New Delhi, Oct 30 (IANS): The commissioning process at the Kudankulam Nuclear Power Project (KNPP) in Tamil Nadu may take up to one year or more as the main accent is on testing safety with gradual increase in capacity levels, a Russian energy expert says.

"The main accent in the course of the commissioning process is made on the safety aspects. All possible deficiencies and deviations are to be observed during this stage," Alexander Uvarov, the director of Moscow-based nuclear energy think-tank AtomInfo, told IANS in an email interview.

"Duration of the commissioning works may take up to one year and sometimes even more," Uvarov said.

The first unit at the Russian-aided KNPP was synchronized with the southern power grid last week. It was stopped within two hours when it had achieved generation levels of 160 MW for system inspections. The unit was reconnected three days later on Oct 25.

KNPP had said the 1,000 MW unit will be gradually synchronized with the grid at the higher capacity levels of 50 percent, 75 percent and 100 percent, adding that with every increase in generation, the plant will have to get regulatory approval from the Atomic Energy Regulatory Board.

"Commissioning of a nuclear power plant is a long-term and difficult process. The main task during the start-up activity is to prove that the actual parameters of the equipment and systems do conform to the design requirements," Uvarov said.

The unit's main systems and equipment will be tested in different modes. On completing the required tests at each capacity level, the unit will be stopped for inspecting its condition, and only then the capacity will be increased to the subsequent higher level.

"During the commissioning it is also to be proved that the actual characteristics of the core and the unit as a whole do conform to the design parameters," Uvarov said.

"The commissioning teams are to get assurance of reliable, correct and efficient operation of the equipment, measuring equipment, automatic control systems and control rods," he added.

The sensitivity around the issue of nuclear safety may be gauged from the fact that agreements with countries like Russia, the US and France to set up nuclear plants are held up because of liability concerns.

Russia's concerns over the operator responsibility in India's nuclear liability law have stalled agreement on Unit 3 and 4 of the Kudankulam project.

"All possible deficiencies and deviations are to be observed during the commissioning stage. The tests are considered to be conducted successfully when the limits and conditions of the safe operation are confirmed," Uvarov said.