Using nuclear observations to improve climate research and GHG emission estimates – the NuClim project

Project NuClim (Nuclear observations to improve Climate research and GHG emission estimates) aims to use high-quality measurements of atmospheric radon activity concentration and ambient radioactivity to advance climate science and improve radiation protection and nuclear surveillance capabilities. It is supported by new metrological capabilities developed in the EMPIR project 19ENV01 traceRadon. This work reviews the scientific objectives of project NuClim in terms of both climate science and radiological protection, and provides an overview of the NuClim field campaign and the various nuclear measurements being implemented within the scope of the project

From robots to drones, the future of decommissioning operations – The CLEANDEM and XS-ABILITY projects

In recent years, there has been an increase in Dismantling & Decommissioning (D&D) operations of nuclear facilities, driven by the ageing of infrastructures and political decisions to phase out nuclear power. These operations, which can last from a few years to several decades, require mature and reliable techniques that meet international standards, local safety regulations, and radiation protection criteria. Despite developments in robotics, sensors, and digital tools that could reduce manual labor and risk exposure, their deployment remains limited due to financial and logistical constraints. The EU-funded projects CLEANDEM and XS-ABILITY address this challenge by upgrading advanced nuclear sensors and mounting most of them on autonomous terrestrial (CLEANDEM) and both terrestrial and aerial (XS-ABILITY) robots. These robots are and will be designed to assist operators by enabling continuous monitoring during D&D processes, reducing radiation exposure (CLEANDEM), and accessing hard-to-reach areas and difficult to measure radionuclides (XS-ABILITY). They also minimize human errors and organizational issues related to limited intervention time and repetitive tasks. CLEANDEM's results were showcased at its final workshop, and XS-ABILITY, launched October 1st 2024, will build upon these developments to further improve safety and efficiency in D&D operations. This work focuses on CLEANDEM's technical developments, and presents XS-ABILITY as one of its perspectives

Research on the safety of heavy-liquid-metal-cooled reactors

Since the fifth edition, dating 1998 to 2002, the Euratom Framework Programmes have supported numerous collaborative projects dealing with the research and development of the heavy liquid metal technology. In this 20+ year's context of outstanding scoring, LESTO – the latest project recently launched – is taking the baton from PASCAL, about to conclude, with ANSELMUS bridging the gap in between. Both PASCAL and LESTO address (on complementary and synergic topics) key safety-related aspects of the technology, sharing the same foundational approach: advancing on the two pillars of experimental testing and software simulation. The two projects also share the focus on ALFRED and MYRRHA, the two heavy-liquid-metal-cooled reactors included in the strategic roadmap of the European Sustainable Nuclear Industrial Initiative. Thanks to the results generated by the two projects, a significant contribution will be delivered to the substantiation of evidences requested for the licensing of ALFRED and MYRRHA and, in perspective, for that of future heavy-liquid-metal-cooled nuclear systems

Towards improvement of the operation and safety of European nuclear power plants through enhanced thermal-hydraulics experiments and analysis

Due to the negligible levels of CO2 it produces, nuclear energy is gaining a more prominent role in the current transition to clean energy. An important aspect to nuclear energy generation is the safety of nuclear installations. To ensure safe operation of nuclear reactors, all facets must be carefully monitored and controlled, and the behavior of the operational and safety systems must be assessed in detail under normal and off-normal conditions. A key aspect herein is the reactor thermal-hydraulics, crucial to ensure heat generated in the core gets transferred to the secondary system, during electricity generation, or designated heat sinks, for emergency scenarios. Two European projects focusing on reactor thermal-hydraulics recently received grants within the Euratom to perform four year research that will enhance the operation and safety of the European nuclear power reactors. PASTELS (PAssive Systems: Simulating the Thermal-hydraulics with ExperimentaL Studies) deals with innovative passive safety systems and investigates the possibility of using reliable experimental data to assess the ability of various European thermal-hydraulic tools to simulate the behavior of these systems. GO-VIKING (Gathering expertise On Vibration ImpaKt In Nuclear power Generation), on the other hand, focuses on the hydraulic interaction between the coolant and crucial nuclear power plant components that are susceptible to flow-induced vibrations. Through experimental and numerical investigations, these interactions are further studied and improved modeling methodologies are developed. In the current paper, the global objectives of both projects, as well as the methodologies and the expected impacts are presented. Moreover, selected results are briefly discussed and conclusions are drawn

The Euratom PULSAR project

PULSAR (PU-238-coupLed dynamic power system for SpAce exploRation and beyond) was a research and innovation project funded by the European Commission between 2022 and 2024. The aim of this project was to establish building blocks for the development of Radioisotope Power Systems (RPS) fueled by Pu-238 with European technologies and standards. Radioisotope Power Systems (RPS) is a key enabling technology for exploration of locations hidden from the sun for prolongated periods, or of deep space, where the sun cannot deliver sufficient power to spacecrafts. This project has brought together leading stakeholders in the field of space and nuclear. PULSAR consortium includes nine partners: Tractebel (coordinator), SCK CEN, CEA, JRC, Airbus DS, ArianeGroup, UBFC, INCOTEC and ARTTIC. The paper provides a presentation of the project, the organization of the different work packages between partners, the objectives and the achievements obtained. Future prospect and expected challenges are presented based on the hypothesis assumed in PULSAR

