A nuclear plant required a reduction in temperature of its water supply, which was causing limitations in its output. Five pumps from Termomeccanica were chosen to handle the cooling process and this enabled a significant increase in power production.
In December 2016, as part of its nuclear power plants modernization project, the Ukrainian state-owned ‘National Nuclear Energy Generating Company, ‘Energoatom’, awarded a contract of approximately €6 million to Termomeccanica Pompe’s Service Division. The contract was for the Yuzhnoukrainsk nuclear power plant (SUNPP) for the supply of five pull out vertical pumps with impeller blade pitch control (TMP model 156 С1PPARS 95) with relative electric motors and soft-starters.
Reference data The Yuzhnoukrainsk plant is located near the city bearing the same name in the province of Mykolaiv, about 350 km south of the capital Kiev. The plant is equipped with three VVER-1000 pressurized water reactors and has a net power generating capacity of 2,850 MW. Currently, it is the second largest of five nuclear power plants of the country.
The pumps from TMP are part of a broad project called ‘Modernization of the Water Circulation Service for South Ukraine NPP17'. The aim of the project is to reduce the average temperature of Lake Tashik, which reaches 40°C during summer time, causing limitations in plant power production. The project estimates an increase in production of around 700 million kWh per year, without modification of the power generation capacity of the plant (source: http://nfr.energoatom.kiev.ua/en/investments.php).
The modernization project involves the use of five pumps supplied by Termomeccanica Pompe and corresponding ponds. The water is pumped from Lake Tashik to cool units one and three of the plant and will no longer be re-introduced directly into the lake. Instead, it will be sprayed by the new pumps to a height of about 20 m to be cooled and collected into the ponds before being re-introduced into the lake and re-used again to cool the power plant's production units.
Size and complexity Termomeccanica’s pumps will work at variable flow rates ranging from a minimum of 49,320 m³/h to a maximum of 50,400 m³/h, with respective heads of 24.8 m and 17.7 m. The variation between these two working conditions will be effected by the actuation of a control system of the impeller blades mounted on the pumps and operated by a control panel.
The pumps use a water-cooled electric motor of a rated power of 4.3 MW and are designed with a fixed stator part, installed in a dry pit, and a removable rotor part. In fact, due to the performance required in terms of flow, the pump weighs almost 100 tons while the removable part weighs 50 tons, consequently allowing an easier maintenance of the wear parts.
Integrated logistics Integrated logistics played a predominant part in the project. Due to the size and weight of the pumps, TMP involved leading logistics companies in the planning of material flows for the complete delivery process; from the suppliers’ facilities to the delivery of the products to the customer.
More specifically, upon the completion of the design stage, the various pump parts were assigned to sub-suppliers carefully chosen from Termomeccanica’s qualified base and equipped with the latest generation CNC machines, so able to guarantee the tolerances required by the 'pull out' characteristic of the pumps.
To make the supply chain more efficient, only one stator part kit was brought to Termomeccanica’s La Spezia plant; the one needed for the functional test. The other four kits were sent directly to the customer by suppliers after the performance of due checks by Termomeccanica. Furthermore, the five removable parts kits were assembled at TMP’s La Spezia workshop, as the assembly activities involved required the company’s in-house expert know-how.
Once the first pump was completed, its functional test was carried out in the presence of the customer. This test checked contractual parameters and the mechanical operation of the pump, and the impeller’s blades rotation system. The pump hydraulics, specifically designed for this project by Termomeccanica’s R&D Department, ensured that contractual operating parameters were reached and even exceeded. The customer was able to witness a maximum efficiency of 87% during the tests carried out at TMP’s La Spezia Test Center, one of the largest and best equipped in Europe.
The first unit was shipped after test completion and process validation, with the next four units assembled and shipped afterwards. To date, the parts of the five pumps are stored at Yuzhnoukrainsk nuclear power plant’s central warehouse, waiting for the completion of the pumping station and spray ponds. The installation of the first two pumps is scheduled for the summer of 2019.
A time-lapse video of the assembly and test of the pump was made at Termomeccanica’s La Spezia plant and is available here.