What Speaks The Speaking Tree? Koodankulam Nuclear Reactor During Its One Year Of Grid Connection
By VT Padmanabhan, R Ramesh, V Pugazhendi, & Joseph Makkoli
03 November, 2014
The first unit of the Koodankulam Nuclear Power Plant (KKNPP-1) attained criticality on 15 Jul 2013 and was grid connected on 22 Oct 2013. During the 365 days since grid connection, the reactor was under outage for 106 days and on maintenance shut-down for 64 days. It generated 2825 million units (MU) of electricity and consumed 538 MU for house-load (own consumption). The original plan to start commercial generation on 22nd April 2014, six months after its grid connection was postponed twice to 22nd Jul 14 and 22nd Oct 14. Now that the reactor has been shudt down on 25 Sep 14 for repair/replacement of turbo-generator, there is no burden of any deadline.
Southern Regional Load Despatch Centre (SRLDC), Bangaluru publishes daily data regarding the productivity and outages of all generating stations connected to the Grid. The full report of a study based on an analysis of the 365 days’ grid data of KKNPP is available here.[i] The main highlights are given below:
1. OUTAGES DUE TO TRIPS
SRLDC reported 21 outages of KKNPP reactor during the first year since its grid connection. Of these, two outages for maintenances in Novemeber 2013 (for 6 days) and July 2014 (59 days) were planned while all others were forced outages. Five out of the 19 forced outages, which were for short duration (less than a few hours) were for mandatory tests. Each of the remaining 14 outages lasted for more than 2 days. These were events known as ‘trips’ or ‘scrams’ in reactor engineering. When the Information and Control (I&C) system detects a defect in the reactor system, which has the potential of maturing into an accident, a trip is actuated, leading to the release of all control rods within three seconds, without the knowledge of the operators. Too many scrams place “unnecessary strain on plant components”. Trip being a bad word, the KKNPP managers have been using a more acceptable word “shut-down”, in their media briefs.
The Kudankulam reactor experienced 14 trips during its 4701 hours of operation. As trip rates are usually calculated per 7000 reactor hours, the rate for KKNPP is 20.8. According to the World Nuclear Association (WNA), the trip rate is 0.37 for all the reactors in the world and 0.25 for 10 best performing reactors. Average loss of productivity per trip for KKNPP is 7.5 days as against 1.5 days for all reactors in WNA analysis. In USA a plant with 25 scrams during 7,000-hours is issued a “red” citation and will be forced to shut down.
2. Analysis of abnormal events by system involved
Besides the 14 trips, there was also an accident in which two workers received serious musculo-skeletal and burn injuries on 14 May 14. Out of the total 15 events, the turbo-generators was involved in 6, the feed-water system was involved in 4, the reactor system was involved in 3 and the description is vague in the case of the remaining two trips. After a trip, a detailed study of the underlying causes and the remedial actions to prevent its recurrence are charted. Such information of trips of other reactors in the world are available in the public domain. In the case of KKNPP, all such information is proprietary of the Russian company and NPCIL holds them in a fiduciary capacity. An analysis of the 14 May pipe burst accident in the feed-water system of KKNPP, published earlier showed the collusion of the operator and the regulator in India for suppressing critical, safety related information.[ii]
Since trips at KKNPP were caused by defects in different systems, it appears that the reactors’ problems are severe and systemic. ‘Experts’ of the Russian company Rosatom and NPCIL are trying to show that the problem is a minor one and is limited to one (T-G) system alone and they already have a solution in hand.
3. The Blind men and the Elephant
In all reports about an outage to SRLDC, the anticipated date of revival is also given. In all the 16 outages, the actual revival took place days after the anticipated date. The case of the maintenance shut-down of 16 July 14 is the most interesting one. On the day of shut down, they promised to be back in 31 days. The revival date was extended seven times and after 59 days, the reactor was online on 14th September. The machine tripped again a few hours later “for excitor diode testing”. One wonders, why this test was not done during the maintenance! These delays indicate that the experts in the commissioning group are totally unfamilar with the machine they have a mandate to tame.
