Advanced Numerical Simulation for the Safety Demonstration of Nuclear Power Plants

Existing commercial nuclear power plants (NPPs) have obtained excellent and outstanding performance records over the past decade. Nevertheless, even though the high safety level already achieved could be maintained without investing new exhaustive research efforts, anticipation of further tighter requirements for even higher standard levels should be made, which implies preparedness for new research. Accordingly, in the near and intermediate future, research will conceivably focus on new emerging trends as a result of further desire to reduce the current uncertainties for better economics and improved safety of the current reactors and requirements of the new reactor designs. As it has been usual in the past, the research will continue serving the short-term needs of the end-users (regulatory bodies, utilities and vendors) which mainly focus on both emerging and pending issues, but it will also contribute to addressing the long-term safety needs or the questions arising from the changes in plant designs and operating modes, and to preparing the emergence of new concepts. The sensibility of the stakeholders for a continuous enhancement of safety, mainly when dealing with the advanced and innovative concepts, will entail the development of reactor concepts able to intrinsically prevent severe accidents from occurring, and, should that not be possible, reduce either their probability or the level of expected consequences on the environment and the populations. That should be done in first priority by design, and not necessarily by improvements or the addition of safety systems. Such anticipatory research will involve new generation simulation tools and innovative experimental programs, to be carried out both in the research facilities currently in operation throughout the world and in new dedicated mock-ups supported by suitable laboratory infrastructures. Enhanced or complementary data banks to be generated and further investigations on human and organizational factors will be the primary research activities, from which the end users will definitely profit. In addition, significant efforts should be devoted to get the maximum benefit from the computation tools already available and start preparing their improvements as well by taking advantage from the development and availability of new computation techniques, such as advanced numerical simulation.