Recent experimental observations have made it clear that cavity formation can occur in light-water reactor internal components fabricated from austenitic stainless during the course of their service life. In order to assess the potential for cavity swelling in these components at end-of-life doses, it is necessary to develop a validated computational model that incorporates the relevant physical mechanisms and accounts for recent experiment data. Such a modeling activity is underway; the model development and some preliminary results are described.
The Transportation Team identified the retrievability and subcriticality safety functions to be of primary importance to the transportation of UNF after extended storage and to transportation of high burnup fuel. The tasks performed and described herein address issues related to retrievability and subcriticality; integrity of cladding (embrittled, high burnup cladding, loads applied to cladding during transport), criticality analyses of failed UNF within transport packages, moderator exclusion concepts, stabilization of cladding with canisters for criticality control; and the need for maintaining a detailed inventory of UNF in dry storage as an ongoing activity.
The U.S. Department of Energy’s (DOE) Light Water Reactor Sustainability (LWRS) Program is developing the fundamental scientific basis to understand, predict, and measure changes in materials and systems, structure, and components (SSCs) as they age in environments associated with long-term operations (LTO) of operating commercial nuclear power reactors.
Materials issues are a key concern for the existing nuclear reactor fleet as material degradation can lead to increased maintenance, increased downtown, and increased risk. Extending reactor life to 60 years and beyond will likely increase susceptibility and severity of known forms of degradation. Additionally, new mechanisms of materials degradation are also possible. The purpose of the
This research effort is a part of the Light-Water Reactor Sustainability (LWRS) Program, which is a research and development (R&D) program sponsored by Department of Energy (DOE) and performed in close collaboration with industry R&D programs that provides the technical foundations for licensing and managing the long-term, safe, and economical operation of current nuclear power plants. The LWRS program serves to help the U.S.
The Light Water Reactor Sustainability Program is a research, development, and deployment program sponsored by the U.S. Department of Energy Office of Nuclear Energy. The program is operated in collaboration with the Electric Power Research Institute’s (EPRI’s) research and development efforts in the Long-Term Operations (LTO) Program. The LTO Program is managed as a separate technical program operating in the Plant Technology Department of the EPRI Nuclear Power Sector with the guidance of an industry advisory Integration Committee.
The LWR Sustainability (LWRS) Program activities must support the timeline dictated by utility life extension decisions to demonstrate a lead test rod in a commercial reactor within 10 years. In order to maintain the demanding development schedule that must accompany this aggressive timeline, the LWRS Program focuses on advanced fuel cladding systems that retain standard UO2 fuel pellets for deployment in currently operating LWR power plants.
This report is a guidance document prepared for the benefit of commercial nuclear power plants’ (NPPs) supporting organizations and personnel who are considering or undertaking deployment of mobile technology for the purpose of improving human performance and plant status control (PSC) for field workers in an NPP setting. This document especially is directed at NPP business managers, Electric Power Research Institute, Institute of Nuclear Power Operations, and other non-Information Technology personnel.
Components serving in a nuclear reactor plant must withstand a very harsh environment including extended time at temperature, neutron irradiation, stress, and/or corrosive media. The many modes of degradation are complex and vary depending on location and material. However, understanding and managing materials degradation is a key for the continued safe and reliable operation of nuclear power plants.
The Advanced Instrumentation, Information, and Control (II&C) Systems Technologies pathway of the Light Water Reactor Sustainability(LWRS) Program conducts a vigorous engagement strategy with the U.S. nuclear power industry, including the nuclear operating companies, major support organizations, the Nuclear Regulatory Commission (NRC), and suppliers.
Light water reactor sustainability (LWRS) nondestructive evaluation (NDE) Workshops were held at Oak Ridge National Laboratory (ORNL) during July 30th to August 2nd, 2012. This activity was conducted to help develop the content of the NDE R&D roadmap for the materials aging and degradation (MAaD) pathway of the LWRS program. The workshops focused on identifying NDE R&D needs in four areas: cables, concrete, reactor pressure vessel, and piping.
The purpose of the non-destructive evaluation (NDE) R&D Roadmap for Cables is to support the Materials Aging and Degradation (MAaD) R&D pathway. A workshop was held to gather subject matter experts to develop the NDE R&D Roadmap for Cables. The focus of the workshop was to identify the technical gaps in detecting aging cables and predicting their remaining life expectancy. The workshop was held in Knoxville, Tennessee, on July 30, 2012, at Analysis and Measurement Services Corporation (AMS) headquarters.
