DOCSLIB.ORG

Immobilization of High Level Waste in Synroc Abstract

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Immobilization of High Level Waste in Synroc Abstract IMMOBILIZATION OF HIGH LEVEL WASTE IN SYNROC A. JOSTSONS and K. D. REEVE, Australian Atomic Energy Commission, Lucas Heights Research Laboratories, Locked Mail Bag No. 1 , Menai, N'SW 223-i Australia Telephone (02) 543-3111, Telex AA 24552 ABSTRACT occurring radioactive elements in a variety of geological cnvi ronmi.-nt s . Synroc. a polyphase titan, boina developed in Australia as a second generation The Synroc strategy for HLW immobiliza- waste form for the immobilization of high- tion was developed in 1978 by Ringwood and 3 11 level waste (HLW) from nuclear plants. The colleagues ' at the Australian National wasteform, produced by reactive hot -press i n _.-,,- University (ANU). The Australian Atomic has excellent resistance to leaching and there Energy Commission (AAEC) began studii-*. on is good evidence that the long-term release Synroc in collaboration with the ANU in 1979 rate of elements from Synroc will be of the and the program has expanded with strong order of 10~" - ] 0~s g/m2 per day at 90°C. support from the Australian Department of The durability of Synroc is not affected . Resources and Energy and the National Energy, significantly by impurities normally present Research, Development and Demonstration Pro- in liquid waste from reprocessing operations gram (NERDDP). This aupport has enabled the and is not sensitive to fluctuations in the construction at Lucas Heights of an inactive composition of the waste-stream. Reducing Synroc demonstration pilot plant with a capa- conditions prevalent during Synroc fabrication city of 10 kg/h of Synroc. Apart: from the ensure that the losses of volatiles such as Cs AAEC and ANU, other groups in Australia are and Ru are restricted to levels of around 0.17« engaged in Synroc research, the most signifi- or better. The important physical properties cant of these being Griffith University, of Synroc are also superior to those of cur- Queensland, which has attracted NERDD1' sup- rent generation wasteforms, allowing greater port . flexibility of options in managing storage and eventual disposal of high-level waste. The Australian Synroc. program benelitid s i gn i f i can t 1 v f*-om thf U.S. pr^grirr on alter- INTRODUCTION native waste forms in the early 1980s. Cur- rently, the major Synroc research outside For about three decades, research on Australia is proceeding under the cover of high—level waste (HLW) immobilization has been bilateral R & D agreements with Italy, Japan under way in many countries resulting in the and the U.K. choice of borosi1icate glass as a first generation waste encapsulation medium. The This paper summarizes our current under- first continuous commercial scale production standing of Synroc as a waste form, its chemi- of vitrified waste was achieved in 1978 in the cal durability and fabrication. AVM plant at Marcoule, France. This technology has been further scaled up in THE SYNKOC PHASE ASSEMBLAGE plants under construction at La Hague in France, and Sellafield in the U.K. ' Addi- Synroc-C, a formulation chosen for the tional vitrification plants based on the Joule encapsulation of HLW from the reprocessing of ceramic melter have been constructed2 or are commercial light water reactor spent fuel, under construction. consists mainly of zirconolite CaZrTi2O7, barium hollandite Ba(Al,Ti)2 Ti6 0,6, perov- Synroc, a polyphase titanate ceramic, is skite CaTiO3 and rutile TiO,. A combination an advanced waste form which is receiving of the first three phases has the capacity to attention as a possible candidate for second accept most of the elements present in HLW. generation waste management. The major phases Under the redox conditions chosen for Synroc in Synroc are similar to naturally occurring fabrication a number of waste elements are minerals known to have retained naturally reduced to the. metallic state and form alloys 537 which are microencapsulatod within the tita- modification by cation ordering, crystallo- natc phases. The composition and mineralogy of graphic shear, or twinning on a unit cell scale Synroc-C is given in Table. 1. is an important mechanism for enhancing the capacity of Synroc phases to immobilize HLW and Table 1. Composition and Mineralogy of imparting flexibility to respond to inevitable Synroc-C variations in waste-stream composition. Composition % Mineralogy (approx wt.%' The "forgiving" nature of Synroc is fur- TiO2 57.