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Suche nach „[Bonfigli] [Giuseppe]“ hat 16 Publikationen gefunden
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    NachhaltigF: Maschinenbau und Mechatronik

    Zeitschriftenartikel

    T. Mull, T. Wagner, Giuseppe Bonfigli, S. Buchholz, Frank Schäfer, E. Schleicher, C. Schuster, M. Sporn

    Safety cases for design-basis accidents in LWRs featuring passive systems

    [In Press]

    Nuclear Engineering and Design, no. Available online 26 February 2021

    2021

    DOI: 10.1016/j.nucengdes.2021.111095

    Abstract anzeigen

    This paper presents results from a series of integral tests performed at Framatome’s INKA test facility in Karlstein (Germany) which simulates a KERENA boiling water reactor (BWR). The scope of the test series was on the behaviour of and interaction between the different passive systems and components under the conditions of extended loss of alternating power (ELAP). These SBO-like conditions were aggravated in three out of four tests by parallel LOCA (Loss of Coolant Accident). The scenarios of all four tests fully correspond to Design Basic Conditions (DBC). They were: main steam line break, feed water line break, reactor pressure vessel (RPV) bottom leak and station blackout (SBO, non-LOCA). In the tests, the passive systems integrated in KERENA and INKA, respectively, have fulfilled their design functions fully satisfactorily and as follows: The Passive Pressure Pulse Transmitter (PPPT) triggered the RPV depressurization without delay. The Emergency Condenser (EC) system removed decay heat along with stored energy from the RPV to the containment. The Containment Cooling Condenser (CCC) system forwarded said power to a heat sink outside of the containment. The passive containment pressure suppression system kept the containment pressure within the design range, partially displacing surplus thermal energy from the drywell to the wetwell, in particular in the early phases after occurrence of LOCA. The passive core flooding system replenished the coolant inventory of the RPV thereby ensuring water levels in the RPV which are fully sufficient for core cooling. Moreover, the systems have cooperated as anticipated by the designers, quietly and without perturbing each other. Hence the test results, which are reported and discussed more in detail within this paper, soundly confirm the underlying design and its passive features. Said tests were carried out as a part of the joint research project EASY (Evidence of Design Basis Accidents Mitigation solely with passive safety Systems), the overarching objective of which was the development and validation of the code system AC2 of GRS (Gesellschaft für Anlagen- und Reaktorsicherheit gGmbH).

    NachhaltigF: Maschinenbau und Mechatronik

    Zeitschriftenartikel

    Giuseppe Bonfigli, S. Buchholz, F. Schäfer, Nadine Kaczmarkiewicz, C. Schuster, M. Sporn

    Safety cases for design-basis accidents in LWRs featuring passive systems Part 2 – Numerical investigations

    Nuclear Engineering and Design, vol. 372, no. February

    2021

    DOI: 10.1016/j.nucengdes.2020.110996

    Abstract anzeigen

    This paper deals with the improvement and validation of numerical tools for the simulation of design basis accidents in nuclear power plants equipped with passive safety systems. Numerical models are implemented in the framework of the 1-D thermal–hydraulic system code ATHLET developed by GRS. Experimental reference data for the validation were obtained at the INKA test facility, a model of the KERENA reactor, reproducing the passive safety systems nearly at full scale. The validation effort focuses firstly on the accuracy of the models for the single passive components, and secondly on the ability of the numerical simulation to reproduce the interaction of all components of the KERENA design under realistic conditions as reproduced in the INKA test facility. Thermal-hydraulic models are presented and validated for two passive components of the KERENA reactor: the passive pressure pulse transmitter and the pressure-controlled flooding valve. Finally, the full model of the INKA facility, including these and other passive components, is discussed and numerical results for simulations reproducing three different design basis accidents are validated by comparison with the corresponding experimental data.

    NachhaltigF: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Nadine Kaczmarkiewicz, Giuseppe Bonfigli, S. Leyer, T. Wagner

    Performance of the Passive Core Flooding System in the Integral Tests of the Project EASY

    49. Jahrestagung Kerntechnik / 49th Annual Meeting on Nuclear Technology (AMNT 2018), Berlin , 29. - 30. Mai 2018

    2018

    Abstract anzeigen

    Among nuclear power generation plants, light water reactors are mainly used at present, and are anticipated to be predominant in the future. To improve the light water reactors the development of the LWRs for the next generation is carried out at various organizations. For example, in the USA the Westinghouse AP-1000 is based on proven technology but with an emphasis on passive safety features. The reactor passive core cooling systems include the core makeup tanks system, passive residual heat removal heat exchanger and in-containment refuelling water storage tank. In Russia has been developed the so-called NPP-2006 project of a VVER-1200 nuclear power plant with a V-392M reactor unit. To provide the safety, protection passive systems which don’t depend upon human errors are widely used in this project. Among these are hydrotanks of the second stage and passive heat removal system. In the presented paper an overview of passive core cooling systems for next generation NPPs is given.

    NachhaltigF: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    S. Buchholz, W. Klein-Hessling, Giuseppe Bonfigli, Nadine Kaczmarkiewicz, N. Neukam, F. Schäfer, T. Wagner

    The Code System AC2 for the Simulation of Advanced Reactors within the Frame of the German EASY Project

    Proceedings of the 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17) [September 3-8, 2017; Qujiang Int’l Conference Center, Xi’an, Shaanxi, China]

    2017

    NachhaltigF: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    S. Buchholz, A. Schaffrath, Giuseppe Bonfigli, Nadine Kaczmarkiewicz, N. Neukam, F. Schäfer, T. Wagner

    Evidence of Design Basis Accidents Mitigation Solely with Passive Safety Systems within the Frame of the German EASY Project

    Proceedings of the 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17) [September 3-8, 2017; Qujiang Int’l Conference Center, Xi’an, Shaanxi, China]

    2017

    NachhaltigF: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Nadine Kaczmarkiewicz, Giuseppe Bonfigli, S. Leyer, T. Wagner

    Influence of Two-Phase Reverse Flow in the Passive Core Flooding System: Experiments and Simulations within the Frame of the German EASY Project

    Proceedings of the 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17) [September 3-8, 2017; Qujiang Int’l Conference Center, Xi’an, Shaanxi, China]

    2017

    F: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Giuseppe Bonfigli, M. Kloker, S. Wagner

    3-D-boundary-layer transition induced by superposed steady and travelling crossflow vortices

    High performance computing in science and engineering '02, [S.l.]

