Nuclear
Garry Young
Garry Young
·Posted in Nuclear
Wed, May 20
EPRI

Good Practices and Lessons Learned from the Long‑Term Operation of Nuclear Power Plants (IAEA TECDOC‑2117) and EPRI’s Role

Enabling Safe, Cost‑Effective Long‑Term Operation of the Global Nuclear Fleet

Challenge

The pursuit of carbon reduction goals and energy security while maintaining grid reliability and affordability has become a strategic imperative for countries around the world. More than two‑thirds of the world’s 400+ operating nuclear power reactors are now over 30 years old, and nearly 200 reactors worldwide have already been authorized for long-term operation. Extending the operating lives of existing nuclear plants—known as Long‑Term Operation (LTO)— is one of the fastest, most cost‑effective ways to deliver large‑scale, carbon‑free electricity.

Achieving LTO requires addressing complex technical challenges related to materials degradation, aging management, regulatory compliance, and asset investment decisions, all while maintaining the highest safety standards. The International Atomic Energy Agency (IAEA) TECDOC‑2117, Good Practices and Lessons Learned from the Long‑Term Operation of Nuclear Power Plants (2026), documents how utilities worldwide have successfully extended nuclear plant lifetimes by combining rigorous safety reviews with proactive modernization and aging management.

EPRI’s Role

EPRI has played a foundational role in advancing the technical basis for LTO through practical science‑based aging management, materials research, and long‑term asset management methodologies.

EPRI-developed frameworks—including Materials Degradation Matrices (MDMs), Issue Management Tables (IMTs), and long‑term asset management approaches—are referenced throughout IAEA TECDOC-2117 in the context of global best practices for identifying aging mechanisms, prioritizing mitigation strategies, and supporting risk‑informed decision‑making for extended operation.

What Was Achieved

IAEA TECDOC‑2117 documents common success factors across regions and reactor technologies, that have emerged which closely align with EPRI research and guidance:

  • Predictive understanding of materials degradation, enabling early identification and mitigation of life‑limiting issues in reactor vessels, internals, steam generators, cables, and concrete structures.

  • Systematic aging management programs (AMPs) integrated into plant operations, inspections, and maintenance planning.

  • Risk‑informed modernization strategies, including selective component replacement, digital upgrades, and targeted refurbishment.

  • Long‑term capital planning tools that support economically optimized investment decisions over 60‑ to 80‑year operating horizons.

The report highlights that plants applying these approaches have demonstrated safe operation beyond original design life while maintaining high capacity factors and strong safety performance.

Value to the Industry

The practices summarized in TECDOC‑2117 reinforce the value of EPRI’s collaborative research model for nuclear plant owners, operators, and regulators:

  • Safety Assurance – Science‑based aging evaluations support continued compliance with evolving regulatory expectations.

  • Cost Control – Risk‑informed asset management enables smarter capital allocation and avoids unnecessary replacements.

  • Operational Reliability – Proactive degradation management reduces unplanned outages and long‑term operational risk.

  • Global Alignment – Shared methodologies help harmonize LTO practices across countries, reactor types, and regulatory regimes.

Global Impact

The TECDOC draws on case studies from North and South America, Europe, Asia, and beyond, covering pressurized water reactors, boiling water reactors, CANDU, and VVER designs. EPRI research is cited in connection with international initiatives such as aging lessons‑learned programs, materials research collaborations, and long‑term operation peer reviews. These efforts help ensure that insights gained in one fleet benefit the entire global nuclear community.

Looking Ahead

As the industry moves toward LTO beyond 60 years—and in some cases toward 80 years and beyond—the challenges of material degradation, knowledge retention, and modernization will intensify. TECDOC‑2117 concludes that continued international collaboration and applied research will be essential.

  • EPRI remains uniquely positioned to support this next phase of long‑term operation through:

  • Advanced materials research for high‑fluence and late‑life conditions

  • Enhanced inspection, monitoring, and data integration technologies

  • Risk‑informed, fleet‑wide asset management tools

  • Knowledge transfer to support workforce continuity

Why It Matters

By translating decades of operating experience into practical, science‑based guidance, EPRI is helping utilities worldwide operate safely, reliably, and economically—today and for decades to come.

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