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Safety issues at India's Kudankulam nuclear plant

Nuclear Monitor Issue: 
V.T. Padmanabhan, Paul Dorfman and A. Rahman

Though the trans-boundary contamination and trans-generational health impacts of the nuclear fuel cycle are recognized, there is no international regulatory framework to enforce uniform safety codes and standards and resolve the conflicts between nations. As reactors are ageing and nuclear technology is becoming widespread, there are risks of more Fukushima-type 'surprises' in future.

One such surprise has been unfolding in India's Kudankulam Nuclear Power Plant (KKNPP) since the fuel loading of a 1000 MWe pressurized water reactor (PWR) in October 2012. During the 33 months of its 'operation', the reactor could not clear the final mandatory test. The utility declared the commissioning of the reactor on 31 December 2014 and the regulator granted the licence to operate the plant on 8 July 2015. This is the only civilian nuclear reactor in the world operating without clearing the commissioning tests.

This case study reveals a total collapse of the regulatory mechanism and the rule of law for the first time in the three decades long history of civil nuclear sector. India is also planning to export reactors to other Asian-African countries, besides importing unproven technologies from abroad. These potential sources of future Fukushimas can be prevented by global intervention only. People interested in nuclear safety are seeking an international regulatory framework, which would be transparent, and participatory. There is no reason to delay this process now.

Introduction and brief history of the project

The construction work of two reactors at the Kudankulam Nuclear Power Plant (KKNPP) started in 2002 at a coastal village, off the Bay of Bengal, in Thirunelveli district of Tamil Nadu State. The first reactor has been under 'operation' since October 2012 and the second reactor is still under construction. Under the India-Russia inter-governmental agreement, Rosatom supplied the equipment and designs, while the Nuclear Power Corporation of India Ltd (NPCIL) did the construction and commissioning work. An independent safety evaluation of the project was impossible as the utility refused to share the documents like the Preliminary Safety Analysis Report, the Detailed Project Report, inspection reports of components etc. with any outside individual or organization. The only sources of information about the reactor were the press releases and annual reports of the utility, the regulator and industry sources in Russia.

Since the first reactor's grid connection on 22 October 2013, the Southern Regional Load Despatch Centre (SRLDC) has been publishing data on power generation and outages of KKNPP on a daily basis. The assessment of the reactor's performance in this report is based on the data from

Equipment defects of the Kudankulam reactors

In spite of the 'iron curtain', a fairly accurate description of the reactor plant construction − counterfeit, underperforming and obsolete equipment and shoddy construction practices – can be made using the bits and pieces of information available from the official sources in India and Russia. These include a defective reactor pressure vessel, an under-performing polar crane, an overhaul of the turbine-generator even before the grid connection and replacement of blades after 4700 hours of operation, and breaking open the double containment to accommodate the missed cables.1

Alarmed by these anomalies, 60 eminent scientists from India's national institutes, including those "who believe that nuclear energy has a legitimate role in securing our energy future" appealed on 13 May 2013 that the government "should consult independent national experts to formulate an inspection regime and carry out a full-fledged inspection into the safety" of the reactors, paying "particular attention to the allegations of sub-standard equipment and components".2

International comparison

According to the US Nuclear Regulatory Commission, commissioning tests known as "initial start-up testing" is "normally completed during fuel loading, pre-critical, initial criticality, low power and power ascension phases to confirm the design bases and demonstrate, to the extent practical, that the plant will operate in accordance with design and that it is capable of responding to anticipated transients and postulated accidents as specified in the Final Safety Analysis Report. The power-ascension test phase should be completed in an orderly and expeditious manner. Failure to complete the power-ascension test phase within a reasonable period of time may indicate inadequacies in the applicant's operating and maintenance capabilities, or may result from basic design problems".3 

Table 1 provides data on intervals between initial fuel loading (IFL) and the first act of criticality (FAC), and between FAC and commissioning (COM), and between IFL and COM for eleven 1000 MW PWRs commissioned during this century. (Dates of criticality and commissioning – not shown in the table − are from the International Atomic Energy Agency's PRIS database. Dates of IFL are from media reports.)