=~1 hollandite 30 ther enhanced by the occurrence of spontaneous ZrO2 5.3 zirconolite 30 adjustments in the proportions of phases in the Al2O3 4.3 perovskite 20 Synroc assemblage in response to variations in BaO A.5 TiO2 + minor ph'ases 15 the waste-stream. One formulation of the Synroc CaO 8.8 allovs 5 constituents shown in Table 1 can immobilize a HLW 20 10.15 or 2O7= HLW loading without diminution in durabi lity.'3 Thus , a Synroc-C with a nominal 107„ HLW loading can accept fluctuations of An important aspect of Synroc solid state ±100% in the level of each constituent of the chemistry is the use of the Ti-TiO2 buffering waste-stream. system provided by the reaction between the excess TiO of the formulation and titanium 2 The Synroc microstructure is tine grained, metal powder added to tho calcined powder M v:m,with alloy phases with diameters in the before hot-pressing. The resultant non- range 0.01 - 0.1 pm encapsulated by the tita- stoichiometric rutile (actually Ti 0 nates. Transmission electron microscopy re- Magnel'i i• phasesi ;\ provide. • s a suppl, y on,2n-r i veals the presence of intergranular glassy Ti3 which stabilizes hollandite and increases films 1 - 3 nm thick.'" The glassy phase also the solubility limit of caesium therein ' . occurs at triple grain junctions. These glassy The buffer also controls the oxygen fugacity, films are not continuous, are rich in process ensuring that most noble metal species in HLW contaminants and usually caesium, and generally are reduced to the metallic state, and pre- account for less than XX of the total volume.' vents the formation of water soluble phases containing caesium. An excess of non- stoichiometric rutile provides Synroc with the CHEMICAL DURABILITY capability to react to unexpected fluctuations in the HLW stream composition. The partition- The most rigorous test of the chemical ing of HLW species in Synroc is summarized in durability of a waste form is provided by Table 2. leaching under conditions where the leach solu- tion remains undersaturated with respect to the wasteform. We use the MCC-l'5 test with regu- Table 2. Partitioning of HLW Species in lar replacement of leachant to measure the Synroc Host Phases""' intrinsic immobilization capacity of the waste form and to evaluate the effects of processing hollandite: Cs, Ba, Rb variables on the durability of Synroc. In all •zirconolite: U, Zr, tetravalent actinides cases, the leach rate of each element from the perovskite: Sr, Na, rare earths and tri- wastpform is calculated from the formula valent and tetravalent. actinides alloy: Mo, Ru, Rh, Pd, Te Differential leach rate (g/ni2 per d) = fraction of element * Lesser amounts of rare earths are also contained in leached x W/At zirconolite, whereas perovskito incorporates significant amounts of uranium. The TiO does not contain significant 2 where W is the initial mass of the test speci- - quantities of HLW species apart from Zr. men in grams, A is the geometric surface area Trace amounts of other phases are usually of the specimen in square metres, and t is the found but generally they do not contain signi- time in days. cant amounts of HLW species. Thus, in Synroc-C incorporating waste with high Na contents. Figure 1 shows the leach rates of the more White8 has observed freudenbergite, nomi- soluble elements in Synroc at 90 C. The rapid nally Na2Al2Ti6 016 which was previously obser- decrease in these leach rates with time is cha- ved in ceramic waste forms by Morgan et al.' racteristic of Synroc and makes the accurate Monazite (Ce,Nd)P0i, is invariably present if determination of long-term leach rates diffi- phosphorus is a contaminant of the HLW.8 cult because conventional methods, such as inductively coupled plasma and atomic absorp- The three major Synroc phases have a range tion spectroscopy, have insufficient sensiti- of cation acceptor sites and various substitu- vity. To overcome this difficulty, and to tion mechanisms which ensure that the solid generate results for the more leach-resistant solubility of HLW species in the host phases is fission products, a hot-cell line was construc- extensive.10 White et al.11, White12, and Kesson ted at Lucas Heights to incorporate into Synroc 99 m and White5'6 have demonstrated that structural a waste solution from the Mo/" Tc production 538 line. The resultan t leach data obtained bv constituents intersecting the specimen surfacesurf . Y-counting is shown in Figure 2. The so leach Elements such as caesium have been identifiied rates .ire based on total activity in the in the glassy regions. Actiniae elements, leaching vessel and include adsorbed and sus- usually simulated in inactive studies by ponded radionuclic s. The- results ag.iin show uranium, have not been detected in intergranu- the incongrucnt dis solution of Synroc over the lar films, which could explain the low initial period investigated and indicate that the total leach rates of this group of elements. leach rates of the rare earths, ruthenium and zirconium approach IXICT". g/m2 per d after three weeks. From 80-1007 of the ram earths and zirconium, and 1 roin 50-70», ol tlie ruthenium are removed by lilt ration through a <).hb yni Cs137 f iiter sug^e F> L i ng I hal most ol 1 h";H' c 1 oiwu ' Ba1«0 are uresent in l!ie le.ulute as 1 suspension.
