Staff Facility Potential Sponsor Understanding heterogeneous Sharrad NNL-CL, DCF, NDA interactions in pond liquors UoM Using chemical understanding to improving effluent treatment by EARP and SIXEP plants Sharrad, Banford NNL-CL, DCF, UoM NDA, Sellafield Ltd, EPSRC Engineering novel decontamination and effluent treatment techniques Sharrad, Banford NNL-CL, NNL- Workington, DCF, UoM EPSRC, NDA, Sellafield Ltd 42

43 5.3.2 Waste Behaviour and Treatment (Lead: Jones) Understanding the behaviour of waste, during retrieval, processing and disposal is a fundamental challenge. This research area covers a wide variety of different waste streams such as ponds and sludges; nuclear graphite, orphan waste Figure 5.4 Waste Behaviour and Treatment Research Themes treatments and liquid treatments. Progress will be achieved through application of research built on the interaction with stakeholders and industry. An underpinning of current approaches will be supported and the search for novel treatments considered Pond sludges and liquors The retrieval and processing of corroded Magnox sludges and associated pond liquors are major challenges in the UK s nuclear clean up and decommissioning programmes. In order to develop an effective approach of dealing with these pond systems, a thorough understanding of the chemical and physical properties of these radionuclide containing sludges is necessary. Studies will focus on particle characterization including size, shape, density, composition, etc ) and on understanding the interaction of radionuclides with sludge particles. This chemistry/chemical engineering approach will complement the ongoing modelling of solid liquid systems currently being developed through an NNL CASE award Graphite The UK graphite moderated reactors will produce somewhere in the region of 99,000 tonnes of irradiated nuclear graphite after operation ceases, this is by far the greatest volume produced worldwide from one country. The management of this graphite waste will require complex planning and consideration due to the volume, nature of the material, operational conditions and post reactor environment, therefore, 43

44 radioactive graphite core dismantling and the management of radioactive graphite waste is an important issue in the UK. There are potential concerns associated with several radioactive isotopes in this material; these are namely 3 H, 14 C, 36 Cl, 60 Co, 152 Eu and 137 Cs. Current data released by the NDA reports that 56,000 tonnes Magnox, 25,000 tonnes AGR plus graphite from other sources, including Windscale piles and test reactors, will lead to 99,000 tonnes of nuclear waste graphite in the UK. Recent research has indicated that it may be possible to reduce the activity of the radioactive graphite waste through novel decontamination techniques. If applied, this would lead to significant reduction in volume and activity of intermediate level waste across the UK. In order to make informed decisions of how best to dispose of large volumes of irradiated graphite waste from the nuclear program, it is necessary to understand fully both the radiological and physical character of the graphite waste as well as the consequent effectiveness of the proposed decontamination and immobilisation treatments. These treatments may include chemical and physical methods to reduce the radiological contamination so that the waste can be classified as LLW. Engineering assessments of the differing approaches will be developed to support waste management strategies and will also be made to determine the suitability of these materials as potential waste forms in future GDF environments Wastes Requiring Additional Treatment Historical activities have created volumes of wastes requiring additional treatment (WRATs) for which no clear management route exists. The majority of the wrat fuel inventory in the UK is currently held at Sellafield. The diversity of WRATs requires versatile methods for treatment and immobilisation. The future management of these WRAT fuels and residues needs to be appropriately assessed and is an appropriate area for targeted research, and process development. 44

45 Waste Characterisation Effective characterisation of the UK s nuclear waste inventory is vital in order to provide appropriate long term management of these wastes, whether that is through continued storage, treatment and/or disposal. This is a cross cutting research programme which involves: identification of characterisation methods that can provide relevant information, methodology development of techniques that can be use in harsh chemical and radiological environments, and application of these methodologies to acquire data on the nature of nuclear site wastes. A combination of generic and specific characterisation methodologies will be required in order to characterise the vast array of waste forms Ongoing Research. Dr Jones has established a strong international track record on the behaviour, characterisation and treatment of graphite waste, mentoring four PhD, one EngD and one PDRA researchers. Graphite decommissioning research has been funded from the EPSRC Diamond and Fission consortia, the EU Euratom FP7 programmes; CARBOWASTE and ARCHER. Sponsorship has also been secured from the NDA (RWMD) HSE (ONR), UKAEA and SERCO. Current projects are outlined in the table below. Table Current research projects in Waste Behaviour and Treatment. Research DCF Staff Facility Sponsor EngD studentship: Isotopic Removal of Graphite Waste Jones DCF, UoM, SERCO FP7 Euroatom CARBOWASTE / HSE (ONR) PhD studentship: Thermal treatment of Irradiated graphite waste PDRA: Leaching behaviour of irradiated graphite waste PhD studentship: Encapsulation of Irradiated Graphite waste Jones UoM FP7 Euratom - CARBOWASTE Jones DCF, UoM FP7 Euroatom CARBOWASTE Jones DCF, NNL-CL, EPSRC- UoM DIAMOND PhD studentship: Jones UoM EPSRC-KNOO 45

