2017 Research Portfolio


Program 41.10.01 - Long Term Operations Program

Last Updated: 05-Apr-2017
Road Maps

EPRI has developed the following roadmaps to guide research in key technical areas. These roadmaps provide a communication tool for determining what success looks like, identifying research tasks necessary to meet goals, and clarifying roles for all stakeholders.

Program Description

Nuclear power plants around the world are an important source of non-carbon emitting generation. Even when major plant components must be replaced or upgraded to extend operating life, these plants often represent a cost-effective, low-carbon asset. The decision to extend nuclear plant life involves a host of interrelated technical, economic, regulatory, and public policy issues. Unknown or uncertain technical inputs impact the decision-making process both directly and indirectly: directly, through design and operational contingencies; and indirectly, through impacts on regulatory actions and public policy.

Recognizing the many technical challenges confronting extended nuclear plant operations, the Long-Term Operations Program is conducting an array of research and development (R&D) activities to ensure that the public, nuclear plant owners, regulatory agencies, and all interested stakeholders have the information needed to make sound decisions regarding the ability of a nuclear plant to sustain safe, reliable, and economic operations.

Research Value

The Long-Term Operations (LTO) Program is developing the technical information on which to base decisions regarding extended nuclear plant life. Research results will not only inform those plant owners considering life extension past 30, 40, or 60 years, but also those with relatively younger plants considering the long-term impacts of aging. Participants in the LTO program gain access to technical solutions and information to support the following needs:

  • Identifying key technical barriers that may be life limiting

  • Investigating cost-effective modernization opportunities

  • Informing potential regulatory issues

  • Informing business case decisions for extended operations

  • Defining the technical basis for aging management programs that can support safe, long-term operations

Research conducted through the LTO Program provides the public, nuclear plant owners, regulatory agencies, and other interested stakeholders with the information needed to make sound decisions regarding the ability of a nuclear plant to sustain safe, reliability, economic operations.


The factors driving interest in long-term nuclear plant operations correspond to specific challenges where technical insight can effectively inform decision making. Although these challenges touch different aspects related to long-term operations – from the physical condition of the plant to the allocation of capital budgets for plant refurbishment – they all require focused R&D to ensure that technical constraints and opportunities are fully understood. The LTO Program is designed to address these constraints and opportunities.

The program accomplishes its objectives through an integrated strategy that involves research defined by the Electric Power Research Institute (EPRI), collaboration on complementary research activities with the Department of Energy's (DOE) Light Water Reactor Sustainability (LWRS) Program, and engagement with other global entities such as the Materials Aging Institute, the International Atomic Energy Agency (IAEA), CANDU Owners’ Group (COG), and Japan’s Central Research Institute for the Electric Power Industry (CRIEPI).

The activities conducted through the LTO Program are identified in association with nuclear plant owners, regulators, and other key stakeholders. The project also builds on the technical experience and expertise accumulated through EPRI leadership in the U.S. license renewal effort in the 1990s and early 2000s.

Research activities are focused in six technical areas:

  • Primary system metals material aging, including the reactor pressure vessel

  • Concrete and containment aging

  • Risk and safety analysis methods

  • Instrumentation and control and information technology

  • Electrical cable aging

  • Aging management programs, plant demonstrations and pilot projects.


EPRI's LTO Program is a large research effort with broad collaboration across EPRI technical program areas and EPRI’s research partners. Key recent results include:

  • Maintenance and updates to a prioritized Long-Term Operation Issue Tracking Table. This table is the basis for collaborative R&D programs between the DOE, NRC Research, international research organizations, and EPRI. The Issue Tracking Table is updated annually to reflect the current state of knowledge, and to ensure that the right research is being done at the right time to support LTO decisions.

  • Participation in the IAEA International Generic Aging Lessons Learned (IGALL) project. EPRI completed a cross-reference assessment of the aging management programs in the IGALL and in EPRI reports to support global implementation of the IGALL; this assessment was posted to the IAEA IGALL website.

  • Worked with DOE LWRS Program to develop a robust database defining the effects of radiation exposure on concrete mechanical properties and initiated a finite element analysis modeling project to quantify the margins of safety for the limiting biological shield wall configuration with up to 80 years of radiation exposure.

  • Collaborated with DOE and NRC Research to develop an integrated roadmap of cable R&D projects to inform long-term operations and determine cable remaining useful life. Recent activities focused on harvesting field aged cables, testing methods for submerged cables, pursuing advances for condition monitoring technology, and synergistic testing of cables in a high-temperature radiation environment.

  • Published a research report on screening and testing for reactive concrete aggregates; these results can be used to support decisions regarding aging management of concrete structures susceptible to degradation due to environmental conditions.

  • Collaborated with DOE to design and install a hot cell at Oak Ridge National Laboratory, which will be used to demonstrate hybrid laser and friction stir welding processes as repair options for highly irradiated materials. Such technologies could be used for repairing reactor vessel internals.

  • Supported technical meetings with the NRC, Advisory Committee on Reactors Safeguards (ACRS), and NRC Commissioners on EPRI work regarding the technical basis for aging management. Two lead plants in the United States, one PWR and BWR, have expressed their intent to submit a second license renewal (SLR) application to the NRC in the 2018 to 2019 timeframe. 

Key Activities

Long-Term Operations research for 2017 will focus on the following:

  • Work with the Boiling Water Reactor Vessel and Internals Project (BWRVIP) to develop a strategy for implementing a surveillance capsule program for monitoring vessel fluence impacts out to 80 years of operation.

  • Work with BWRVIP and the Materials Reliability Program (MRP) to update and revise EPRI reports needed to inform the technical basis for second license renewal in the United States, and extended operations around the world. High-priority technical reports cover vessel internals, cast stainless materials, and nickel-based alloys inspections.

  • Analyze temperature and radiation data collected from a PWR and BWR to assess and adjust actual temperature and radiation data for cable systems in operating plants.  This data will be used to inform remaining useful life (RUL) qualifications.

  • Work with DOE and NRC Research to harvest cables from shutdown plants to assess field aged cable conditions and perform accelerated aging tests.

  • Publish technical reports providing the technical basis to inspect, monitor and evaluate civil structures with potentially reactive aggregates.

  • Continue R&D efforts on characterization, modeling, and mitigation of intergranular stress corrosion cracking in nickel alloys and irradiation-assisted stress corrosion cracking in stainless steel.

  • Support global efforts through IAEA to revise the IGALL document with additional operating experience and lessons learned on best practices for aging management.

  • Demonstrate the hybrid laser and friction stir advanced welding techniques on irradiated samples in a hot cell at the Oak Ridge National Laboratory.

  • Work with DOE LWRS program to support an integrated control modernization project at a host plant. 

Selected reports and products may be prepared in whole or in part in accordance with the EPRI Quality Program Manual that fulfills the requirements of 10CFR50 Appendix B and 10CFR21. The QA status of reports and products will be marked and identified.

Program Manager
Sherry Bernhoft, 704-595-2740, sbernhoft@epri.com