XXX ciclo di Dottorato
Dottorato di ricerca in Ingegneria Industriale
Curriculum in Ingegneria Nucleare e Sicurezza Industriale
Allievo: Morena Angelucci
Coupling between System and CFD codes
for the analyses of thermal-hydraulic phenomena
relevant for LMFR
Relatori:
Prof. Ing. Nicola Forgione (DICI-UNIPI)
Dott. Ing. Ivan Di Piazza (ENEA-Brasimone)
Dott. Ing. Daniele Martelli (DICI-UNIPI)
GENERAL OBJECTIVES OF THE RESEARCH
The main aim of this work is the development and optimization of coupling tools between Thermal-Hydraulic System codes and CFD codes, for the analyses of thermal-hydraulic phenomena inherent to the Generation IV nuclear reactors cooled by liquid heavy metals. Part of the work is devoted to the process of Verification and Validation (V&V) of the developed tools for the coupled calculations through the comparison with experimental data. For this purpose, experimental campaigns with the NACIE-UP facility were performed in collaboration with R.C. ENEA Brasimone, in order to collect data both on the overall system behavior and local data for the test section, allowing the comparison for both system code and CFD code numerical results.
WORK PERFORMED IN THE FIRST YEAR
The first part of the first year was devoted to the literary review on the main topics related to the research activities. The coupling methodologies can be classified with respect to several aspects and can involve different types of code (system codes, CFD codes, neutronics kinetic codes, structural codes). Among them, the works related to the in-line coupling between thermal-hydraulic system codes and CFD codes have been considered, in order to analyze the strategies adopted and the applications of the developed models. Moreover, a literary review on the heat transfer for liquid metals was also accomplished.
Most of the first year was committed to the collaboration with the R.C ENEA Brasimone for the experimental campaign with the NACIE-UP facility for the analysis of the convective heat transfer in a wire-spaced fuel rod bundle cooled by heavy liquid metal at low Reynolds number. The experimental test matrix that was performed included 20 steady state tests. The post-processing of data focused on the calculation of the Nusselt number and the comparison of the obtained results with some correlations found in literature for rod bundles cooled by liquid metals. The remaining part of the year was dedicated to the acquisition of the competences for the use of the tools involved in this work (TH SYS code RELAP5, Ansys Fluent CFD code, MATLAB software), for the setup of a RELAP5 model of the NACIE-UP facility and the CFD model for the test section. Some preliminary calculations were also performed.
WORK PERFORMED IN THE SECOND YEAR
During the second year, the work on the coupled simulations for the NACIE-UP facility focused on the optimization of the CFD model for the fuel pin simulator. After a grid independence study, it resulted that a non-structured non-conformal coarser mesh (25M elements) was able to evaluate the pressure drop and the overall heat transfer in the bundle and resulted to be the best compromise between precision and required computational efforts, in order to perform the coupled calculations with the computational power available. The CFD model was used to perform a first coupled simulation together with the RELAP5 nodalization of the NACIE-UP loop thanks to a MATLAB script in charge of the exchange of data between the STH and CFD codes. Concerning the experimental activities at ENEA Brasimone R.C. with NACIE-UP some preliminary tests were accomplished. Since the facility underwent some upgrades with respect to the previous campaign, preliminary tests on LBE circulation were performed in order to test the new device for the injection of gas (Ar or Ar+3%H2) and a prototypical thermal mass flow meter. Then, a quasi-static and
zero power test was carried out with the aim to evaluate heat losses trough the structure.
Another application of the coupling tool was the tuning to a pool system, the CIRCE (CIRCulation Experiment) experimental facility (also located at ENEA Brasimone R.C.). A simplified model with a 2D CFD domain was employed for the simulation of a PLOHS+LOFA accidental scenario and the main results have been compared with experimental data. A 3D CFD model of the pool was also developed and used to perform shorter simulations, both isothermal and non-isothermal tests. Numerical results were compared with analogous simulations with 2D CFD model and with experimental data. The coupled calculations showed interesting results, with some discrepancy with respect to the experiments essentially due to some simplifications in the modelling. One of the limitations was the lack of the modelling of the heat exchange between the pool and the test section. To overcome this problem, a new utilization of the coupling tool was developed to allow the heat transfer through a boundary (wall), between the CFD and the RELAP5 domain. This methodology was initially assessed in a simple pipe geometry.
