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10 THE HINDU SUNDAY, MARCH 11, 2012CHENNAI

The Kudankulam Nu-clear Power Plant(KKNPP) in TamilNadu has become

part of the regular news in therecent past. Safety of the pub-lic has been given the utmostpriority at all stages of theKKNNP construction, in-cluding from the selection ofthe site, designing the proc-esses, and erection of theplant buildings and equip-ment. The Nuclear PowerCorporation of India Limited,which has built the two Rus-sian reactors at Kudankulam,has so far clocked a cumu-lative 350 years of safe reac-tor operation in the 20reactors that are operating inIndia.

KKNPP has been built onthe sea coast like any otherelectricity generating stationincluding the coal-firedplants. Since the sea waterlevel rises due to wave run-up, storm surge, tide varia-tion and tsunami, the planthas to be protected fromthese natural events. KKNPPis well protected from a pos-sible rise in sea level by locat-ing the entire plant site at ahigher elevation. The safegrade elevation of KKNPPsite has been kept at 7.5metres above the MSL (meansea level) and a shore protec-tion bund has been construct-ed all along the shore to aheight of + 8.0 metres to theMSL. All the buildings alongwith their respective equip-ment are located at higherelevations as shown in Figure1 (at left). In addition to hav-ing a higher grade elevation,all the safety-related build-ings are closed with doublegasket leak tight doors.

KKNPP is located in IndianSeismic Zone II, which is theleast seismic potential regionof our country. However, fordesigning of the plant, de-tailed studies were conductedto conservatively estimatethe extent of ground motion

applicable to the specific sitewith reference to seismotec-tonic and geological condi-tions around it so that thenuclear plant was designedfor a level earthquake whichhas a very low probability ofbeing exceeded. The plant’sseismic sensors safely shutdown the reactor in case theseismicity exceeds the presetvalue. Thus, despite KKNPPbeing located in a very lowseismic zone, it is adequatelydesigned to withstand theseismic events.

The two reactors that havebeen built at Kudankulam areadvanced models of the Rus-sian VVER-1000 MW Pres-surised Water Reactor whichis a leading type of reactorworldwide. VVER is a Russiannomenclature for water-cooled and water-moderatedreactors. Each reactor at Ku-

dankulam will generate 1000MW. It uses low-enricheduranium fuel in oxide matrix,housed in sealed zirconium-niobium alloy tubes. KKNPPVVER 1000 adopts the basicRussian design with en-hanced safety features tomake it in line with IAEAGEN III reactors. Further,certain additional safety fea-tures were incorporated likepassive heat removal systemand core catcher, taking it toGEN III+ category.

The following safety func-tions are performed in anyoperational state of thereactor:

Control of the Reactivity(control of fission chain reac-tion), removal of heat fromthe fuel core and confinementof radioactivity.

For the control of reactiv-ity, control rods are provided,

which will ensure the shut-down of the reactor, therebyterminating the chain reac-tion, whenever the action iscalled for. The control rodsare designed to fall by gravityto shut down the reactor.

The salient safetyfeatures of KKNPP

- Passive heat removal sys-tem to provide cooling for theremoval of decay heat usingatmospheric air.

- Higher redundancy forsafety system.

- Double containment. - Additional shut down sys-

tems like quick boron andemergency boron injectionsystems to ensure absolutesafety for shut down of thereactor, when needed.

- Core catcher to providesafety in the unlikely event offuel melt-down

- Passive hydrogen re-com-biners which do not need anypower supply to absorb anyhydrogen liberated inside thecontainment.

The above systems havebeen developed based on ex-tensive R & D and simulatedtesting by the Russian designinstitutes. The functionalperformance of these systemshave been established duringthe commissioning stage.

