Optimizing the Schedule for Anti-Corrosion Treatment of Steel Structures at Safety Class 2 Facilities: Practical Recommendations

Abstract. This article presents experience in using high-build polymer compounds for anti-corrosion protection of NPP steel structures. It examines technological solutions that reduced the duration of work by 20% while maintaining compliance with NP-041-22 requirements. The material is intended for specialists involved in construction and reconstruction at facilities using nuclear energy.



Relevance of the Problem

Corrosion damage to steel structures at facilities using nuclear energy (FUNE) is a significant factor that reduces reliability and safety. Maintaining the integrity of load-bearing and enclosing structures requires the timely and high-quality application of protective coatings. The traditional technology, which involves sequential application of a primer and several finish coats with process pauses for polymerization, creates bottlenecks and risks disrupting adjacent works under tight construction schedules.



During work at one safety class 2 facility, the general contractor faced a time constraint in which the classic 'primer + 2-3 enamel coats' scheme did not provide the required productivity. A technical solution was needed to reduce the duration of anti-corrosion treatment of NPP steel structures without lowering the protection class or coating durability.



Selection of a Technological Alternative

Specialists of TechAtomStroy proposed and implemented the replacement of traditional paint-and-varnish materials with high-build polymer compounds and high-solids epoxy enamels. The key technical differences of the approach used were as follows:

The high viscosity and adhesion of the material make it possible to form a monolithic coating in a single cycle, eliminating the need for a multilayer structure. An additional advantage is improved maintainability and resistance to radiation exposure, which is critical for controlled access zones and rooms containing safety-system equipment.



Organization of the Production Process

The entire technological process was adapted to the requirements applicable to work at nuclear power facilities and included the following stages.



1. Surface Preparation

Abrasive blasting was carried out to Sa 2.5 according to ISO 8501-1 (complete removal of contaminants and a visually clean metal surface). The roughness profile was measured. For safety class 2 steel structures, this level of cleaning is mandatory in accordance with NP-041-22 requirements.



2. Priming

A high-build zinc-rich primer was used, providing both barrier and electrochemical protection. The material was applied by airless spraying.



3. Application of the Finish Coating

The finish layer was formed in one pass to a thickness of 600 microns. Thickness control was performed by visual and magnetometric methods on every square meter of the surface.



4. Quality Control

Adhesion tests (cross-cut method) and porosity checks using a spark holiday detector were performed. The results were recorded in non-destructive testing reports, which are mandatory documents for acceptance of the work by Rostechnadzor.



Achieved Results

The use of high-build polymer compounds at the safety class 2 facility produced the following quantitative results:



• The total duration of anti-corrosion treatment was reduced by 20% by decreasing the number of layers and eliminating intercoat downtime.

• Labor requirements for painting personnel and auxiliary operations were reduced (covering adjacent zones, installation and dismantling of scaffolding).

• The handover of the work front to adjacent divisions was accelerated, which helped maintain the general contractor's schedule.



Conclusions and Recommendations

Based on the implemented project, TechAtomStroy recommends that general contractors and subcontractors performing anti-corrosion treatment of NPP steel structures consider high-build polymer compounds as an effective tool for optimizing construction production. This technology not only reduces calendar time but also provides the required level of coating reliability and durability when NP-041-22 regulatory requirements are observed.



To obtain a detailed assessment of the applicability of this technology at your facility, including analysis of the specification and calculation of projected savings in time and labor, send a request to the technical department of TechAtomStroy through the feedback form on the website.



*This material is advisory in nature and is based on practical experience in performing work at safety class 2 facilities.