Load more

Recommended publications
  • 1, 2002, Sheraton Crystal City Hotel, Arlington, Virginia
    Minutes for the Nuclear Energy Research Advisory Committee Meeting September 30 to October 1, 2002, Sheraton Crystal City Hotel, Arlington, Virginia NERAC members present: John Ahearne Dale Klein (Monday only) Thomas Cochran Robert Long Joseph Comfort Warren F. Miller, Jr. Michael Corradini Sekazi Mtingwa Jose Luis Cortez Richard Reba (Monday only) Maureen Crandall (Monday afternoon Joy Rempe and Tuesday only) Allen Sessoms Allen Croff Daniel Sullivan James Duderstadt (Chair) John Taylor Marvin Fertel (Monday only) Neil Todreas Beverly Hartline Joan Woodard (Monday only) Andrew Klein NERAC members absent: Steve Fetter Lura Powell Leslie Hartz C. Bruce Tarter J. Bennett Johnston Ashok Thadani (ad hoc) Linda C. Knight Charles E. Till Benjamin F. Montoya Also present: Ralph Bennett, Director for Advanced Nuclear Energy, Idaho National Engineering and Environmental Laboratory David Berg, Office of Environmental Management, DOE Nancy Carder, NERAC Staff Herbert Feinroth, President, Gamma Engineering Corp. John Gutteridge, University Programs, NE, USDOE Norton Haberman, Senior Technical Advisor, NE, USDOE Anthony Hechanova, Director, AAA University Participation Program, University of Nevada at Las Vegas R. Shane Johnson, Associate Director, Office of Technology and International Cooperation, NE, USDOE Silvia Jurisson, Department of Chemistry, University of Missouri, Columbia Owen Lowe, Associate Director, Office of Isotopes for Medicine and Science, NE, USDOE William Magwood, Director, NE, USDOE William Martin, Washington Policy Institute
    [Show full text]
  • Ceramic Mineral Waste-Forms for Nuclear Waste Immobilization
    materials Review Ceramic Mineral Waste-Forms for Nuclear Waste Immobilization Albina I. Orlova 1 and Michael I. Ojovan 2,3,* 1 Lobachevsky State University of Nizhny Novgorod, 23 Gagarina av., 603950 Nizhny Novgorod, Russian Federation 2 Department of Radiochemistry, Lomonosov Moscow State University, Moscow 119991, Russia 3 Imperial College London, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK * Correspondence: [email protected] Received: 31 May 2019; Accepted: 12 August 2019; Published: 19 August 2019 Abstract: Crystalline ceramics are intensively investigated as effective materials in various nuclear energy applications, such as inert matrix and accident tolerant fuels and nuclear waste immobilization. This paper presents an analysis of the current status of work in this field of material sciences. We have considered inorganic materials characterized by different structures, including simple oxides with fluorite structure, complex oxides (pyrochlore, murataite, zirconolite, perovskite, hollandite, garnet, crichtonite, freudenbergite, and P-pollucite), simple silicates (zircon/thorite/coffinite, titanite (sphen), britholite), framework silicates (zeolite, pollucite, nepheline /leucite, sodalite, cancrinite, micas structures), phosphates (monazite, xenotime, apatite, kosnarite (NZP), langbeinite, thorium phosphate diphosphate, struvite, meta-ankoleite), and aluminates with a magnetoplumbite structure. These materials can contain in their composition various cations in different combinations and ratios: Li–Cs, Tl, Ag, Be–Ba, Pb, Mn, Co, Ni, Cu, Cd, B, Al, Fe, Ga, Sc, Cr, V, Sb, Nb, Ta, La, Ce, rare-earth elements (REEs), Si, Ti, Zr, Hf, Sn, Bi, Nb, Th, U, Np, Pu, Am and Cm. They can be prepared in the form of powders, including nano-powders, as well as in form of monolith (bulk) ceramics.