The Department of Energy’s (DOE’s) Light Water Reactor Sustainability (LWRS) Program is a five year effort that works to develop the fundamental scientific basis to understand, predict, and measure changes in materials and systems, structure, and components as they age in environments associated with continued long-term operation of existing commercial nuclear power reactors. This year, the Materials Aging and Degradation (MAaD) Pathway of this program has placed emphasis on emerging nondestructive evaluation (NDE) methods that support these objectives.
Several international organizations have made significant progress in the characterization and performance evaluation of other disposal design options and host rock characteristics (clay/shale, granite), most of which were very different from those studied in the U.S. The DOE recognizes that close international collaboration is a beneficial and costeffective strategy for advancing disposal science. This report describes the active collaboration opportunities available to U.S. researchers, and presents specific cooperative research activities that have been recently initiated within DOE’s disposal research program.
This work plan proposes to build a systematic knowledge base for the thermal aging behavior of cast stainless steels (CASSs) within a limited time of five years. The final output of execution of the plan is expected to provide conclusive predictions for the integrity of the CASS components of LWR power plants during the extended service life up to and beyond 60 years.
The document describes the initial work on designing and developing requirements for a total system performance assessment (TSPA) model that can support preliminary safety assessments for a mined geologic repository for high-level waste (HLW) and spent nuclear fuel (SNF) in salt host rock at a generic site. A preliminary generic salt TSPA model for HLW/SNF disposal has been developed and tested for an isothermal repository in salt, for emplaced waste that is assumed to have no decay heat; for salt repositories containing heat-generating HLW/SNF, the present study develops model requirements based on features, events, and processes (FEPs) screening and proposed sensitivity analyses for heat-generating waste. These may better guide the construction of a more representative salt TSPA model.
The study summarizes the initial work on numerical modeling, simulations, and experimental results related to nuclear waste storage in a salt repository. The study reflects the project's preliminary effort at simulating the fluid flow and heat transport processes, before treating the fully coupled thermal-mechanical-hydrologic-chemical (TMHC) coupled processes in the future.
The natural barrier system (NBS) is an integral part of a geologic nuclear waste repository. The report describes progress in development of an integrated modeling framework that can be used for systematically analyzing the performance of a natural barrier system and identifying key factors that control the performance. This framework is designed as an integrated tool for prioritization and programmatic decisions.
This report summarizes research activities on engineered barrier system (EBS) model integration with the generic disposal system model (GDSM), and used fuel degradation and radionuclide mobilization (RM) in support of the EBS evaluation and tool development within the UFD campaign.
This roadmap is intended to advance deep borehole disposal (DBD) from its current conceptual status to potential future deployment as a disposal system for spent nuclear fuel (SNF) and high-level waste (HLW). The objectives of the DBD RD&D roadmap include providing the technical basis for fielding a DBD demonstration project, defining the scientific research activities associated with site characterization and postclosure safety, and defining the engineering demonstration activities associated with deep borehole drilling, completion, and surrogate waste canister emplacement.
Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). Consequently, the ability to better characterize and quantify safety margin holds the key to improved decision making about light water reactor design, operation, and plant life extension. A systematic approach to characterization of safety margins and the subsequent margins management options represents a vital input to the licensee and regulatory analysis and decision making that will be involved.
The Nuclear Power 2010 (NP 2010) Construction and Operating License/Design Certification (COL/DC) Demonstration program together with the financial incentives provided by the Energy Policy Act of 2005 are the two primary reasons why a number of license applications for new nuclear construction are before the NRC today, and why the first new nuclear plants in over 30 years are under construction in the United States.
Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world. Coupled thermal, hydrological, mechanical, and chemical (THMC) processes have a significant impact on the long-term safety of a clay repository. This report documents results from three R&D activities: (1) implementation and validation of constitutive relationships, (2) development of a discrete fracture network (DFN) model for investigating coupled processes in the excavation damaged zone, and (3) development of a THM model for the Full-Scale Emplacement Experiment tests at Mont Terri, Switzerland, for the purpose of model validation. One major goal is to provide a better understanding of the evolution of the excavation damage zone in clay repositories.
While both wet and dry storage have been shown to be safe options for storing UNF, the focus of the program is on dry storage of commercial UNF at reactor or centralized locations. This report focuses on the knowledge gaps concerning extended storage identified in numerous domestic and international investigations and provides the UFDC’s gap description, any alternate gap descriptions, the rankings by the various organizations, evaluation of the priority assignment, and UFDC-recommended action based on the comparison.