NUCLEAR SERVICES
Ageing under control
OCTOBER 1, 2024
Alberto Cordero Aneas
Ageing Management Engineer and Consultant | LinkedIn
Have you ever wondered how a nuclear power plant ages?
Beyond merely generating electricity, these structures represent a technological heart that requires constant care. Much like a vehicle’s inspection, nuclear power plants rely on technical inspections and meticulous maintenance programs to ensure safe operation over time, introducing the concept of Nuclear Power Plant Life Management.
Ageing Management Plan (AM Plan) for nuclear power plants refers to the set of strategies and activities designed to maintain the optimal conditions of the structures, systems, and components (SCCs) of a NPP. The main objective is to ensure these elements can perform their functions safely throughout the plant’s operational life.
The regulation governing the Life Management of nuclear power plants in Spain is the Securuty Instruction IS-22 of the Consejo de Seguridad Nuclear (CSN). This instruction sets the criteria for aging management of NPP components, including long-term operation. The scope and content of the AM Plan will, at a minimum, follow the methodology of the U.S. regulation 10 CFR 54 “Requirements for Renewal of Operating Licenses for Nuclear Power Plants” and its associated documents developed by the U.S. Nuclear Regulatory Commission (NRC), known respectively as the “Standard Review Plan for Review License Renewal Applications for Nuclear Power Plants” (NUREG-1800), “Generic Aging Lessons Learned (GALL) Report” (NUREG-1801), and the American Nuclear Energy Institute (NEI) Guide No. 95-10.
License Renewal and Long-Term Operation
In Spain, for a nuclear power plant to continue operating beyond its 40-year design life, it is crucial to meet the license renewal requirements set by the CSN. This includes submitting the following at least 3 years before the expiration of the plant’s operating license:
- Integrated Aging Assessment and Management Plan (PIEGE): A document encompassing the activities of the PLiM.
- Supplement Proposal for the Safety Study:Including studies and analyses that justify the aging management of the plant’s SSCs during the long-term operation (LTO) period.
- Technical Specifications Revision Proposal: Including necessary changes to maintain safe operating conditions during LTO.
- Radiological Impact Study.
- Radioactive Waste Management Plan Revision Proposal.
Aging Management Programs
Aging Management Programs (AMPs) are maintenance programs based on international operational experiences, needed for an effective life management. They include identifying aging mechanisms such as cracking and corrosion, continuous monitoring, and technical evaluations to detect signs of deterioration, and implementing corrective measures to maintain operational safety. Moreover, these maintenance programs are “living” entities, subject to periodic updates based on internal and external operational experiences from nuclear power plants.
Implementation Reports and Measuring Effectiveness
To ensure the effective implementation and success of AMPs, it is crucial to prepare detailed reports that periodically collect the results of inspections carried out on the SSCs within the program’s scope. These reports should identify any signs of degradation, compliance with inspection frequencies, corrective actions taken to mitigate or repair possible degradation, related internal and external operational experiences, and any modifications to the AMP during the evaluated period. From the conclusions of these implementation reports, it is possible to obtain the necessary information to assess and quantify the effectiveness of an AMP. This evaluation is conducted using performance indicators, created from a common methodology but adapted specifically to each plant.
Based on the results of these reports, along with the evaluation of an AMP’s effectiveness over a specific period, it is possible to feed back into the maintenance programs, determining the improvements and updates required, always maintaining them always keeping them “alive”.
In Spain, plants such as Almaraz, Trillo, Ascó, Cofrentes, and Vandellós II are actively managing their operation beyond their 40-year design life. This achievement is a testament to the success of Nuclear Power Plant Life Management, which, through the rigorous implementation of aging management programs and compliance with CSN regulations, can continue operating safely beyond their original design life. Moreover, this milestone not only underscores the importance of life management in the nuclear sector but also highlights the coordinated approach between operators and regulators, playing a fundamental role in nuclear technology.