Construction of four India designed 700 MW pressurised heavy water reactors (PHWR) are progressing at a quick pace and the first one is expected to go on stream end 2016 or early 2017, said senior officials of Nuclear Power Corporation of India Ltd (NPCIL).

The NPCIL is building two 700 MW atomic power plants each at Kakrapar Atomic Power Station (KAPS) in Gujarat and Rajasthan Atomic Power Station (RAPS).

For NPCIL that has been building 220 MW and 540 MW pressurised heavy water reactors (PHWRs), it is a major jump to go in for 700 MW PHWRs.

"It is the first of its kind reactor in the country," Lokesh Kumar, project director for the third and fourth units at KAPS told IANS over phone from Kakrapar in Gujarat on Monday.

The Atomic Energy Regulatory Board (AERB), the sectoral regulator, is carefully poring over the reports submitted by the units before according its sanction.

NPCIL has two units of 220 MW each at KAPS which are operating successfully. It is the third unit at KAPS with a capacity of 700 MW that is expected to go operational first out of the four under construction.

"We are the torch bearers for this kind of reactor in the country now. Once the first unit goes on stream, it will be easy for other three," Kumar said. Queried about the project status, he said: "We are in a crucial stage. The construction work is at its peak. We have energised the start-up transformer. The power system is ready for the unit that would go on stream."

According to him, work on commissioning of the other systems have begun while the civil construction work is nearing completion. "This week we will start the installation of the reactor coolant channel. The coolant channel installation work will be over in two months time. Nuclear piping work has begun in the two units," Kumar said.

He said stator installation work on the turbine will begin this week. "We plan to start unit 3 by the end of 2016 or early 2017. Then commissioning of unit 4 would happen," Kumar said.

Concrete was first poured in November 2010 for the 3rd unit at KAPS and in March 2011 for the fourth unit. Though the first unit was expected to go on stream in 2015, owing to erratic supply of components the progress of work got delayed, Kumar said. As to the percentage of physical progress, Kumar said the third unit is 75 percent complete and the fourth unit is 65 percent.

"The overall project cost for the two units is around Rs.11,459 crore. The project would be completed within the budget. There will be no cost escalation," he added.

At RAPS where the other two 700 MW reactors are built at an outlay of Rs.12,300 crore, the preparatory work to install the coolant channels are on for the seventh unit under construction.

"Welding of end shield and calandria is over. Preparation work for core components - coolant channels - has started. It will take six months to complete," B.C. Pathak, project director for 7th and 8th units at RAPS, told IANS. He said the seventh unit was expected to go on stream sometime in 2017-18 and almost 57 percent of the physical work had been completed. As for the eighth unit, the overall physical progress was around 40 percent.

The NPCIL is setting up two units at KNPP with Russian equipment. The second unit on which work has been completed to the extent of 98.50 percent is expected to start the fission process in December 2015.