Demolition of the Voronezh nuclear power plant.
The Voronezh nuclear power plant (hereinafter referred to as the nuclear power plant) is located in the suburbs of Voronezh. The construction of the nuclear power plant was carried out from 1981 to 1992 and later it was mothballed. The average completion percentage of the facility was 90%.
This object has the most complex structural elements to be dismantled, the thickness of the walls of the object is varied from 0.6 to 3 meters, which are made of heavy concrete grades from M500 to M800, using a connecting reinforcing mesh in several layers of reinforcement with a diameter of 42-48 mm. According to the design documentation developed during the construction of the nuclear power plant, the walls of the containment shell of the reactor compartment ensure complete safety of structural elements in the event of a direct hit from an aircraft, which indicates the highest strength characteristics of this facility.
In January 2020, Rosenergoatom Concern JSC (Rosatom State Corporation) signed an agreement with Volgaspetsstroy LLC for demolition with stages.
The originally developed design included the principle of performing work with diamond wire rope cutting installations with further element-by-element disassembly of reinforced concrete structures using tower cranes. At the same time, according to the initial design documentation, the total labor intensity of the work associated with the presence of construction workers in hazardous areas was more than 1,000,000 man-hours, in connection with which the initial cost of work on the project was 20,566 million USD (approx.).
Volgaspetsstroy LLC was faced with the task of developing the safest and most cost-effective dismantling technology, which was subsequently implemented.
Before the start of the work by Volgaspetsstroy LLC, the dismantling design documentation was completely revised, taking into account the use of new best world technologies and solutions for dismantling and waste management. The work execution process according to the new design documentation included three stages of work execution.
At the first stage of the work, the reinforced concrete structures of the special water treatment building were dismantled. The structure of the building has a structure made of precast-monolithic reinforced concrete in a fixed formwork made of reinforced concrete cell slabs, the maximum construction height is elev. 17.7 meters. The thickness of the main walls and floors of the building is 0.6 meters, individual constructions, such as shafts and wells, have a wall thickness of up to 1.5 meters.
At the second stage of the work, the dismantling of the reactor compartment lining was carried out, with a precast-monolithic reinforced concrete structure in a permanent formwork of reinforced concrete cell slabs and is a square with dimensions in the axes of 63 x 63 meters, symmetrically covering the shell. The maximum height of the building of the reactor compartment is elev. 33.2 meters. The thickness of the main walls and floors is 0.6-0.9 meters.
At the first stage of the work, the reinforced concrete structures of the special water treatment building are dismantled. The structure of the building has a structure made of precast-monolithic reinforced concrete in a fixed formwork made of reinforced concrete cell slabs, the maximum construction height is elev. 17.7 meters. The thickness of the main walls and floors of the building is 0.6 meters, individual structures, such as shafts and wells, have a wall thickness of up to 1.5 meters.
At the second stage of the work, the demolition of the reactor compartment lining is carried out, with a precast-monolithic reinforced concrete structure in a permanent formwork of reinforced concrete cell slabs and is a square with dimensions in the axes of 63 x 63 meters, symmetrically covering the shell. The maximum building height of the reactor compartment is elev. 33.2 meters. The thickness of the main walls and floors is 0.6-0.9 meters.
The third stage of the work includes the dismantling of the main building of the reactor compartment, a structure made of a sealed reinforced concrete shell of a cylindrical shape, installed on a foundation slab with dimensions of 64.2 x 65.0 meters. The shell of the reactor is made of cylindrical monolithic reinforced concrete with a diameter of 33 meters and has an altitude elevation. 54,800 meters. The reinforced concrete structures are completed by a metal dome, the height of the top of the dome is 67.1 meters. The thickness of the walls of the cylindrical shell is 1.6 meters, it has a triple mesh of reinforcement made of reinforcement with a diameter of 42 – 48 mm.
The work execution technology proposed by Volgaspetsstroy LLC made it possible to reduce the cost of the contract by up to 2 times compared to the initial maximum cost of the tender, as well as achieve the following advantages:
(1) the use of manual labor of people in the danger zone has been significantly reduced from 308 workers to 12 workers (from 1,000,000 man-hours according to the initial design to 4,500 man-hours according to the technology of Volgaspetsstroy LLC), which is one of the main achievements on the project, since human safety and health is the most important value in the production of work;
(2) Mandatory processing and recycling of waste into secondary products has been introduced, as a result of which 99.9% of waste will be recycled into a secondary product with zero environmental charges for negative impact on the environment. At the same time, the Customer’s savings will amount to 26,5 million USD (approx.);
(3) The technology of manual dismantling was replaced with a fully mechanized one using unique technology;
(4) The cost of work has been halved from 20,566 million USD up to 10,466 million USD (approx.);
(5) The terms of work have been significantly reduced.
The new technology for demolition works introduced by Volgaspetsstroy LLC largely excludes the use of manual labor and the presence of workers in the dangerous work area. The demolition of reinforced concrete structures is carried out using demolition excavators with attached hydraulic equipment: hydraulic shears and hydraulic hammers. To solve the problem of demolition this object, Volgaspetsstroy LLC used the most modern special equipment and attachments capable of performing the difficult task of demolition the structural elements of this object at high altitudes. The demolition process involved three high-altitude demolition excavators manufactured by Liebherr and Case, with boom lengths up to 34 meters and capable of carrying attachments weighing up to 7.5 tons, while the equipment used has no analogues in Russia. For auxiliary work and demolition at the lower elevations, Komatsu excavators are used in the amount of 6 units at a time. The entire volume of the obtained scrap of reinforced concrete undergoes mandatory sorting using hydraulic magnets, in order to separate the bulk of the metal. In the future, the waste of reinforced concrete, which is maximally cleared of metal, undergoes a crushing process, as a result of which a crushed stone-sand mixture is obtained at the output for reuse in the spheres of industrial, social and road construction.
As a result of the work carried out at the facility:
The first two stages were completed in 8 months, the third stage is underway.
Following the completion of work on demolition the object, secondary resources will be obtained: Metal scrap: 13,539 tons, Concrete scrap: 100,362.5 tons. At the same time, the volume of waste not suitable for recycling will be only 36.5 tons.