    [Show full text]
  • Economic Development Board 1 South Australia
    ECONOMIC DEVELOPMENT BOARD 1 SOUTH AUSTRALIA 3 August 2015 Rear Admiral the Honourable Kevin Sca rce AC CSC RAN (Rtd) Roya l Commissioner for the Nuclear Fuel Cycle Royal Commission Level 5, 50 Grenfell Street Adelaide SA 5000 Dear Commissioner RE: Nuclear fuel Cycle Royal Commission I write to provide a discussion paper prepared by ThinkCiimate for the Economic Development Board (EDB), that responds to the four issues papers released by the Nuclear Fuel Cycle Roya l Commission on: Exploration, Extraction and Milling; Further Processing and Manufacture; Electricity Generation; and Management, Storage and Disposal of Waste. In October 2014, in the absence of reliable and cu rrent data and evidence on the nuclear value chain, the EDB commissioned ThinkCiimate Consulting to prepare a discussion paper. The purpose of the discussion paper was to explore the opportunities for an expanded role for South Australia in the nuclear value chain and to provide a high level business case to indicate if there is sufficient economic potential to warrant a more thorough investigation. The discussion paper, provided to you as Attachment 1 to this letter, explores the economic opportunities for South Australia at each point in the nuclear value cha in and, therefore, responds to the four Issues Papers released. The discussion paper concludes that: • There is potentially a major economic opportunity for South Australia in the safe management of spent nuclear fuel based on merging mature Intermediate Spent Fuel Storage Installation (ISFI) technology with Generation IV recycling and reactor technology. • Further a preliminary project assessment finds that a proposed configuration of an ISFSI and Integrated Fast Reactor (IFR) technology would utilise up to approximately 99% of the stored fuel to generate electricity as a low-cost, emissions free baseload with potentially significant economic benefits to South Australia within a relatively short timeframe.
    [Show full text]
  • Progress Report
    SYNROC STUDY GROUP PROGRESS REPORT August 1991 SYNROC STUDY PROGRESS REPORT August 1991 The Broken Hill Proprietary Company Limited (A.CN. 004 028 077) CRA Limited (A.C.N. 004 458 404) Energy Resources of Australia Limited (A.C.N. 008 550 865) Western Mining Corporation Limited (A.C.N. 004 184 598) Australian Nuclear Science and Technology Organisation Australian National University OVERVIEW This Progress Report has been prepared by the Synroc Study Group (SSG), comprising staff members of The Australian Nuclear Science and Technology Organisation (ANSTO), The Australian National University (ANU), BHP, CRA, Energy Resources of Australia (ERA) and Western Mining Corporation (WMC). It also draws upon work undertaken for the SSG by consultants from Nuclear Assurance Corporation (market estimates), the Swedish Nuclear Fuel and Waste Management Company (SKB) (cost estimates and other data) and Wave Hill Associates (US and international perspectives). Synroc is applicable solely to the immobilisation of liquid high-level waste after such waste has been separated from spent fuel in a reprocessing operation; use of Synroc therefore requires prior construction of a reprocessing plant An alternative management strategy, based upon direct disposal of encapsulated spent nuclear fuel, does not require reprocessing, and therefore makes no use of Synroc. The SSG has examined both of these alternatives and also a third, which is to defer decision-making on reprocessing versus direct disposal for a lengthy period while spent fuel is held in interim storage. The SSG recognises that many utilities and countries have deferred decisions as between reprocessing and direct disposal of spent fuel. The construction of interim spent fuel storage facilities and related infrastructure appears to be a practical strategy in the short term, although for many utilities and countries this period of satisfactory and acceptable deferral may be starting to run out.