4. Seven failed attempts to pass the final test
On 1st May 2014, the Atomic Energy Regulatory Board (AERB) gave its consent for the final test (C-3), in which the reactor power is raised to 900 MW, and then to 1000 MW for a limited duration of time, brought down to 900 MW and stabilized at that level for at least 7 days. During the C-3 phase (5th May 14 and 25 Oct 14 -173 days) the reactor could operate only for 64 days because of five trips and one maintenance. All the 7 attempts to conduct C-3 test by the commissioning crew at KKNPP failed. After the sixth attempt, the reactor was placed under maintenance on 16 Jul to 13 Sep 14 (59 days). The generator was online for another 12 days from 15 to 26 Sep 2014. During this period, the power output never reached 900 MW.
5. Comparison with other reactors of similar capacity
The reactors at KKNPP are certified as Generation-3. There are only two other operating reactors in the world, belonging to this genre. Nuclear industry claims that Gen-3 reactors are inherently safe, more ecofriendly and have much lower construction time. Shin Wolsong-1 reactor in S. Korea was commercially commissioned in Jul 2012, 1715 days after the first pour of concrete. KKNPP is nowhere near its target, even 4618 days after its first pour of concrete. KKNPP-1 is unlikely to start commercial operation even 400 days after its grid connection. There are two other VVER-1000 MW reactors which took longer – Bushehr in Iran-751 days, and Temelin-1 in Czech Republic -536 days. These were due to geo-political reasons. The best among the recently commissioned reactors on this count – Tianwan-2 and Hongyanhe-2 both in China were commercially commissioned on the 94th and 109th day of grid connection respectively.
Three other VVER-1000 reactors -Kalinin-3 & 4 and Rostov-2 – commissioned in Russia during the past 10 years had a gap of 250+ days between the grid connection and the commercial production. The electricity generated during the commissioning phase by them was 11.9, 14.2 and 14.9 MU per day respectively as against 6.3 MU p.d of KKNPP.(IAEA PRIS database)
6. Counterfeit and obsolete equipment
A study by an international team of authors, includings academics from the Cochin University of Science and Technology (CUSAT), Bremen University and Sussex University, based on official documents from the Atomic Energy Regulatory Board (AERB), NPCIL and their Russian counterparts had concluded that major equipment like the reactor presssure vessel (RPV) and the polar crane are obsolete and counterfeit.[iii] Many of the equipment rendered surplus due to post-Chernobyl and post-Soviet cancellation of over 25 VVER-1000 reactors have been incorporated in Kudankulam, China, Iran and also in Russia’s Kalinin and Rostov power stations. The study underliens that the polar crane, a safety related equipment has only 80% of its name-plate capacity.
The first outage at KKNPP, on the day of grid connection was caused due to ‘reverse power’. In simple terms, what it means is that the generator, which is supposed to produce electricity became a consumer of electricity. The reactor consumes about 2 million units of electricity a day, when it is not working. Not a big sacrifice for the Southern grid.
7. The Speaking Tree
Dr BK Subbarao, nuclear phyisicist who had designed a pressurized water reactor for Indian Navy’s nuclear submarine had written a year ago that KKNPP reactor is a speaking tree. Since her marriage with the grid, KKNPP-1 has spoken for 4701 hours in 14 episodes. She spoke for 56 days during the first ninety days. Her eloquence is being progessively replaced by silence. During the past ninety days, we heard her speak only during nine days. The officials of Rosatom and NPCIL are busy in finalizing the deal for the fifth and sixth reactors, while the commissioning crew at Kudankulam is experiencing the worst nightmares in their lives. In spite of all the postponments, unmet deadlines, a major accident and very high trip rates unheard of during the commissioning of any modern reactors, it is business as usual. This cannot go on. KKNPP has all the ingredients of a perfect disaster and is a global catastrophic risk. The people of the world, their children and their children’s children to be born yet, expects more proactive decisions from the Government of India at the highest level. All deals be frozen, the fuel assemblies must be removed from the reactor core and placed in the spent fuel pool immediately, before it is too late. This must be followed by an impartial safety audit by a body of independent scientists and a thorough financial audit by the Comptroller and Auditor General of India.
The authors are independent analysts working on nuclear safety, food safety and other environmental-health issues at the Society for Science, Ethics and Environment (SO-SEE).
[email protected] 9198467 63770
The commander of the commissioning crew, the Station Director and their team of scientists, engineers and technicians and also experts from the AERB have all experienced emergencies lived through by a senior reactor operator in Europe during the past two decades of his services. The nation salutes those brave men and the regulator’s scientists for handling the crises calmly and for averting a major nuclear disaster.
VT Padmanabhan et.al, https://www.academia.edu/9052309/WHAT_SPEAKS_THE_SPEAKING_T
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