heavy water reactors -india

Heavy water reactors 

Advanced  heavy water reactors

India developing the advanced heavy water reactors (AHWR) as third stage  in its plan to utilize  thorium to fuel its overall nuclear power program.  The AHWR is a 300 Mwe gross (284 MWe  net ) 920 Mwt ) reactor moderated by heavy water at low pressure . The Calandria  has about 450 vertical pressure tubes and the coolant is boiling light water circulated by convention a large heat sink “ gravity driven water pool -with 7000 cubic meters  of water is  near the top of reactor building. Each fuel assembly has 3 th - U-233 oxide pins and 24 pu-th oxide pins around  a central rod with burnable absorber . Burn up of 24 Gwd /t is envisaged.  It is designed to be self- sustaining in relation to U-233 bred  from th-232 and have a low pu  inventory and consumption, with slightly negative void coefficient of reactivity.

It is designed for 100 year plant life and is expected to utilize 65 per cent  of energy of fuel, into two -thirds of that energy coming from thorium via U-233.

Once it fully operational, each AHWR fuel assembly will have the fuel pins arranged in three concentric ring  arranged .

Inner  : 12 pins th-U-233 with 3 per cent U-233
Intermediate  : 18 pins th-U-233 with 3.75 per cent U-233
Outer        :  24 pins th -pu-239 with 3.25 per cent pu

The fissile plutonium content will decrease from the initial 75 per cent to 25 percent at equilibrium discharge burn up level.

As well as U-233, some U-232 is formed, and the highly gamma-active daughter products of this confer a substantial proliferation resistance.

In 2009 an export version of this design was announced : the AHWR-LEU . These will use  low enriched  uranium plus thorium as a fuel dispensing with Plutonium in put. About 39 per cent of power will come from thorium (via situ conversion to U-233 ) and burn up will be 64 GW/dt . Uranium enrichment level will be  19.75 per cent giving 4.21 per cent average fissile contact of U-th fuel. While designed  for closed cycle, this is not required. Plutonium  production will be less than in light water reactors, and fissile  proportion will be less and pu-238 portion three times as high giving inherent proliferation resistance. The AEC says that “ the reactor is manageable with modest industrial infrastructure with the reach of developing countries.

In the AHWR-LEU the fuel assemblies will be configured.

Inner rings : 12 pins th- U with 3.55 per cent of U-235
Intermediate : 18 pins th-U with 4.34 percent U-235
Outer ring     : 24 pins th-U with 4.444 per cent U-235

HEAVY WATER REACTORS

There are presently 44 commercial heavy water reactors (HWRs) operating or under construction in six countries. For a number of years these HWRs have been world leaders in the achievement of high annual and life time capacity factors and have proven to be viable alternative to light water reactors.

In addition to achieving high capacity factors on base load plants, HWRs have also when required given very good load following service operating performance on critical items such as fuel and steam generators has been excellent and HWRs have experienced very low fueling costs due to the use of natural uranium fuel.

HWRs represent new technology and the development potential is being actively perused by investigations of advanced designs in Argentina , Canada ,India and Japan.

Basic features of heavy water reactors

Two basic types of commercially HWRs have been developed. One type developed  by Siemens/ KWV in Germany,employs a pressure vessel containing the complete reactor core. The other type Candu reactors, was developed by Atomic energy of Canada Limited (AECL) in collaboration with Ontario Hydro and Canadian manufacturers.  It employs several hundred pressure tubes rather than a single pressure vessels- both types of commercial HWRs  use  heavy water reactors as the moderator and have several key basic features.

. An excellent neutron economy permit’s the practical use of once though natural uranium fuel cycle.
. On -power refueling  which offers several fundamental benefits : higher capacity facts by eliminating periodic refueling shut down, reduced need for core reactivity and flux distribution control  mechanism or power  replacement of defective fuel and easy assess for service inspection.

Pressurized heavy water is used as a coolant in all currently operating commercial HWRs, however experimental and prototype pressure tube HWRs have been built in several countries to evaluate use of carbon dioxide, light water and organic fluids as coolant options .

Most HWRs currently use natural uranium often, with objection of being independent of uranium enrichment facilities. The use of slightly enriched  uranium fuel results in a significant improvement in fuel cycle cost and uranium utilization. Plutonium and or uranium form spent light water reactors fuel can also be efficiently burned in existing HWR designs offering synergism between HWRs and LWRs.