    [Show full text]
  • Letterhead World Nuclear Association
    ISSUES PAPER 4 – MANAGEMENT, STORAGE, DISPOSAL OF NUCLEAR AND RADIOACTIVE WASTE Submission from the World Nuclear Association to the South Australian Nuclear Fuel Cycle Royal Commission Introduction The World Nuclear Association is grateful for this opportunity to answer the Commission’s questions regarding the management, storage and disposal of radioactive wastes in South Australia. There is considerable international experience in handling radioactive material and wastes, which it may be noted are neither particularly hazardous nor hard to manage relative to some other toxic industrial wastes. The storage and handling of civil nuclear wastes has been safely undertaken for more than 50 years. The aim in radioactive waste management is to protect people and the environment utilising three general principles – concentration and containment, dilution and dispersal, delay and decay. The first two principles are also used in the management of other, non-radioactive, wastes. The third principle works by storing the waste long enough until radioactive decay renders the waste no longer radiologically hazardous. Unlike some other toxic wastes, such as heavy metals, the principal hazard associated with nuclear waste – radioactivity – diminishes with time. The pillar of any national waste management plan is the responsible implementation of an institutional framework. Authoritative international organisations provide advice on institutional frameworks for the management of nuclear wastes. These include the International Atomic Energy Agency (IAEA), the Nuclear Energy Agency (NEA) of the Organisation for Economic Co-operation and Development (OECD), the European Commission (EC) and the International Commission on Radiological Protection (ICRP). International agreements in the form of conventions under the auspices of the IAEA have also been established, such as the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management.
    [Show full text]
  • Inquiry Into Nuclear Prohibition
    PARLIAMENT OF VICTORIA LEGISLATIVE COUNCIL Environment and Planning Committee Inquiry into nuclear prohibition Parliament of Victoria Legislative Council Environment and Planning Committee Ordered to be published VICTORIAN GOVERNMENT PRINTER November 2020 PP No 181, Session 2018–2020 ISBN 978 1 922425 12 6 (print version), 978 1 922425 13 3 (PDF version) Committee membership CHAIR DEPUTY CHAIR Cesar Melhem Clifford Hayes Western Metropolitan Southern Metropolitan Dr Matthew Bach Melina Bath Jeff Bourman David Limbrick Eastern Metropolitan Eastern Victoria Eastern Victoria South Eastern Metropolitan Andy Meddick Dr Samantha Ratnam Nina Taylor Sonja Terpstra Western Victoria Northern Metropolitan Southern Metropolitan Eastern Metropolitan Participating members Georgie Crozier, Southern Metropolitan Dr Catherine Cumming, Western Metropolitan Hon. David Davis, Southern Metropolitan Dr Tien Kieu, South Eastern Metropolitan Bev McArthur, Western Victoria Tim Quilty, Northern Victoria ii Legislative Council Environment and Planning Committee About the Committee Functions The Environment and Planning Committee (Legislation and References) is established under the Legislative Council Standing Orders Chapter 23—Council Committees and Sessional Orders. The Committee’s functions are to inquire into and report on any proposal, matter or thing concerned with the arts, environment and planning the use, development and protection of land. The Environment and Planning Committee (References) may inquire into, hold public hearings, consider and report on other matters that are relevant to its functions. The Environment and Planning Committee (Legislation) may inquire into, hold public hearings, consider and report on any Bills or draft Bills referred by the Legislative Council, annual reports, estimates of expenditure or other documents laid before the Legislative Council in accordance with an Act, provided these are relevant to its functions.
    [Show full text]
  • The Safety of the Nuclear Fuel Cycle
    Cov-Safety Nuclear FuelCyc 3588 10/10/05 16:04 Page 1 Nuclear Safety The Safety of the Nuclear Fuel Cycle NUCLEAR•ENERGY•AGENCY Nuclear Safety The Safety of the Nuclear Fuel Cycle Third edition © OECD 2005 NEA No. 3588 NUCLEAR ENERGY AGENCY ORGANISATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT ORGANISATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT The OECD is a unique forum where the governments of 30 democracies work together to address the economic, social and environmental challenges of globalisation. The OECD is also at the forefront of efforts to understand and to help governments respond to new developments and concerns, such as corporate governance, the information economy and the challenges of an ageing population. The Organisation provides a setting where governments can compare policy experiences, seek answers to common problems, identify good practice and work to co-ordinate domestic and international policies. The OECD member countries are: Australia, Austria, Belgium, Canada, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Korea, Luxembourg, Mexico, the Netherlands, New Zealand, Norway, Poland, Portugal, the Slovak Republic, Spain, Sweden, Switzerland, Turkey, the United Kingdom and the United States. The Commission of the European Communities takes part in the work of the OECD. OECD Publishing disseminates widely the results of the Organisation’s statistics gathering and research on economic, social and environmental issues, as well as the conventions, guidelines and standards agreed by its members. * * * This work is published on the responsibility of the Secretary-General of the OECD. The opinions expressed and arguments employed herein do not necessarily reflect the official views of the Organisation or of the governments of its member countries.
