OECD/NEA Data Bank Scientific and Intergral Experiments Databases in Support of Knowledge Preservation and Transfer

The OECD/Nuclear Energy Data Bank was established by its member countries as an institution to allow effective sharing of knowledge and its basic underlying information and data in key areas of nuclear science and technology. The activities as regards preserving and transferring knowledge consist of the: — Acquisition of basic nuclear data, computer codes and experimental system data needed over a wide range of nuclear and radiation applications. — Independent verification and validation of these data using quality assurance methods, adding value through international benchmark exercises, workshops and meetings and by issuing relevant reports with conclusions and recommendations, as well as by organising training courses to ensure their qualified and competent use. — Dissemination of the different products to authorised establishments in member countries and collecting and integrating user feedback. Of particular importance has been the establishment of basic and integral experiments databases and the methodology developed with the aim of knowledge preservation and transfer. Databases established thus far include: — IRPhE – International Reactor Physics Experimental Benchmarks Evaluations, — SINBAD – a radiation shielding experiments database (nuclear reactors, fusion neutronics and accelerators), — IFPE – International Fuel Performance Benchmark Experiments Database, — TDB – The Thermochemical Database Project, — ICSBE – International Nuclear Criticality Safety Benchmark Evaluations [1], — CCVM – CSNI Code Validation Matrix of Thermal-hydraulic Codes for LWR LOCA and Transients [2]. This paper will concentrate on knowledge preservation and transfer concepts and methods related to some of the integral experiments and TDB

Physique des réacteurs et transmutation

La transmutation des transuraniens par recyclage en réacteur permet de ramener en quelques siècles de refroidissement la radio-toxicité des déchets de haute activité à vie longue mis au stockage au niveau de celle de l'uranium naturel ayant servi à produire la même quantité d'énergie en cycle ouvert. Les principales difficultés pour sa mise en oeuvre découlent des propriétés neutroniques et physiques des actinides mineurs, aboutissant à privilégier les réacteurs à spectre rapide, avec toutefois de gros problèmes de faisabilité du combustible pour les options d'incinération "hétérogène" où les actinides mineurs sont chargés à part dans des cibles spécifiques placées dans les réacteurs électrogènes, ou dans une double strate de réacteurs sous-critiques dédiés. Quant aux produits de fission à vie longue, leur transmutation ne semble pas, en l'état actuel des études, pouvoir présenter une option de gestion suffisamment efficace

Longitudinal course of physical and psychological symptoms after a natural disaster

Background: After disaster, physical symptoms are common although seldom recognized due to lack of knowledge of the course of symptoms and relation to more studied psychological symptoms. Objective: This study aimed to investigate the change in the reporting of different physical symptoms after a disaster, including possible factors for change, and whether psychological symptoms predict physical symptoms reporting at a later point in time. Method: A longitudinal study of citizens of Stockholm who survived the 2004 Indian Ocean tsunami. A total of 1,101 participants completed questionnaires on somatic symptoms, general distress, posttraumatic stress, exposure, and demographic details 14 months and 3 years after the disaster. Physical symptoms occurring daily or weekly during the last year were investigated in four symptom indices: neurological, cardiorespiratory, gastrointestinal, and musculoskeletal. We used generalized estimating equations (GEE) analysis to determine odds ratios for a change in symptoms, and pathway analysis to predict the influence of psychological symptoms on physical symptoms. Results: There was a general decrease of reporting in all physical symptom indices except the musculoskeletal symptom index. The change in the neurological symptom index showed the strongest association with exposure, and for women. General distress and posttraumatic stress at 14 months postdisaster predicted physical symptoms at 3 years. Conclusion: Physical symptoms were predicted by psychological symptoms at an earlier time point, but in a considerable proportion of respondents, physical symptoms existed independently from psychological symptoms. Physicians should be observant on the possible connection of particular pseudoneurological symptoms with prior adversities

Fuel management in Phenix and Super-Phenix

Translated from French (IAEA Int. Conf. on fast breeder reactors Lyon (FR) 22-26 Jul 1985)SIGLEAvailable from British Library Document Supply Centre- DSC:9091.9F(RISLEY-Trans--5187)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Innovative Core Design for Generation IV Sodium-Cooled Fast Reactors

The design of innovative cores for Generation IV Sodium-cooled Fast Reactors (SFRs) must chiefly focus on improving safety performance levels and competitiveness, with the aim of achieving all fundamental goals set for Generation IV systems. In this context, one priority is to create a core design such that, in the event of a serious accident, all risks of generalised fuel meltdown are avoided. The core must therefore be optimised to reduce the sodium void reactivity effect whilst acting as a self-converter with respect to the fuel itself. Design options are compared by using the physical sensitivity and parametric studies that were carried out, in order to highlight the most attractive approach for meeting the goals. A very large number of combinations of theses design options are possible For a high power EFR-type core (1500 MWe) with Oxide fuel (UO2-PuO2), the goals can be met, with the sodium void effects nearly halved, to a value of around 3 to 4 dollars, by selecting options, such as: - a tight grid assembly design, - introduction of a sodium plenum in the assembly's upper section, - introduction of a moderator material. Use of a denser fuel such as Carbide is shown to be very attractive. Its higher density means that a near-zero Internal Breeding Gain can be achieved. Most importantly, its thermal conductivity, which is significantly higher than that of the oxide fuel allows for optimisation options. Either the overall core volume can be reduced by increasing linear power density, or the margin between fuel operating temperature and melting point can be increased. Some resuls from core simulations are presented. Further studies should focus on a detailed characterisation of the selected cores, in particular involving ULOF and UTOP type accident transient calculations. These analyses alone will be suitable arbitrators to identify the real safety level achieved