New nuclear reactor designs are expected to have a higher level of safety than current designs. As part of the efforts to achieve this, important safety issues related to the new designs need to be identified at an early stage, and research required for problem resolution defined. These proceedings bring together the papers presented at the OECD/NEA Workshop on Advanced Nuclear Reactor Safety Issues and Research Needs. Conclusions of the workshop discussions are offered at the end of the book, which will be of particular interest to all those involved in planning and designing the next generat.

Co-sponsored by the International Atomic Energy Agency and organised in collaboration with the European Communities.

The global utilization of nuclear energy has come a long way from its humble beginnings in the first sustained nuclear reaction at the University of Chicago in 1942. Today, there are over 440 nuclear reactors in 31 countries producing approximately 16% of the electrical energy used worldwide. In the United States, 104 nuclear reactors currently provide 19% of electrical energy used nationally. The International Atomic Energy Agency projects significant growth in the utilization of nuclear power over the next several decades due to increasing demand for energy and environmental concerns related to emissions from fossil plants. There are 28 new nuclear plants currently under construction including 10 in China, 8 in India, and 4 in Russia. In the United States, there have been notifications to the Nuclear Regulatory Commission of intentions to apply for combined construction and operating licenses for 27 new units over the next decade. The projected growth in nuclear power has focused increasing attention on issues related to the permanent disposal of nuclear waste, the proliferation of nuclear weapons technologies and materials, and the sustainability of a once-through nuclear fuel cycle. In addition, the effective utilization of nuclear power will require continued improvements in nuclear technology, particularly related to safety and efficiency. In all of these areas, the performance of materials and chemical processes under extreme conditions is a limiting factor. The related basic research challenges represent some of the most demanding tests of our fundamental understanding of materials science and chemistry, and they provide significant opportunities for advancing basic science with broad impacts for nuclear reactor materials, fuels, waste forms, and separations techniques. Of particular importance is the role that new nanoscale characterization and computational tools can play in addressing these challenges. These tools, which include DOE synchrotron X-ray sources, neutron sources, nanoscale science research centers, and supercomputers, offer the opportunity to transform and accelerate the fundamental materials and chemical sciences that underpin technology development for advanced nuclear energy systems. The fundamental challenge is to understand and control chemical and physical phenomena in multi-component systems from femto-seconds to millennia, at temperatures to 1000?C, and for radiation doses to hundreds of displacements per atom (dpa). This is a scientific challenge of enormous proportions, with broad implications in the materials science and chemistry of complex systems. New understanding is required for microstructural evolution and phase stability under relevant chemical and physical conditions, chemistry and structural evolution at interfaces, chemical behavior of actinide and fission-product solutions, and nuclear and thermomechanical phenomena in fuels and waste forms. First-principles approaches are needed to describe f-electron systems, design molecules for separations, and explain materials failure mechanisms. Nanoscale synthesis and characterization methods are needed to understand and design materials and interfaces with radiation, temperature, and corrosion resistance. Dynamical measurements are required to understand fundamental physical and chemical phenomena. New multiscale approaches are needed to integrate this knowledge into accurate models of relevant phenomena and complex systems across multiple length and time scales.

A National Post-Irradiation-Examination (PIE) Workshop was held March 29-30, 2011, in Washington D.C., stimulated by the DOE Acting Assistant Secretary for Nuclear Energy approval on January 31, 2011 of the "Mission Need Statement for Advanced Post-Irradiation Examination Capability". As stated in the Mission Need, "A better understanding of nuclear fuels and material performance in the nuclear environment, at the nanoscale and lower, is critical to the development of innovative fuels and materials required for tomorrow's nuclear energy systems." (2011) Developing an advanced post-irradiation capability is the most important thing we can do to advance nuclear energy as an option to meeting national energy goals. Understanding the behavior of fuels and materials in a nuclear reactor irradiation environment is the limiting factor in nuclear plant safety, longevity, efficiency, and economics. The National PIE Workshop is part of fulfilling or addressing Department of Energy (DOE) missions in safe and publically acceptable nuclear energy. Several presentations were given during the opening of the workshop. Generally speaking, these presentations established that we cannot continue to rely on others in the world to provide the capabilities we need to move forward with nuclear energy technology. These presentations also generally identified the need for increased microstructural understanding of fuels and materials to be coupled with modeling and simulation, and increased accessibility and infrastructure to facilitate the interaction between national laboratories and participating organizations. The overall results of the work of the presenters and panels was distilled into four primary needs 1. Understanding material changes in the extreme nuclear environment at the nanoscale. Nanoscale studies have significant importance due to the mechanisms that cause materials to degrade, which actually occur on the nanoscale. 2. Enabling additional proficiency in experimentation and analysis through robust modeling coupled with advanced characterization. 3. Advancing the infrastructure and accessibility of physical and administrative systems needed to meet the needs of participating organizations that are subject to different time cycles and constraints that make working and collaborating the national laboratories challenging. 4. Pursuing in-situ analysis and instrumentation to support the examination of dynamic changes to materials' microstructure, deformation, and surface effects as they occur with time scales rather than the static comparison offered by current PIE methods. This Workshop Report responds to the research challenges for advanced/future PIE needs for nuclear materials development outlined by Energy Secretary Chu and the DOE-NE Research and Development Roadmap report, which was delivered to Congress in April 2010, (DOE-NE, 2010) by identifying the technial needs for fuel and material development specifically related to PIE. The information from the panels address these research challenges by identifying specific needs related to each of the topical areas. The focus of the Workshop was to identify gaps in the enabling capabilities for nuclear energy research and to identify high-priority fundamental capabilities to enable research to be completed that would likely have high impact on enabling nuclear energy as a significant contributor to energy production portfolios.

On the basis of the principles included in the Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, this Safety Requirements publication establishes requirements applicable to the design of nuclear power plants. It covers the design phase and provides input for the safe operation of the power plant. It elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.