NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenEuropan Campus Rottal-InnZeitschriftenartikel
E. Bubelis, D. Castelliti, L. Guo, X.-N. Chen, A. Rineiski, M. Schyns, M. Sarotto, Rui Li, F. Gabrielli, L. Andriolo, G. Bandini, F. Belloni
Safety studies for the MYRRHA critical core with the SIMMER-III code
Annals of Nuclear Energy, vol. 110, pp. 1030-1042
2017
DOI: 10.1016/j.anucene.2017.08.021
Abstract anzeigen
The presented studies are carried out within the European 7th framework project MAXSIMA, in which the MYRRHA reactor, which stands for Multi-purpose hYbrid Research Reactor for High-tech Applications, developed at SCK-CEN (Belgian Nuclear Research Centre), is investigated. The SIMMER code is employed for severe accident investigations of the reactor at KIT and SCK-CEN in both critical and ADS subcritical modes. In this paper only studies for the critical core are presented. The SIMMER-III model has been set up and assessed first for the neutronic feedback coefficients. Its calculated fuel, coolant and structure feedbacks agree well with the results evaluated by means of the European Reactor ANalysis Optimized System (ERANOS). For benchmarking of the SIMMER-III coupled neutronics and fluid-dynamics model, several Unprotected Transients due to Over Power (UTOP) have been calculated and compared with results of transient system codes. Very good agreement is demonstrated. In case of the largest and quickest reactivity insertion under hypothetical accident conditions, the reactor is assumed to turn for a short time into a slightly prompt supercritical state, but a quite mild power excursion takes place. Blockage accidents are studied in detail with SIMMER only. In total three scenarios have been investigated, namely the blockages of a single fuel assembly (FA), the protected core blockage scenario and the damage propagation of defective pin failures. Our studies demonstrated no core damage propagation can possibly occur under the different blockage scenarios.
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenEuropan Campus Rottal-InnZeitschriftenartikel
L. Andiolo, X.-N. Chen, A. Rineiski, Rui Li
3D numerical study of LBE-cooled fuel assembly in MYRRHA using SIMMER-IV code
Annals of Nuclear Energy, vol. 104, pp. 42-52
2017
DOI: 10.1016/j.anucene.2017.02.009
Abstract anzeigen
The present paper is based on the work carried out in the framework of the European FP7 project MAXSIMA, in which MYRRHA safety studies are performed. MYRRHA is a pool-type 100 MWth system with MOX fuel designed to operate both in ADS and critical modes. It uses lead-bismuth eutectic (LBE) as primary coolant. The MOX fuel has almost the same density as the LBE coolant. In case of pin failure fuel pellets may break into chunks and particles carried by the coolant upwards and redistributed in the reactor pool. The transmutation group at IKET/KIT mainly with the numerical analysis tool is involved for studying severe accidents for MYRRHA reactor design. The highlight of the current work is that 3D simulations with explicit modelling on the gaps between fuel assemblies and 3D macroscopic pin bundle models are performed for the first time using a reactor safety analysis code, SIMMER-IV, with 3D geometry. In this paper, the numerical analyses are conducted for a single fuel assembly blockage and 19 pin-rods on basis of an LBE coolant experiment. The 3D analysis has been applied with both scales namely fuel assembly scale and pin bundle scale. For the fuel assembly scale, the evaluation of a single fuel assembly blockage using non-axisymmetric geometry configuration in the subcritical mode is addressed. For the pin bundle scale, the 3D pin bundle simulations show a good agreement from the experiment conducted at KALLA liquid metal laboratory. Note that this is the only code applied by now for blockage analyses after pin failure in MYRRHA. The current work has formed a solid basis for the safety analysis for MYRRHA in the future.
