Performance Assessment for Geological Disposal of Graphite Waste Containing TRISO Particles

This paper presents a deterministic performance assessment for spent fuel from deep-burn modular hightemperature reactors (DBMHRs) in the proposed Yucca Mountain repository. Typical DBMHR designs utilize fuel elements manufactured from graphite. The fuel itself is made of TRISO particles containing the fissile material. The performance of the DBMHR spent fuel (DBSF) was evaluated in terms of the annual dose to the reasonably maximally exposed individual (RMEI) under various hydrogeological conditions. Part of this evaluation was an analysis of the graphite waste matrix and of the TRISO particles under repository conditions, the result of which indicates that the lifetime of the graphite matrix greatly exceeds that of the TRISO particles and that it is the graphite, not the TRISO particles, that serves to sequester the radionuclides within the fuel matrix. Under all 14 cases considered, DBSF is seen to comply with the annual dose standards set in Part 197 of Title 40 of the Code of Federal Regulations, for exposure via groundwater contamination under current climatic conditions. Parametric studies for the effect of waste matrix lifetime on annual dose received by the RMEI indicate that repository performance is sensitively linked to waste matrix durability because most radionuclides including actinides are likely to be released congruently with the graphite matrix

Soziale Sicherung im Lebenslauf – Finanzielle Aspekte in längerfristiger Perspektive am Beispiel der Alterssicherung in Deutschland

"Zunehmende Risiken im Lebenslauf und die Forderung nach vermehrter individueller Flexibilität stellen eine Herausforderung für die adäquate Gestaltung sozialer Sicherung dar, z.B. für die Alterssicherung. In diesem Beitrag wird dargestellt, wie 'soziale Risiken' in öffentlichen und (subventionierten) privaten Alterssicherungssystemen (einschließlich betrieblicher Einrichtungen) berücksichtigt werden. Dies erfolgt am Beispiel der Situation in Deutschland. Ein solcher Vergleich unterschiedlicher Sicherungssysteme wird um so wichtiger, da in vielen Ländern die Rolle des Staates als 'Produzent' sozialer Leistungen reduziert wird. Ausgehend von Zielen und Konzeptionen zur Gestaltung sozialer Sicherung im Alter stehen im Zentrum dieses Beitrags Auswirkungen verschiedener Typen öffentlicher und privater Alterssicherungssysteme auf die Einkommenslage im Alter bei Eintritt bestimmter sozialer Risiken, wie Einkommensverlust durch Arbeitslosigkeit, Krankheit, Pflege von Kindern. Dabei wird der Einsatz unterschiedlicher Instrumente - unter ihnen der von Zeitkonten - betrachtet. Schließlich wird die Verlagerung von Risiken und Verantwortung im Falle zumindest partieller Privatisierung sozialer Sicherung diskutiert - Verlagerungen vom Staat auf private Haushalte, von Arbeitgebern auf Arbeitnehmer. Für den Fall, dass private Sicherungssysteme obligatorisch werden, ist zu erwarten, dass sie mit zu einem Instrument der staatlichen Sozialpolitik werden und manche der sozialen Risiken zu berücksichtigen haben, wie dies bislang in staatlichen Systemen erfolgte." (Autorenreferat)"Growing insecurity over the life course and an increasing demand for more individual flexibility are a challenge for adequate social security, for example in old age. This paper outlines how 'social risks' are taken into account in public as well as (subsidised) private pension schemes (including occupational schemes), such as those in Germany. This becomes more important because in many countries the role of the state as provider of social security benefits is being scaled down. Starting from objectives and concepts for designing social security for old age, the major focus of the paper is the effects of different types of public as well as private pension schemes on income in old age in relation to different social risks, such as loss of income in case of unemployment, illness, caring for children and by using different instruments (among other things, time saving accounts). Finally, the shift of risks and responsibility in the (at least partial) privatisation of social security - from state to private households, from employers to employees - is discussed. If private schemes become mandatory, they may become an instrument of (public) social policy and have to cover some of the social risks that public schemes have in the past." (author's abstract

