Chennai, Russia's integrated nuclear power company, Rosatom State Atomic Energy Corporation, on Thursday said it has started shipping pipe spools of the main coolant pipeline (MCP) for the fourth 1,000 MW atomic power plant unit at Kudankulam in Tamil Nadu.

In a statement, Rosatom said an MCP set comprises 16 pipe spools. The total weight of the shipment is more than 347 tons, and the net weight is about 253.5 tons.

"During the month of August, the entire set will be shipped from Petrozavodsk to Saint Petersburg sea port, via motor transport, for loading onto a ship," it said.

The distance from Petrozavodsk in Russia to the construction site of Kudankulam is about 10,000 km.

The main coolant pipeline, 850 mm in diameter and 146 m long, connects basic equipment of the nuclear power plant's primary circuit, such as reactor, steam generators and reactor coolant pumps.

The MCP has been designed for coolant circulation at a temperature of up to 320 degrees Celsius and at a high pressure of about 160 atm.

India's atomic power company, Nuclear Power Corporation of India Ltd (NPCIL) is building four more plants - Units 3,4,5 and 6 - of 1,000 MW each in Kudankulam in Tirunelveli district.

The first two units of similar power generation capacity had gone on stream long back.