46 Microstructural (DTA) Characterisation of Irradiated Nuclear Graphite using Finite Element Analysis PhD studentship: Jones DCF, UoM EPSRC-FunGrap Fundamentals of current and future uses of nuclear graphite Advance HTR graphite behaviour Jones DCF, UoM FP7 Euroatom ARCHER Graphite Behaviour Study Jones DCF, UoM NGRG NDA (RWMD) - Technology and Research Investment PhD studentship: Methods for processing orphan wastes Sharrad NNL-CL, DCF, UoM, EPSRC DIAMOND PhD studentship and PDRA: REFINE: REduction of spent Fuel In a closed loop Nuclear Energy cycle PhD studentship: Development of SPH modelling techniques to support waste management Sharrad NNL-CL, NNL- Workington, DCF, UoM EPSRC Banford UoM NNL supported EPSRC Case award The capabilities of the decommissioning group have been strengthened through establishing three active graphite laboratories at the UoM and successfully securing sponsorship from the NDA/NNL for key research projects to be carried out by students at the NNL-CL. 46

47 Research Progression Research Progression Waste Behaviour and Treatment - Graphite EU FP8 EPSRC Industry EPSRC EU FP7 EPSRC Diamond Graphite waste treatment and disposal HSE Student placement in NNL-CL Legacy graphite Current 2011 Future Figure 5.5 Graphite Waste Behaviour Research Progression Nuclear graphite decommissioning research commenced at the UoM in 2007 funded by the NDA with the objective of understanding the behaviour of graphite waste and developing novel treatment methodologies. In 2007, Dr Jones established a fully equipped and controlled laboratory as well as two supervised laboratories at the UoM, principally for leaching and thermal treatment of graphite waste with micro structural analysis. Funding was secured from the EPSRC - Diamond Consortium, EU-FP7 CARBOWASTE: Treatment and Disposal of Irradiated Graphite and other Carbonaceous Waste and most recently the EPSRC funded Fundamentals of Current and Future Use of Nuclear Graphite. Links to industry have been established with the NDA-Technology and Research Investment Proposal (jointly with UKAEA) Graphite behaviour in final repository conditions: and from the HSE/NDA ( ). Dr Jones has developed strong collaborative links with UK researchers (Leeds, Sussex, Huddersfield and Nottingham) and European industrial / research members through the CARBOWASTE Program. In 2011 the first studentship research programme was 47

48 established at the NNL CL, secured through the NDA UoM access agreement and partly funded from the EPSRC Diamond Consortium. The key objectives of the graphite research programme at the DCF are to lead in graphite waste technologies, in order to reduce isotopic content with pre-treatment of materials prior to disposal, remove isotopes through direct chemical and physical thermal treatment using controlled chemical processes, and understand the containment behaviour of graphite through methods such as encapsulation. Currently Dr Jones has a NDA EPSRC funded research student bursaries at the NNL. This project provided the opportunity for the postgraduate student, Bereket Hagos, to access the active facilities at NNL-CL via the third party access agreement. This requires an understanding the long term behaviour of the final waste form under repository conditions, funding from which will be sort from the EPSRC, the EU-FP8 call and from industrial investment with support from nuclear stakeholders. This research progression demonstrates the growth of a research area through collaboration and use of research facilities. This model will be used to develop the other sub areas of this theme, where access to NNL CL and DCF are critical. One further example of this is the recently funded collaborative electrochemical/molten salts research programme which involves both industry and universities, utilising the NNL facilities Potential Future Research Projects Work will shortly commence on an EPSRC funded project evaluating the use of electrochemical processes and molten salts to process orphan materials. For graphite, the immediate focus in this area will be the next phase of graphite research and potential follow on FP7 programme. Projects in this area will utilise the unique DCF/NNL experimental facilities to carry out leading research. A list of potential research projects currently under development is given Table