Table 1: Intervals between fuel loading and commissioning – 1000 MWe reactors



Initial Fuel loading

Interval in days




Tianwan -2












S.Wolsong 1

S Korea





Hanul -5

S Korea


















Czech Rep











Tianwan -1







Czech Rep

















KKNPP stands out from all others. It should be noted that it has not been commissioned properly even after more than 1000 days.

Power ascension tests

The Atomic Energy Regulatory Board (AERB) lists 45 different tests in the C Phase Power Ascension Tests, in three sub-phases of C-1, C-2 and C-3, which are conducted after the generator is connected with the grid. In C-1 and C-2, reactor power is raised to 50% of Full Power (FP) and to 75% FP respectively. The main tests of C-3 phase are non-stop operation at 90% FP for 7 days and at 100% FP for 100 days. C-1 and C-2 tests take about 10 days, while C-3 tests need 120 days. Adding another 30-40 days for regulatory deliberations and the utility should have received the licence for regular operation 160-170 days after the grid connection. The commissioning was scheduled to be completed within 180 days of the grid connection, i.e. on or before 22 April 2014.4

The commissioning could not progress as pre-planned because of shutdowns due to trips (SCRAMs) and maintenance, and under-performance of the reactor during working days.5 During the 435 days of grid connection from 22 October 13 to 31 December 2014, the reactor experienced 19 SCRAMs and three maintenance outages. Five of the SCRAMs that kept the generator off-grid for a total of 580 minutes could have been initiated by the operator as part of the commissioning tests. The remaining 14 SCRAMs – the 'real ones' − and three maintenance outages kept the reactor down for a total of 92 days and 139 days respectively. KKNPP's SCRAM rate (calculated per 7,000 reactor hours) is 20.8 per year as against 0.37 for all the reactors in the world and average loss of productivity per trip is 6.5 days as against 1.5 days for the reactors in a World Nuclear Association analysis.6

After the completion of the 'non-stop 7 days 90% FP' test on 23 June 2014, three attempts to conduct the 100% FP test failed and the plant was shut down for maintenance from 16 July until 15 September 2014. The output was less than 900 MW from 15 to 27 September 2014 and then the reactor tripped due to turbine problems. It resumed operation on 7 December 14 and attained full power three days later, heralding the fourth attempt for non-stop 100% FP. On 30 December 2014, the reactor had completed 20 days non-stop operation at 100% FP and the AERB had extended the deadline to complete the C-3 test till 30 April 2015.

Commissioning, post-commissioning performance and AERB consent

On 31 December 2014, the NPCIL hurriedly declared that the commissioning of the reactor was complete. A press release signed by the KKNPP site director said "unit No 1 has been declared commercial operation from midnight (0000 hours!) of 31 December 2014."7 Quoting him, a national newspaper reported: "We've received the nod from our high command for commencing the commercial power generation".8 As the 'nod' was received just six hours before the appointed time, there was no celebration, no song and dance, no fireworks and no press conference.

On 14 January 2015, on the 36th day of the non-stop 100% FP test, the reactor SCRAMed for the 15th time and was down till 17 January.9 Full power was resumed on January 20 and continued for 89 days until 18 April 2015. From April 19 onwards, the output started declining systematically and on 9 May 2015, the reactor tripped for the second time since its commissioning due to a "problem in steam generator level control".10 The decline of output continued even after the restart and the unit was shut down for 60 days maintenance on 24 June 2015.

Instead of asking the utility to repeat the 100% FP test, the AERB granted the Licence for Regular Operation of KKNPP on 8 July 2015. The press release said that the decision to grant the licence "is the culmination of in-depth review over many years of the safety aspects related to the design, construction and commissioning of the unit with respect to compliance with the specified requirements". It is silent about the final test and there is no mention about the Advisory Committee of Project Safety Review.

