This article examines amendments to NP-001-15, General Provisions for Ensuring the Safety of Nuclear Power Plants, which entered into force in 2025, and their impact on requirements for maintainability of building structures. A comparative analysis is provided of the durability of different types of anti-corrosion and fire-protective coatings, including polyurea, epoxy systems, polyurethane compounds, and standard enamels. The economic feasibility of using coatings with a 30-50 year service life to increase the capital class and reduce operating costs is demonstrated. A payback calculation is provided using a deaerator trestle as an example.
Regulatory Changes and Updated Maintainability Requirements
In 2025, Rostechnadzor approved amendments to NP-001-15, General Provisions for Ensuring the Safety of Nuclear Power Plants. The document entered into force on September 29 and introduced changes to the regulatory framework for design, construction, and operation of facilities using nuclear energy (FUNE). The key innovation was stricter requirements for maintainability of NPP buildings and structures as one of the factors affecting safety and assigned service life.
Maintainability in the nuclear industry is defined as the ability of a structure to retain operability during maintenance and repair, taking into account restrictions related to radiation conditions and personnel access. For steel structures with protective coatings, this requirement includes:
• minimum frequency of protective-layer restoration;
• compatibility of repair compounds with the original coating;
• ability to perform repairs within compressed timeframes, during scheduled preventive maintenance outages.
Relationship Between Maintainability and Capital Class
The capital class of an NPP building or structure is determined at the design stage and depends on the calculated service life, operating conditions, and the durability and maintainability of the structures. According to NP-010-16, the operating organization is required to develop a service-life management program for equipment, pipelines, and building structures. When service life is extended, justification of continued operation is required, for example in accordance with RB-167-20, Recommendations for Justifying the Residual Life of Building Structures at Facilities Using Nuclear Energy.
Selecting a coating with a confirmed long service life makes it possible to:
• assign the structure to a higher capital class;
• reduce the number of unscheduled repairs;
• lower maintenance costs over the life cycle.
Economic Consequences of Power-Unit Shutdown
A power-unit shutdown for repair is accompanied by:
1. direct losses from underproduction of electricity, amounting to millions of rubles per hour at current tariffs;
2. costs of reactor cooldown, removal of fuel assemblies, and coolant drainage - procedures that take weeks;
3. additional dose loads on personnel.
For this reason, designers and operating organizations are interested in maximizing the repair interval of all building elements, including protective coatings on steel structures.
Comparative Analysis of Coating Durability
Regulatory Changes and Updated Maintainability Requirements
In 2025, Rostechnadzor approved amendments to NP-001-15, General Provisions for Ensuring the Safety of Nuclear Power Plants. The document entered into force on September 29 and introduced changes to the regulatory framework for design, construction, and operation of facilities using nuclear energy (FUNE). The key innovation was stricter requirements for maintainability of NPP buildings and structures as one of the factors affecting safety and assigned service life.
Maintainability in the nuclear industry is defined as the ability of a structure to retain operability during maintenance and repair, taking into account restrictions related to radiation conditions and personnel access. For steel structures with protective coatings, this requirement includes:
• minimum frequency of protective-layer restoration;
• compatibility of repair compounds with the original coating;
• ability to perform repairs within compressed timeframes, during scheduled preventive maintenance outages.
Relationship Between Maintainability and Capital Class
The capital class of an NPP building or structure is determined at the design stage and depends on the calculated service life, operating conditions, and the durability and maintainability of the structures. According to NP-010-16, the operating organization is required to develop a service-life management program for equipment, pipelines, and building structures. When service life is extended, justification of continued operation is required, for example in accordance with RB-167-20, Recommendations for Justifying the Residual Life of Building Structures at Facilities Using Nuclear Energy.
Selecting a coating with a confirmed long service life makes it possible to:
• assign the structure to a higher capital class;
• reduce the number of unscheduled repairs;
• lower maintenance costs over the life cycle.