WORK PERFORMED IN THE THIRD YEAR
During the third year, the work on NACIE-UP coupled simulations continued performing the blind calculations of three specified tests. This activity allowed to participate to a benchmark among STH and STH-CFD coupled codes in the frame of the EU HORIZON 2020 SESAME project. Due to the rather expensive computational time required by coupled calculation of NACIE-UP, just the initial and final steady states of the three tests and a part of one transient (out of three) were simulated. Further, it was not possible to work extensively on post-tests analysis and code optimization, which, was partially covered using another experimental test. In the frame of the collaboration with ENEA Brasimone R.C, an experimental campaign with NACIE-UP was performed in 2017. The performed test matrix was characterized by power and mass flow transient aiming at integral system and local (bundle) thermal-hydraulic analyses. The produced data have been using for the validation of STH, CFD and multi-scale approaches in the benchmark activity organized within SESAME.
The coupled code application to pool systems (CIRCE facility) focused on the improvement of the simulation of the PLOHS+LOF accidental scenario test on the CIRCE-ICE configuration, with the implementation of the developed coupling at thermal boundaries strategy in order to consider the conjugate heat transfer between the main test section (STH domain) and the pool (CFD domain) in the calculation. The same coupling technique was also used to perform coupled calculations for the analysis of heat exchange in the new test section HERO Steam Generator, recently installed in the facility CIRCE. Moreover, the STH-CFD coupled codes were also used to model the complete CIRCE-HERO facility, where the main pool was modelled with a 3D realistic CFD domain, whereas the main test section and the water secondary side was simulated with the STH code RELAP5. The CIRCE-HERO developed models were used to perform simulations in support of the experimental campaign and are accomplished in the framework of the EU HORIZON 2020 MYRTE project.
ATTIVITÀ FORMATIVE / FORMATIVE ACTIVITIES
No. Activities already completed Period N.
hours Language
1 Short course on RELAP/SCDAPSIM August 1-5, 2011 40 English
2 Corso introduttivo all’uso di STAR-CCM+ July 12-13, 2012 16 English
3
Workshop tematico “LFR-Gen IV: Stato
attuale della tecnologia e prospettive di sviluppo”
January 15-16,
2015 12 Italian
4
Corso base-Applicazione della direttiva PED 97/23/CE in materia di attrezzature a
pressione
February 18, 2015 7 Italian
5 MAXSIMA Lecture Series “Safety features of HLM reactor systems“ March 24-27, 2015 20 English
6 English for writing and presenting scientific papers
January-March
2015 20 English
7 ANSYS Summer School September 23-25,
2015 24 Italian
8 Presentation skills for public speaking
(C1 level) February, 2016 20 English
9
2nd ESNII plus Summer School: “The challenges of the future Gen IV Reactors:
safety issues in support to the design and operation”
May 9-11, 2016 23 English
10 SESAME Workshop Meeting on V&V and UQ July 5-6, 2016 15 English
11 SESAME BPG Work Meeting July 7-8, 2016 16 English
RESEARCH EXPERIENCE IN OTHER INSTITUTIONS
PERIOD HOST INSTITUTION ACTIVITIES CARRIED OUT AND RESULTS
From 09/02/2015 to 15/04/2015
ENEA R.C. Brasimone (BO), supervisor Dr. Ing Ivan Di Piazza
Experimental campaign activity on a fuel pin bundle cooled by liquid metal (Lead-Bismuth Eutectic) for heat transfer characterization in steady state conditions.
From 23/05/2016 to 10/06/2016
ENEA R.C. Brasimone (BO), supervisor Dr. Ing Ivan Di Piazza
Experimental activity on the heavy liquid metal cooled facility NACIE-UP for a preliminary characterization with heat losses and LBE circulation measurements.
