While the construction work of Rooppur Nuclear Power Plant (RNPP) is progressing at its project site as per schedule, manufacturing and testing works of various equipment for the plant is going on in Russia in full swing.
As part of technical control, hydraulic tests of the reactor pressure vessel (RPV) and the first steam generator for the unit-1 of RNPP have recently been completed at the Volgodonsk branch of “AEM-technology” “Atommash” in Russia, said Rosatom, the Russian contractor of the project.
The country’s first-ever nuclear power plant will have two power units -- each of 1,200MW capacities – which will be equipped with the latest Russian generation 3+ VVER-1200 reactor.
In a statement, the Rosatom said the tests confirmed the strength and tightness of base metal as well as of weld joints of the both, which belong to items of first safety class in a nuclear power plant.
After having been fully sealed, the 11-metre-tall RPV was tested in an underground caisson. The RPV was filled with distilled water, which was heated up to 100˚C and a maximum pressure of 24.5MPa (1.4 times higher than the working pressure) was built for testing, it noted.
Reactor pressure vessel is a vertical cylindrical vessel with an elliptical bottom and contains a reactor core and the internals.
Similarly, in another testing, all holes of the steam generator were closed with special blind covers. Primary and secondary circuits of the steam generator were filled with distilled water.
Rosatom said the primary circuit was tested at a pressure of 24.5MPa and water temperature of 350˚C.
The secondary circuit was tested at a pressure of 11.45MPa and water temperature of 300˚C. In both cases, the pressure was 1.4 times higher than the operating pressure.
The steam generator is a heat exchanger that is 14 metres in length, more than four metres in diameter, and weighs 350 tons. The Unit-1 of RNPP will have four such steam generators.
Earlier in the same factory, welding of steam generator bottom -- final manufacturing stage was completed.
Before welding, the steam generator vessel was fed with SG tubes. The automatic welding of the bottoms was performed at a temperature of 120-190˚C for five days. The welding of two joints uses 700kg of wire and 900kg of flux.
Meanwhile, “AEM-technology Petrozavodskmash” completed assembly and welding of ring weld joints of four main coolant pumps for unit-1 of RNPP.
Rosatom said the coolant pumps (RCP) at a nuclear power plant helps coolant circulation from the reactor to the steam generators and operates under a coolant pressure of 160 atmospheres and at a temperature of 300˚C.
A coolant pump weighs more than 31 tons and 3.5 metres in height and more than three metres in width. Each unit of RNPP will have four such coolant pumps. At the next stage, RCP bodies will undergo heat treatment and hydraulic tests.
Rosatom said Atomenergomash is a single-source supplier of all the equipment of the RNPP reactor compartment and a significant part of the turbine hall equipment.
