IAEA Launches NEXSHARE to Validate Safety and Performance of Advanced Nuclear Reactors

The design and licensing of new reactors heavily rely on computer codes to define safe operational boundaries and ensure system functionality.

The International Atomic Energy Agency (IAEA) is spearheading a global collaboration effort to validate the safety and performance of advanced nuclear reactors through its Nuclear Harmonization and Standardization Initiative (NHSI). In a pioneering interregional workshop held in Vienna last month, the IAEA established the Network for Experiment and Code Validation Sharing (NEXSHARE), aimed at facilitating the deployment of safe and secure small modular reactors (SMRs) and other advanced reactors.

NEXSHARE Objectives

NEXSHARE aims to connect users with comprehensive information, including a database of SMR experimental facilities, and promote efficient resource utilization for experiments and a harmonized approach to code validation. "Modelling software and experimental data are essential for rigorous testing and validation procedures needed for advanced reactors," said Aline des Cloizeaux, Director of the IAEA’s Division of Nuclear Power. "NEXSHARE is well designed to facilitate this cooperation."

Workshop Details

The workshop, co-organized with the Organization for Economic Cooperation and Development’s Nuclear Energy Agency (OECD-NEA) from June 18-21, featured 77 participants from 29 countries and three international organizations. It covered topics like experimental testing, code validation programs, and common approaches in testing and code validation. The event also included group sessions that will inform future publications and collaborative activities within NEXSHARE.

Importance of Code Validation

The design and licensing of new reactors heavily rely on computer codes to define safe operational boundaries and ensure system functionality. These codes need verification and validation to handle new components, systems, and behaviors not previously modeled. "The NEXSHARE network is crucial for achieving global cooperation in code validation efforts to help facilitate the deployment of SMRs and other advanced reactors," stated Piyush Sabharwall from the US Department of Energy’s Idaho National Laboratory.

Safety and Regulatory Standards

To address the challenges of safety demonstrations for advanced reactors, including SMRs, the IAEA is developing a dedicated safety guide within its Safety Standards framework. The outcomes of the workshop will contribute to specific recommendations on using experimental data for computer codes in SMR safety assessments. The IAEA also offers Technical Safety Reviews for SMRs to support the experimental aspects of safety analysis computer codes.

Key Achievements and Future Plans

Since its inception in 2022, NHSI’s Industry and Regulatory Tracks have achieved significant milestones, including developing a generic high-level user requirement document specific to SMRs and creating the Management, Supply Chain, and Quality (MSCQ) network. On the regulatory side, NHSI has facilitated information sharing among regulatory bodies and established a collaborative review process for advanced reactors.

The next NHSI plenary meeting is scheduled for October 21 in Vienna during the International Conference on Small Modular Reactors and their Applications. This gathering will further discuss and enhance the collaborative efforts towards the safe and efficient deployment of advanced nuclear technologies.

Quotes

Anna Bradford, Director of the IAEA’s Division of Nuclear Installation Safety, emphasized, "Further development of computer codes is aimed to support the claims on safety advantages of SMRs. These claims must be backed by robust safety demonstrations, which are a crucial prerequisite for the deployment of SMRs."

Martina Adorni, a Nuclear Safety Specialist at OECD-NEA, noted the importance of updating validation matrices for existing reactors and extending them to emerging challenges of new reactor designs. "The cooperation with the IAEA NEXSHARE initiative is crucial," she said.

The establishment of NEXSHARE marks a significant step towards enhancing the safety and performance validation of advanced nuclear reactors, ensuring that SMRs and other innovative technologies can be deployed effectively to support the global clean energy transition.