IAEA, Vienna, 2009, IAEA-TECDOC-1624, ISBN 978–92–0–111309–
2. ISSN 1011–4289
Nuclear power produces 15% of the world’s electricity. Many countries are planning to either
introduce nuclear energy or expand their nuclear generating capacity. Design organizations are
incorporating both proven means and new approaches for reducing the capital costs of their advanced designs. In the future most new nuclear plants will be of evolutionary design, often pursuing economies of scale. In the longer term, innovative designs could help to promote a new era of nuclear power.
Since the mid-1980s it has been recognized that the application of passive safety systems (i.e. those whose operation takes advantage of natural forces such as convection and gravity), can contribute to simplification and potentially improve economics of new nuclear power plant designs. The IAEA Conference on The Safety of Nuclear Power: Strategy for the Future, which was convened in 1991, noted that for new plants ‘the use of passive safety features is a desirable method of achieving simplification and increasing the reliability of the performance of essential safety functions, and should be used wherever appropriate. Some new designs also utilize natural circulation as a means to remove core power during normal operation. The use of passive systems can eliminate the costs associated with the installation, maintenance, and operation of active systems that require multiple pumps with independent and redundant electric power supplies. However, considering the weak driving forces of passive systems based on natural circulation, careful design and analysis methods must be employed to ensure that the systems perform their intended functions.
To support the development of advanced water cooled reactor designs with passive systems,
investigations of natural circulation are conducted in several IAEA Member States with advanced
reactor development programmes. To foster international collaboration on the enabling technology of passive systems that utilize natural circulation, the IAEA initiated a Coordinated Research Project (CRP) on Natural Circulation Phenomena, Modelling and Reliability of Passive Systems that Utilize Natural Circulation in 2004. As one output of this CRP, this publication describes passive safety systems in a wide range of advanced water-cooled nuclear power plant designs with the goal of gaining insights into the system design, operation, and reliability.