Higher nuclear safety and good performance will be important to achieve enhanced confidence in the safety advanced  HWR s design since this is a world trend for all reactor types. The improved safety is based on operational experience proven technologies and conclusive research and development.

A target of which is being perused in several national programs is to reduce the radiological burden on operating and maintenance staff . This is being achieved  through such means as careful optimization of tritium management, early detection of leaks, rapid location and on power removal of failed fuel, improved shielding and coolant purification s and better control of sealing materials.

Sale of reactors by India

Nuclear power corporation of India limited (NPCIL) is ready to sell pressurized heavy water reactors of 220 Mwe  or 540 Mwe capacity to other countries according to Atomic Energy Commission (AEC) chairman Srikumar  Banerji. Dr. Banerji  who gave overview of country’s atomic energy program said work had started on ingenious pressurized heavy water reactors of 700 MWe  capacity each ( two at Kakrapur  in Gujarat  and two Rawatbhatta  in Gujarat and the first pour of concrete was planned later.

India and Canada nuclear energy

AS India  and Canada resume nuclear ties after 36 years, Indian companies discuses Mo U with their Canadian counter parts at the nuclear industry conference and trade show which ended Ottawa in Canada on Friday .

The India representative said “thrust on developing an indigenous nuclear energy program India insists on 60 percent indigenous component in nuclear power plants. So all these countries U.S.,Russia, France and others which have got contracts to build nuclear power plant will need indigenous components. We invited Canadian nuclear   companies to join our eight-company consortium to participate the India nuclear business.

This is first high level interaction by Indian nuclear companies with their Canadian counter parts after two companies signed a nuclear agreement  during prime Minister Manmohn Singh visit here for G-20 summit last year.

Since India nuclear program started with CANDU reactor donated by Canada in 1950, India was invited to the nuclear show organization of CANDU industries . CANDU stands for Canadian deuterium uranium in reference to the use of natural uranium and deuterium oxide (heavy water ) in Canadian invented reactors .

But Canada snapped ties with India after 1974 Pokran  test alleging that India used its CANDU technology to make the bomb.

It took the two countries 36 years to resume nuclear ties last year after the nuclear supplier group (NSG)allowed India access to nuclear technology and fuel in 2009.

present status of westinghouse nuclear reactors

AP 1000 nuclear power plant -present status of new build  nuclear reactors (Westinghouse )

Preconstruction and construction activities

Pre construction

Pre -construction activities include excavating  to site, preparing the nuclear concrete, ordering the material with long lead time, and building plant access roads, ware houses, administrative buildings and temporary structures to support a site construction and component assembly activities.

Construction

Construction begin when first concrete is poured as nuclear island  base mat. The nuclear island base mat is a concrete pad that acts on common foundation upon which the containing vessels, the shield building and auxiliary buildings are assembled.

The containment vessel is composed of an elliptical bottom head, a cylindrical shell is typically and elliptical upper head. The cylindrical  shell is typically assembled into three rings for placement vessel . The auxiliary building is used for fuel building and houses   the main operator control room for the plant.

Typical lead time for building AP 1000 nuclear power plant according Westinghouse .

pre  construction time -     18 months
Construction time      -       48 months
Start up time             -          6 months

AP 1000 current new build activities in China 

As industry has been well aware, the worlds first AP 1000 generation 111+ nuclear power plants are under construction in china following the agreement signed  in July 2007 with state nuclear power technology corporation of China for four  AP 1000 units, Westinghouse in consortium with Shaw Group inc is on schedule for first unit in china to begin commercial operation in 2013.

Sanmen   unit 1 &2

Construction began in 2009 on two AP 1000 plants in Sanmen county, Zhejiang province in China . Sanmen and 1 Haiyang construction mile stone have been achieved . Lessons are being learned on these first units . One of them highlights the advantage AP 1000 modular design. A six month delay occurred  in settling the containment vessel bottom head but the subsequent Sanmen construction milestones have been achieved and are back on track because the modular design allowed parrel work. Containment vessel rings 1,2 and 3 have been set on unit 1, with the fourth ring  to be set up in January 2011, while bottom head and ring I have been  installed on unit 2. The major mile stone for Sanmen for unit 1 -to install the reactor vessel and steam generators is expected to be met in 2011.  Commercial operation is scheduled to begin November 2013 for unit 1 and September 2014 for unit 2.

