A containment structure is a key safety component in nuclear power plant designs, with the purpose of protecting people and the environment in the event of a nuclear emergency. As stated in the 2015 Vienna Declaration on Nuclear Safety, new nuclear power plants are to be designed and constructed with the objective of preventing accidents in he commissioning and operation and, should an accident occur, mitigating possible releases of radionuclides causing long-term off site contamination and avoiding radioactive releases large enough to require long-term protective measures and actions.
In order to reflect the objective of the Vienna Declaration on Nuclear Safety within the IAEA Safety Standards, the Fourth Consultancy on Safety Guide NS-G-1.10 - Design of Reactor Containment Systems for Nuclear Power Plants was held from 24 to 28 August 2015. During this meeting, invited experts reviewed guidance and provided recommendations supporting a revision of NS-G-1.10, focusing on minimizing radiological releases in accident conditions. While recommendations developed for new nuclear power plants were judged as appropriate enough to be circulated to the Nuclear Safety Standards Committee for comments, expectations for existing nuclear power plants need to be elaborated upon in order to better reflect the outcomes of various design re-assessments conducted at different plants following the Fukushima Daiichi accident.