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Science and Technology of Nuclear Installations
Volume 2017, Article ID 1936894, 13 pages
Research Article

STH-CFD Codes Coupled Calculations Applied to HLM Loop and Pool Systems

1Dipartimento di Ingegneria Civile e Industriale, University of Pisa, Pisa, Italy
2Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C. R. ENEA Brasimone, Camugnano, Italy

Correspondence should be addressed to M. Angelucci; ti.ipinu.rof@icculegna.anerom

Received 26 June 2017; Accepted 29 August 2017; Published 9 October 2017

Academic Editor: Tomasz Kozlowski

Copyright © 2017 M. Angelucci et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This work describes the coupling methodology between a modified version of RELAP5/Mod3.3 and ANSYS Fluent CFD code developed at the University of Pisa. The described coupling procedure can be classified as “two-way,” nonoverlapping, “online” coupling. In this work, a semi-implicit numerical scheme has been implemented, giving greater stability to the simulations. A MATLAB script manages both the codes, oversees the reading and writing of the boundary conditions at the interfaces, and handles the exchange of data. A new tool was used to control the Fluent session, allowing a reduction of the time required for the exchange of data. The coupling tool was used to simulate a loop system (NACIE facility) and a pool system (CIRCE facility), both working with Lead Bismuth Eutectic and located at ENEA Brasimone Research Centre. Some modifications in the coupling procedure turned out to be necessary to apply the methodology in the pool system. In this paper, the comparison between the obtained coupled numerical results and the experimental data is presented. The good agreement between experiments and calculations evinces the capability of the coupled calculation to model correctly the involved phenomena.