The Good, the Bad and the Ugly: A Study of the Organization through the Lens of Popular Films of the Western World

This chapter examined portrayals of the morality of organizations using the lens of Western films. The work explored six decades of film, analyzing the organizational contexts and their agents, in order to understand filmmakers’ and audiences’ perceptions of organizational settings. In order to examine the organization as an entity within film, this chapter provided a content analysis of plot summaries from a purposefully selected body of top grossing box office films spanning 60 years. The plot summaries constituted a strong basis for identifying the characteristics of the organization as they are largely descriptive in nature and as such do not offer any evaluation or analysis of the film. Any assumptions about the character of organizations (or their members/employees) are unconscious, and as such they constitute a verbal description of what competent observers would say has occurred within the film. The plots were coded to reveal perceptions of positive, neutral, or negative organizational contexts and actions. This approach exposed the filmmakers symbolic placing of the organization in order to provide backdrops for the narrative. The plot analysis revealed that throughout the decades there has been a sophisticated portrayal in film of the role of the organization and the agents therein. A generally negative view of organizational contexts was demonstrated, with only religion and education shown as positive within the films selected. It was recognized that there would be value in extending this research to analyze a larger body of works. The selection criteria resulted in a wide but not comprehensive corpus of film genres. The body of works was sufficient to reveal the complexity of attitudes to organizational values and delivery which has evolved through time. Different selection criteria and more substantial narrative text could serve to confirm these results. Further implications for future research were discussed. While in the real-life sphere, there has been an emphasis on organizational standards and “corporate governance” delivering ethical exemplars, the film contexts highlight the complexities of delivering trusted organizations. The reality that there remains the potential for organizational corruption is well understood by the general public and clearly depicted within the film world. The conceptual contribution is original as limited work has been conducted on the organizational context in films. This work revealed the possibility of using this approach to further develop a greater understanding of perceptions of organizations

Porcine circovirus type 2 (PCV2)-infection and re-inoculation with homologous or heterologous strains: virological, serological, pathological and clinical effects in growing pigs.

Long-term PCV2 infection and/or concurrent infection with genotypes PCV2a and PCV2b may play a role in the development of clinical porcine circovirus-associated disease (PCVAD). To evaluate this premise, 24 11-week-old specific pathogen-free (SPF) pigs were randomly assigned to 1 of 4 treatments: negative controls, a single inoculation with PCV2a, single inoculation followed by re-inoculation with a homologous PCV2a strain, or repeated inoculations with heterologous strains (PCV2a, PCV2b). Pigs were evaluated for clinical signs daily through 140 days post inoculation (dpi). Serum samples were collected every other day from dpi 0 through 14 and weekly thereafter. PCV2-inoculated pigs were viremic by dpi 2 and 13 of 18 pigs remained viremic at 140 dpi. No statistical differences in the onset, level, or duration of PCV2 viremia were detected among treatment groups. Anti-PCV2 antibodies were detected between 14 and 28 dpi and were present through 140 dpi without statistical differences in antibody response among treatment groups. In the current study, pigs had extended viremia combined with detectable tissue PCV2 antigen levels despite the presence of high levels of anti-PCV2 antibody; however, no clinical disease was observed

Functional interaction of vascular endothelial-protein-tyrosine phosphatase with the angiopoietin receptor Tie-2

