Safety Investigation of in-box LOCA for DEMO Reactor: Experiments and Analyses

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UNIVERSITÀ DI PISA

DOTTORATO DI RICERCA IN INGEGNERIA INDUSTRIALE

Curriculum in Ingegneria Nucleare e Sicurezza Industriale

Ciclo XXIX

Safety Investigation of in-box LOCA for DEMO Reactor: Experiments and Analyses

Author: Marica EBOLI

Supervisors: Nicola FORGIONE (UNIPI), Alessandro DEL NEVO (ENEA), Werner MASCHEK (KIT)

Co-Supervisor: Walter AMBROSINI (UNIPI)

Description of the research activity (synthesis)

The cooperation between DICI (Department of Industrial and Civil Engineering) of University of

Pisa and the Experimental Engineering Division (FSN-ING) of ENEA C.R. Brasimone, is long lasting

and EUROfusion has strengthened this cooperation. In this international framework, the Ph.D.

research activity is conducted at ENEA C.R. Brasimone under the EUROfusion Consortium Breeding

Blanket Design and Safety Project. In particular, it is a cross cutting activity falling into specific

tasks, i.e. “WPBB-5.4.2 PbLi water reaction” and “WPBB-3 WCLL Breeding Blanket design”, and it

was connected with “WPSAE Safety and Environment”.

The renewed interest for the Water Cooled Lithium Lead breeding blanket concept has focused on

R&D activity connected with the potential interaction between lithium-lead and water. In this

framework, the research activity is devoted to perform deterministic safety analysis of the WCLL

BB in-box Loss Of Coolant Accident. Currently, no code is able to deal contemporarily with

phenomena connected to thermodynamic interaction and to chemical reaction. Starting from this

point, main and innovative goal of the Ph.D. research activity is twofold: 1) setting-up a qualified

computer code for deterministic safety analysis of the WCLL BB in-box LOCA, also in support to the

design of the breeding blanket and its connected systems, 2) validating the code against

experimental data available in literature or provided by the new LIFUS5/Mod3 campaign

specifically designed for code validation purposes. To address this objective, a series of

intermediate steps were fulfilled during these three years of research activity.

During the first year, a comprehensive literature review was conducted, with main focus on the

phenomena relevant to the safety of the WCLL breeding blanket. Past experiments and numerical

activities have been identified and reviewed. The study highlighted a good comprehension of the

phenomena and processes connected with PbLi and water interaction, but also the lack of

qualified and reliable numerical codes able to predict such kind of phenomena involved during a

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postulated in-box LOCA accidental scenario. Starting from the outcomes of the literature review,

the PbLi/water chemical reaction model was implemented in SIMMMER-III and SIMMER-IV codes

after the revision of selected subroutines in the source code. In order to obtain a qualified code for

deterministic safety analysis, a Verification and Validation (V&V) procedure was established and

conducted. The first step, verification, consists in the process of determining whether a

computational model correctly implements the intended conceptual model or mathematical

model. It was successfully completed in simple geometric configuration, comparing the calculated

hydrogen generation results with the theoretical stoichiometric value. Finally, the preliminary

validation of the model on the basis of the experimental data of BLAST Test#5 was completed,

comparing the results with the previous calculations performed without chemical reaction.

The second year of the research activity was devoted to the design and follow up of a new

experimental campaign in LIFUS5/Mod3. The experimental campaign is unique and innovative,

focused on chemical reaction code model validation. The final design of Separate Effect Test

facility experiments in LIFUS5/Mod3 was fulfilled 1) to improve the knowledge of the physical

phenomena during the transient evolution, including the identification of parameters triggering

the initial pressure peak; 2) to provide qualified experimental data for supporting the

development and for validating the empirical model of chemical reaction and hydrogen

production, by means of adequate and controlled initial and boundary conditions. Supporting and

pre-test analyses by SIMMER-III and RELAP5/Mod3.3 codes were executed to provide useful data

(e.g. injection pressure, water mass flow rate, volume of cover gas, temperature map, hydrogen

measurement line) for the final design of the facility configuration and instrumentation choice.

Meanwhile, the preparation of

technical specifications for the procurement of mechanical

components, control system and instrumentation was carried out.

The third year of the research activity completed the main goal of the Ph.D. The SIMMER codes

validation was carried on establishing a standard methodology for code validation based on a

three-step procedure: 1) the initial condition results, 2) the reference calculation results, and

3) the results from sensitivity analyses. The methodology was applied to all available LIFUS5 tests.

