Construction and Installation Works at NPPs: From Dismantling to Commissioning - A Full Range of Services

This article analyzes the key aspects of performing construction and installation works at facilities using nuclear energy. It reviews the regulatory framework, including NP-041-22 and STO NOSTROY industry standards, as well as requirements for the organization of combined works, maintenance of as-built documentation, and construction supervision by Rostechnadzor. Typical violations identified during inspections are presented together with recommendations for preventing them. The material is based on practical experience in implementing projects at NPP sites.



Construction and installation works at nuclear power plants and other facilities using nuclear energy differ fundamentally from general industrial construction. In addition to standard quality and schedule requirements, a multi-level regulatory system applies here, aimed at ensuring nuclear and radiation safety at all stages - from site preparation to commissioning.



For general contractors and subcontractors specializing in construction and installation works in the nuclear industry, it is critically important to understand the procedure for developing work execution plans (PPR), the rules for carrying out combined construction and installation works at NPPs, the requirements for as-built documentation, and Rostechnadzor construction supervision procedures.



Regulatory Framework for Construction and Installation Works at NPPs

The construction of nuclear power plants is regulated by a set of federal rules and regulations (FNP), industry standards, and technical recommendations. The fundamental document for building structures is NP-041-22, "Safety Requirements for Building Structures of Nuclear Power Plant Buildings and Facilities", which establishes requirements for categorizing structures according to their level of responsibility for radiation and nuclear safety.



With regard to the actual execution of works, the key documents are:



• STO 95 12009-2017, "Facilities Using Nuclear Energy. Construction of Nuclear Power Plants. Rules for Conducting Combined Construction and Installation Works" - regulates the procedure for work performed by several organizations simultaneously on one construction site or in one room during NPP construction.

• STO 95 12008-2017, "Facilities Using Nuclear Energy. Construction of Nuclear Power Plants. Requirements for Handling As-Built Documentation" - establishes unified rules for preparing, transferring, and storing as-built documentation.

• STO NOSTROY 2.23.83-2012, "Facilities Using Nuclear Energy. Installation of Process Pipelines at NPPs" - defines the sequence and scope of work for installing pipeline systems for VVER reactors.

• STO 95 104-2015, "Facilities Using Nuclear Energy. Development of Work Execution Plans. General Requirements" - establishes requirements for the content, development procedure, approval, and endorsement of PPRs for construction and installation works during new construction of facilities using nuclear energy.



Organization of Combined Construction and Installation Works at an NPP Site

The specifics of power-unit construction involve a large volume of combined works, where civil construction operations and installation of thermal-mechanical equipment (TME) are performed simultaneously at the same facility. The regulations distinguish between two main modes:



• "Clean" installation - performed in rooms where construction works have been completed, final finishing has been carried out, and bases have been prepared.

• Combined installation - performed while construction works are still ongoing, which requires enhanced coordination between contractors and additional safety control measures.



Practice shows that the key success factors in organizing combined construction and installation works at facilities using nuclear energy are:



1. A time-scaled network schedule with critical paths agreed upon by all participants.

2. A system of access permits and work permits for operations in confined conditions.

3. Operational quality control at each stage with the execution of inspection certificates for concealed works.

4. Geodetic support for the installation of equipment and structures.



Construction Control and Supervision: Requirements and Typical Violations

Construction control during construction and installation works at NPPs is carried out both by contractor organizations (incoming, operational, and acceptance control) and by Rostechnadzor as part of federal state construction supervision.



During inspections, Rostechnadzor assesses:



• The availability of certificates permitting work that affects the safety of capital construction facilities.

• The adequacy of the qualifications of personnel performing construction, installation, and commissioning works.

• The developer's quality assurance system (QAS) and quality assurance programs (QAP).

• Compliance of the performed works with the requirements of design documentation, technical regulations, and industry standards.



According to Rostechnadzor official reports, the most frequent violations related to nuclear power plants are:

The most typical causes of these violations are insufficient control by management and weak discipline in complying with QAP requirements at the execution level.



Specifics of Dismantling and Repair Works at Facilities Using Nuclear Energy

In addition to new construction, a significant volume of construction and installation works at facilities using nuclear energy relates to reconstruction, major repairs, and repurposing of existing buildings. Dismantling works at such facilities are regulated by SP 325.1325800.2017, "Buildings and Structures. Rules for Carrying Out Dismantling and Disposal Works", as well as by internal regulations.



Key features of dismantling works at such facilities include:



• Mandatory preliminary radiation survey of the structures to be dismantled.

• Availability of a demolition work organization plan (PORS) approved by the operating organization.

• Special requirements for handling radioactive waste (RW) generated during the work.

• Enhanced control of dust suppression and prevention of contamination spread.



Conclusions and Recommendations

Comprehensive execution of construction and installation works at NPPs requires not only technical competence from the contractor, but also deep immersion in the industry regulatory framework. The key conditions for successful project implementation are:



1. Development and approval of PPRs in accordance with STO 95 104-2015.

2. Strict compliance with NP-041-22 requirements for building structures of various safety classes.

3. Maintaining as-built documentation in accordance with STO 95 12008-2017.

4. Coordination of combined works according to the rules of STO 95 12009-2017.

5. Implementation of quality assurance programs (QAP) at all stages - from incoming inspection of materials to acceptance of completed facilities.



To request a commercial proposal for construction and installation works, dismantling, reconstruction, or major repairs at facilities using nuclear energy, please send technical specifications indicating the scope of work, the safety class of the structures, and the required deadlines to the commercial department of TechAtomStroy LLC via the feedback form on the website. Based on the data provided, a cost estimate and schedule for construction, installation, and commissioning works will be prepared.



*Prepared on the basis of NP-041-22, STO 95 12009-2017, STO 95 104-2015, NP-001-15, and official lists of typical violations published by Rostechnadzor.*