Haying unit 1& 2

Construction began in 2009 as two AP 1000 plants being built in Haiyang,Shandong  province in China. The Haiyang effect already benefiting from lessons learned at Sanmen via reduced component fabrication times. The commercial operation of unit 1 & 2 is schedule to begin May 2014 and March 2015 respectively.

AP-1000   current  new build activities in U.S.

Pre construction work is in progress for four AP 1000 plants in U.S. Laying the ground work for domestic nuclear units to be built in three decades. The construction of these plants will begin once nuclear regularity commission issues the combined  operating licenses (COL)which are expected in 2011.

Vogtle plant

 
Pre construction of two AP 1000 plants under way at Al ini .W. Vogtile  electric generating plant in Waynesboro Georgia (U.S. ). The two new units will supplement the existing earlier generation units 1& 2 to support growing energy consumption unit 3 & 4 are targeted to begin commercial operation)  in April 2016 and April 2017. President Obama  and secretary of energy Steven Chu announced the award of  the first conditional dept of energy federal loan guarantees for nuclear power facility to Georgia power for Vogtle units.

V.C.summer plant


South Carolina electric gas  ( Principal subsidiary of Scana Corporation ) and  San-tee Cooper ( South Carolinas state owned utility) received  approval in 2009 from public service commission of South Carolina(U.S.) to build AP 1000 plants  at V.C.Summer nuclear station in Jenkins-villi,South Carolina(U.S.)  supplement  the existing earlier generation unit 1 .This allowed preconstruction activities to proceed. Westinghouse in consortium with Shaw Group inc is building the infrastructure to support construction, including completion of main plant access  road and bridge excavation unit 2 nuclear Island and installation of more than 400 sections of circulating water system piping. The V.C. Summer project achieved  more than 1.6 million safe work hours without a lost  working day case in September 2010. The first containment vessel plate  schedule to arrive on site at any time ,with bottom head assembly to begin in February. Modular site assembly schedule begin in 2011. Receipt of COL is expected in late 2011 or early 2012. Unit 3 & 4  schedule to begin commercial operation in 2016 and 2019 respectively.


Recent Chinese party  and government leadership in recent report said that the Westinghouse nuclear units works out 4.5 million dollars per MW ( about RS 19.7 crores  per MW) compared to 3.5 million dollars per MW (about  RS 15.4 crores per MW).These costs should be compared with the cost of RS 7 crores to 8 crores per MW of indigenous reactor of PHWR designs.

NPCIL negotiators now have higher cost considerations also to contend with the talks with Westinghouse .

Even AREVA building generation 111 + nuclear reactors plants at Finland and in France are facing undue delay in construction thereby increasing the cost of power per MW .

One thing that favor Westinghouse nuclear reactors is their experience  as half nuclear power plants are built in  world are with Westinghouse design.   

carbon capture and storage and developments

Carbon capture and storage developments

Carbon capture and storage(CCS) is alternatively referred to as carbon capture and sequestration is means of mitigating the contribution of fossil emissions to global warming, based on capturing carbon dioxide CO2 from large point sources such as such as fossil fuel power plants, and storing such way that it does not enter the atmosphere . It can also be used to describe the scrubbing of CO2 from ambient air as a Geo engineering technique .

Although CO2 has been injected into geological formations for various purposes, the long term storage of CO2 is relatively new concept. The first commercial example is Wey burn in 2000,integrated plant scale CCS power plant to begin operating in September 2008 in east German power plant Schwarz pump e  run by Vattenfall, in the hope of answering about technological feasibility and economic efficiency . 

CCS applied a modern conventional power plant could reduce CO2 emissions to the atmosphere by 80-90 percent  compared to plant without CCS. The IPCC estimates that economic potential of CCS could between 10-55 percent of the total carbon mitigation effect until 2100.

NTPC and carbon capture

NTPC India ‘s highest power producer in talks with Toshiba corporation to build a pilot project in India for capturing and storing carbon emissions a Toshiba official said. The Japanese power equipment  maker aim its first 5 megawatt carbon capture plant in India. The project    may be similar plant Mikawa in Japan “ now that we have just finished in Japan, we would like to bring that the technology to other parts of world “  Kanji Ural  managing director Toshiba India said “ if think in five years we should have it “ India plan to add 64,000 MW or the equivalent of 50 nuclear power plants, in coal fired  electric plants by 2017. The nation is searching for ways to reduce carbon dioxide emissions after having agreed to reduce green house gases in proportion to gross domestic product (GDP)by 25 percent from 2005 level by 2025. NTPC is trying to cut blackouts and increase supplies.

