Die Wirkung und Qualität von BIZ-Beratungen in den Bundesländern Burgenland und Tirol: Ergebnisse einer aktuellen Studie im Auftrag von AMS Tirol und AMS Burgenland zur Bildungs- und Berufsberatung im AMS-Kontext

[Einleitung] Die Frage nach der Beratungswirkung wurde in den letzten Jahren auch vermehrt in Bezug auf die Bildungs- und Berufsberatung gestellt. Das AMS Tirol und das AMS Burgenland widmeten im Jahr 2015 genau diesem Thema eine Studie, wobei deren BerufsInfoZentren (BIZ) im Fokus standen. Die BIZ des AMS bieten nämlich neben Informationen zu den Themen "Beruf", "Bildungs- und Berufswahl", "Aus-, Um- und Weiterbildung" auch persönliche Einzelberatung durch BIZ-BeraterInnen an. Diese dauert ca. 45 Minuten und findet üblicherweise einmalig, manchmal auch mit einem Folgetermin statt. Die forschungsleitenden Fragestellungen dieser Studie, die vom sozialwissenschaftlichen Forschungs- und Beratungsinstitut abif realisiert wurde, sind: Wie kann Wirkung überhaupt gemessen werden? Was sind die Wirkungen der Bildungs- und Berufsberatung durch die BIZ-BeraterInnen? Was macht "gute" Beratung aus? Welche Empfehlungen für die Beratung und Wirkungsmessung lassen sich daraus ableiten

Self-passivating W-Cr-Y alloys: characterization and testing

The use of self-passivating tungsten alloys for the first wall armor of future fusion reactors is advantageous concerning safety issues in comparison with pure tungsten. Bulk W-10Cr-0.5Y alloy manufactured by mechanical alloying followed by HIP resulted in a fully dense material with grain size around 100 nm and a dispersion of Y-rich oxide nanoparticles located at the grain boundaries. An improvement in flexural strength and fracture toughness was observed with respect to previous works. Oxidation tests under isothermal and accident-like conditions revealed a very promising oxidation behavior for the W-10Cr-0.5Y alloy. Thermo-shock tests at JUDITH-1 to simulate ELM-like loads resulted in a crack network at the surface with roughness values lower than those of a pure W reference material. An additional thermal treatment at 1550 °C improves slightly the oxidation and thermo-shock resistance of the alloy

Thermal shock of tungsten carbide in plasma-facing conditions

Tungsten carbide (WC) has been found to have higher resistance to plasma-induced thermal shock compared to rolled tungsten. The electron beam device JUDITH 1 was used to simulate likely thermal shock conditions induced by edge localised modes and plasma disruptions. Loading conditions of 100–1000 cycles, heat fluxes of 0.19–1.13 GW/m2 and base temperatures of 400–1000 °C were employed on two candidate WC-based materials: a monolithic WC ceramic, and a WC-FeCr composite. Surprisingly, the monolith outperformed the composite under all conditions. This was unexpected, particularly at 400 °C, based on the calculated thermal shock resistance parameters. The result was explained by preferential melting of the metallic FeCr binder. Compared to available data collected under identical conditions on rolled tungsten plate, monolithic WC had lower surface roughness from thermal shock damage, particularly when tested at 400 °C. This shows promise for its use as a plasma facing material. Strategies for further improving performance are discussed

Recrystallization and composition dependent thermal fatigue response of different tungsten grades

Industrial pure tungsten grades, manufactured by using a variety of manufactured techniques, are available worldwide in many different types of semifinished products, i.e. rods, wires, ribbons, and sheets. Thereby, the recrystallization temperature varies depending on the applied degree of deformation but also depending on the materials composition, i.e. the materials purity and in particular the level of certain impurities. In order to compare different available industrial tungsten grades and a newly developed PIM-W grade, on the one hand recrystallization studies at three different temperatures from 1300 to 1800 °C for 1 h were performed using Vickers hardness testing. On the other hand, the thermal shock induced low cycle thermal fatigue response of the material in its different recrystallization stages was done using high heat flux tests at 1000 °C base temperature, applying 1000 shots with 1 ms and 0.38 GW/m2 and post mortem characterization, i.e. profilometry and metallography. The obtained results are related to the chemical composition of the individual tungsten grades obtained from Auger electron spectroscopy analyses on cold fracture surfaces

High pulse number thermal shock testing of tungsten alloys produced by powder injection molding

The investigation of plasma facing materials (PFM) subjected to a large number (≥10,000) of thermal shocks is of interest to determine long term morphological changes which might influence component lifetime in and plasma performance of a fusion reactor. The electron beam facility JUDITH 2 was used to simulate these conditions experimentally. In this study eight different tungsten grades produced by powder injection molding (PIM) were investigated: Two pure tungsten grades, one with 2 wt% Y₂O₃, three with 1, 2 and 3 wt% TiC, and two with 0.5 and 1 wt% TaC. Samples of 10 × 10 × 4 mm³ were brazed to a copper cooling structure and subjected to 10⁵ thermal shocks of 0.5 ms duration and an intensity of L$_{abs}$=0.55 GW/m² (F$_{HF}$=12 MWs½/m2) at a base temperature of T$_{base}$ = 700 °C. The PIM grades showed damages in general comparable with a sintered and forged pure tungsten reference grade (>99.97 wt% W) that complies with the ITER specifications. One exception was the 2 wt% TiC doped material which failed early during the experiment by delamination of a large part of the surface. The Y₂O₃ doped material showed a comparatively good performance with respect to crack width (<15 μm) and roughening (R$_{a}$ = 0.75 μm), but showed melt droplets of ∼3–4 μm diameter, while the 1 wt% TiC doped material showed wide cracks (up to 50 μm) and strong roughening (R$_{a}$ = 2.5 μm). The paper discusses the post-mortem analysis of all grades, comparing them with respect to roughness (from laser profilometry), crack network characteristics and local melt droplet formation or other special morphological features (from SEM images) as well as crack depth (from metallographic cross sections)

The EUROfusion materials property handbook for DEMO in-vessel components—Status and the challenge to improve confidence level for engineering data

The development of a specific materials database and handbook, for engineering design of in-vessel components of EU-DEMO, is an essential requirement for assessing the structural integrity by design. For baseline in-vessel materials, including EURFOER97, CuCrZr, Tungsten as well as dielectric and optical materials, this development has been ongoing for several years within the Engineering Data and Design Integration sub-project of the EUROfusion Materials Work Package. Currently the database is insufficient to ensure reliable engineering design and safety or hazard analysis and mostly does not yet exist in established nuclear codes. In this paper the current status of EU-DEMO database and handbook for key in-vessel materials is provided. This comprises practical steps taken to obtain the raw data, screening procedures and data storage, to ensure quality and provenance. We discuss how this procedure has been utilized to produce materials handbook chapter on EUROFER97 and the critical challenges in data accumulation for CuCrZr and Tungsten, planned mitigations and the implications this has on structural design. Finally, key elements and methodology of our strategy to develop the materials database and handbook for the in-vessel materials are outlined, including concepts to accommodate sparse irradiated materials data and links to EU-DEMO engineering design criteria