Helping countries enhance measures and improve processes to ensure the safety of nuclear power plants against internal and external hazards is the focus of an IAEA Safety Guide issued last month.
The Guide Protection Against Internal and External Hazards in the Operation of Nuclear Power Plants (SSG-77) offers guidance on enhanced protection against internal and external hazards in nuclear power plants operations as well as updated recommendations based on lessons learned from incidents and accidents in nuclear power plants worldwide.
"Internal and external hazards, such as those induced by climate change, are evolving, and some may pose elevated levels of threat to the operational safety of nuclear power plants. At the same time, the operators of nuclear power plants are enhancing their protection against the potential effects of internal and external hazards through diverse means such as physical barriers and operational safety measures," said Anna Hajduk Bradford, Director of the IAEA Nuclear Installation Safety Division.
The publication includes specific recommendations for preparedness and response to prevent, protect and mitigate the effects of various hazards that may occur inside and outside nuclear power plants, such as fire or internal flooding, earthquakes, tsunamis, volcanoes, extreme weather, electromagnetic interference and combinations of these.
One of the key elements covered is that while it might not be practical or possible to prevent a hazard or its impacts from triggering an anticipated operational occurrence, hazard management should ensure that, to the extent practicable, a hazard does not trigger a more severe plant state, leading to accident conditions, such as fires that can result in failure of critical electrical cables, damage to safety systems as well as hardware failures. multiple safety system failures.
All countries with nuclear power plants are encouraged to utilize this safety guide to conduct a self-assessment or to request assistance from the IAEA to identify potential gaps and continuously improve the plants resilience to internal and external hazards, Bradford added.
The IAEA Safety Standards serve as a global reference for protecting people and the environment from the harmful effects of ionizing radiation. The aim of the SSG-77 is to contribute to that purpose by providing, together with other IAEA safety requirements and related recommendations, the best practices and approaches to address operational aspects for hazard protection and address applicable combinations of hazards.
Highlighting the importance of this publication, Bharat Patel, a user of the guide, who is a policy officer from the European Commission said: "Operating experience and data from European nuclear power plants show that the operators must be vigilant to various hazards, including fire. The publication of the SSG-77 is timely since the next topical peer review in the frame of the European Unions Nuclear Safety Directive will specifically address the subject of fire protection at nuclear installations."
The recommendations in this Safety Guide are primarily for operating organizations of nuclear power plants and regulatory bodies. The recommendations are also of interest to other organizations involved in the design, construction, commissioning, operation and decommissioning of nuclear power plants, including technical support organizations, vendor companies such as designers, engineering contractors, manufacturers, research establishments and universities providing services in support of a nuclear power plant, as well as organizations involved in mitigating such hazards.
"The consideration of the hazards varies from plant to plant, depending on the location and the design," said Kazufumi Nagashima, an IAEA nuclear safety officer and focal point for this publication. Many countries are recognizing that human and organizational performance are essential and common to all such facilities, in order to effectively protect them from internal and external hazards."
Operational safety measures against these hazards include aspects such as defining roles and responsibilities of personnel, communication of forecast information inside and outside the plant, management of the effects of plant design changes, and training and exercises.