Europan Campus Rottal-InnZeitschriftenartikel
M. Seebauer, V. Grimm, Robert Feicht
An experimental study of corporate social responsibility through charitable giving in Bertrand markets
Journal of Economic Behavior & Organization, vol. 124, no. April, pp. 88-101
2016
DOI: 10.1016/j.jebo.2015.11.005
Abstract anzeigen
We experimentally investigate a Bertrand market with homogenous goods in which sellers can announce the donation of a share of their profits to an existing non-profit organization. In a 2 × 2 design, we vary the credibility of announcements and the efficiency of the contributions to the public fund. We find that sellers’ donations are strictly positive independently of the credibility of the announcements, and their donations are higher if announcements are credible and efficiency is high. However, market outcomes in terms of prices and profits do not differ significantly in any treatment that allows for contributions to a public fund. Analysis of buyer decisions reveals that prices are the main driver of purchase decisions while higher donations only affect purchase decisions when they are credible and price differences are negligible. Our results indicate that under intense competition the possibility of attracting customers through corporate social responsibility activities is limited, although the constant positive level of contributions suggests that norms lead to a certain minimum level of corporate social responsibility.
NachhaltigEuropan Campus Rottal-InnZeitschriftenartikel
G. Denuault, M. Mátéfi-Tempfli, H. Bülter, C. Dosche, Stefan Mátéfi-Tempfli, G. Wittstock
Electrochemical analysis of nanostructured iron oxides using cyclic voltammetry and scanning electrochemical microscopy
Electrochimica Acta, vol. 222, pp. 1326-1334
2016
Abstract anzeigen
Iron oxides in general and especially hematite, α-Fe2O3, have become promising materials for the alkaline water electrolysis and photoelectrochemical water splitting, respectively. In the present study electrocatalytic electrodes with a thin film of α-Fe2O3 and with vertically aligned α-Fe2O3 nanowires were prepared. Cyclic voltammograms of the α-Fe2O3 nanowires revealed differences including a series of three unreported cathodic signals when compared to previously published voltammograms for polycrystalline iron oxides. The generation-collection mode of scanning electrochemical microscopy (SECM) using nanostructured Pt microdisc probes was exploited to detect soluble reaction products formed at the voltammetric peaks of the α-Fe2O3 electrode. SECM tip-substrate voltammetry unexpectedly showed that the reduction of FeVI to FeIII on the cathodic sweep is accompanied by significant O2 evolution.
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenEuropan Campus Rottal-InnZeitschriftenartikel
L. Guo, S. Wang, A. Rineiski, W. Maschek, Rui Li, M. Flad
Numerical investigation of SIMMER code for fuel-coolant interaction
International Journal of Hydrogen Energy, vol. 41, no. 17, pp. 7227-7232
2016
DOI: 10.1016/j.ijhydene.2016.01.080
Abstract anzeigen
Fuel-coolant interaction (FCI) is a very complex but important issue in the safety analysis of the severe accidents for nuclear reactors due to the rapid multiple thermos–hydrodynamic activities. Until now, there are still large uncertainties existing in various phases during the FCI process, such as the melt solidification, fragmentation and relocation, film boiling on the melt surface, coolant vaporization and following vapor explosion, and so on. SIMMER-III code was first developed to analyses core disruptive accidents in liquid-metal fast reactors (LMFRs) as an integral numerical tool coupling multiphase thermal hydraulic code with neutron kinetics model, and was demonstrated its reasonable flexibility in some FCI simulations. In this paper, the applicability of the code in simulating the premixing phase of FCI process is verified in comparison with a related jet-type experiment in literature. In addition, the sensitivity analysis on several key parameters of the related models in the SIMMER code was performed to assess the impacts in the simulation of the FCI premix phase. It is expected that the results can provide some numerical experience for the uncertainty analysis of FCI calculation using SIMMER-III code.