CANCUN and developments on carbon capture and storage 

The inclusion of carbon capture and storage s (CCS) in the U.N. ‘s  clean development mechanism (CDM) is boon for middle east, and north sea oil industries which would use the scheme to subsidize the extraction of even more oil from the ground.

carbon dioxide capture and storage in geological formations is now eligible as a basis for CDM projects as a result of U.N. Climate change conference( COP16) in Cancun. This is likely to be greatest benefit to oil companies which are hastily re branding  techniques known as  Enhanced Oil  Recovery (EOR) as means to store carbon under ground.

EOR was originally developed as means to extract more oil from fields that were reaching the end of their life  span. This is still its primary purpose  rather than reducing the emissions. If included  in the CDM a calculation of “ reductions “ would be made in relation the amount of CO2 pumped into old oil wells  . The calculation would not consider the far larger volume CO2 released into atmosphere through extraction and burning more oil. As has been seen with CDM methodologies the ‘tack in  effect of subsidizing a fossil fuel based energy model is not considered relevant to how off set “ reductions “ are calculated.

Looking further a head CCS is being  promoted as ‘clean  coal ‘ in the electricity sector, as well as attracting  interest from variety of industrial sector (notably steel) that are keen to claim emissions reductions without engaging in fundamental clean development path or technological overall. What all these technologies have common in an assumption that capture, transport and storage of carbon can be variably achieved on large scale. This has not yet been  proven, and there are more reasons to believe that this will be neither technically feasible nor economically viable.

The Cancun decision is not end of the storing CCS in CDM, implementing the agreement requires that series of issues are ‘resolved in a satisfactory manner. The decision catalogs a series of fit falls, including  risk that CO2 storage is not permanent and could leak from under ground geological formations . Other environmental and public health risk, and legal liabilities in the case of leaks or damage to the environment, property or public health remain to be addressed. The text of this decision also claims that projects will need to make ‘adequate  provision for restoration of damaged  Eco-system and full compensation for effective  communities in the event of release of carbon dioxide .’ ’ The CDM contains no mechanism to enforce such provisions, and nature of scheme ( which primarily a mean for subsiding pollutants) makes it unlikely that such provisions will emerge.

If serious assessment of risks and uncertainty surrounding CCS were carried out, such projects would never allowed to proceed. However it would   be naive to think that a technical decision will stand in the way of political pressure.

The push for CCS comes from Norway, Saudi Arabia ( with backing of OPEC) and the U.K. In the past , the Alliance of Small Island States (AOSIS) and Brazil have vocally opposed CCS but made concession in Cancun in return for progress  on other issues they considered to be non-negotiable.

Norway ,the U.K. and Australia have pushed CCS because they have common interest in technologies export, with former having developed EOR techniques to extend the life span of north sea oil. The gulf states, meanwhile envisage a series of potentially lucrative new projects . Further backing in this regard comes from Algeria and Indonesia.

On corporate side Shell, BP have heavily promoted the inclusion of CCS in CDM as well as under auspices of international chamber of commerce and international emission trading associations. The world coal association a global industrial association comprising the major international coal producers and stake holders also claimed that lobbying for inclusion in CCS in CDM . “ One of key topics we came to Cancun for “

The first projects would take a few years even if  agreement on CCS is concluded in Durban in 2011, but it is clear that CCS in CDM could prove to be lucrative market.

Developments in U.S.

In Washington the  energy department  recently awarded 575 million dollars for carbon capture research -and development projects in 15 states.

The exponential technique involves storing carbon dioxide emission from coal plants and other sources under ground , in an attempt to reduce pollution blamed  for contributing to global warming.

‘This is an major step for word in the fight to reduce carbon emission from industrial plants”  said U.S. energy secretary. “ these new technology will not only help fight climate change, they will create jobs now and help position the United States to lead world in clean coal technologies, which will only increase in demand in the years a head.”

Energy department has invested more than 4 billion dollars in carbon storage and capture matched by more than 7 billion dollars in private investments . The newest money  will fund 22 projects in 15 states, ranging from evolution of geologic sites for carbon storage to develop of turbo -machinery and engines to help improve carbon capture and storage.  The projects in states including California, Pennsylvania, Colorado, New York, Texas  are being funded from economic stimulus law.

