Integrity Of Reactor Pressure Vessels In Nuclear Power Plants

This publication is intended to assist nuclear utilities in optimizing the service life of nuclear power plants. It reviews the latest research on the effects of neutron irradiation on the steels and welds of reactor pressure vessels within light water cooled and moderated reactors.

Pressurized thermal shock (PTS) analysis, which is a part of reactor pressure vessel (RPV) structural integrity assessment, is associated with large thermal shocks and, in some cases, with low temperature repressurization of the RPV after a certain time. At present, several different procedures and approaches are used for RPV integrity assessment. This publication provides benchmark calculation and analysis which compare effects of individual parameters on the final RPV integrity assessment. Based on this, the publication provides recommendations for best practice for their implementation in PTS procedures.

The master curve approach for assessing the fracture toughness of a sampled irradiated material has been gaining acceptance throughout the world. This direct measurement approach is preferred over the correlative and indirect methods used in the past to assess irradiated reactor pressure vessel (RPV) integrity. The master curve methodology already has been or is being assimilated into the ASME Boiler and Pressure Vessel Code, ASTM standards, USNRC regulations, German regulations (KTA 3203), IAEA PTS guidelines for WWER reactors as well as the VERLIFE "Unified Procedure for WWER Component Lifetime Assessment" and other industry guidance documents governing RPV integrity analysis. As this report was prepared using the results of many research projects and experiments, these guidelines for application will be used for a long time to evaluate and assess the residual life of RPVs.

Reactor Pressure Vessels (RPVs) contain the fuel and therefore the reaction at the heart of nuclear power plants. They are a life-determining structural component: if they suffer serious damage, the continued operation of the plant is in jeopardy. This book critically reviews irradiation embrittlement, the main degradation mechanism affecting RPV steels, and mitigation routes for managing the RPV lifetime. Part I reviews RPV design and fabrication in different countries, with an emphasis on the materials required, their important properties, and manufacturing technologies. Part II then considers RVP embrittlement in operational nuclear power plants using different reactors. Chapters are devoted to embrittlement in light-water reactors, including WWER-type reactors and Magnox reactors. Finally, Part III presents techniques for studying embrittlement, including irradiation simulation techniques, microstructural characterisation techniques, and probabilistic fracture mechanics. Irradiation Embrittlement of Reactor Pressure Vessels (RPVs) in Nuclear Power Plants provides a thorough review of an issue that is central to the safety of nuclear power generation. The book includes contributions from an international team of experts, and will be a useful resource for nuclear plant operators and managers, relevant regulatory and safety bodies, nuclear metallurgists and other academics in this field Discusses reactor pressure vessel (RPV) design and the effect irradiation embrittlement can have, the main degradation mechanism affecting RPVs Examines embrittlement processes in RPVs in different reactor types, as well as techniques for studying RPV embrittlement

This publication provides information about the master curve approach for assessing the structural integrity of reactor pressure vessels (RPVs) under current and future operation and accident conditions in nuclear power plants (NPPs). This direct measurement of fracture toughness approach is technically superior to the correlative and indirect methods used in the past to assess irradiated RPV integrity. The results in the report should allow utility engineers and scientists to directly measure fracture toughness using small surveillance sized specimens and apply the results using the master curve approach for RPV structural integrity assessment in NPPs.