Risk Assessment of Severe Accident-induced Steam Generator Tube Rupture


Book Description

This report describes the basis, results, and related risk implications of an analysis performed by an ad hoc working group of the U.S. Nuclear Regulatory Commission (NRC) to assess the containment bypass potential attributable to steam generator tube rupture (SGTR) induced by severe accident conditions. The SGTR Severe Accident Working Group, comprised of staff members from the NRC's Offices of Nuclear Reactor Regulation (NRR) and Nuclear Regulatory Research (RES), undertook the analysis beginning in December 1995 to support a proposed steam generator integrity rule. The work drew upon previous risk and thermal-hydraulic analyses of core damage sequences, with a focus on the Surry plant as a representative example. This analysis yielded new results, however, derived by predicting thermal-hydraulic conditions of selected severe accident scenarios using the SCDAP/RELAP5 computer code, flawed tube failure modeling, and tube failure probability estimates. These results, in terms of containment bypass probability, form the basis for the findings presented in this report. The representative calculation using Surry plant data indicates that some existing plants could be vulnerable to containment bypass resulting from tube failure during severe accidents. To specifically identify the population of plants that may pose a significant bypass risk would require more definitive analysis considering uncertainties in some assumptions and plant- and design-specific variables. 46 refs., 62 figs., 37 tabs.










Advanced Concepts In Nuclear Energy Risk Assessment And Management


Book Description

Over the past 30 years, numerous concerns have been raised in the literature regarding the capability of static modeling approaches such as the event-tree (ET)/fault-tree (FT) methodology to adequately account for the impact of process/hardware/software/firmware/human interactions on nuclear power plant safety assessment, and methodologies to augment the ET/FT approach have been proposed. Often referred to as dynamic probabilistic risk/safety assessment (DPRA/DPSA) methodologies, which use a time-dependent phenomenological model of system evolution along with a model of its stochastic behavior to model for possible dependencies among failure events. The book contains a collection of papers that describe at existing plant level applicable DPRA/DPSA tools, as well as techniques that can be used to augment the ET/FT approach when needed.




Nuclear Safety in Light Water Reactors


Book Description

La 4e de couverture indique : Organizes and presents all the latest thought on LWR nuclear safety in one consolidated volume, provided by the top experts in the field, ensuring high-quality, credible and easily accessible information.










Steam Generators for Nuclear Power Plants


Book Description

Steam Generators for Nuclear Power Plants examines all phases of the lifecycle of nuclear steam generators (NSGs), components which are essential for the efficient and safe operation of light water reactors (LWRs). Coverage spans the design, manufacturing, operation and maintenance, fitness-for-service, and long-term operation of these key reactor parts. Part One opens with a chapter that provides fundamental background on NSG engineering and operational experiences. Following chapters review the different NSG concepts, describe NSG design and manufacturing, and consider the particularities of SGs for VVER reactors. Part Two focuses on NSG operation and maintenance, starting with an overview of the activities required to support reliable and safe operation. The discussion then moves on to tubing vibration, followed by the water and steam cycle chemistry issues relevant to the NSG lifecycle. Finally, a number of chapters focus on the key issue of corrosion in NSGs from different angles. This book serves as a timely resource for professionals involved in all phases of the NSG lifecycle, from design, manufacturing, operation and maintenance, to fitness-for-service and long-term operation. It is also intended as a valuable resource for students and researchers interested in a range of topics relating to NSG lifecycle management. - Fulfills the need for a detailed reference on steam generators for nuclear power plants - Contains comprehensive coverage of all phases of the nuclear steam generator lifecycle, from design, manufacturing, operation and maintenance, to fitness-for-service and long-term operation in one convenient volume - Presents contributions from key manufacturers and research institutes and universities




Probabilistic Safety Assessment of WWER440 Reactors


Book Description

The aim of this book is to summarize probabilistic safety assessment (PSA) of nuclear power plants with WWER440 reactors and demonstrate that the plants are safe enough for producing energy even in light of the Fukushima accident. The book examines level 1 and 2 full power, low power and shutdown PSA, and summarizes the author’s experience gained during the last 35 years in this area. It provides useful examples taken from PSA training courses the author has lectured and organized by the International Atomic Energy Agency. Such training courses were organised in Argonne National Laboratory (Chicago, IL, USA), Abdus Salaam International Centre for Theoretical Physics (Trieste, Italy), Malaysia, Vietnam and Jordan to support experts from developing countries. The role of PSA for the plants is an estimation of the risks in absolute terms and in comparison with other risks of the technical and the natural world. Plant-specific PSAs are being prepared for the plants and being applied for detection of weaknesses, design improvement and backfitting, incident analysis, accident management, emergency preparedness, prioritization of research and development and to support the regulatory activities. There are three levels of PSA, being performed for full power and low power operation and shutdown operating modes of the plants: level 1, 2 and 3 PSA. The nuclear regulatory authorities do not require the level 3 PSA for the plants in the member countries of the European Union. This means that only a limited number of NPPs in Europe have the level 3 PSA available. However, in the light of the Fukushima accident the performance of such analyses is strongly recommended in the future. This book is intended for professionals working in the nuclear industry, researchers and students interested in safety of operational plants.