President Barrack Obama wants to cost effective deployment of carbon capture and storage within 10 years despite questions about the technology and skepticism about  feasibility. He created a task force this year changed with  coming up with a plan to over come barriers to such deployment.   

Environment and nuclear energy

Environment and nuclear power

Until we can successfully  educate  global electorate one real pros and cons of nuclear power as we will not be able to engage in a healthy national discussion on the topic. Nuclear power plants generate 20 per cent of U.S. energy they don’t burn hydrocarbons when they produce electricity. They don’t produce any green house gases or combustion by products. By substituting for fossil fuels in electricity sector, nuclear energy has significantly reduce U.S. emissions of air pollutants and green house gases.

More than one quarter  of America electricity comes from clean air sources, including nuclear power plants, hydro electric , wind and solar energy facilities. Nuclear energy is the only large scale -clean air electricity since that can be expanded widely to produce large amounts of energy. In 2009 U.S. nuclear power plants prevented the emissions of 0.6 million short tons of nitrogen oxide emissions that nuclear power plants prevent annually is the equivalent of taking 29 million passenger cars off the road.

In 2009 U.S.nuclear power plants prevented the emissions of     647 million metric tons of carbon dioxide . This is nearly as much as carbon dioxide as released from all U.S. passenger cars. The environmental protection agency EPA will begin to regulate green house gases emissions pollutants under new rule issued in 2010. EPA already regulates both nitrogen oxide and sulfur dioxide under clean air act.

The environmental responsibility is an important part of nuclear power plant management .The companies that operate nuclear power plants work voluntarily to protect nearby wild life and their habitats

America’s 104 nuclear power plants provide 20 percent of electricity.  Among clean air sources nuclear energy  plays even greater role . Only 29 per cent of America  come clean air sources and nuclear power plants generate almost 70 per cent of its.

Many scientists believe that carbon dioxide emissions increase earth’s temperature, bringing about changes in climate . According U.S. environmental protection agency 85 per cent of U.S. green house gases emissions are carbon dioxides. Nuclear energy plays vital role in green gases mitigation has been established in variety of studies by inter governmental panel on climate change, Columbia university’ s  earth institute, the national academies of science from 13 leading industrial and developing nations and international atomic energy  agency.

To compare the green house gas impacts of electricity generation from various sources the generation of 1 million kilowatt hours of electricity produces.

996 metric tons of carbon dioxide  from coal fired plant
809 metric tons of carbon dioxide from oil fired plant
476 metric tons of carbon dioxide from natural gas fire plant
Zero metric tons of carbon dioxide from  nuclear power plant

In 2009 the use of nuclear power to generate electricity avoided the emissions of nearly as much as carbon dioxide as released from all U.S. passenger cars combined. If nuclear power were not used, about 125 millions tons of national 136 million tons passenger car would have to be eliminated to keep U.S. carbon dioxide emissions from increasing. More than 400 nuclear power plants world wide produce 14 per cent of the world electricity, reducing carbon dioxide emissions by more than 2.5 million metric tons per years.

The nuclear energy institute stands by industry views as essential on essential elements of climate change policy. The industry believes that an effective climate change policy  depends on port folio of energy sources including nuclear energy and renewable to help prevent green house gases.

Some environmentalists are in deed covering around nuclear energy that because the nuclear fission process produces virtually no green house gasses emissions, unlike burning of fossil fuel such as coal or natural gas. Those two fossil fuel account 70 per cent of U.S. electricity in 2008. Also fission produces neither sulfur dioxide nor nitrogen oxides, the fossil fuel pollutants that cause acid rain.

Life cycle analysis is a mechanism for measuring the total environmental impact of various energy sources. The environmental researchers have evaluated total emission various from energy sources. This include emissions resulting from all aspects of each energy source- construction operation, dismantling and disposal . According to university of Wisconsin study the life cycle impact of nuclear energy is among the lowest if any form of electricity generation comparable with renewable technologies such as wind geo-thermal power  

NUCLEAR PLANT  SITE : water use and habitat for wild life.

Protecting the  environment extends to safety , managing used fuel, protect environment in all these ways, under strict regulations and thorough voluntary programs. Cooling water discharged from a nuclear power plant contains no harmful pollutants and it meets government act requirement and state standards temperature mineral contents.

