Defect assessment procedures for high temperature applications. Final report TW5-TTMS-005, D5

The objective of this task is to develop the high temperature part of a design code for fusion reactor components build from EUROFER. This development includes fracture mechanical rules for the assessment of detected defects under creep and creep&ndash;fatigue conditions. The assessment procedures R5, R6, JNC, A16, Partial Safety Factors were investigated and tested. As the most suitable procedure is chosen R5 and it is further verified by comparison with finite element simulations using the EUROFER material data. These simulations consist of evaluation of C(t) parameter for several geometries (CT specimen,cylinder with fully circumferential crack subjected to the internal pressure, cylinder with semi&ndash;elliptical circumferential crack subjected to the internal pressure and Mock-Up test blanket module (TBM) geometry). The R5 procedure provides very good accordance with FE simulations and it is suitable for lifetime assessment. Therefore the guide for R5 application is implemented in the report.<br /

Manufacturing influences on microstructure and fracture mechanical properties of polycrystalline tungsten

Polycrystalline tungsten is a promising candidate for future fusion applications as plasma facing material due to its good thermophysical properties at high temperatures. Fracture mechanical properties of sintered and rolled, commercially available polycrystalline tungsten are characterized taking into account the strong anisotropy due to different grain shape and orientation with respect to the rolling direction. The fracture mechanics investigations are accompanied by fractographic analyses of two tungsten plate grades with varying cold working ratios of two different manufacturers (PLANSEE SE, Austria and A.L.M.T Corp., Japan). In this respect three point bending tests (3-PB) with sub sized fracture mechanical specimens in different orientations of the anisotropic microstructure are performed at three temperatures, ranging from 25 °C to 400 °C at a deflection rate of 2 µm s − 1. In addition, crack initiation and crack growth mechanisms depending on texture and cold working ratio are investigated by means of scanning electron microscopy (SEM)

ANSYS Creep-Fatigue Assessment tool for EUROFER97 components

The damage caused by creep-fatigue is an important factor for materials at high temperatures. For in- vessel components of fusion reactors the material EUROFER97 is a candidate for structural application where it is subjected to irradiation and cyclic thermo-mechanical loads. To be able to evaluate fusion reactor components reliably, creep-fatigue damage has to be taken into account. In the frame of Engi- neering Data and Design Integration (EDDI) in EUROfusion Technology Work Programme rapid and easy design evaluation is very important to predict the critical regions under typical fusion reactor loading conditions. The presented Creep-Fatigue Assessment (CFA) tool is based on the creep-fatigue rules in ASME Boiler Pressure Vessel Code (BPVC) Section 3 Division 1 Subsection NH which was adapted to the material EUROFER97 and developed for ANSYS. The CFA tool uses the local stress, maximum elastic strain range and temperature from the elastic analysis of the component performed with ANSYS. For the as- sessment design fatigue and stress to rupture curves of EUROFER97 as well as isochronous stress vs. strain curves determined by a constitutive model considering irradiation influence are used to deal with creep-fatigue damage. As a result allowable number of cycles based on creep-fatigue damage interaction under given hold times and irradiation rates is obtained. This tool can be coupled with ANSYS MAPDL and ANSYS Workbench utilizing MAPDL script files