One of the most important stages of construction – welding of the main circulation pipeline (MCP) – has been completed in the reactor department of Belarus NPP Unit 1 (the principal contractor is Group of Companies ASE). MCP assembling started on June 4 and completed on August 21. Over 78 days specialists welded all 28 butt welds controlling the operations step-by-step.
“The welding of pearlite section of MCP in 78 days instead of prescribed 84 days is a confirmation that one of the most complex stages of the nuclear power unit construction has been raised to automatic performance,” Dmitry Romanets, Director for Belarus NPP Construction of JSC EC ASE, stressed. “In our work we were guided by time the similar operation was done at Unit 2 of Novovoronezh Phase II under construction where the reactor coolant pump was welded in 72 days. In fact, the Engineering Division of ROSATOM has set a new sectoral standard for this process requiring to carry it out in less than 80 days,” he said.
In coming days, specialists of PJSC Energospetsmontazh plan to complete overlaying austenitic stainless steel on inner welds of MCP which would protect the pipeline from corrosive environs.
The main circulation pipeline (diameter - 850 mm, wall thickness - 70 mm, total length – more than 130 m) connects essential equipment of the primary circuit: reactor, steam generators and reactor coolant pumps. MCP is designed for the coolant (water) circulation at temperature of 350oC and pressure of 17.6 MPa.