NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Europan Campus Rottal-Inn
L. Guo, Rui Li, S. Wang, M. Flad, W. Maschek, A. Rineiski
Numerical investigation of SIMMER code for fuel-coolant interaction
International Journal of Hydrogen Energy, vol. 41, no. 17, pp. 7227-7232
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.
NachhaltigF: Elektrotechnik und MedientechnikI: IQMA
Q. Yang, Y.-W. You, L. Liu, H. Fan, W. Ni, D. Liu, C. Liu, Günther Benstetter, Y. Wang
Nanostructured fuzz growth on tungsten under low-energy and high-flux He irradiation
Scientific Reports (Nature Publishing Group), vol. 5, no. Article number: 10959, pp. 1-9
F: Elektrotechnik und MedientechnikI: IQMA
D. Liu, Günther Benstetter, W. Wang, J. Zhang
Effect of pressure on the deposition of hydrogen-free amorphous carbon and carbon nitride films by the pulsed cathodic arc discharge method
Journal of Vacuum Science & Technology A, vol. 22
Hydrogen-free amorphous carbon and carbon nitride films were deposited using the pulsed cathodic arc discharge at different argon and nitrogen pressures. The surface and mechanical properties of these films were found to strongly depend on the gas pressure. The tetrahedral amorphous carbon and hard films with smooth surfaces (rms roughness: ) were prepared at lower gas pressures. Incorporation of an increasing amount of nitrogen in films caused a decrease in filmhardness. All the films were covered with the thin graphite-like surface layers. The filmhardness was correlated to the soft surface layer thickness, and the films with thinner surface layers exhibit higher hardness. The mean energies of pulsed plasma beams were measured as the functions of argon and nitrogen pressures. The mean energies of plasma beams decrease in an exponential fashion with increasing gas pressure due to the carbon ion collisions with the neutral gas species. The effects of mean energies of deposited species on the filmdeposition were explained in terms of the thermal spike migration of surface atoms. The formation of graphite-like surface layers is associated with the low-energy deposition process. The low-energy species diffusing on filmsurface lead to the formation of graphite-like films with plenty of grains. The higher-energy species may produce the strong thermal spike at filmsurface, and contribute to the formation of bonded structure at a bonded matrix.