Abstracts of Invited Talks

In the present moment, nuclear science and industry reunites at least 4 generations of employees. At some point, each one of them felt or will feel unique and outstanding, not comparable with any other. The youth dreams of first nuclear professionals revolving around dense, potent source of energy capable to provide electricity to each home in increasingly affordable and innovative way, gets a new dimension for the current generation of young professionals: a potential of halting the climate change in a way that is respectful for environment and societies. Fulfilling this potential is what the current novices will be facing all their careers.

Ensuring the central role of nuclear energy in the face of the climate and developmental challenge takes much more than vision and charisma of the youth. It also requires skillful application of experience and lessons drawn from successes and failures. On the other hand, this vision, its scope and timescale goes beyond one career or even one lifetime – it will need to be passed to those who come after.

Nuclear, with all its initial and current challenges and opportunities, needs complex approach to building a well-functioning, multigenerational community that results not only in cooperating and tolerating one another. The inclusion, adapted approach and drawing the best traits of each of the generations, starting with those who remember the first Magnox started up to those who soon will hear about neutrons for the first time, will facilitate answering to the issues of the current times while ensuring smoothness, resilience and sustainability of nuclear science and industry.

The Erasmus Mundus joint Master of Science in SAfe and REliable Nuclear Applications (SARENA) is a European cooperation and mobility program in the field of higher education. Unique in Europe, the Master SARENA aims to develop scientific, technical and management skills enabling engineers to work in all nuclear energy-related fields and applications.

Initiated and coordinated by the French Engineering school IMT Atlantique, it is supported by a consortium of four European universities recognized for the excellence of their research and training offer in the field of Nuclear Science and Engineering, namely Universidad Politécnica of Madrid (Spain), University of Technology Lappeenranta (Finland) and University of Ljubljana (Slovenia). Responding to the needs expressed by the actors in the Nuclear sector, SARENA also enjoys broad support from industries (EDF, Orano, ASSYSTEM, GEN Enerjia), public institutions and research organizations (Andra and CEA especially for France).

Fully taught in English, the 2 years Master includes three complementary semesters of specialization followed by a semester dedicated to the thesis project in industry or within a research laboratory. The Master offers two tracks and therefore two different mobility paths: 1. Radioactive Waste Management and Decommissioning track with a mobility at IMT Atlantique and Universidad Politécnica of Madrid. 2. Nuclear Reactors Operation and Safety tarck with a mobility at IMT Atlantique, University of Technology Lappeenranta and University of Ljubljana. At the end of the Master, students are awarded a double degree.

Finally, having received the Erasmus Mundus label for 4 intakes, the Master SARENA benefits from 66 excellence scholarships covering all participation, installation and living costs of the students.

There is a significant need for 3-D steady-state and transient neutron transport algorithms and codes that yield accurate, high-fidelity solutions using reasonable computing resources and time. These tools are essential for modeling innovative nuclear systems, such as next generation reactor designs, as they allow fast but accurate simulation of these systems in a large variety of configurations. The existing methods generally compromise heavily between accuracy and affordability in terms of computation times.

We have developed a novel time-dependent algorithm based on the Transient Fission Matrix (TFM) method and implemented into the RAPID code system. These new algorithms have been computationally verified using several computational benchmarks and experimentally validated using the JSI TRIGA Mark-II reactor.

We have demonstrated that RAPID can yield high-fidelity time-dependent solutions in seconds and minutes on a single computer core by pre-calculating a database of response functions and coefficients, while such calculations are impractical using standard Monte Carlo or deterministic methods.

GPU-based supercomputing is enabling a significant advancement in CFD capabilities for nuclear reactors. In fact, pre-exascale GPU-based super-computers such as ORNL’s Summit are allowing for the first time to perform full core CFD calculations with URANS and LES approaches.

However, computing power alone is however only part of the story. Several advances in computational fluid dynamics methods and their implementation had to be introduced to achieve this milestone. As part of this talk we discuss in particular the development of NekRS, a novel GPU-oriented variant of Nek5000, an open source spectral element code in development at Argonne National Laboratory. NekRS delivers peak performance for key kernels on the GPUs, and good scaling performance even on GPU architectures. Recent performance measurements showed that NekRS, when running on GPUs, outperforms the CPUs by 40x.

The combination of extreme computational power and novel algorithms has enables a significant leap forward. In this talk we examine in particular two recent demonstrations : (i) the full core URANS simulation of the Nuscale Small and Modular reactor (SMR) including the modeling of spacer grids, (ii) the full core simulation of the active region of the pebble bed core of the Mark-I Berkeley’s Flouride-Cooled High Temperature (FHR) reactor. We also examine how these calculations are being used to improve the fidelity of more traditional approaches such as porous media models for pebble beds.

In the final part of this talk we discuss the future of the field ,as exascale systems are due to come online in the near future.

The nuclear sector is currently facing challenges from two different directions. On the one hand, safe operation must continue to be guaranteed for systems with a service life of several decades. On the other hand, new reactor concepts are being developed, for whose novel systems the necessary reliability must first be proven. Germany's central technical support organization GRS investigates the various issues that arise from these challenges. Typical research topics include the behavior of passive safety systems in new reactor concepts as well as the investigation of vibration phenomena in BWR reactor cooling circuits and the enhanced fuel rod cladding corrosion in PWR.

The ITER project is a collaboration of 35 countries to build the world’s largest fusion energy device, to demonstrate the feasibility of fusion power at an industrial scale. Recent years have seen rapid progress in construction, manufacturing, and – starting in mid-2020 – assembly phase. Currently, about 73% of the overall work required to achieve First Plasma has been completed. On the ITER worksite, this progress is visible firstly in the completion of key buildings and infrastructures. The tokamak building was declared ready for equipment as of Spring 2020. Commissioning of the connection to the EU grid and the substation for the steady-state electric network is complete; and commissioning of other key plant support systems (e.g., cooling water, cryoplant, pulsed power for magnet systems) is well underway.

On the manufacturing front, progress is equally impressive. The base and lower cylinder of the cryostat have been installed and welded together in the tokamak pit; the upper cylinder is also complete and in storage. The first two poloidal field (PF) coils were turned over to ITER in early 2020; PF6 has been installed, PF5 will be installed in the coming weeks, and four additional PF coils are in advanced stages. Factory tests of the first central solenoid (CS) module will be completed; the first two modules will be shipped in the coming months, and five more modules in various stages of manufacturing. The first 7 of 18 toroidal field (TF) coils have been delivered to ITER, starting in April 2020, and progress on the remaining TF coils is ongoing. The thermal shield sections have been delivered, and the lower cryostat thermal shield has been installed. The first vacuum vessel sector arrived onsite in August 2020, and – together with two TF coils and a section of the vacuum vessel thermal shield – is being incorporated into the first sub-assembly. An important aspect of this progress is that, for most of the major first-of-a-kind components, the capability has now been demonstrated to fabricate according to ITER’s demanding specifications.

With this progress achieved, ITER is well into Assembly Phase, and the next few years will be dominated by assembly, installation, system commissioning and integration. Following First Plasma, the path toward the achievement of the Q = 10 project goal has been consolidated in a Staged Approach, with all systems to be installed before the start of full fusion power operation in 2035. While the Covid-19 pandemic has had impacts – both on the ITER worksite and in factories in Member countries – the project remains largely on track; even if some delays occur with regard to the goal of First Plasma in 2025, we expect to stay fully on track for Full Fusion Power in 2035.

Highlights from each of these areas (manufacturing, commissioning, tokamak assembly) will be presented along with the updated status and plans.