During development of the vertebrate vascular system essential signals are transduced via protein-tyrosine phosphorylation. Null-mutations of receptor-tyrosine kinase (RTK) genes expressed in endothelial cells (ECs) display early lethal vascular phenotypes. We aimed to identify endothelial protein-tyrosine phosphatases (PTPs), which should have similar importance in EC-biology. A murine receptor-type PTP was identified by a degenerated PCR cloning approach from endothelial cells (VE-PTP). By in situ hybridization this phosphatase was found to be specifically expressed in vascular ECs throughout mouse development. In experiments using GST-fusion proteins, as well as in transient transfections, trapping mutants of VE-PTP co-precipitated with the Angiopoietin receptor Tie-2, but not with the Vascular Endothelial Growth Factor receptor 2 (VEGFR-2/Flk-1). In addition, VE-PTP dephosphorylates Tie-2 but not VEGFR-2. We conclude that VE-PTP is a Tie-2 specific phosphatase expressed in ECs, and VE-PTP phosphatase activity serves to specifically modulate Angiopoietin/Tie-2 function. Based on its potential role as a regulator of blood vessel morphogenesis and maintainance, VE-PTP is a candidate gene for inherited vascular malformations similar to the Tie-2 gene

Bestimmung toxischer organischer Bestandteile in radioaktiven Abfällen

Von dem in der Bundesrepublik anfallenden radioaktiven Abfall sind etwa 99% schwach radioaktiver Abfall (1) (Low Active Waste "LAW"). In ein Endlager, wie zum Beispiel das ehemalige Erzbergwerk Konrad in Salzgitter, dürfen nur konditionierte radioaktive Abfälle eingelagert werden. Daher müssen Flüssigkeiten oder nicht kompaktierbare Feststoffe (nicht bis 30 MPa formstabil) verfestigt werden. Ausgenommen von dieser Regelung sind metallische Reaktorkernteile, Feststoffe mit einem Schmelzpunkt oberhalb 300°C, wenn bei dieser Temperatur kein verflüssigtes Material freigesetzt wird, und Bitumenprodukte (2). Zur Verfestigung der schwach radioaktiven Abfälle wird meist Zement verwendet (3). Bisher wurde bei den zementverfestigten, schwach radioaktiven Abfällen die Aktivität als Hauptgefahrenpotential angesehen. Diese Abfälle können aber auch organische und anorganische Substanzen enthalten, die durch ihre Chemotoxizität möglicherweise eine wesentlich größere Gefahr darstellen. Aus diesem Grund ist die Vermischung von radioaktiven Abfällen und toxischen Substanzen in der Bundesrepublik Deutschland verboten (4). Um diese Anforderung zu kontrollieren, insbesondere da ab 1993 das Endlager Konrad in Betrieb genommen werden soll, besteht ein großes Interesse der Physikalisch-Technischen Bundesanstalt (PTB) in Braunschweig und des Bundesministeriums für Umwelt, Naturschutz und Reaktorsicherheit (BMU) an einem Verfahren, mit dem toxische organische Substanzen in zementverfestigten, radioaktiven Abfällen nachgewiesen werden können (5). Eine Liste organischer Problemstoffe ist im technischen Bericht NTB 85-61 der Nationalen Genossenschaft für die Lagerung radioaktiver Abfälle (NAGRA) aufgeführt (6). Es handelt sich dabei um Substanzen, die persistent und hochtoxisch, kanzerogen oder teratogen für Menschen oder andere Organismen sind. Neben diesen organischen Substanzen, die aufgrund ihrer Toxizität problematisch sind, sind gemäß (6) auch solche Substanzen in die Liste der Problemstoffe aufzunehmen, die in größeren Mengen (mehr als 500 kg) im Endlager vorkommen können, stark ätzend, explosiv, leicht löslich oder flüssig sind. Eine weitere mögliche Gefahrenquelle könnten die durch radioaktive Strahlung initiierten Reaktionen der organischen Substanzen sein. Diese Reaktionen verlaufen im ersten Reaktionsschritt über Radikalionen (7). Es ist daher denkbar, daß, wie bei den radikalisch verlaufenden Hochtemperaturverbrennungsprozessen, aus weniger gefährlichen Substanzen, hochtoxische Verbindungen entstehen (zum Beispiel die Bildung von polychlorierten Dioxinen aus Chlorkohlenwasserstoffen bei der Müllverbrennung) (8). Auch können chemische Reaktionen der organischen Verbindungen mit der Zementmatrix nicht ausgeschlossen werden