Economic Consequences of Power-Unit Shutdown
A power-unit shutdown for repair is accompanied by:
1. direct losses from underproduction of electricity, amounting to millions of rubles per hour at current tariffs;
2. costs of reactor cooldown, removal of fuel assemblies, and coolant drainage - procedures that take weeks;
3. additional dose loads on personnel.
For this reason, designers and operating organizations are interested in maximizing the repair interval of all building elements, including protective coatings on steel structures.
Comparative Analysis of Coating Durability
Strategy for Selecting a Coating with Maintainability in Mind
When choosing a coating type for a specific NPP zone, the following principles are recommended:
Polyurea coatings (50 years) - for zones where repair is extremely difficult or associated with radiation risks, such as spent-fuel pools, deaerator trestles, and rooms with safety-system equipment. They eliminate the need for restoration during the entire life cycle of the unit.
Epoxy coatings (30 years) - for most industrial zones where access for repair is possible within 2-3 scheduled preventive maintenance outages.
Standard enamels (3-5 years) - only for auxiliary and temporary structures that do not affect safety.
Economic-Efficiency Calculation (Using a Deaerator Trestle as an Example)
Initial data: deaerator-trestle zone, steel-structure area - 2000 m², operating conditions - high humidity and limited access for repair.
When choosing a coating type for a specific NPP zone, the following principles are recommended:
Polyurea coatings (50 years) - for zones where repair is extremely difficult or associated with radiation risks, such as spent-fuel pools, deaerator trestles, and rooms with safety-system equipment. They eliminate the need for restoration during the entire life cycle of the unit.
Epoxy coatings (30 years) - for most industrial zones where access for repair is possible within 2-3 scheduled preventive maintenance outages.
Standard enamels (3-5 years) - only for auxiliary and temporary structures that do not affect safety.
Economic-Efficiency Calculation (Using a Deaerator Trestle as an Example)
Initial data: deaerator-trestle zone, steel-structure area - 2000 m², operating conditions - high humidity and limited access for repair.
Additional advantages of the polyurea coating:
• no need to stop equipment for inter-repair restoration;
• possibility of local touch-up without taking the structure out of service;
• reduction of dose loads on maintenance personnel.
Conclusions
The introduction of amendments to NP-001-15 increases the importance of maintainability of building structures when justifying the capital class of NPP buildings. The use of coatings with a 30-50 year service life, such as polyurea and modern epoxy systems, makes it possible to:
• increase the capital class without changing load-bearing structures;
• reduce life-cycle operating costs by 60-70%;
• minimize the risks of unscheduled power-unit shutdowns.
Investments in durable protective coatings should be considered not as an expense item, but as a means of ensuring continuous safe operation and reducing total cost of ownership.
To obtain a commercial proposal for applying polyurea, epoxy, and other durable coatings at facilities using nuclear energy, send a technical specification indicating the structure area, required protection class, and operating conditions to the commercial department of TechAtomStroy LLC through the feedback form on the website. Based on the submitted data, a cost estimate, construction-and-installation work schedule, and feasibility study for selecting the coating type will be prepared.
• no need to stop equipment for inter-repair restoration;
• possibility of local touch-up without taking the structure out of service;
• reduction of dose loads on maintenance personnel.
Conclusions
The introduction of amendments to NP-001-15 increases the importance of maintainability of building structures when justifying the capital class of NPP buildings. The use of coatings with a 30-50 year service life, such as polyurea and modern epoxy systems, makes it possible to:
• increase the capital class without changing load-bearing structures;
• reduce life-cycle operating costs by 60-70%;
• minimize the risks of unscheduled power-unit shutdowns.
Investments in durable protective coatings should be considered not as an expense item, but as a means of ensuring continuous safe operation and reducing total cost of ownership.
To obtain a commercial proposal for applying polyurea, epoxy, and other durable coatings at facilities using nuclear energy, send a technical specification indicating the structure area, required protection class, and operating conditions to the commercial department of TechAtomStroy LLC through the feedback form on the website. Based on the submitted data, a cost estimate, construction-and-installation work schedule, and feasibility study for selecting the coating type will be prepared.