License Renewal and Long-Term Operation (LTO) of Nuclear Power Plants

U.S. License Renewal Process

The U.S. approach to license renewal is heavily regulated, with the Nuclear Regulatory Commission (NRC) overseeing the process. Nuclear plant operators must submit a comprehensive renewal application, which includes detailed technical and safety analyses. The NRC evaluates this application to ensure the plant’s critical systems continue operating safely.

The NRC does not impose a strict limit on the number of license renewals. Plants initially designed for a 40-year lifespan may be approved to operate for 60 or even 80 years, provided they meet safety requirements. Several U.S. nuclear plants are currently pursuing extensions to operate for up to 80 years, demonstrating the feasibility of long-term operation under strict regulatory supervision.

European Approach to Nuclear Plant Life Extension

In most European countries, the process for extending nuclear plant operations differs. Instead of formal license renewals, plants undergo periodic safety reviews every 10 years. These reviews ensure compliance with safety requirements and include evaluations of safety functions, radiological protection and the integration of technological advancements. The framework for these reviews is outlined in international publications, such as the International Atomic Energy Agency (IAEA) Standards for Safety of Nuclear Power Plants: Design (SSR-2/1, Rev. 1).

Although European plants were originally not expected to operate beyond their projected lifespan, changing energy policies driven by carbon reduction goals and energy security have sparked interest in extending plant operations. Unlike in the United States, no formal license renewal process exists. Instead, safety reviews after a certain plant age would be augmented to address long-term operational issues. However, guidelines for these assessments are still under development.

Importance of Strategic and Technical Planning in the LTO Process

High-level strategic and technical planning is necessary to navigate the significant physical modifications and testing required for the LTO process and ensure a successful project. A high-level strategic and implementation plan for LTO requires developing an overall strategy for life extension, which may include feasibility studies, aging management plans and initial safety assessments. Moreover, the technical work plan outlines the tasks required to implement the LTO, including safety analyses, component upgrades, engineering design and quality assurance protocols.

Long-term operation or life extension of nuclear plants requires thorough planning and execution. Below is an overview of the key activities involved in this complex process.

1. Pre-Assessment and Feasibility Study. The LTO process begins with an initial assessment of the plant’s condition and systems, including a feasibility study. This study evaluates whether extending the plant's operational life is technically and economically viable while also considering public acceptance and lessons from other facilities.
2. Aging Management Program. Developing an aging management program or improving the current program is a core component of the LTO process. This involves monitoring and assessing the impact of aging on key plant components, such as reactor pressure vessels, pipes, electrical systems and concrete structures.
3. Safety Analysis and Risk Assessments. Rigorous safety analyses ensure that the plant can continue to operate safely throughout its extended life. These assessments account for aging impacts and potential hazards, focusing on risk mitigation strategies.
4. Component Replacement and Upgrades. Components that have reached the end of their design life are replaced or refurbished. Systems critical to safety are upgraded, and cost-benefit analyses help prioritize the replacement of aging components.
5. Engineering Design and Modifications. Detailed engineering designs are developed for system modifications or replacements. These designs must meet current safety standards and regulatory requirements to ensure ongoing compliance.
6. Quality Assurance and Testing. Quality assurance protocols and stringent testing procedures are applied to ensure new components and systems perform as expected. This phase ensures reliability and safety during extended operations.
7. Continuous Monitoring and Evaluation. After the LTO is granted, continuous monitoring and aging management programs remain in place to track component performance and ensure operational safety.
8. Lessons Learned and Continuous Improvement. Best practices and lessons learned from other LTO projects are applied to improve future operations and optimize plant performance during the extended life phase.

Extending the Life of Nuclear Facilities

As global energy policies evolve, interest in extending the operational life of nuclear power plants has gained momentum. Whether through formal license renewals, as seen in the United States, or periodic safety reviews in Europe, utilities and regulatory bodies must prioritize safety, aging management, and technological advancement in nuclear plants.