INSTITUTE for TRANSURANIUM ELEMENTS, KARLSRUHE: Annual

UALREPORT90 Institute FOR T Iransuranîum Elements H JOINT ; RESEARCH LJ CENTRE COMMISSION OF THE EUROPEAN COMMUNITIES EUR 13815 EN ç COMMISSION OF THE EUROPEAN COMMUNITIES Joint Research Centre INSTITUTE FOR TRANSURANIUM ELEMENTS KARLSRUHE Annual Report 1990 TUAR-90 fARt EUROP Blblioih. 1991 tjek EUR 13815 EN Published by the COMMISSION OF THE EUROPEAN COMMUNITIES Directorate-General Telecommunications, Information Industries and Innovation Bâtiment Jean Monnet LUXEMBOURG LEGAL NOTICE Neither the Commission of the European Communities nor any person acting on behalf of the Commission is responsible for the use which might be made of the following information Luxembourg: Office for Official Publications of the European Communities, 1990 Catalogue nummer: CD-NA-13815-EN-C ECSC-EEC-EAEC, Brussels Luxembourg, 1990 Printed in the Federal Republic of Germany Abstract Basic Safety Research on Nuclear Fuels in 1990 centered on studies of the interrelation between structure, fission gas release and operating conditions of high burn-up LWR fuel. Basic mechanisms of fission product release were clarified in so-called single-effect studies. As an input parameter for safety studies, the specific heat capacity of molten UO2 was measured up to 8000 K. The investigations of Safety Aspects of Fuel Operation revealed that structural and chemical changes limit the operation of mixed nitride fuels to centre temperatures below 2000 K. Studies on the Safe Handling of Fuel Materials concentrated on the spread of airborne contamination in accident situations. Of primary concern in the field of Actiniae Determination and Recycling was the nuclear transmuta• tion of long-lived radioactive waste constituants and the recycling of self- generated Pu. Progress in the Characterisation of Waste Forms and of High Burn-Up Fuel was achieved by simulating the effects of long- term storage on leachibility and mechanical stability of waste glasses. An electrochemical study is helping to better understand UO2 corrosion in aqueous solutions, an important asset in the evaluation of spent fuel storage possibilities. An instrument for the non-destructive characterisation of spent fuel in terms of minor actinide and fission product inventory was developed and undergoes testing. In the field of Actinide Research, especially 1:1:1 and 1:2:2 neptunium and plutonium compounds were prepared and characterised for solid state measurements. Band structures of actinide inter me tall ics were calculated. Photoelectron spectroscopy was performed with PuSe and UAlNi. and high-pressure phases as well as compressibilities were determined by X-ray diffraction for PuC*2, PuSe, Pm, and a Pm-Sm alloy. The pressure dependence of the optical reflectivity was measured for several pnictides and chalco- genides of U and Th, and equipment for the determination of the electrical resistivity of actinides under pressure was set up. The effectiveness of acoustic aerosol agglomeration under static conditions with different sound sources and under various geometries was confirmed in an Exploratory Research project. An extension to a dynamic environment as a first step to open air applications is under study. As scientific-technical Support to Community Policies, the Institute for Transuranium Elements has continued to perform analytical work for the Commission's Safeguards Directorate. The development of a high-speed optical pyrometer for temperature measurements in an industrial environment as well as experiments to enhance the efficiency of industrial filters by ultrasonic techniques are being pursued in the context of Commission programmes for Technology Transfer and Innovation. In support to the Commission's Directorate General for External Relations and in collaboration with the IAEA and the Radium Khlopin Institute, a robotized system for the preparation and conditioning of samples from a reprocessing plant for mass spectrometry was installed at the Radium Institute in Gatchina, near Leningrad. Major contract Work for Third Parties in 1990 dealt with the study of dissolution characteristics of high burn-up fuel, with the preparation of minor actinide alloys, with the production of alpha-emitting nuclides for radio-therapy, and with the transfer of fuel pin codes to national research institutions and licencing authorities. A project to analyse fuel rods from commercial power reactors was under pre• paration. Table of Contents Foreword 9 Executive Summary 11 MAIN ACHIEVEMENTS AND MILESTONES 1. Specific Programmes 19 1.1 Basic Research on Nuclear Fuels 19 Introduction 19 Structural investigations and basic studies on fuels - Oxide fuel transiente Fission poroduct behaviour in transient-tested LWR fuel samples,studiedby trans mis s ion, scanning, and replica