    [Show full text]
  • Back-End of the Fuel Cycle: Spent Nuclear Fuel and Irradiated Materials
    MODULE 6.0: BACK-END OF THE FUEL CYCLE: SPENT NUCLEAR FUEL AND IRRADIATED MATERIALS Introduction Welcome to Module 6.0 of the Fuel Cycle Processes Directed Self-Study Course! This is the sixth of nine modules available in this directed self-study course. The purpose of this module is to provide an understanding of nuclear fuel and materials after their use for generating power in a reactor - referred to as the “back-end” of the fuel cycle - and the differences between the open and closed fuel cycles. Unlike the other parts of the fuel cycle, the spent nuclear fuel (SNF) is highly radioactive and heat-generating; and thus, the facilities, hazards, and safety approaches are fundamentally different. The module has seven learning objectives. This self- study module is designed to assist you in accomplishing the learning objectives listed at the beginning of the module. The module’s self-check questions will help you assess your understanding of the concepts presented. Before you Begin It is recommended that you have access to the following materials: ◙ Trainee Guide Complete the following prerequisites: ◙ Module 1.0: Overview of the Nuclear Fuel Cycle ◙ Module 5.0: Fuel Fabrication How to Complete this Module 1. Review the learning objectives. 2. Read each section within the module in sequential order. 3. Complete the self-check questions and activities within this module 4. Check off the tracking form as you complete the self-check questions and/or activity within the module. 5. Contact your administrator as prompted for a progress review meeting. 6. Contact your administrator as prompted for any additional materials and/or specific assignments.
    [Show full text]
  • Methodology to Manage Material and Waste from Nuclear Decommissioning Waste Management & Decommissioning Working Group
    Methodology to Manage Material and Waste from Nuclear Decommissioning Waste Management & Decommissioning Working Group Methodology to Manage Material and Waste from Nuclear Decommissioning Waste Management & Decommissioning Working Group, World Nuclear Association Title: Methodology to Manage Material and Waste from Nuclear Decommissioning Produced by: World Nuclear Association Published: February 2019 Report No. 2019/001 Cover image: Yankee Atomic Electric Company © 2019 World Nuclear Association. Registered in England and Wales, company number 01215741 This report reflects the views of industry experts but does not necessarily represent those of the World Nuclear Association’s individual member organisations. Contents List of Figures & Tables vi Executive Summary vii Preface ix Chapter 1: Introduction 1 Chapter 2: Decommissioning Strategies 3 2.1 Introduction 4 2.2 External influences 4 2.3 Operator influences 5 2.4 Decommissioning strategy options 9 2.5 Influence of plant end state on decommissioning strategy 10 Box: Definition of ‘end state’ 11 2.6 Decommissioning planning 13 Chapter 3: Inventories 17 3.1 Introduction 18 3.2 Influence of inventory on materials management 19 3.3 Inventory types 20 3.3.1 Physical inventory 21 3.3.2 Radiological inventory 22 Box: Activated and contaminated equipment and structures 24 Box: European Union radioactive waste inventory 26 3.3.3. Chemical and biological inventory 28 Chapter 4: Waste Routing 29 4.1 Introduction 30 4.2 Influence of decommissioning strategy on waste route 31 4.3 Influence of inventory
    [Show full text]
  • Process and Waste Form Options for Plutonium Immobilization
    WM’05 Conference, February 27 – March 3, 2004, Tucson, AZ LOW-RISK ALTERNATIVE WASTE FORMS FOR ACTINIDE IMMOBILIZATION M.W.A. Stewart, B.D. Begg, R.A. Day, S. Moricca, E.R. Vance, P.A. Walls Australian Nuclear Science and Technology Organisation (ANSTO), PMB 1, Menai, NSW 2234, Australia, www.synrocansto.com, www.ansto.gov.au ABSTRACT Ceramic and glass-ceramic synroc waste forms can be tailored to meet the unique requirements of actinide waste forms. The key is the use of waste form chemistry design to make waste forms flexible enough to handle real waste streams, coupled with proven economic process technologies, to produce waste forms that meet the unique requirements for actinide waste streams, particularly Pu. The synroc waste forms are much more durable than baseline borosilicate glasses and are able to incorporate