Damaged Turbo-Generator At Koodankulam Nuclear Power Plant, Overhauled Before Grid Connection?
By VT Padmanabhan, R Ramesh, V Pugazhendi & Joseph Makkolil
22 November, 2014
The first VVER-1000 reactor at the koodankulam Nuclear Power Project in India under commissioning tests has been lying idle since 26 September 2014 due to problems of turbo-generator. Two years before its grid connection, the Russian-made turbine was overhauled by a private contractor and this fact was kept as a guarded secret. In spite of the overhaul, KKNPP turbine failed within hours of grid connection and was responsible for five trips, which kept the reactor off-grid for 59 days. It could not be revived even after a two-month long maintenance during August- September 2014. Usually the first overhaul of a new turbine is done after completion of 5 to 10 years of work. The extreme damage of the turbine could have been due to the mal-functioning of vibration monitoring instrument made by a Russian company charged for selling counterfeit parts. Failure of instrumentation in other systems have the potential for catastrophic accidents. The Government of India has so far refused to investigate the charges of corruption and failure of the quality assurance system at KKNPP which have implictions for the safety of the reactor.
The VVER-1000 (MW) reactor at koodankulam in India (8°10′08″N 77°42′45″E) now under commissioning tests was connected to the Southern Regional Grid on 22 Oct 2013, 4253 days after the first pour of concrete. This is a Generation-III reactor designed by OKB Gidropress, a subsidiary of the Russian state atomic energy corporation Rosatom. The date of commercial commissioning planned initially for 22 April 2014 has been postponed three times to 22 Jul 2014, 22 Oct 2014 and recently to 22 Jan 2015. The delay is due to defects of turbine-generator and according to media reports, the root cause is domestic object damage (DOD) in the Low Pressure (LP) sector. In the petition for the last postponement to the Central Electricity Regulatory Commission (CERC), the Nuclear Power Corporation of India Limited (NPCIL) submitted that “while raising power, an increase in turbine thrust bearing temperature was observed and the temperature touched the operational limit on reaching power level of 850 MW. For attending this technical problem, turbine-generator was taken off the bar and reactor was shut down on 26 September 2014. (The) first and 2nd stage turbine blades and diaphragm have been damaged which are being replaced by taking from Unit-II. The replacement of blades and diaphragm would take about from 7 to 8 weeks time”.[i] On the day of the above submission (27 Oct 2014) the total damage was not assessed by NPCIL as the “turbine high pressure casing” was “being dismantled to carry out inspection and to identify the problem along with specialists of the turbine manufacturer from Russian Federation”.1
Brief History of Performance since grid connection
During its 365 days of 'marriage' with the grid, the reactor operated only for 182 days. There were 14 unplanned, automatic shut-downs known as trips, a major accident in the feed-water system and two maintenance outages, which kept the reactor off the grid for 175 days. The accident[ii] and the performance of the reactor since grid connection[iii] have been analyzed and reported earlier. Nine out of 14 trips were due to problems of the reactor and the feed-water system. The turbine-generator (T-G) was involved in 5 trips which kept the reactor idle for 59 days. Trips and maintenances related to the T-G kept the reactor idle for a total of 123 days.
The T-G is a key component with about two years of manufacturing lead time, weighs 1700 tons and costs about Rs 1000 crores. Its non-performance is causing a daily production loss of 24 million units of electricity and a financial loss of Rs 10 crores, besides the interest on the capital investment. In spite of these, the NPCIL has not explained the causes of TG complications. After blocking more than Rs 15,000 crores as dead investment, the NPCIL boasts that the problem will be solved by cannibalisation of the second reactor, as if the second reactor is a reserve of spares and equipment, an organ donor, for the first one.
Overhaul before the grid connection?