From 13/02/2017 to 31/03/2017
ENEA R.C. Brasimone (BO), supervisor Dr. Ing Ivan Di Piazza
Experimental campaign activity on the heavy liquid metal cooled facility NACIE-UP consisting in thermal-hydraulic analysis during transient with power and flow variation and heat transfer evaluation on a wire-spaced fuel pin bundle simulator.
CONFERENCES, WORKSHOPS, SEMINARS ATTENDED IN ITALY AND ABROAD
▪ 16th International Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16), Chicago, IL,
August 30-September 4, 2015. Oral presentation: “Experimental characterization of a 19-pin Fuel
Bundle in the NACIE-UP facility”.
▪ SESAME Workshop Meeting on V&V and UQ, Albanova University Center, Stockholm, Sweden,
July 5-6, 2016. Oral presentation: “NACIE-UP wire-wrapped FPS experiment”.
▪ International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear
Systems for Sustainable Development (FR17), Yekaterinburg, Russian Federation, June 26–29 2017. Oral presentation: “NACIE-UP: a HLM loop facility for natural circulation experiments”.
▪ 25th International Conference On Nuclear Engineering (ICONE 25), Shanghai, China, July 02-06
2017. Oral presentation: “RELAP5 STH and Fluent CFD coupled calculations of a PLOHS + LOF
transient in the HLM experimental facility CIRCE”.
▪ Workshop tematico ADP MiSE-ENEA (PAR2016-LP2) Generation IV Lead Cooled Fast Reactor:
Stato Attuale Della Tecnologia E Prospettive Di Sviluppo, Bologna, Italy 26-27/09/2017. Oral
presentation: “Application of RELAP5/mod3.3 – Fluent coupling codes to CIRCE-HERO”.
OVERALL LIST OF PUBLICATIONS RELATING THE DOCTORATE COURSE
Journal papers
▪ Angelucci M., Di Piazza I., Martelli D., “Experimental campaign on the HLM loop NACIE-UP facility with instrumented wire-spaced fuel pin simulator”, Nuclear Engineering and Design, 332 (2018) 137– 146.
▪ Bassini S., Di Piazza I. Antonelli A., Angelucci M., Sermenghi V., Polazzi G., Tarantino, M. “In-loop oxygen reduction in HLM thermal-hydraulic facility NACIE-UP”, Progress in Nuclear Energy, 105 (2018) 137–145.
▪ M. Angelucci, D. Martelli, G. Barone, I. Di Piazza, N. Forgione, “STH-CFD Codes Coupled Calculations Applied to HLM Loop and Pool Systems”, Science and Technology of Nuclear Installations, Article ID.1936894, Volume 2017, October 2017.
▪ Di Piazza I., Angelucci M., Forgione N., Marinari R., Tarantino M., “Heat transfer on HLM cooled wire-spaced fuel pin bundle simulator in the NACIE-UP facility”, Nuclear Engineering and Design, 300 (2016) 256–267.
Conference papers
▪ M. Angelucci, D.Martelli, N. Forgione, “RELAP5 STH AND FLUENT CFD COUPLED CALCULATIONS OF A PLOHS + LOF TRANSIENT IN THE HLM EXPERIMENTAL FACILITY CIRCE”, Proceedings of 25th
International Conference On Nuclear Engineering (ICONE 25), 02-0h July 2017, Shanghai, China.
▪ Angelucci M., Di Piazza I., Forgione N., Tarantino M., Polazzi G., Sermenghi V., “NACIE-UP: a HLM loop facility for natural circulation experiments”, Abstract for International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear Systems for Sustainable Development (FR17), Yekaterinburg, Russian Federation, 26–29 June 2017.
▪ Di Piazza I., Angelucci M., Forgione N., Marinari R., Polazzi G., Sermenghi V., Laffi L., Giannotti D., Tarantino M., “Experimental Fuel Pin Bundle characterization in the NACIE-UP HLM Facility”, Proceedings of the 16th International Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16), Chicago, IL, August 30-September 4, 2015.
