Indian nuclear power station, Rajasthan Atomic Power Station (RAPS) Unit 5 of NPCIL, recorded continuous operation of 765 days before its manual shutdown. During the period of continuous run from 2 August 2012 to 6 September 2014, the unit operated without any outage.
The longest operating period for any power reactor belongs to Ontario Power Generation's Pickering 7, which was shut down on 7 October 1994 after operating continuously for 894 days.
The RAPS site hosts eight PHWRs, of which two 700MW PHWRs are under construction, making it India's largest nuclear site in terms of number of reactors. It is also home to the first and latest PHWRs.
The RAPS site is situated on the right bank of the Rana Pratap Sagar Lake, formed between two dams. This Nuclear Power Corporation of India Ltd. (NPCIL) site is a monument of state-of-art technology in NPCIL. Starting with its maiden pressurised heavy water reactor (PHWR) at RAPS Unit 1, the site has undergone scaling-up from 220MWe reactors of units 1 to 6, to state-of-art design with several further safety enhancements in the 700MWe reactors of units 7 and 8.
RAPS Unit 5, an indigenously designed PHWR of 220MW, is fuelled with natural uranium and moderated and cooled by heavy water, and was first connected to the grid on 22 December 2009. By July 2014, the unit had generated about 8,663 million kilowatt-hours of electricity since the beginning of its commercial operation on 4 February 2010.
Maintaining equipment without failure and catching degradations before they develop into failures has proven to be one of the most important challenges. The keenness to observe what is not visible to the eye through techniques such as vibration analysis and thermal imaging, as well as the conducting of post-job reviews, has helped in the refinement of procedures and tools. This has resulted in a reduction of job repetition and downtime of equipment. Identification and correction of minor deficiencies at this initial stage as well as regular inspection and performance monitoring of systems/equipment, routine equipment changeover, and regular preventive maintenance on standby equipment are the contributor to safe continuous operation for a long period.
To enhance the performance of NPCIL plants further, we continue to improve safety culture and reinforce the methodology of conduct in the areas of operation and maintenance with corporate support and guidance.