neutron absorbers and U-238 for criticality control during processing and within the repository. They offer proliferation resistance advantages over baseline borosilicate glasses, as it is much more difficult to retrieve the Pu for reuse. In addition, synroc ceramics can reduce the radiation dose to workers compared to borosilicate glasses. ANSTO has extensive experience designing waste forms and has produced Pu-doped waste forms via hot-uniaxial pressing, cold-pressing and sintering (similar to MOX fuel production) and hot-isostatic pressing. INTRODUCTION Actinide-bearing waste streams offer unique immobilization challenges. Actinides typically have very long half-lives and may be fissile, thus requiring criticality control and safeguards measures. Actinide waste streams can also range from pure to very impure. The synrocANSTO team from the Australian Nuclear Science and Technology Organisation (ANSTO) has over 25 years continuous experience in the design and development of radioactive waste forms and process routes that have been tailored for a variety of niche applications.
    [Show full text]
  • The Effect of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization" (2018)
    Clemson University TigerPrints All Dissertations Dissertations 12-2018 The ffecE t of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization Robert L. Grote Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Recommended Citation Grote, Robert L., "The Effect of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization" (2018). All Dissertations. 2248. https://tigerprints.clemson.edu/all_dissertations/2248 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. THE EFFECT OF COMPOSITION ON THE STRUCTURE SYMMETRY AND STABILITY OF TUNNEL-STRUCTURED HOLLANDITE CERAMICS FOR NUCLEAR WASTE IMMOBILIZATION A Dissertation Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Materials Science and Engineering by Robert Lansing Grote December 2018 Accepted by: Dr. Kyle Brinkman, Committee Chair Dr. Rajendra Bordia Dr. Fei Peng Dr. Lindsay Shuller-Nickles ABSTRACT The ceramic phase hollandite is a component material for some multi-phase ceramic waste forms and has been a prominent ceramic waste form for the immobilization of cesium and strontium radionuclides. The immobilization of cesium is difficult due to its large size and water solubility. This dissertation is focused on understanding the fundamental structure of hollandite and the effect cesium doping has on the properties of hollandite in order to develop a more effective and efficient waste form for cesium immobilization.
    [Show full text]
  • Synroc for Plutonium Disposal AU0019553
    Synroc for Plutonium Disposal AU0019553 ADAM JOSTSONS and E. R. (LOU) VANCE Australian Nuclear Science and Technology Organisation PMB 1 Menai NSW 2234 SUMMARY in turn would be loaded into standard Defense Waste Processing Facility (DWPF) canisters for A pyrochlore-rich titanate ceramic has been chosen HLW glass and the molten glass would be poured by the US DOE for excess weapons Pu around them to provide an external gamma immobilisation in the USA. The development of radiation barrier. this wasteform was based on the synroc strategy which aims to immobilise radioactive waste in The Australian Nuclear Science and Technology durable multiphase titanate ceramics with phases Organisation (ANSTO) has been developing chosen to be similar to titanate minerals that exist in titanate ceramic wasteforms since 1980 through its nature and have immobilised U and Th for billions synroc program. ANSTO is participating with the of years. The evolution of the pyrochlore-rich Lawrence Livermore National Laboratory (LLNL). ceramic for Pu immobilisation from earlier synroc the lead laboratory on plutonium immobilisation for variants is described and the choice of process steps the US DOE office of Fissile Materials Disposition is discussed. Leaching studies demonstrate that the (MD). Other members of the team are Argonne release rate of Pu from the wasteforms in aqueous National Laboratory, Pacific Northwest National media is very low and similar to those of U and the Laboratory and the Westinghouse Savannah River neutron absorbers Gd and Hf that will ensure Company Technology Center. The US DOE has avoidance of nuclear criticality in repository expressed a preference for siting the immobilisation environments.
    [Show full text]