Power units at the South Ukrainian nucler power plant in the Nikolaev region is on the verge of terrible state of emergency – steam generators of all three units are in a preemergency state, the correspondent «Donbass Today» reports referring to own source at nuclear station.
«Emissions of the radioactive water from the reactor circuit to the turbine generator side, and through it – in environment became frequent, – tells a source. – However instead of prescribed by the procedures in this case decrease of power of nuclear reactors NAEK “Energoatom”, on the contrary, considers a possibility of its increase, creating a threat of a large-scale accident, when radioactive contamination may reach the Crimea, DNR and LNR».
Given rise in the 80th
At the South Ukrainian NPP three power units with water-water reactors of the VVER-1000 series, constructed in the 1980, according to the design of JSC OKB Gidropress (Podolsk, the Moscow region), are under operation. In the reactor shop of each power unit there are four steam generators. They consist of thousand of heatexchange tubes for running under a high pressure of the primary side coolant for the purpose of transmission of energy to the secondary side, where steam, not containing radioactive substances, moves to the turbine.
But over time under the influence of high temperature and pressure, and also of the corresponding chemistry in heatexchange tubes appear defects, leading to their plugging during the planned outages, which is carried out by specialists of the nuclear power plant.
Approach to a big accident
The source notes that the existing regulations allow to use steam generators with 10 % of the plugged tubes without a little considerable loss of power. At the same time, according to the available information, in 2012 management of the South Ukrainian nuclear power plant, without coordination with JSC OKB Gidropress, self-willedally took the decision on possible operation of steam generators with 20 % of plugged heatexchange channels on all three power units. Now the technical state of steam generators considerably worsened, on some steam generators the quantity of the plugged tubes comes nearer to 30 % that is the maximum acceptable indicator.
By estimates of the experts, use of steam generators with 30 % of plugged heatexchange tubes still is possible, but under condition of proportional decrease in thermal reactor power that respectively will lead to reduction of performance of the power plant. However, instead the head division of the South Ukrainian nuclear power plant – NAEK Energoatom corporation considers a question of increase in thermal power of the reactor to 106 % with a view of ensuring the growth of the electric power production: this power plant for 95 % provides with the electric power the Odessa, Nikolaev and Kherson areas.