This “radical choice” would even be “a major technological advance”, according to the two partners. Thus, it brings together in a single environment 3D models and advanced simulations of reactor operation including thermo-hydraulic, neutronic and mechanical aspects. Throughout the life cycle, the traceability of the project’s engineering data can also be monitored. “The digital twin must save time on the exchange of information between teams, which can represent the full-time equivalent of a team of five engineers”says Jean-Luc Alexandre, the co-founding director of Naarea. It must also improve operational efficiency, reduce costs and delays, and strengthen the demonstration of safety. “At Naarea, with the exception of support and corporate functions, everyone works on the digital twin, or around 250 people.”
Daring, this technical choice was recognized by the awarding of the 2024 national engineering grand prize at the end of October. In 18 months, Naarea and Assystem managed to develop a first version of a digital twin of the XAMR which integrates the basic design elements of the minireactor. Assystem managed to “harmonize modeling technologies with neutron analyses, overcoming complex challenges essential to the success of the project”. The partners are now working on a second version, which will be “populated with experimental data in salt chemistry and material resistance” before arriving at a third version “which will integrate all the experimental data, provided by the real physical twin planned for 2028, and which must corroborate the calculations”indicates Jean-Luc Alexandre.
A laboratory for coupling calculation codes
But the digital twin will not be enough to obtain a license for the reactor and submit the construction authorization file to the Nuclear Safety Authority (ASN). The scientific calculation tools specific to molten salt and fast neutron nuclear power still need to be developed, even if they already exist for 3rd generation pressurized water reactors. They will then have to be approved. “Today, the digital twin is not a safety demonstration tool, recognizes Jean-Luc Alexandre. But the ASN is interested in its use as a support to simulate accidents, degraded modes and demonstrate control of containment… We have the burden of proof that it can be used for this purpose.”
To help them develop and integrate these tools, Naarea and Assytem have created a laboratory, which will be open to other partners, particularly academic ones. “What is innovative is to couple calculation codes for the safety demonstration. To achieve this, we have put in the common laboratory all the advanced activities that we will need by 2028 and which are emerging”explains Christian Jeanneau, international executive vice-president, project management and digital at Assystem.
This involves integrating large language model (LLM) or Internet of Things (IoT) tools into the digital twin. “We will develop solutions for automated verification and monitoring of exploitation via the Internet of Things”indicates Jean-Luc Alexandre. To achieve this, Naarea and Assystem have adopted a 5-year strategic roadmap. In the meantime, the paper is resisting. “At Naarea, we already have 4,500 documents”observes the director of the start-up. And this is just the beginning.
Source: www.usinenouvelle.com