In the mean time, a Hyderabad based private contractor claims to have overhauled the T-G set well before its grid connection. The website of the company, Powermech Projects says that they had “executed overhauling of 1000 MW Nuclear Turbine, at KKNPP. The works included disassembly, paint removal of internal components and assembly of the turbine set consisting of one HP Cylinder, three LP cylinders and 5 bearing pedestals in KKNPP Unit No 1”.[iv]
There is no mention about this major event in the milestone of KKNPP anywhere in the NPCIL documentations. The time of the overhaul is not precisely known, but it appears that it was done in 2011, when the T-G defects were reported by a section of the media. In a strongly worded response to this, the NPCIL praised her Russian partner saying that they “have, in fact, supplied an upgraded rotor in place of earlier version and they actually test their turbines in a test-bed to check whether it functions as per specifications before they are shipped out. Around 120,000 tonnes of power plant equipment have landed in koodankulam, and during transit some got damaged. The Russians have replaced the damaged items free of cost. It is normal for technical personnel from the equipment suppliers to come to the project site and there is nothing unusual about it”.[v]
According to the Russian official website nuclear.ru, “on February 27, 2004 Silovye Mashiny Concern steam-tested 1000-MW turbine manufactured for the Indian koodankulam nuclear power plant under construction. This is the first of two turbines Silovye Mashiny (now OJSC Power Machine) is to manufacture for the Indian plant as part of US$ 200 million-contract for supply of equipment”.[vi] Erection of the Turbine- Generator was completed during September 2008.[vii]
There are altogether 10 turbine plants of this genre in Russia, China, Ukraine and Iran with a total operating experience of more than 100 years. The average availability factor is claimed to be 99.6%. The vendor, OJSC Power Machines, with “unique technical and technological experience in designing and manufacturing power plant equipment for Tianwan NPP, Kudankulam NPP, Bushehr NPP, confirms its readiness to take part in the projects of new NPP unit construction in the countries of South-East Asia.”[viii] The manufacturer claims that their turbine has several passive and active measures to protect blades and diaphragms against erosion.
Such a wonderful, world-class, test-bed-checked machine with an upgraded rotor and improved diaphragms and blades, had to be overhauled even before generating a single unit of electricity. Even after the overhaul, the machine worked on and off for just 4700 hours, tripped five times and was forced on a maintenance outage lasting 59 days. Neither the overhaul, nor the long duration maintenance helped.
Vibration Monitoring Instruments from a fraud company
According to Prof V Prakash monitoring of vibration is very important for safe operation of all kinds of turbines. A working turbine is in perpetual motion producing vibration, which are monitored continuously by a series of measuring devices, all of which will work in tandem to ensure that there is no loss of information. These devices identify the problems if any at the onset and help to prevent damages. Are the measuring instruments at KKNPP genuine? In May 2012, Alexander Murach, head of Informtekh was convicted and sentenced to three years in prison for selling counterfeit measuring equipment meant of nuclear and hydro power turbines. The company, which did not have any production licence, gave fake certificates claiming that the equipment had passed the mandatory tests. According to NPCIL, KKNPP did receive 'communication equipments' from Informtech.[ix] Prakash underlines that turbine defect did not develop in one day and had the monitoring equipment been genuine, the defect could have been identified at the beginning itself.[x]
The industry norm and practices for T-G overhaul
According to the Recommendations for the Inspection and Overhaul of Steam Turbines (2nd Edition, 1995) by VGB PowerTech Service Gmbh the first T-G overhaul may be conducted after 100,000 equivalent operating hours (EOH- about 14 reactor years) and if no major issues or problems are found during that overhaul, subsequent overhaul may be conducted at the 100,000 EOH intervals.[xi] The US Electric Power Research Institute (EPRI) specifies that overhauls should be conducted every 80,000 EOH. General Electric advertises that their steam turbines are designed for 12 years between major overhauls but their official service guidelines specify 5 years between overhaul.[xii]
Two VVER-1000 T-G sets commissioned in this century were overhauled in China and Russia recently. China's Tianwan-1 reactor was grid connected on 12th May 2006 and its commercial operation commenced 110 days later. The first overhaul of Tianwan T-G commenced on the 7th refuelling (after 49,000 hrs of operation) on January 10th, 2014.[xiii] Russia's Kalinin-3 VVER-1000 reactor's T-G was grid connected in December 2004. The first overhaul of T-G and other equipment was carried out in July-August 2010,[xiv] after working for 38,000 hours.[xv]
The Damaged Generator Transformers
In 2007, KKNPP received two single phase generator transformers (24-400 kV, 417 MVA) made in Ukraine in a damaged condition. The transformer upgrades 24 kV to 400 kV for eviction and if it trips, the reactor will have to be shut down. Larsen and Tuburo (L&T), NPCIL's construction contractor "dismantled the entire parts of the transformer, rectified, re-assembled and tested it without compromising the manufacturer’s quality and safety standards.”[xvi] It is not known if the NPCIL investigated this event to know the cause of damage and fix the responsibility. L&T says that the damage occurred during transit. The transformer has a manufacturing lead time of more than a year and costs about US$ 6 million. The receipt of two transformers in a damaged condition is not mentioned in the annual report of NPCIL.
