N. R. A. Elsalamouny “Numerical investigation of Severe Accident Phenomena based on Experimental investigations applying BEPU approach” doctoral dissertation defence

Author, Institution: Noura Ragab Abdelaty Elsalamouny, Lithuanian Energy Institute

Science area, field of science: Technological Sciences, Energetics and Power Engineering, T006

Scientific Supervisor: Chief Researcher Dr. Tadas Kaliatka (Lithuanian Energy Institute, Technological Sciences, Energetics and Power Engineering, T006)

Dissertation Defence Board of Energetics and Power Engineering Science Field:
Chief Researcher Dr. Viktorija Grigaitienė (Lithuanian Energy Institute, Technological Sciences, Energetics and Power Engineering, T006) – chairperson
Assoc. Prof. Dr. Linas Paukštaitis  (Kaunas University of Technology, Technological Sciences, Energetics and Power Engineering, T006)
Dr. Davide Pizzocri (Politecnico Di Milano, Italy, Technological Sciences, Energetics and Power Engineering, T006)
Assoc. Prof. Dr. Giedrė Streckienė (Vilnius Gediminas Technical University, Technological Sciences, Energetics and Power Engineering, T006)
Dr. Andrius Tamošiūnas (Lithuanian Energy Institute, Technological Sciences, Energetics and Power Engineering, T006)

Dissertation defence meeting will be at the conference room at Lithuanian Energy Institute (Breslaujos 3 – 202, Kaunas)

The doctoral dissertation is available at the library of Kaunas University of Technology (Gedimino 50, Kaunas) and on the internet: N. R. A. Elsalamouny el. dissertation.pdf

© N. R. A. Elsalamouny, 2025 “The text of the thesis may not be copied, distributed, published, made public, including by making it publicly available on computer networks (Internet), reproduced in any form or by any means, including, but not limited to, electronic, mechanical or other means. Pursuant to Article 25(1) of the Law on Copyright and Related Rights of the Republic of Lithuania, a person with a disability who has difficulties in reading a document of a thesis published on the Internet, and insofar as this is justified by a particular disability, shall request that the document be made available in an alternative form by e-mail to doktorantura@ktu.lt.”

Annotation: The need for experimental and numerical analysis of the physical phenomena that lead to severe nuclear accidents has significantly increased after the Fukushima Daiichi accident. The main goal of this dissertation is to develop a methodology for numerical analysis of severe accidents leading to partial fuel bundle melting by integrating experimental results with advanced modelling approaches for symmetric and asymmetric geometries and applying the best estimate approach for the calculation results. In this work, experimental data from the PHEBUS and QUENCH programs were used. Numerical investigations were performed using the severe accident code RELAP/SCDAPSIM together with the SUSA tool for the best estimate approach application. Also, the CORSOR-M model, for the evaluation of fission product release, was implemented in the RELAP/SCDAPSIM code. The CORSOR-M model provided reliable estimates of Cs/I release in early bundle degradation phases, while later stages require more advanced models. The uncertainty analyses confirmed the reliability of simulations for symmetric geometries. For asymmetric geometries, the investigation results showed that the pseudo-symmetrical approach allows accurate predictions under quenching phase, where this model underestimates hydrogen generation. The use of component-level approach for the simulation of asymmetric geometries improved predictive accuracy of the calculation results. As a result, this first-of-its-kind methodology extends the applicability of severe accident codes, enhances predictive accuracy, and provides new insights into simulation and investigation of hydrogen generation, cladding oxidation, and fission product release under severe accident conditions.