Plant life management for safe long-term operation

Once nuclear power plants have reached the end of their nominal licensed operating life, they must undergo special safety reviews and ageing assessments of their essential structures, systems and components to validate or renew their license to operate for terms beyond the service period originally intended.   Some countries have given a high priority to extend the designed lifetime of their reactors from 40 years to 60 or 80 years.

Plant life management programme (PLiM)

The safety considerations of a nuclear power plant are paramount. Those safety requirements have to be met to extend or renew an operating license. To achieve the goal of the long term safe, economic and reliable operation of a nuclear power plant, a Plant Life Management, or PLiM programme is essential. Its objective is to identify all of the factors and requirements for the overall life cycle of the plant.

PLiM programmes for long-term operation are in place in many countries. They integrate ageing and economic planning to maintain a high level of safety and optimize plant performance by dealing successfully with extended life ageing issues, maintenance prioritization, periodic safety reviews, and education and training.

PLiM is particularly useful in helping plant owners make an informed decision on continuing to operate their plants longer than their originally assumed design life.

In the PLiM process, nuclear power plants integrate the operations, maintenance, and engineering, regulatory, environmental and economic planning activities so they can manage the material condition of a plant, optimize plant operating life, and maximize plant value while maintaining plant safety.

Benefits of PLiM

A PLiM process can be applied to identify components that are critical to plant safety and power generation. Ageing degradation mechanisms that can lead to an unexpected or unplanned functional failure can be determined.

PLiM provides opportunities for value creation by considering the effects of alternative operation and maintenance practices and provide financially optimized, long-term ageing management plans.

PLiM can also be used to optimize reliability, availability, capacity factors, cost of operation and maintenance, capital cost and staffing; and integrate these to achieve the lowest cost for electricity while maintaining safe operation during the life time of the plant.

Recognizing the importance of ageing management for nuclear power plants, the IAEA develops guidelines to improve PLiM programmes for long term operation and delivers training, technical assistance and expert mission to Member States. Individual projects deal with different aspects of nuclear power plant life management, with the aim to increase the capabilities of interested Member States in implementing and maintaining competitive and sustainable nuclear power.