The KKNPP commissioning crew drawn from other reactor campuses and academic institutions have gone back to their respective institutions, feeling dejected as their dream of commissioning the first 1000 MW pressurized water, billed as the best and safest in the world, turned into a nightmare. Mean while, the top leadership of the NPCIL-Rosatom combine is busy negotiating the deal for the 5th and the 6th reactors, without proving that the reactors already built can be operated safely. The plea for an impartial safety audit of KKNPP by eminent scientists from the national institutes, retired senior civilian and military officials and the former chairman of the Atomic Energy Regulatory Board was ignored by the Government of India. In fact, the Prime Minister's office functioned as a public relation agency of NPCIL until May 2014. The people from the peninsular India will be the immediate and proximate victims of a nuclear disaster at KKNPP. They, the safety experts and concerned citizens world-wide expect a proactive and creative initiative from the Central Government. The issue at hand is restoring the rule of law, which is the cardinal principle of the Constitution of India.
Full report at:
Acknowledgement: We are extremely grateful to PS Ganapathi Iyer, K Satish, KEK Satheesh and Neetujan- colleagues at So-SEE for their support, encouragement and editorial assistances.
Conflict of interest – None declared
Dr. V. Pugazhenthi is acclaimed for his rigorous and credible studies on health impact of radiation around Kalpakkam nuclear site. He is an activist belonging to the Doctors for Safer Environment
Dr. R. Ramesh a medical practitioner, who has written books on the geology of Kudankulam
VT Padmanabhan is a researcher in health effects of radiation. He has led epidemiological investigations among people exposed to high radiation in Kerala. He has also studied the occupational radiation hazards among workers of Indian Rare Earths, genetic effects of children exposed to MIC gases in Bhopal, health hazards to workers in a viscose rayon unit in Madhyapradesh and reduction of birth weight of babies near a beverage bottling plant in Kerala. He has visited several contaminated sites in Belarus and Japan and had extensive interactions with the survivors.His papers have been published in International Journal of Health Services, Journal of American Medical Association, International Perspectives in Public Health, the Lancet and Economic and Political Weekly. He is a member of the European Commission on Radiation Risk, an independent body of experts appointed by the Green MEPs in Europe. He can be reached at firstname.lastname@example.org
Central Electricity Regulatory Commission , New Delhi Petition No. 408/MP/2014
Date of Hearing : 27.10.2014 , Date of Order : 10.11.2014. http://www.cercind.gov.in/2014/orders/SO408.pdf
[ii] VT Padmanabhan, et.al, 2014 Report Of The 14 May 2014 Accident At The Kudankulam Nuclear Power Plant, https://www.academia.edu/7345624/REPORT_OF_THE_14_MAY_2014_ACCIDENT_
[iii] VT Padmanabhan, et.al, 2014, What Speaks The Speaking Tree? Performance Analysis Of India's Kudankulam Reactor During Its One Year Of Grid Connection. https://www.academia.edu/9052309/WHAT_SPEAKS_THE_SPEAKING_TREE_
[v] IANS, Oct 27 2011, No faulty equipment supplied by Russia for Kudankulam: NPCIL http://www.bharatdefencekavach.com/print.aspx?newsid=1749&langid=1&mid=53
[viii] Vitaly Nedavny, Chief Engineer for K -1200-6,8/50 Steam Turbine Project. Equipment of OJSC “Power Machines” for new international projects of NPP rated 800 – 1200 MW. www.pennwell.websds.net/2013/bangkok/pga/papers/t3s2o3-paper.pdf
[ix] NPCIL letter No NPCIL/VSB/CPIO/2670/HQ/2013/884 dated May 24, 2013
[x] V. Prakash, 03 November, 2014, Koodankulam: Corruption To Impending Disaster – The Missing Link? Countercurrents.org. http://www.countercurrents.org/prakash031114.htm
[xii] John Latcovich, et al, 2005, IMIA – WGP 42 (05) International Association of Engineering Insurers 38 th Annual Conference – Moscow 2005 Maintenance and Overhaul of Steam Turbines. http://www.steamforum.com/pictures/wgp4205%20Turbine.pdf
[xvi] G. Gurujanarthan, 2012, Concord- In-house Journal of L&T Construction April - June 2012 • Volume-35 • Issue-2. www.lntecc.com/homepage/documents/concordapr12.pdf
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