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenEuropan Campus Rottal-InnZeitschriftenartikel
A. Rineiski, W. Maschek, B. Vezzoni, Rui Li, C. Matzerath Boccaccini, M. Flad
Impact of the Bell–Plesset instability on centralized sloshing in pool geometry
International Journal of Hydrogen Energy, vol. 41, no. 17, pp. 7126-7131
2016
DOI: 10.1016/j.ijhydene.2016.01.152
Abstract anzeigen
The theoretical and numerical analyses have been conducted to investigate the kinetic energy attenuation characteristics on basis of identical geometry and liquid properties together with an existing centralized sloshing experiment. The goal of this paper is to assess the quantitative impact of the Bell–Plesset (BP) instability on the sloshing motion. The results show that BP instability plays a certain role in azimuthal energy dissipation when the sloshing waves are moving inwards and converging in cylindrical geometry. The velocity attenuation is calculated via a perturbation flow equation assuming the initial perturbation length 1 mm, it shows that the velocity could be suppressed by 25% due to BP instability. The corresponding simulation using particle method has been performed. With the help of numerical simulation, the initial perturbation length is approximated as 1.3 mm which is in line with the assumption in the theoretical analysis.
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenEuropan Campus Rottal-InnZeitschriftenartikel
A. Rineiski, W. Maschek, Rui Li, C. Matzerath Boccaccini, M. Marchetti, V. Kriventsev
Bell-Plesset Instability Analysis for an Inward Centralized Sloshing
Nuclear Engineering and Design, vol. 297, pp. 312-319
2016
DOI: 10.1016/j.nucengdes.2015.12.010
Abstract anzeigen
Liquid sloshing is a typical phenomenon when liquid in a container has an unrestrained surface. In fast reactors under core disruptive accidents (CDAs) conditions specific sloshing motions could be encountered that can be described as a centralized sloshing. It is important to investigate the mitigating and augmenting factors for such centralized sloshing motions. Any retardation or instability effects that reduce the compaction speed and resulting reactivity ramp rate are of importance, requiring an understanding of the kinetic energy dissipation of an inward centralized slosh. In this paper, the Bell–Plesset (BP) instability has been studied theoretically and numerically based on a corresponding inward centralized sloshing experiment. The theoretical analysis is based on the classical perturbation theory and the simulation has been conducted by a fully mesh-free, Lagrangian particle numerical method. With our experimental data, the initial perturbation length 1.3 mm is approximated by the numerical calculation as supplement of the purely theoretical analysis. The outward and inward sloshing timings have been re-checked from the experiment that the inward velocity is reduced by around 20% compared to outward velocity. It experimentally confirms reasonably well the numerical result 17.5%. The experimental, numerical and theoretical analysis show that BP instability plays a certain role in azimuthal energy dissipation when the sloshing waves are moving inwards and converging in cylindrical geometry, for the experiment case the velocity reduction may be 17.5%.
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenEuropan Campus Rottal-InnBeitrag (Sammelband oder Tagungsband)
C. Lau, Sascha Kreiskott
Strategische Herausforderungen im Energievertrieb
Zukunftsorientierte Unternehmensführung in der Energiewirtschaft, Wiesbaden
2015
ISBN: 978-3-658-07816-4
Abstract anzeigen
Die Vertriebe im Energiemarkt Deutschlands stehen vor gro⇓en Herausforderungen. Bei steigenden Kosten für die Verbraucher und die Energieversorgung geht die Ertragssituation der Vertriebe aufgrund verschiedener Effekte zurück. Die gestiegenen Kosten befeuern den Wettbewerb, was Kunden aus der profitablen Grundversorgung in kaum profitable Akquiseprodukte treibt. Durch abnehmende Mengen bei abnehmenden Margen entsteht eine Situation, in der Energieversorger über Adjustierungen ihres Geschäftsmodells nachdenken müssen. Den Vertrieben verbleibt eine Reihe von strategischen Optionen, um sich den veränderten Marktbedingungen anzupassen und der sich abzeichnenden Abwärtsspirale zu entziehen: Digitalisierung, werthaltige Akquise, neue Geschäftsmöglichkeiten rund um Heimsteuerung, Sicherheits- und Komfortdienstleistungen sowie möglicher Vertriebsnutzen aus Big Data werden näher untersucht. Nicht zuletzt bietet die Energiewende weitere Geschäftspotenziale durch Vertrieb und Optimierung von regenerativer Erzeugung.
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