TIRUNELVELI: India's first 1,000MW pressurised water reactor at Kudankulam in south Tamil Nadu attained criticality on Saturday midnight, setting the stage for power generation before end of August.

The plant is getting commissioned six years after the scheduled date.

The milestone was achieved at 11.05pm last night after the "Boron dilution process" allowed neutron concentration to go up and start nuclear fission, generating heat.

Experts from Nuclear Power Corporation of India Limited, Russian Kursatov Institute of Atomic energy and Atomic Energy Regulatory Board observers monitored the process.

"In the first stage, the unit is expected to start generating 400MW power in 30 to 45 days. After fulfilling procedural and regulatory requirements, power generation will be increased stage by stage," Sinha said at a joint press conference with Nuclear Power Corporation of India Limited ( NPCIL ) chairman K C Purohit and executive director Nageswara Rao . Besides a team of Atomic Energy Regulatory Board ( AERB ) and NPCIL scientists, Russian experts would also monitor the progress constantly, he said.

Project site director R S Sundar said neutron multiplication in the reactor's core started around Saturday noon and was progressing further with dilution of boric acid in the primary coolant water, a process that marks the beginning of the process of attaining criticality. The boron dilution process would trigger nuclear fission which would in turn generate heat that is used to produce steam. The steam is used to operate the turbine to generate power, Sinha said. The initial contribution of 400MW will take the country's nuclear power generation to 5,780MW.

The Unit I of the plant had dummy fuel loaded into it in April 2010 and the hot run of nuclear steam supply system was conducted in August 2011. After successful testing, the dummy fuel was removed in June 2012 and in October, nuclear fuel was loaded. The reactor was loaded with fuel assemblies containing about 80 tonnes of uranium oxide. Subsequently, a number of safety tests at the operating temperature and pressure were carried out.

Sinha said the reactors at the plant had enhanced safety features ensuring the highest level of safety, in line with the current international standards. "All doubts raised about the safety of the plant have been addressed and people are convinced," Sinha said.

Work on the second unit is progressing in full swing. Civil work at the sites for units III and IV was also progressing, Sinha said. Apart from Kudankulam, work on units 3 and 4 of Kakrapar Atomic Power Project (2X700 MW) and units 7 and 8 of Rajasthan Atomic Power Project (2X700 MW) is also in progress. On completion of these projects, India's installed nuclear power generation capacity would touch 9,580MW, he said.

(With inputs from PTI)

