•Modified, sufficiently conservative creep-fatigue design rules for cyclic softening steels.•Creep tests on pre-softened EUROFER97 reveal considerable impact of cyclic softening on creep rupture ...time.•Evaluation of the creep tests verifies the independence of the Monkman-Grant relationship on cyclic softening.•Implementation of the modified creep-fatigue rules in existing design criteria is simplified by introducing the cyclic softening stress factor.•Assessment of creep-fatigue in LCF tests with hold-times demonstrates the applicability of the modified rules to cyclic softening steels.
Based on existing lifetime and damage models a new approach is developed for the assessment of creep-fatigue lifetime of components made out of cyclic softening steel, in particular EUROFER97. For the application of the new creep-fatigue rules among others lifetime data from special tests, in particular creep tests on pre-fatigued specimens are required. Therefore, a test matrix is proposed and conducted for EUROFER97 in which the efforts are minimized by utilizing the Monkman-Grant relationship and its independence on pre-cyclic deformation and cyclic softening, respectively. To facilitate their implementation in existing design criteria the new creep-fatigue rules are simplified by introducing the cyclic softening stress factor with which the impact of cyclic softening on creep rupture time is considered. The assessment of creep-fatigue in LCF tests with hold-times performed on EUROFER97 using the new rules demonstrates their applicability to cyclic softening ferritic-martensitic steels without being overly conservative. A draft for implementing the simplified rules in the respective chapter of structural design code is elaborated in addition.
Silicon Carbide (SiC) is a relatively new entry in the world of solid-state detectors. Although SiC response to neutrons is more complex than the one obtained with diamonds, the measured energy ...resolution (FWHM/Ed<4%) makes SiC an interesting alternative to diamond and silicon detectors for fast neutrons. The results obtained from the measurements of the response of a 100μm thick SiC detector to neutrons in the energy range between 3 and 20 MeV at the n_TOF spallation source at CERN are presented in this paper.
By selecting the neutron energy by means of the time of flight, the detector response to quasi-mono-energetic neutrons was measured. The main neutron-induced nuclear reactions were identified in the measured pulse height spectrum. Detection efficiency as a function of neutron energy was measured and interpreted based on available neutron cross section and by making use of Monte Carlo simulations.
•Preliminary design of the JT-60SA FILD detector is described.•JT-60SA FILD motion is presented.•JT-60SA FILD thermal behaviour is presented.•JT-60SA FILD mechanical response during disruptions is ...presented.
A fast-ion loss detector (FILD) is being designed for the JT-60SA tokamak. In this work, the preliminary mechanical design of this diagnostic is described. The expected motion needed to move the probe head between the parking and the measuring positions has been estimated by numerical simulations. A finite element thermal assessment of the detector is presented, to characterize its thermal response during the operation of the machine. Finally, the results of a preliminary electromagnetic analysis are reported to evaluate the impact of major disruptions on the structural components the system.
Dust characterization in FTU tokamak De Angeli, M.; Maddaluno, G.; Laguardia, L. ...
Journal of nuclear materials,
08/2015, Letnik:
463
Journal Article
Recenzirano
Dust present in the vessel of FTU has been collected and analysed. Being FTU a device with full metal plasma facing components for the whole life and equipped with a liquid lithium limiter (LLL) make ...FTU of special interest from a point of view of dust studies.
Analyses were conducted by standard dust analysis methods and by dedicated analysis, as X-rays and neutron diffraction, to investigate the presence of lithium compounds due the presence of the LLL in FTU.
Dust collected near the LLL presents a different elemental composition, namely Li compounds, compared to the dust collected in the rest of the vessel; in particular LiO2, LiOH, and Li2CO3. On the basis of these results, the formation of Li2CO3 is proposed via a two steps process.
Results of fuel retention measured by thermal desorption spectroscopy (TDS) method show that fuel retention should not be an issue for FTU.
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