electron microscopy 20 Study of the radial distribution ofXe and Cs by EMPA 28 Characterisation of simulated high burn-up fuel (SIM-fuel) and Kr release measurements 28 Radiation damage in UO2' Damage production and recovery in the U-sub- lattice of ion-implanted UO2 between 5K and 2000 K 31 Leaching, hydration and surface analysis o f unirradiated UO2 33 Determination of oxygen potential ofFBR oxide fuel at very high burn-ups 35 Study of problems related to reactor safety 36 Introduction 36 Examination of a dual-density Zr02 thermal insulator after contact with liquid UO2 36 Post-irradiation examination of a Silene specimen 37 Examination of samples from the reactor core ofTMI-2 40 Study of high-temperature properties of nuclear materials 41 Introduction 41 Specific heat of urania up to 8000 K 42 Graphite melting at high pressure 43 Emissivity behaviour in refractory metals and oxides 44 Laser flash equipment for thermal diffusivity measurements 45 Theoretical activities 45 Participation in the Phebus source term modelling project 45 Code implementation work 46 Modelling the chemistry of irradiated fuel 47 Thermodynamic properties studies 48 Thermodynamic properties of(UJ?u)N 48 Industrial applications 49 Acoustic lévitation techniques 49 Modelling work 49 General fuel pin code development (TRANSURANUS) 49 A nalysis of experiments using TRANS URANUS 52 Radioactive waste modelling 57 1.2 Safety Aspects of Fuel Operation and Handling 59 Introduction 59 Investigation of the operational limits of (U,Pu)N fuels 59 Fire experiments under realistic laboratory conditions 66 Duct transport of big particles (TRABI) 69 1.3 Actinide Determination and Recycling 71 Introduction 71 Follow up of the workshop on partitioning and transmutation of minor actinides 71 Status of the irradiation in KNKII 72 Status of the irradiation experiment SUPERFACT 72 Calculations of the results of recycling self-generated Pu in a PWR at 50 GWd/t burn-up per cycle 72 System-immanent long-lived radio isotope transmutation 75 Investigation of the (U,Np)-N and (U,Am)-0 systems 77 Actinide separation by high-pressure cation exchange - The neptunium case 78 Recovery of minor actinides from scrap materials 80 Absorption spectroscopy of solutions of Pu and Cm 81 Extraction of actinides and other constituents from HAW by TRPO 82 1.4 Characterisation of Waste Forms and of High Burn-Up Fuel 87 Introduction 87 Spent fuel characterisation and related studies 87 Radiation damage effects in waste glasses 87 Validation of algorithms forKic determination from Vickers indentations: The short rod fractometer, application up to 450°C 89 Ceramic waste forms 91 Surface analysis of glasses 91 Electrochemical analysis related to UO2 corrosion 92 Characterisation of UO2 and MOX spent fuel 97 Modelling of the underground water contamination in a spent fuel deposit 104 Characterisation of highly active glasses 106 Non-destructive assay of spent nuclear fuel 108 1.5 Actinide Research 109 Objectives 109 Preparation and characterisation of actinide metals and compounds 109 Introduction 109 Preparation and refining of actinide metals 109 Preparation of alloys 109 The crystal chemistry of the AnMX and AnM.2^-2 compounds 111 The actinide pnictides of the Th^4 structure type 111 Preparation of single crystals of large families o f isostructural compounds 112 Structure of organometallic compounds 113 Structure ofactinideflV) nitrato complexes 114 Solid state physics studies on actinide systems 115 Theoretical studies 115 Neutron studies 117 X-ray resonant magnetic scattering 121 Photoemission study of the electronic structure ofUNiAl 121 High-pressure studies on actinide systems 122 B1-type compounds 122 Study of dioxides 126 Crystal structures ofUP2, UAs2, UAsS, and UAsSe in the range up to 60 GPa 126 A high-pressure study ofTh3P4 and some U3X4 compounds 127 HPXRD study of oxychalcogenides 128 X-ray diffraction studies on samarium up to 1 Mbar 128 Actinide information centre 129 The data bank system THERSYST for thermophysical property data ofactinides 129 2. Exploratory Research 133 Acoustic aerosol scavenging 133 Introduction 133 Static experiments 133 Future research directions 138 Discussion and conclusions 141 3. Scientific-Technical Support to Community Policies 143 Introduction I43 Support to DG XVII 143 Laser ablation I43 Analysis of fines coming from the dissolution ofLWR fuel 145 Determination ofNp by ICP-MS 147 Gamma spectrometry 150 The Caldex tracer experiment 151 Components for an on-site safeguards laboratory 151 Intrinsic densitometry techniques for high burn-up Pu solutions 157 Support to DG I 159 Installation and field testing of a robotized system for sample preparation and conditioning for mass spectrometry in Gatchina (USSR) 159 Support to DG XIII 159 Construction of a multichannel

Load more