The Russian version of commissioning and licensing

The Russian News Agency TASS reported on 2 January 2015 that "the reactor has been commissioned for warranty-period operation. An act on a provisional transfer of power unit No. 1 to operation was signed by the Russian and Indian sides. This means that a year-long period of operation on warranty has begun. Upon the results of these twelve months, the power unit will be fully transferred to the Indian side".11

On 8 July 2015, the day the AERB Board of Directors met in Mumbai to grant the licence to KKNPP, the Prime Minister of India met the President of the Russian Federation at Ufa in Russia. At the press conference after the bilateral meeting, the Indian Ambassador to Russia said: "The Kudankulam 3 and 4 contracts have already been signed. There is a General Framework Agreement which has been signed. There is what is called the Long Cycle Supply of Equipment which is a contract that has been signed. That is what the (Indian) Prime Minister and President Putin noted with satisfaction as progress in the nuclear energy cooperation".12

International peer-review of India's nuclear regulator

In March 2015, two months after the declaration of completion of commissioning and three months before the grant of the licence, an IAEA mission reviewed India's regulatory framework for safety of nuclear power plants and recommended that "the Government should embed the AERB's regulatory independence in law, separated from other entities having responsibilities or interests that could unduly influence its decision making".13


While the future of the reactor is uncertain, the NPCIL is busy constructing the third and the fourth units from the same vendors and negotiating for import of 20 more reactors from Russia, France and the USA. India is also planning to export nuclear power plants to other Asian-African countries.

Some six decades after the birth of the civilian nuclear energy and meltdown of six reactors, the world is now realizing the need for a global system of regulation that works. J.J. Bevelacqua, theoretical nuclear physicist, health physicist and senior reactor operator and a key player in the Three Mile Island and Hanford cleanup activities, says that "three major reactor accidents in a span of 35 years offer a sobering reminder that the current regulatory approach has not produced the desired results, and that change is warranted" and "an ideal regulatory framework would be proactive, internationally accepted, supported by the public, anticipate accident events, constantly challenge accepted practices, and prevent major accidents".14

The presence of a junk reactor in the South Indian coastal village loaded with 4,000 kg of fissile materials and fission products, poses a persistent threat of a global catastrophic risk. The experiences so far show that those who crafted this Frankenstein's monster will not de-craft it. As the reactor's instability has been demonstrated repeatedly and its future is unpredictable, the best option is to remove the fuel from the core and subject the project to a peer review by a credible international agency consisting of nuclear regulators, safety scientists and civil society representatives. The past nuclear disasters were accidents, in the sense that they were not predicted in advance. This predicted one, whose trans-boundary impacts may even be larger than the last one, can only be prevented by global action in which scientists, technologists and law-makers will have major roles to play. In this process, we will also be creating a truly global and democratic regulatory mechanism for the so-called civilian side of the fission technology. Like for the fissile material, an international regime is necessary for the control and regulation of fission technology also.

V.T. Padmanabhan is an epidemiologist and scholar of nuclear safety. He has conducted health studies among people exposed to ionizing radiation and chemicals and written extensively on safety aspects of nuclear power plants in India. Most of his papers can be accessed from

Dr Paul Dorfman works at the Energy Institute, University College London (UCL): and also with Joseph Rowntree Charitable Trust, Nuclear Consulting Group; European Network of Scientists for Social and Environmental Responsibility; Advisory Group UK MoD nuclear SDP; European Nuclear Energy Forum, Transparency and Risk Working Groups.

Dr A. Rahman is a retired nuclear safety specialist with over 35 years of experience in both civil and military nuclear establishments in the UK and Europe. He worked as Radiation Consultant to the Kingdom of Saudi Arabia, as a Senior Lecturer at the Ministry of Defence in the UK.


1. V.T. Padmanabhan, et al. 2012. Nuclear_Safety_Issues_of_Vver-1000_Reactors_at_Kudankulam_India

2. Choksi, AH, 2013.

3. U.S. Nuclear Regulatory Commission June 2013, Revision 4, Regulatory Guide, Office Of Nuclear Regulatory Research, Regulatory Guide 1.68, Initial Test Programs for Water-Cooled Nuclear Power Plants..

4. Central Electricity Regulatory Commission New Delhi Petition No. 72/MP/2014, Date of Order : 12.5.2014.

5. V.T. Padmanabhan et al, 2014,






11. TASS, 02 Jan 2015, Kudankulam-1 transferred to India for warranty-period operation,

12. -Secretary_in_Ufa_on_Prime_Ministers_ongoing_visit_July_8_2015


14. J. J. Bevelacqua, 2013, Nuclear Regulation in the United States and a Possible Framework for an International Regulatory Approach, International Nuclear Safety Journal, vol.2 issue 1, 2013, pp.1-14.