Prevention, mitigation and management of potential accidents in nuclear power plants

NEA Working Group on the Analysis and Management of Accidents (WGAMA) meeting, 13-15 September 2021

The NEA Working Group on the Analysis and Management of Accidents (WGAMA) held its annual meeting virtually on 13-15 September 2021 to discuss its ongoing work and activities related to potential accidental situations in nuclear power plants. The meeting brought together over 100 delegates from 26 member countries, as well as representatives from the International Atomic Energy Agency (IAEA) and the European Commission

The working group aims to assess and enhance the technical basis needed for the prevention, mitigation and management of potential accidents in nuclear power plants. It also facilitates international collaboration on accident management analyses and strategies. In this context, the group currently focuses on three main topics: reactor coolant system thermal-hydraulics, computational fluid dynamics (CFD) for nuclear reactor safety and severe accident management.

During the meeting, members held an extensive discussion to identify strategic orientations for WGAMA country reports, one of the key pillars that support the group’s programme of work. Members also focused on the group’s achievements  during the ongoing COVID-19 pandemic, including 20+ task group meetings and 2 workshops: the Workshop on Experimental Validation and Application of CFD and CMFD codes to Nuclear Reactor Safety Issues (CFD4NRS-8) and the Specialist Workshop on Advanced Measurement Method and Instrumentation for Enhancing Severe Accident Management in a Nuclear Power Plant, Addressing Emergency, Stabilisation and Long-term Recovery Phases (SAMMI-2020).

The group also discussed proposals for three potential new activities: CFD for Nuclear Reactor Safety Phase 6 – Supporting an Enlarged Use; Technical Bases and Guidance for Analyses of Design Extension Condition without Significant Fuel Degradation (DEC-A), jointly with the NEA Working Group on Fuel Safety (WGFS); Application Tests for Realisation of Inverse Uncertainty Quantification and Validation Methodologies in Thermal-Hydraulics (ATRIUM).

Considering that the safe operation of nuclear power plants is based on a large volume of experimental data, the group also discussed a fourth new activity that will focus on the harmonisation of methodologies for experimental data collection and qualification.

Another highlight of the discussion was the session dedicated to the NEA’s nuclear safety research activities relating to the Fukushima Daiichi nuclear power plant accident, including the Thermodynamic Characterisation of Fuel Debris and Fission Products Based on Scenario Analysis of Severe Accident Progression at Fukushima Daiichi Nuclear Power Station Phase 2 (TCOFF-2), the Preparatory Study on Analysis of Fuel Debris (PreADES) Project, the Analysis of Information from Reactor Building and Containment Vessel and Water Sampling in Fukushima Daiichi NPS (ARC-F) Project and the Next Phase Project Fukushima Daiichi NPS Accident Information Collection and Evaluation (FACE).

Finally, the group thanked its outgoing chair Luis Enrique Herranz of the Spanish Center for Energy, Environmental and Technological Research (CIEMAT) for serving as chair for six years and elected Hideo Nakamura of the Japan Atomic Energy Agency (JAEA) as its new chair.

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