The post-test analyses highlighted open issues of test execution and of experimental data, as well

as code limitations and capabilities. The qualitative accuracy evaluation was performed through a

systematic comparison between experimental and calculated time trends based on the

engineering analysis, the resulting sequence of main events, the identification of

phenomenological windows and of relevant thermo-hydraulic aspects. Finally, the accuracy of the

code prediction was evaluated from quantitative point of view by means of selected, widely used,

figures of merit. As conclusion of the activity, the validated SIMMER code was pioneering applied

to the WCLL BB in-box LOCA. Preliminary safety investigations were carried out to evaluate the

consequences of the double ended water pipe break in the breeding zone and to investigate

possible countermeasures to mitigate the transient.

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TABLE OF THE STUDY PROGRAMME

# Training activities performed during the Ph.D. Period Hours

1 RELAP/SCDAPSIM User Training Workshop July 2012 40 2 Corso introduttivo all’uso di STARCCM+ July 2012 15

3 ANSYS CFD summer school September

2012 25 4 Fluid Mechanics and Chemistry for Safety issues in HLM nuclear reactors (VKI) November 2013 25 5 Academic English “Writing a scientific research article” Jan-Feb 2014 40 6 La radioprotezione negli impieghi industriali delle radiazioni ionizzanti March 2014 15 7 Applicazione della direttiva PED 97/23/CE in materia di attrezzature a pressione February 2015 8 8 Training course on Thermal Hydraulics May 2015 1 week 9 School of Fusion Technologies (KIT) September

2015 2 weeks

PUBLICATIONS

International Journals

[1] M. Eboli, A. Del Nevo, A. Pesetti, N. Forgione, P. Sardain, Simulation study of pressure trends in the case of loss of

coolant accident in Water Cooled Lithium Lead blanket module, Fusion Eng. Des., 98-99 (2015) 1763-1766.

[2] M. Eboli, N. Forgione, A. Del Nevo, Implementation of the chemical PbLi/water reaction in the SIMMER code, Fusion Eng. Des., 109–111 part A (2016) 468-473.

[3] M. Eboli, A. Del Nevo, N. Forgione, M. T. Porfiri, Post-Test Analyses of LIFUS5 Test#3 Experiment, Fusion Eng. Des. (2017), In press, Corrected proof, Available online 22 March 2017.

[4] A. Del Nevo, E. Martelli, P. Arena, G. Bongiovì, G. Caruso, P.A. Di Maio, M. Eboli, G. Mariano, R. Marinari, F. Moro, R. Mozzillo, F. Giannetti, G. Di Gironimo, A. Tarallo, A. Tassone, R. Villari, Advancements in DEMO WCLL breeding

blanket design and Integration, International Journal of Energy Research, 11 May 2017.

[5] A. Del Nevo; P. Agostini; P. Arena; G. Bongiovì; G. Caruso; G. Di Gironimo; P. A. Di Maio; M. Eboli; R. Giammusso; A. Giovinazzi; E. Martelli; G. Mariano; F. Moro; R. Mozzillo; A. Tassone; D. Rozzia; A. Tarallo; M. Tarantino; M. Utili; R. Villari, WCLL breeding blanket design and integration for DEMO 2015: status and perspectives, Fusion Eng. Des., (2017 In press, Corrected proof, Available online 22 March 2017.

International conferences

[1] M. Eboli, A. Del Nevo, A. Pesetti, N. Forgione, P. Sardain, Water-LiPb interaction study, 28th Symposium on Fusion Technology (SOFT2014), Sept. 29-Oct. 3, 2014, San Sebastian, Spain.

[2] M. Eboli, N. Forgione, A. Del Nevo, Implementation of the Chemical PbLi/Water Reaction in the SIMMER Code, 12th International Symposium on Fusion Nuclear Technology (ISFNT12), Sept. 14-18, 2015, Jeju Island, South Korea.

[3] M. Eboli, N. Forgione, A. Del Nevo, Consistent post-test analyses of LIFUS5 experiment, 29th Symposium on Fusion Technology (SOFT2016), Sept. 5-9, 2016, Prague, Czech Republic.

Technical reports

[1] A. Del Nevo, M. Eboli, A. Neri, M. Serra, Specifica di fornitura per lo studio sperimentale dell’interazione metallo liquido

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[2] M. Eboli, N. Forgione, A. Del Nevo, PbLi water chemical interaction model–implementation in SIMMER-III Ver. 3F code, DM-N-R-197, 12/02/2016

[3] M. Eboli, N. Forgione, A. Del Nevo, M.T. Porfiri, Interim report on progress in validation of SIMMER-III code with chemical

reactivity model versus experimental data, DM-D-R-207, 24/03/2016.

[4] M. Valdiserri, M. Eboli, Progettazione e realizzazione quadri elettrici di potenza, di segnale e cablaggi in campo impianto

LIFUS5/Mod3, L5-I-S-214, 7/04/2016.

[5] M. Eboli, A. Del Nevo, N. Forgione, Verification and validation – Pre-test analyses by SIMMER code with the implemented

PbLi water chemical reaction, DM-D-R-225, 30/06/2016.