49 Table Future Research Projects: Waste Behaviour and Treatment. Research DCF Staff Facility Potential Sponsor PhD studentship: Pretreatment of irradiated graphite waste Jones NNL-CL, UoM, NGRG, RCRD EPSRC (Nuclear FiRST DTC) PhD studentship: Radiolytic oxidation of graphite - DCF PhD studentship: Irradiation behaviour of Gen IV graphite PhD studentship: long term behaviour of graphite in Geological Disposal Facility (GDF) conditions PDRA: Isotopic speciation and identification in graphite PDRA: Gaseous and aqueous release of 14 C and 36 Cl species within graphite EngD: Graphite behaviour and irradiation damage processes EngD: Graphite behaviour under confining pressure ASGARD: processing of carbide fuels Use of molten salts for the segregation of ILW/LLW mixtures and minimisation of LLW Characterisation of contaminated concrete Pimblott, Jones Jones Jones Jones Jones Jones DCF DCF, NGRG, DIAMOND DCF, NNL-CL, RCRD DCF, RCRD, NNL- CL NGRG, RCRD, NNL-CL NNL-CL, NGRG, RCRD, SERCO EPSRC (Nuclear FiRST DTC) EPSRC (Nuclear FiRST DTC) NDA, EPSRC NDA, EPSRC, EU FP8 NDA, EPSRC, EU FP8 NDA, HSE ONR, Serco Jones NGRG, RCRD HSE, EDF-energy Sharrad NNL-CL, UoM EU FP7 Sharrad Banford NNL-CL, NNL- Workington, UoM NNL-CL, DIAMOND (Harwell) Industry, EPSRC NNL, UoM 49

50 5.3.3 Decommissioning Technologies (Lead: Lennox/Stancu) As waste management and decommissioning activities progress towards more hazardous wastes and facilities, there will be an increasing need for remote systems to aid waste retrieval, characterisation/monitoring, intervention and dismantling of plant Tele-operation and ROVs The current baseline technology for intervention is based on tele-operation using devices such as manipulators and Remote Operated Vehicles (ROV). Usually these are operated without direct line of sight using cameras, have limited feedback and require highly skilled operators. Research in this area will focus on enhancing the performance of this baseline technology to improve performance. Figure 5.6 Decommissioning Technologies Research Themes Semi-autonomous Systems This research area builds on the tele-operation and will consider the potential for the deployment of semi-autonomous systems within a decommissioning context for characterisation/monitoring of facilities and wastes, and for decommissioning/dismantling operations. It will involve research in sensors, control systems and communication. There is also an interesting potential opportunity here to link with other initiatives from other sectors such as aerospace, subsea and defence Visualisation/Imaging of Plant This research area is focussed on developing an understanding of the environment within a nuclear facility in order to aid the decommissioning planning and implementation. This will range from imaging of the facility to gather geometric data relating to the physical components and their relative locations. This will involve the integration of technologies such as laser scanning, LIDAR and 3D point cloud reconstruction. Potential integration with radiation mapping would be of benefit in 50

51 planning of decommissioning activities and aid deployment of remote devices. One ongoing project is the autonomous system for mapping fuel ponds Decommissioning Technologies Dismantling and Size Reduction This area will focus on key technologies that could provide step changes in the implementation of decommissioning activities. One example would be the use of laser cutting for dismantling operations. Additionally, the opportunities for technology transfer from other industrial sectors will be considered through applied R&D. Links will be made with NAMRC to take advantage of advanced manufacture technology, equipment and facilities; for example: access to high power laser technology Ongoing Research Three research groups in the School of Electrical Engineering are working on aspects of nuclear decommissioning. These are Control Systems (robotics, autonomy, process control), Sensing, Imaging and Signal Processing (sensors) and Microwave and Communications Systems (microuavs and communications). Specific projects with DCF involvement are listed below. Table Current research projects in Decommissioning Technologies. Research DCF Staff Facility Sponsor PhD studentship: Micro AUVs Lennox NNL- EPSRC Workington PDRA: Advances in robust Lennox UoM EPSRC control methods and applications to flying discs PDRA: NDT of pipelines Lennox UoM BP, Pipeline Engineering, EPSRC PhD studentship and PDRA: Control and monitoring of large scale processes, including Sellafield vitrification plant Lennox UoM EPSRC, Invensys Current research efforts and new projects began migrating from Manchester to West Cumbria at DCF and the NNL Workington facility from January

