At the Smolensk NPP, the specialists completed all the work within the framework of programmed maintenance and of large-scale modernization of the power unit’s No. 3 equipment. It was performed in order to extend its service life for an additional period of time. Currently, the third power unit is operating at a nominal power level.

Uniqueness and complexity of its maintenance was consisted of a large number of operations on the implementation of modern security systems as well as of large-scale modernization and equipment replacement.

The third power unit life extension means a lot for the Smolensk NPP, - Pavel Lubensky, Director of the Smolensk NPP noted. – Comprehesive modernization significantly improves equipment reliability and security systems of the NPP and it will make it possible to substantiate the possibility of operating the unit for an additional period of time and to ensure further uninterruptible power supply to consumers”.

In the course of repair work that began in May 2018, power unit No. 3 of the Smolensk NPP underwent almost complete renewal and technical re-equipment. A team of professionals consisting of specialists from the Smolensk NPP, assembly organizations, research institutes, design companies of Russia, as well as equipment manufacturers for nuclear power plants performed an enormous amount of work on equipment replacement, on improving special systems and on facility renovation. More than 2 thousand km of cable were laid, more than 2 thousand sets of equipment were installed. At the reactor system, 204 assembly channels and DU-800 valves were replaced.

A large amount of work was done to improve the reliability of the turbines: all low and high pressure cylinders of the turbine №5 were overhauled (as well as high pressure cylinders of the turbine №6), the control of rotors and of a blade row was performed to extend the service life.

Renovation also covered a main control room and a central panel, main circulation pumps, drum separators, pressure manifolds, pipelines and transformers, alarm system, water supply and electricity supply, chemical investigation equipment and dosimetry monitoring equipment. Replacement of the equipment which has developed the resource is made, and it is thousands of valves, units, fittings, mechanisms, electric drives.

As part of the extension of the unit's service life, a comprehensive inspection of the technical condition of the non-replaceable equipment items and an in-depth safety assessment were performed.

The main task of modernization was the commissioning of fundamentally new systems. A multifunctional data-measuring system “Scala-micro” was implemented in conjunction with a per-channel system for controlling the coolant flow. Its implementation significantly increased efficiency of the monitoring technological process and equipment condition; reliability of the visualizing the parameters was also improved.

Reactor CPS was replaced by comprehensive control and safety system which was designed to ensure reactor system’s safety in all modes of operation.

The full-scale automated coolant leak detection system was implemented, the emergency cooling system of the reactor and hydrotesting of repeated forced circulation circuit were upgraded. The ventilation and air conditioning system has been completely updated. One of the unique and large-scale operations was the supply, installation and commissioning of local modern software and hardware complexes for the equipment control and management system. They replaced the previously existing complex of functional-group control and technological protection of reactor compartment and turbine house equipment. The modern software and hardware complex which allows to perform information exchange of data between all local complexes and systems and to transmit the parametric data of equipment’s operating condition both to operators of the main control

room and to field operators at operational workstations of local control panels in real time mode.

It’s worth reminding that the power unit No. 1 and the power unit No. 2 of the operating Smolensk NPP have already been approved for the operating during the extended service life plus another 15 years. Three RBMK‑1000 units are currently in operation at the Smolensk NPP. The station annually produces about 20 billion kWh; this is 13% of the energy produced by all Russian NPPs, or more than 75% of the total amount of electricity produced by the Smolensk energy providers.