A large number of processsystems are provided for thepurpose of heat removal fromthe reactor fuel core. In addi-tion, to remove the decay heatafter the shut down, a seriesof safety systems are provid-ed which are backed by thediesel electricity generatorsets. The safety systems areprovided in four trains, eachtrain containing a set of safetysystems, both active and pas-

sive systems. Each set of safe-ty trains is provided with adedicated diesel generator setof 6 MW. The passive heatremoval system provides thecore cooling in case of rareoccasion of non availabilityall the diesel generators. Thissystem uses the simple atmo-spheric air to take away theheat from the reactor throughsteam generators by using thenatural principle of convec-tion. One safety train is suffi-cient to completely ensureheat removal from the fuelcore. However, three addi-tional safety trains, i.e., addi-tional 300% systems areprovided making the KKNPPreactors among the safest re-actors.

The confinement of radio-activity is achieved by theprinciple of defence in depth.This concept provides a set ofbarriers, one after the other,so as to contain radioactivitywithin the reactor building.This concept is illustrated inFigure 2 (at right).

The reactor building hasdouble containment struc-ture. The primary or innercontainment is a pre-stressedconcrete structure, with thethickness of 1.2 metres. Thisinner containment is provid-

ed with leak-tight inner steelliner. The outer containmentknown as secondary contain-ment is a reinforced concretestructure with thickness of0.6 metres. The multiple bar-riers, as shown in Figure-2,including the containmentstructure, ensure that no ra-dioactivity reaches the publicdomain. The double contain-ment structures also protectthe plant from external haz-ards like hurricane, shockwaves, air attacks, seismic im-pact, floods, etc.

In addition, there are twoimportant systems whichprovide safety function, viz.,hydrogen re-combiners and acore catcher. The hydrogenre-combiners are passive de-vices. Hydrogen, if generatedduring any accident condi-tions, is recombined in thepassive hydrogen re-combin-ers to convert it to water. Thisprevents any hydrogen explo-sion within the containmentas happened at Fukushima inJapan in March 2011. Thereare 154 hydrogen re-combin-ers at various locations with-in the containment.

The core catcher is a spe-cial feature of KKNPP. It is ahuge vessel weighing 101tonnes. In case of an extreme

hypothetical case, wherein anevent causes damage to thefuel core resulting in partialcore damage, the core catcherwill collect the molten core,cool it and maintain it in sub-critical state.

At Kudankulam, a fish pro-tection facility is provided inthe intake of sea water. Thisfacility assists juvenile fish,which drift along with theflow of cooling sea water,from not getting trapped inthe machinery. The fish arehelped in getting back to thesea and the fish population isthus conserved.

The product water and do-mestic water requirement ofKKNPP are fully met by a de-salination plant at theKKNPP site, based on Me-chanical Vapour Compres-sion technology. Thus it canbe safely concluded that thereactors at KKNPP are thebuilt with the state of the arttechnology, with the bestsafety features that will en-sure safe operation of the re-actors, without any impact tothe environment and thepublic.

(M. Kasinath Balaji is SiteDirector, KKNPP and S.V.Jinna is Chief Engineer, Engi-neering & Utility Services)

Safety is at the core of Kudankulam nuclear reactorsM. Kasinath Balaji &S.V. Jinna

Renewable energy sourcesare attractive but in a

sense, powerless. Maybe,someday we’ll all live inhouses with photovoltaic rooftiles but in the real world, a1GW of solar plant will re-quire 60 square miles of solarpanels. When the demand in-creases, you can fire up morecoal, but how will you causethe wind to blow and the sunto shine 24x7? The earth isalready so disabled by the in-sidious poison of greenhousegases that even if we stop allfossil fuel burning immedi-ately the consequences ofwhat we have already donewill last for 1,000 years.

Each year, we are taking out400 million more tonnes ofcoal from the earth’s crust.The coal reserves are deplet-ing at a high rate. Tonnes ofcarbon dioxide are being re-leased into the atmosphere.Wind energy and solar energyare so dilute that huge capitalis required to produce anyscalable amount of electricityfrom them. The separate gridthat has to be installed in largeareas will result in huge pow-er losses before the electricitygenerated reaches theconsumer.