    2014

    ISBN: 978-3-642-63947-0

    F: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Giuseppe Bonfigli, P. Jenny

    Application of the multi-scale-finite-volume method to the simulation of incompressible flows with immersed boundaries

    New results in numerical and experimental fluid mechanics, Berlin; Heidelberg, vol. 112

    2010

    ISBN: 978-3-642-14242-0

    F: Maschinenbau und Mechatronik

    Zeitschriftenartikel

    Giuseppe Bonfigli, P. Jenny

    An efficient multi-scale Poisson solver for the incompressible Navier-Stokes equations with immersed boundaries

    Journal of Computational Physics, vol. 228, no. 12, pp. 4568-4587

    2009

    Abstract anzeigen

    The iterative-multi-scale-finite-volume (IMSFV) procedure is applied as an efficient solver for the pressure Poisson equation arising in numerical methods for the simulation of incompressible flows with the immersed-interface method (IIM). Motivated by the requirements of the specific IIM implementation, a modified version of the IMSFV algorithm is presented to allow the solution of problems, in which the varying coefficient of the elliptic equation (e.g. the permeability of the medium in the context of the simulation of flows in porous media) varies over several orders of magnitude or even becomes zero within the integration domain. Furthermore, a strategy is proposed to incorporate the iterative procedure needed by the IIM to converge out constraints at immersed boundaries into the iterative IMSFV cycle. No significant deterioration of performance of the IMSFV method is observed with respect to cases, in which no iterative improvement of the boundary conditions is considered.

    F: Maschinenbau und Mechatronik

    Zeitschriftenartikel

    Giuseppe Bonfigli

    Numerical solution of the incompressible Navier-Stokes equations with explicit integration of the pressure term

    Proceedings in Applied Mathematics and Mechanics (PAMM), vol. 7, no. 12, pp. 4100019-4100021

    2007

    Abstract anzeigen

    We propose a formulation of the incompressible Navier-Stokes equations considering a Poisson equation with Neumann boundary conditions for the pressure, and innovative boundary conditions for the velocity. Numerical tests show that the proposed formulation ensures solenoidality of the velocity field. If the initial condition is not divergence-free, exponential decay is observed in time for the error in the fulfillment of the continuity equation.

    F: Maschinenbau und Mechatronik

    Zeitschriftenartikel

    Giuseppe Bonfigli, M. Kloker

    Secondary instability of crossflow vortices: validation of the stability theory by direct numerical simulation

    Journal of Fluid Mechanics, vol. 583, pp. 229-272

    2007

    Abstract anzeigen

    Detailed comparison of spatial direct numerical simulations (DNS) and secondary linear stability theory (SLST) is provided for the three-dimensional crossflow-dominated boundary layer also considered at the DLR-Göttingen for experiments and theory. Secondary instabilities of large-amplitude steady and unsteady crossflow vortices arising from one single primary mode have been analysed. SLST results have been found to be reliable with respect to the dispersion relation and the amplitude distribution of the modal eigenfunction in the crosscut plane. However, significant deviations have been found in the amplification rates, the SLST results being strongly dependent on the necessarily simplified representation of the primary state. The secondary instability mechanisms are shown to be local, i.e. robust with respect to violations of the periodicity assumption made in the SLST for the wall-parallel directions. Perturbations associated with different local maxima of the spanwise periodic eigenfunctions develop independently from each other interacting only with the primary vortices next to them. Characteristic structures induced by different secondary instability modes have been analysed and an analogy with the Kelvin–Helmholtz instability mechanism has been highlighted.

    F: Maschinenbau und Mechatronik

    Hochschulschrift

    Giuseppe Bonfigli

    Numerical simulation of transition and early turbulence in a 3-d boundary layer perturbed by superposed stationary and traveling crossflow vortices

    2005

    F: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Giuseppe Bonfigli, M. Kloker

    Secondary instability of superposed steady and unsteady crossflow vortices

    New results in numerical and experimental fluid mechanics IV, Berlin; New York, vol. 87

    2004

    ISBN: 978-3-540-20258-5

    F: Maschinenbau und Mechatronik

    Vortrag

    Giuseppe Bonfigli, M. Kloker

    Comparison of DNS and stability theory with respect to the secondary instability of crossflow vortices

    Euromech Fluid Mechanic Conference (EFMC) 2003, Toulouse, Frankreich

    2003

    F: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Giuseppe Bonfigli, M. Kloker

    Spatial Navier-Stokes simulation of crossflow-induced transition in a three-dimensional boundary layer

    New results in numerical and experimental fluid mechanics, Berlin; Heidelberg; New York, vol. 11

    2001

    ISBN: 978-3-540-41552-7

    F: Maschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Giuseppe Bonfigli, M. Kloker

    Three-dimensional Boundary-Layer Transition Phenomena Investigated by Spatial Direct Numerical Simulation

    Laminar-Turbulent Transition, Berlin, Heidelberg

    2000

    ISBN: 978-3-642-08752-3