Session: 07-04: Experiments and Analyses - III

Paper Number: 136017

136017 - Preliminary Assessment of Cathare-Modelica Codes Coupling for Safety Analyses in Nuclear Cogeneration 

Abstract: 

To assure a viable energy transition towards a low-carbon future energy mix, nuclear energy has gained more attention in the last years due to its peculiarities, e.g., reliable, stable and low-carbon energy production. In particular, reliability and stability are essential properties an energy source must have to assure a suitable integration in environments with high penetration of intermittent renewable energy sources. Moreover, nuclear as a low-carbon thermal energy source is suitable to decarbonize non-electrical sectors, as the ones of the production of hydrogen and fresh water. In this frame, Small Modular Reactors became a widely studied technology due to their advantages of potential enhanced safety, economic viability due to series production, ease of installation and modularity. For these reasons, small-scale reactors are considered one of the most valid candidate to be embedded in future energy mix scenarios for cogeneration in presence of renewable energy sources, namely Hybrid Energy Systems. However, the introduction of Small Modular Reactors in Hybrid Energy Systems for cogeneration can result in different transients induced by the thermal users on the nuclear power plant, which must be carefully considered when performing a safety assessment.

To this purpose, the paper describes the methodology adopted to perform a code coupling useful for future safety analyses. In particular, the coupling is performed between a well-assessed thermal hydraulic system code used to perform nuclear safety analyses, namely CATHARE, and a widely-adopted a-causal dynamic modelling language, namely MODELICA, exploiting the features of both modelling codes. The work was carried out by means of the Functional Mock-up Interface, a well-assessed tool used to perform co-simulations and model-exchange simulations via Functional Mock-up Units.

To achieve the objective, Functional Mock-up Units were first generated from a CATHARE 3 model of a reference design of Small Modular Reactor by means of tools directly related to the system code itself, namely ICoCo and ICoCo2FMI. ICoCo (Interface for Codes Coupling) is a C++ class library which permits to couple CATHARE with other ICoCo-compliant codes, whereas ICoCo2FMI is an open source tool which permits to generate Functional Mock-up Units from CATHARE models. After, some stand-alone and coupling tests with already developed MODELICA Functional Mock-up Units were performed. Finally, a preliminary model of Balance Of Plant developed adopting the MODELICA language was used to perform final coupling tests for steady state operations of the nuclear power plant. The results, although preliminary, show good coupling capabilities between the two codes, providing an excellent starting point to perform future assessments of some transients to be used for safety analyses of nuclear systems in cogeneration.

Presenting Author: Alessandro De Angelis University of Pisa

Presenting Author Biography: Alessandro De Angelis has a BSc and a MSc in Energy engineering from University of Pisa with a final thesis on the application and further validation of a similarity theory for heat transfer to supercritical pressure fluids. After the graduation, he worked as a researcher for the Department of Civil and Industrial Engineering at University of Pisa, where he started to be involved in International collaborations on Light-Water Small Modular Reactors safety issues. On January 2022 he started a doctoral research project in Nuclear Engineering at University of Pisa on safety assessment and design issues of nuclear cogeneration with Small Modular Reactors. His research interests are nuclear thermal-hydraulics and dynamic systems modelling adopted for safety analyses of nuclear cogeneration in hybrid energy systems, mainly using thermal-hydraulics system codes, CFD and dynamic modelling languages.

Authors:

Alessandro De Angelis University of Pisa
Paolo Olita CEA Cadarache
Walter Ambrosini University of Pisa