Nuclear radiation contain-ment, waste disposal and nu-clear weapons proliferationare manageable problems in away that global warming isnot. A report by researchers ofMIT forecasts that world-wide, energy demand wouldtriple by 2050.We have notime to experiment with vi-sionary sources of energy; civ-ilisation is in imminentdanger. Unless we see someenergy miracle, nuclear ener-gy seems to be the only op-tion. There is no currentlyavailable renewable energysource which can meet our24-hour base load electricityrequirements. Accidents,though, in the past have un-fortunately raised specula-tion. Indeed, speculation doesarise when we live in an un-certain era. It’s like we have tochoose the most certainuncertainty.

Talk of climate, the mostknowledgeable are the most

worried. Talk of nuclear ener-gy, the most knowledgeableare the least worried. Whatneeds to be done is to spreadawareness, impart educationand disseminate informationto all the vehement anti-nu-clear environmentalists.

It is high time they wereconvinced not to stall thegrowth of the advanced safenuclear reactors or else therising demand for energy willhinder our run to becoming adeveloped nation. The origi-nal U.S. nuclear power plantsof the 1950s descended frompropulsion units in nuclearsubmarines. But the currentGen 3+ reactors are a big im-provement.

As far as nuclear waste isconcerned, waste storage fordisposal or recycling is donein corrosion-proof containersthat can withstand long yearsof heat and moisture. Thereare proposals to create a glob-al nuclear fuel company un-der the IAEA which willcollect nuclear waste from re-actors across the globe, re-

process it and thenredistribute the fuel to thosepower plants.

We are also on the way todeveloping thorium-based re-actors. India has the greatestpotential for thorium reactorsconsidering the vast thoriumreserves under its belt. Thereare great examples of nuclearenergy in the world. Interest-ingly, Finland has ordered abig reactor specifically tomeet the terms of the Kyotoprotocol on climate change.France is already 77% nuclearenergy dependent, Belgium58%, Sweden 45%, South Ko-rea 40% and still counting.

Five out of six people todaylive in the developing world.Shortages of finance, infras-tructure and efficiency are themain obstacles to optimal re-newable energy usage. Ger-many can afford to phase outits reactors but that is not thecase with India and China.Currently, India is facing asupply-side deficit of 8%.Thedemand is growing at 8% an-nually. The situation is fragile.

Remember hydel power is re-stricted to geographicallysuitable sites. Wind energyand solar energy are intermit-tent. Wind is dependent onappropriate windspeeds andsolar energy depends on thelocation of the sun. We arethus reduced to just twochoices, coal or nuclear.

Nuclear plants have to ac-count for every radioactiveatom of waste. But coal-firedplants dump tonnes of deadlyrefuse into the atmosphere atzero cost. If this scenario pre-vails for 20-30 years more,our planet will become so hotthat land many times the areaof Ukraine and Japan will be-come inhabitable.

It’s time for that free rideover the “Once Green Earth”to end. It is time for us todecide whether to let 1 GW ofelectricity release 19,000tonnes of carbon dioxide intothe atmosphere or developnuclear energy for an energysafe future.

(The writer’s email ID isipshittarun@gmail.com)

Let’s face it... the alternatives are attractive, but not feasibleIpshit Tarun

IT’S THE SAFEST: Unfounded fears should not hold up the commissioning of the Kudankulam plant. — FILE PHOTO: A. SHAIKMOHIDEEN

Kudankulam has been inthe news and how! Little

did I imagine in 2002 thatthis remote area of southernTamil Nadu where there aremore ant-hills and dry windsthan paddy fields andwinding rivers would capturethe public imagination for allthe wrong reasons!

When we first came toreside here, the township inChettikulam was being builtat a feverish pace. Mydaughter was just two and wewere allotted a ground-floorapartment. There were notrees or plants in theneighbourhood. Snakes,scorpions and centipedessniggered at our discomfort.The water we received camefrom a borewell some 10 kmaway. Sometimes, the trucksferrying water came late atnight and even those who’dbeen toiling endlessly at the

plant site had to wait to taketheir shower. Rice cooked inthis water had a yellow tinge.But what tormented us themost were the heaps of dustthat piled up inside ourhomes each time the strongeastern winds blew. It wasnot enough to mop and cleanthe house just once each day.In desperation, we boardedup all our windows.Whenever we longed to seethe blue sky or gulp fresh air,we quietly stepped outdoors.My daughter was constantlyill and the searing heat addedto her woes.

