Lifetime of nuclear power plants – how long

Nuclear power plants are like Wegner chairs: with moderate maintenance, their reliability lasts not just a few decades, but generations. Most nuclear power plants today can last up to 80 years and even longer. They are updated and serviced continuously, and do not age like humans. If we build a nuclear power plant today, our grandchildren or maybe even great-grandchildren can still cook at home from the energy it creates.

The design life of the reactors was initially 40 years, a figure somewhat taken out of thin air. Today we have become much smarter. The United Nations Economic Commission for Europe (UNECE) [1] writes about life expectancy:

UNECE
Nuclear power plants were originally approved for between 30 and 40 years of operation, but there is no fixed technical limit for a plant’s operating life.

US Department of Energy finds the operation of nuclear power plants can be extended to 80 years or more [2].

Lifetime extension process #

Technical assessment and planning #

The condition of the reactor’s, design, construction, components, materials, safety functions are carefully reviewed by a comprehensive safety assessment to identify any weaknesses or potential challenges in terms of extending the lifetime. This include aging of materials, corrosion, wear, potential malfunctions or the need to meet updated safety standards and regulatory requirements and developing a plan to address them.

Repair and replacement #

Based on the evaluation, any necessary upgrades or repairs are identified. Weaknesses or defective components identified during the inspection are repaired or replaced as necessary. Repair may include welding, surface treatment, or other techniques to restore component functionality and integrity. If components cannot be effectively repaired, they are replaced with new or upgraded components to improve reactor performance and lifetime.

Over time, neutron irradiation from the reactor core causes the metal in the reactor vessel to become brittle. But this can be restored with a recognized process called annealing by which a material is heated and then slowly cooled to reduce internal stresses and improve its structural properties [3].

Annealing can be applied to various components of nuclear power plants, including reactor tanks, pipelines and pressure vessels.

Upgrading control systems #

This includes upgrading control systems, modernizing security systems, implementing advanced technology, improving monitoring and diagnostics, and testing and validating the upgrades. The aim is to improve the reactor’s performance, safety and efficiency through the modernization and implementation of advanced systems and technologies.

The economics of life extension #

Life extension of nuclear power plants is often considered one of the cheapest methods to increase the overall life and utilization of an existing nuclear power plant. The IEA’s Projected Cost of Generating Electricity finds it cheaper to extend the life of nuclear power plants than to build both new nuclead and renewable energy [4].

LTO means operating beyond their original license period or expected operating period. It enables nuclear power to generate reliable, cheap and low-emission electricity for many years longer than originally envisaged, thereby maximizing their value.

There are several reasons for this. An existing nuclear power plant already has the necessary infrastructure and licenses in place and the staff at the plant already have considerable experience and expertise in operating the reactor. Thus, it cannot be economically justified to shut down nuclear power plants prematurely, as a number of countries in the world have done.

Since the costs of nuclear power are front-loaded, a mere twenty-year extension means the LCOE of nuclear drops 50 percent.

Extension of nuclear in the world #

Of the US nuclear power plants, about 90% have had their operating licenses extended, extending operations to 60 years. A subsequent renewal can boost the process to 80 years [5].

In 2021, the Nuclear Regulatory Commission (NRC) approved a second twenty-year extension for the Surry plant in Virginia built in 1972. It will now be able to operate until 2052—a lifetime of 80 years [6].

And the NRC is now preparing to authorize nuclear plants for up to 100 years [7].