State-run Nuclear Power Corporation (NPC) on Saturday started pre-service inspection of the reactor pressure vessel (RPV) of the first 1,000-Mw unit of the Kudankulam project. This was another key step in the run-up to the commissioning of the unit before fuel loading.
The inspection will take 10 to 12 days. The report of inspection will be submitted to the Atomic Energy Regulatory Board (AERB) for review and obtaining clearance for fuel loading.
NPC Chairman and Managing Director Kailash Chandra Purohit told Business Standard: “The inspection is carried out by a special high precision automatic, computer-controlled and remotely operated machine, which is designed to work under water. The RPV, which has been manufactured in the Russian Federation to the highest quality standards, is the heart of the reactor, which houses fuel assemblies. The pre-service inspection will provide the reference base line data for future, apart from validating the functioning of automatic inspection machine. As the RPV will be inaccessible after the start of operation, subsequent inspections will be carried out remotely using the same machine.” During the life-time of the plant, in-service inspections of the RPV are to be carried out once in four years, according to Purohit.
As reported by Business Standard earlier, NPC hopes to load fuel in the third week of July and approach for criticality will start before the commencement of power production. Four to five weeks for the start of production since fuel loading is necessary, considering time necessary for full man-machine interface.
N Nagaich, executive director, said the RPV had gone through rigorous inspection at various stages, right from the selection of material and the billet stage to forging, fabrication, and post-fabrication. These inspections were carried out by experts from NPC and Russian Regulators. A specialist group of AERB also reviewed the inspection details. The RPV has been tested to a pressure of 250 kg/sq cm, as against the normal operating pressure of 160 kg/sq cm, which it has withstood successfully.