Gradually, things startedfalling in place. An RO(reverse osmosis) plant wasset up. Seawater wasconverted into water fit fordrinking. Trees were plantedand within the next fewyears, we saw thetransformation before ourvery eyes. The winds hardlyoverburdened our homes

with dust. This rain shadowarea soon started to get moreshowers and flowers andfruits began to grow inabundance. No man’s landwas no longer a wasteland.

Then the world watchedFukushima, and the clouds ofmistrust rapidly spread tothese shores. Today, nuclear-power-bashing has becomethe rage. Fishermen fear fortheir lives. Emissariesemerge from the woodworkand move blatantly fromvillage to village, whipping upa campaign against nuclearpower. Some of their anticsclearly defy logic.

They have taken the lawinto their own hands. They“can” block the roads and

prevent sincere Centralgovernment employees fromdischarging their duties. Iopen an NCERT CivicsReader. It reminds me in nouncertain terms that we are acountry that’s federal in formand unitary in spirit. Thecomplexities of Centre-Staterelationships leave me spell-bound.

Our domestic helpersspeak of these events inhush-hush tones. They askme whether the house I livein will be erased after wehave been hounded out of thetownship!

In the bustling town ofNagercoil, about 45 minutesaway, shopkeepers run dieselgenerators to overcome the

unbearable power cuts. Smallindustries find it difficult tostay afloat. Thousands ofworkers face the risk ofunemployment. There aremore carbon emittingvehicles on the roads thanever before. Pollution levelsare touching an unbearablehigh. The vegetable markettries to lure customers withgooseberries as big astomatoes. Bananas, carrots,aubergines and even shallotshave never looked more bigand beautiful. Insecticides,pesticides and fertilizershave increased crop outputs.There are more peoplesuffering from cancer thanthe Regional Cancer Centrecan handle.

reactor was pumped backinto the river. Before andduring my pregnancy, Idrank the tap water suppliedto us from the same river. Ididn’t go even so far as to boilthis water. Nothing wentwrong.

My appeal to all mycountrymen is to trust ourtechnocrats. We, the familiesof the personnel who work inthese reactors, treasure ourlives as much as you do. Ourchildren study in the schoolwithin the township. We tryto teach them to valuescience, not to denounce it.They are not frogs in a well.They know that in order toprogress, man must bewilling to explore thefrontiers of the unknown. Bevigilant but do not panic. Thegrowth of a nation dependson its people.

(The writer is a freelancejournalist and her email ID is

susandavis.c@gmail.com)

But that’s fine. There’smore danger in a nuclearpower plant. Everyone talksabout Hiroshima andFukushima. Somewhere anuclear bomb and the falloutfrom an old reactor havefused to make a clean, greensource of energy a larger-than-life monstrosity. Forthose who live here, thesechanges evoke mixedemotions. True, everyone hasa right to question the safetyof these reactors. But let ustake a few moments to turnthe pages of history. India setup its first atomic powerplant in the 1950s. Till date,nuclear power operatorshave, by and large,maintained the highestsafety standards imaginable.

Between 1994 and 1999, Ilived at Rawatbhata,Rajasthan. Reactor 2 on thebank of the river Chambalwas still generating power.The water used to cool the

Is nuclear power the demon it’s made out to be? Susan Davis The water used to cool the Rawatbhata reactor was pumped

back into Chambal river. Before and during my pregnancy, Idrank the tap water supplied to us from the same river. I didn’tgo even so far as to boil this water. Nothing went wrong.

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TH Puducherry/ 1 OpenPg_01 User: cogmn 03-10-2012 22:33 Color: CMYK