Journal papers under review
▪ R. Marinari, I. Di Piazza, M. Tarantino, M.Angelucci, D. Martelli, “Experimental tests and post-test analysis of non-uniformly heated 19-pins fuel bundle cooled by Heavy Liquid MEtal”, send to Nuclear Engineering and Design
Conference papers (submitted but not yet published)
▪ Angelucci M., Di Piazza I., Tarantino M., Marinari R., Sermenghi V., Polazzi, G., “Experimental tests with non-uniformly heated 19-pins fuel bundle cooled by HLM”, 26th International Conference On Nuclear Engineering (ICONE 26).
▪ Pacio J., Daubner M., Wetzel T., Di Piazza I., Tarantino M., Angelucci M., Martelli, D., “Experimental peak temperature factors in rod bundles cooled by Heavy-Liquid Metals”, 26th International Conference On Nuclear Engineering (ICONE 26).
▪ Gonfiotti B., Barone G., Angelucci M., Martelli D., Forgione N., Del Nevo A., Tarantino M., “Thermal hydraulic analysis of the CIRCE-HERO pool-type facility”, 26th International Conference On Nuclear Engineering (ICONE 26).
▪ Forgione N., Angelucci M., Barone G., Giannetti F., Lorusso P., Hollands T., Papukchiev A., Polidori M., Cervone A., Di Piazza, I., “Blind simulations of NACIE-UP experimental tests by STH codes”, 26th International Conference On Nuclear Engineering (ICONE 26).
▪ Marinari R., Di Piazza I., Angelucci M., Martelli D., “Post-Test CFD analysis of non-uniformly heated 19-pin fuel bundle cooled by HLM”, 26th International Conference On Nuclear Engineering (ICONE 26).
International Technical Reports
▪ N. Forgione, M. Angelucci, G. Barone, et al., “NACIE-UP blind simulations”, SESAME-GA 654935 Deliverable D5.18, October 2017.
▪ I. Di Piazza, M. Angelucci, G. Polazzi, V. Sermenghi, “NACIE-UP data for PLOFA experiment”, SESAME-GA 654935 Deliverable D4.10, October 2017.
▪ I. Di Piazza, M. Angelucci, G. Polazzi, V. Sermenghi, “NACIE-UP experimental setup and test matrix for PLOFA experiment”, SESAME -GA 654935 Deliverable D4.9, January 2016.
▪ I. Di Piazza, M. Angelucci, G. Polazzi, M. Tarantino, “Experimental results on free convection in heavy liquid metals using the NACIE facility”, SEARCH-CN 295736 Deliverable D2.4, May 2015.
▪ I. Di Piazza, M. Angelucci, G. Polazzi, M. Tarantino, “Experimental results on forced convection in heavy liquid metals using the NACIE facility”, SEARCH-CN 295736 Deliverable D2.6, May 2015. ▪ I. Di Piazza, M. Angelucci, G. Polazzi, M. Tarantino, “Post-test analysis on free and forced convection
measurements in HLM using NACIE facility”, SEARCH-CN 295736 Deliverable D2.7, May 2015. Other Technical Reports
▪ C. Ulissi, M. Angelucci, G. Barone, R. Lo Frano, N. Forgione, “Application of RELAP5/mod3.3 – Fluent coupling codes to CIRCE-HERO”, CERSE-UNIPI 511/2017, September 2017.
▪ I. Di Piazza, M. Angelucci, V. Sermenghi, G. Polazzi, “Experimental Tests in the HLM facility NACIE-UP with non-uniformly heated 19-pins fuel bundle”, Adp MSE-ENEA LP2.C1, September 2016.
▪ M. Angelucci, D. Martelli, D. Rozzia, N. Forgione, A. Giovinazzi, F. D’Auria, W. Ambrosini, “Verification and Validation of RELAP5 STH and FLUENT CFD Coupled Codes Applied to Pool Systems”, Adp MSE-ENEA LP2.C1, September 2016.