52 Research Progression Given the considerable amount of work undertaken at the university that has relevance to nuclear, the intention for the short-term future is to identify challenges related to this research in the nuclear industry and to work with companies willing to support this work. In particular, companies will be approached to support TSB and KTP initiatives. A major focus of current research is in the development of autonomous systems. A collaborative project with aerospace experts from UMARI is currently being developed, and an EPSRC proposal was submitted in August With the appointment of Stancu, autonomous systems research is expected to expand further into ground based vehicles and fault tolerant control. It is anticipated that future funding in this area will be supported by SMEs servicing the nuclear industry and also larger companies including Sellafield Ltd. DCF will provide the ideal base to establish links with the nuclear industry. The autonomous systems research will benefit considerably through the access to the NNL Workington facilities where ground and air based vehicles can be tested. Further interest in this area will be generated by a 2-day robotics and autonomous systems workshop, the development costs for which have been applied for from EPSRC. 52

53 Research Progression Behaviour of Water-Ceramic Oxide Systems Sellafield DOE Bechtel Bettis EPSRC H 2 production from aqueous slurries H 2 production from adsorbed water on oxide surfaces H 2 /O 2 chemistry over oxide surfaces PuO 2 storage & disposition H 2 formation in Hanford waste tanks H 2 production from aqueous systems Current 2011 Future Figure 5.7 Decommissioning Technologies Research Progression It is anticipated that the on-going micro-auv project, exploring the potential for using this technology to monitor the nuclear ponds at Sellafield will be continued with support from Sellafield Ltd. Future work on this project will explore both the mechanical development of the AUVs and also the requirements to communicate wirelessly in harsh environments Potential Future Research Projects The University is linked into the ongoing TSB feasibility study evaluating the requirements of the nuclear industry for robotic/remote systems from Tele-operation to Teleautonomy. The plan for this area is to attract funding from an industrial/research council partnership and potentially a further submission to FP7. Additionally this area is being proposed as a potential demonstrator for the technology cluster with the Energy Coast Initiative. The vision here is to utilise the DCF and access to the NNL Workington facility as a basis for a robotics research cluster in West Cumbria. 53

54 A list of potential research projects currently under consideration for development is given in below. Table Future Research Projects in Decommissioning Technologies. Research DCF Staff Facility Potential Sponsor PhD studentships and PDRA: Development of Autonomous Systems Lennox DCF, NNL- Workington EPSRC, Industrial Consortium (including NNL and Sellafield) PDRA: Application of microauvs for monitoring nuclear ponds PhD Studentships Further projects to be developed once Dr Stancu is in post PDRA: Application of Laser Techniques to decommissioning, for remote cutting and decontamination Lennox Stancu Banford DCF NNL- Workington DCF, NNL- Workington NNL- Workington, NAMRC EPSRC, Sellafield Ltd. DCF EPSRC, Industry Sustainability in Decommissioning, Policy, Practice and Decision Making (Lead: Banford) Policy, strategy and stakeholders are key factors in the implementation and success of any waste management and decommissioning project. These factors along with environmental and technical considerations influence the chosen solution, end point and timing of activities Waste Management and Decommissioning Policy and Strategy Research in this area will consider the relationship of national and international policy on waste management and decommissioning activities; particularly with respect to political, economic, social 54 Figure 5.8 Waste Management and Decommissioning Policy and Strategy

55 and technical issues. The definition of facility and site end point is a key issue in this area Sustainability and Lifecycle Analysis Research in this area will focus on the development of approaches to evaluate decommissioning and waste management options. Building on the existing SPRINg project and the ongoing lifecycle analysis of reactor decommissioning the aim will be to develop industrially relevant techniques to assess options and underpin decision making and stakeholder engagement Systems Engineering Nuclear waste management and decommissioning projects are by their nature complex, potentially involving many steps, over extended periods and on integrated sites. These projects also have many interfaces with other projects both on and off site and many regulatory interactions. It is proposed to research the potential application of systems engineering approaches to these types of projects. These techniques have the potential to aid decision making particularly in the areas of legacy plant hazard reduction, decommissioning strategy and site wide strategy. Potential links with US National Laboratories will be explored Management of Projects Decommissioning of nuclear facilities are significant projects, comparable with major construction projects, with the added complications associated with radiological hazards, contaminated material and socio-political environment. Research in this area will focus on best practice in engineering project management that could benefit the implementation of nuclear decommissioning. Current research projects include: Table Current Research Projects in Sustainability in Decommissioning, Policy, Practice and Decision Making Research DCF Staff Facility Sponsor PDRA: Lifecycle Analysis of Banford / DCF, UoM Nuclear Decommissioning Azapagic Assessment of management of contaminated concrete Banford DCF, UoM 55