[6] A. Del Nevo, M. Eboli, Specifica di fornitura del sistema di misura dell’idrogeno prodotto dalla reazione PbLi-H2O in

condizioni rilevanti del WCLL BB – Appendice. Supporto alla progettazione della linea idrogeno, L5-I-S-232, 27/10/2016.

[7] M. Eboli, N. Forgione, A. Del Nevo, SIMMER-III Ver.3F Mod.0.1 validation against LIFUS5 Test#3 experiment, DM-D-R-241, 16/01/2017.

[10] M. Eboli, N. Forgione, A. Del Nevo, SIMMER-III Ver.3F Mod.0.1 validation against LIFUS5 Test#6 experiment, DM-D-R-249, 13/02/2017.

[13] M. Eboli, A. Del Nevo, N. Forgione, Setting up of a numerical tool for PbLi/water interaction simulation, EUROfusion Project Deliverable, WPBB-DEL-D-542-01, February 2015.

[14] M. Eboli, A. Del Nevo, N. Forgione, Design of the experiment for code validation, EUROfusion Project Deliverable, WPBB-DEL-D-542-02, November 2015

[15] M. Eboli, A. Del Nevo, N. Forgione, Execution of experiments – Status, EUROfusion Project Deliverable, WPBB-DEL-BB-5.4.2-T003-D001, May 2016.

[16] M. Eboli, A. Del Nevo, N. Forgione, Verification and validation – Pre-test analyses by SIMMER code with the implemented

PbLi water chemical reaction, EUROfusion Project Deliverable, WPBB-DEL-BB-5.4.2-T003-D002, June 2016.

[17] M. Eboli, A. Del Nevo, N. Forgione, M. T. Porfiri, Set up safety analysis code SIMMER III for WCLL safety analysis, including

water-LiPb reaction, EUROfusion Project Deliverable, WPSAE-2.1.1, December 2014.

[18] M. Eboli, A. Del Nevo, N. Forgione, M. T. Porfiri, Interim report on progress in validation of the SIMMER code with chemical

reactivity model versus experimental data, EUROfusion Project Deliverable, WPSAE-2.3.1-T01-D01, March 2016.

[19] A. Del Nevo, M. Eboli, E. Martelli, Report to define the limits related to the adoption of a WCLL BB coupled with a Heat

Storage Facility, EUROfusion Project Deliverable, WPBOP-3.1.3-01-01, March 2015.

[20] D. Rozzia, M. Eboli, E. Martelli, M. Utili, A. Del Nevo, Investigation in support of the conceptual design of the energy storage

system for WCLL BB EUROfusion Project Deliverable, WPBOP-3.1.3-01-D02, April 2016.

[21] A. Del Nevo, E. Martelli, M. Eboli, Summary of key parameters for the design of the Blanket RH System, EUROfusion Internal Deliverable, WPBB-DEL-D-311-03, July 2014.

[22] A. Del Nevo, E. Martelli, M. Eboli, Summary of key parameters for the design of the PHTS and related BoP for the WCLL, EUROfusion Internal Deliverable, WPBB-DEL-D-311-04, July 2014.

[23] A. Del Nevo, E. Martelli, M. Eboli, Safety relevant aspects identified for the WCLL BB, EUROfusion Internal Deliverable, WPBB-DEL-D-311-02, August 2014.

[24] A. Del Nevo, E. Martelli, M. Eboli, First Summary of specific design requirement for WCLL BB, EUROfusion Internal Deliverable, WPBB-DEL-D-311-01, February 2015.

[25] A. Del Nevo, E. Martelli, M. Eboli, Magnetic material amount and distribution in WCLL blanket zone, EUROfusion Internal Deliverable, WPBB-DEL-D-311-05, March 2015.

[26] A. Del Nevo, E. Martelli, M. Eboli, Operational parameters for WCLL release 2014, EUROfusion Internal Deliverable, WPBB-DEL-D-313-01, March 2015.

[27] A. Del Nevo, G. Di Gironimo, R. Mozzillo, A. Lanzotti, P. A. Di Maio, P. Arena, G. Bongiovì, R. Giammusso, F. Moro, D. Flammini, R. Villari, E. Martelli, M. Eboli, W. Ambrosini, S. Paci, CAD, Neutronic ,Thermo-hydraulics & Thermo-mechanical

analyses – Contribution to DDD2014, EUROfusion project deliverable, WPBB-DEL-BB-3.2.1-T001-D001, March 2015.

[28] A. Del Nevo, E Martelli, M. Eboli, 2014 Design and Analysis Strategy Plan (DASP2014) for WCLL BB, EUROfusion Project Deliverable, WPBB-DEL-D1C03, July 2015.

[29] A. Del Nevo, E Martelli, M. Eboli, Design Description Document (DDD) 2014 for WCLL, EUROfusion Project Deliverable, WPBB-DEL-D-312-01-A, July 2015.