Status of Serpent Monte Carlo code in 2024

The Serpent Monte Carlo code has been in public distribution for 15 years, and has a large international user basis with both research and commercial applications. Serpent is currently developed as part of the Kraken multi-physics framework, which has dedicated capabilities for core-level reactor physics analyses. In Kraken, Serpent can be used either as a high-fidelity neutronics solver, or for generating homogenized group constants for the Ants nodal neutronics code. The neutron and photon transport modes in Serpent enable using the code also for various stand-alone applications beyond reactor physics, such as radiation shielding and fusion neutronics. This paper presents a review of the current status and capabilities of Serpent, corresponding to the latest release 2.2.1. The main features are introduced, with references to publications with more detailed methodological descriptions

Current capabilities and future developments of Monte Carlo code MCS

The Monte Carlo code, MCS was developed at the Ulsan National Institute of Science and Technology (UNIST) in 2011. In the initial development phase, the primary focus was on developing a Monte Carlo code for the high-fidelity multicycle analysis of large-scale power reactors, especially pressurized water reactors. For the power reactor analysis, capabilities including refueling and shuffling of fuel assemblies, on-the-fly Doppler broadening of neutron cross-sections, and multiphysics coupling were implemented in the MCS. Beyond reactor analysis and capabilities, MCS has been developed to extend its applications. The MCS has been used for radiation shielding, group constants generation, sensitivity, uncertainty, and transient analysis. This study provides a general overview of MCS capabilities

Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition

The flux distribution tallies using the proper orthogonal decomposition (POD) called “the POD tallies” have been developed in our previous study. The POD tallies can achieve dimensionality and statistical uncertainty reduction for a finely discretized flux distribution. Some characteristics of the POD tallies, which are left by our previous work, are revealed in the present study. Firstly, the POD tallies with the track length estimator are newly implemented. Since the statistical uncertainty of the POD tallies is reduced compared with the cell tallies, the POD tallies with the track length estimator can obtain the most precise result among the present implantations. Secondly, the basis vectors obtained by the deterministic and the stochastic methods are compared. The statistical uncertainty of the snapshot data invokes the degradation of the extracted basis vectors. This result indicates that the deterministic method might be more efficient for the snapshot calculation. Finally, the impact of the covariances of expansion coefficients on the statistical uncertainty of expanded flux distribution is investigated. The reconstructed statistical uncertainty considering only the variances of the expansion coefficients differs from the reference. This result reveals that the covariances of the expansion coefficients are important to estimate the statistical uncertainty of the local flux in the flux distribution

Optimization progress of large-scale radiation shielding Monte Carlo simulation software based on AIS variance reduction technique system: MCShield

The development of novel nuclear facilities has brought safer and more efficient energy options but also poses significant challenges for radiation shielding calculations. MCShield, developed by the Radiation Protection and Environmental Protection Laboratory at Tsinghua University, is a Monte Carlo program designed for coupled neutron/photon/electron transport in radiation shielding calculations. It incorporates a system of variance reduction techniques based on Auto-Importance Sampling (AIS) to address the deep penetration problem commonly encountered in the field of radiation shielding. The accuracy and computational efficiency of MCShield have been validated through benchmark problems and real-world applications. However, the current AIS system faces limitations in complex scenarios, user-friendliness, and reliance on user experience. To address these issues, we optimized the size, shape, and energy parameters for the AIS variance reduction method, expanded the use of regular virtual surfaces, and introduced an irregular AIS virtual surface method. Additionally, we developed an automatic generation method for AIS virtual surfaces and implemented automatic calculation for these surfaces. AIS Energy Bias Method was proposed to improve convergence across different energy intervals. These improvements enhance the applicability and refinement of the AIS virtual surface parameters, significantly boosting the overall performance of MCShield

Magic-RR project overview: objectives, methodology and expected results

Most research reactors (RRs) in Europe are over 60 years old, and there are only limited efforts underway (e.g., PALLAS and JHR projects) to partially replace this aging infrastructure. Continued safe operation (CSO) of these reactors is crucial to sustaining the EU’s leadership in nuclear materials development and qualification for advanced reactor designs and to ensuring a steady supply of medical isotopes. Extending the licenses for these reactors to ensure CSO requires comprehensive aging management reviews (AMRs) and time-limited aging analyses (TLAAs) of key structures and components. However, current challenges include a limited understanding of irradiation-induced degradation and corrosion mechanisms, a shortage of data on RR structural materials under high-fluence conditions necessary for CSO, the lack of predictive, physics-based models for irradiation damage in aluminum alloys, and insufficient surveillance specimens for some reactors. Additionally, there are no dedicated design codes for reactor vessels and core structures made of aluminum, and there is no standardized approach in Europe for aging management of operating RRs. To address these issues, a new project, Research on M