56 A comparison of organizational structures in decommissioning of nuclear and oil & gas facilities Incorporating Sustainability in Legacy Waste and Decommissioning Banford / Kidd DCF WS Atkins Banford / Ross DCF, NNL-CL, UoM NNL These projects are carried out by Prof Anthony Banford through his Royal Academy of Engineering Visiting position at the UoM and his joint UoM/ NNL appointment Research Progression This research theme is truly multidisciplinary in nature and the university has ongoing research in a range of schools that is relevant to nuclear decommissioning, including nuclear and non-nuclear based research. This research spans the Engineering and Physical Science faculty and also potentially the Manchester Business School and other schools. Furthermore, through the DNI and the NNL the university research team has access to key players in the industry, regulators and stakeholders who can add to this research base. Research Progression Waste Management and Decommissioning Policy and Strategy Industry EPSRC NED EPSRC Industry EPSRC Systems Engineering techniques to support SLCs EPSRC NED Development of systems engineering to support decision making Waste Management and Decommissioning systems analysis Multi School Research Current 2011 Future Figure 5.9 WM&D Policy and Strategy Research Progression 56

57 The progression plan is to establish research into systems engineering, sustainability and decision making at DCF by linking with existing capability. Initially the existing research will be supplemented through focussed masters level project work on specific topics of importance to the industry and the outputs of these will be used to focus industrial engagement for future industrial/ research council funded projects Potential Future Research Project A collaborative proposal for research council funding for this work is being planned. It will be led by DCF, and draw on UoM resources in CEAS, MACE, MBS and others Schools. Stakeholder engagement and involvement is clearly essential to the success of such a project. A further application is to be made for industrial funding of a project on systems engineering. A list of potential research projects currently under consideration is given below. Table Future Research Projects in Sustainability in Decommissioning, Policy, Practice and Decision Making. Research DCF Staff Facility Potential Sponsor Metrics to support decision making in Legacy Waste and Decommissioning Banford / Azapagic DCF UoM, NNL Systems Engineering approaches to aid waste management decision making Evaluation of In Situ decommissioning options Lifecyle Analysis of UK waste management options Banford DCF, UoM Potential international collaboration, EPSRC Banford DCF, UoM NDA, SLCs Banford DCF EPSRC This progression plan will bring academic research in the areas of sustainability and systems engineering to West Cumbria to engage with the key industry players and stakeholders. 57

58 6 Long-term Outputs The research programmes of the DCF will offer the following outputs: fundamental knowledge of phenomena central to nuclear energy systems, an independent expertise base, exchange with academic, community and nuclear stakeholders, international collaboration with universities and national laboratories in the EU, the Americas and Asia, nuclear stakeholder benefits (in solutions and savings). These activities will contribute to the long-term socio-economic impact in West Cumbria. Output will be via: publication in academic peer-review literature, presentation at national and international meetings, and knowledge transfer directly to Sellafield Ltd and other SLCs as well as via participation in NNL activities. Ultimately, it is the intention to take research from the academic environment through to deployment by collaboration with the SLCs, Tier 2 contractors and Cumbria based SMEs. The research programme will provide the following measurable actions: world-leading research facility targeting the fields of radiation sciences (chemistry and radiation damage to materials) and nuclear engineering decommissioning, and a community of graduate students and post-doctoral associates, addressing the challenges of the nuclear industry. Progress against these goals will be assessed by an international advisory panel with input from UK stakeholders to demonstrate industry buy-in and commitment to the research programmes. 58

59 Appendix A. Dalton Cumbrian Facility Academic Staff Radiation Science Team Lecturer, Radiation Damage to Materials Professor, Radiation Chemistry Enrique J-Melero Dalton Fellow Lecturer, Interfacial & Surface Chemistry NNL Central Lab. Simon Pimblott EPSRC Energy Research Chair Sven Koehler Dalton Fellow Dalton Cumbria Facility 59