Nuclear power is the world’s largest source of emission free energy. Nuclear power plants produce no controlled air pollutants, such as   sulfur and particulates, or  green house gases. The use of nuclear power in place of other energy sources help to keep the air clean preserve the earth’s climate to avoid ground level ozone formation and prevent acid rain.

Nuclear power has important implications for national security. Inexpensive nuclear power, in combination with fuel cell technology , could significantly reduce dependency on foreign oil.

The nuclear power plants have experienced an admirable safety record. About 20 percent of electricity generated in U.S. comes from nuclear power and last forty years of this production not a single fatality has  occurred  as a result of operation of  a civilian nuclear power plants in United States. In comparison many people die in coal mining accidents, every year and approximately ten thousand Americans die every year from pollution related to coal burning.

The nuclear power industry generates approximately 2000 tons of solid waste  annually in U.S. in comparison coal fuelled power plants produce 100,000,000 tons of ash is laced with poisons such as mercury and nitric oxide. Even this 2000 tons of nuclear waste is not a technical problem. Reprocessing of nuclear fuel and implementation of integral fast reactor technology, will enable us to turn the vast majority  of what is currently considered waste into  energy.

Unfortunately the voting public has been victimized for forty years of miss information regarding  safety of nuclear power . The graphs on nuclear energy  showing it to be safe economical and in national interests are countered by anti nuclear activist using fear tactics to frighten the electorate into inaction.

Advocates are fond of noting that nuclear power provides 70 per cent of country carbon free energy. But nuclear energy is not really zero carbon free system, since you have to build power plants, mine and enrich uranium and transport processed fuel all of which typically, rely on CO2 emitting fuel sources. Even when entire life cycle is taken in to account, however, nuclear energy warms the planet much less than coal or natural  gas.

While its commonly accepted that  nuclear power has relatively dainty foot  print, the question of whether new reactors would be the most cost effective to lower electricity related emission is still hotly debated. The fuel itself is relatively in expensive for the time being.  But noted a time a recent price estimates for large plant  12  billion dollars to 18 billion dollars that’s  before you consider the nuclear industry’s history of major cost overruns.

The government nuclear regularity commission has set  safety goal for every reactor in the country. The chances of an accident that results in radioactivity being released to the environment must be no more than one in million, as determined by probabilistic risk assessment. But even the longest of odds will never safely every one especially after  the cataclysmic drilling accident in Gulf Mexico. In recent years, a number of leaks of radio active water have stroked environmental ire, although nearby residents were not exposed to dangerous  doses of radiation. The real problem is that after 50 years we still don’t  have a long term plan  for storing high level commercial nuclear waste.

It is worth noting that uranium is very efficient energy source. One ton of natural uranium can produce the same number of Kilowatt hours as 16,000 tons of coal or 80,000 barrels of oil.

At the same time every energy technology has it pit falls. So if nuclear power can play a role in cooling the planet ,think that this energy should deserve to stay.  

India -nuclear energy

India -nuclear energy

Nuclear power is fourth -largest source of electrical  energy after thermal, hydro, and renewable sources of electricity .As 2010 India has 20 nuclear power plants generating 4,560 MW , while 4 other nuclear power plants under construction and more expected to generate an additional 2720 MW. India nuclear industry is undergoing rapid expansion with plan to increase nuclear out put to 63,000 MW by 2032. The country is involved in the development of nuclear fission reactors though its participation ITER  projects and global leader in development of thorium based fast breeder reactors.

India has already been using imported enriched uranium and are currently International  Atomic Energy Agency (IAEA) safe guards, but it has developed various aspects of nuclear fuel cycle to support its nuclear reactors . Use of heavy water reactor have been particularly attractive for the nation because it allows uranium to be burnt with little  or no enrichment capability .India has also done a great amount of work in development of thorium centered fuel cycle. Experiments  are going on for developing thorium based reactors.

India is already committed to spending about 177 million dollars till the end of present 5 year plan period ending March 2012 for further exploration of uranium resources in addition to the present capacity.

There are also clear signs  that the government of India so also its China counter part, will do their utmost to lay their hands on uranium, wherever and whatever form available.

Recently just before retirement the then chairman of Department of Atomic Energy (DAE) and very well known figure in India’s energy circles, Anil Kakodkar has  said publicly that rejuvenation of India’s  nuclear power program-me should make it necessary to continue efforts to establish newer deposits and exploitation of uranium to meet the indigenous  nuclear power program demands of the future.

India is Asia’s’ 3rd largest energy consumer and its needs  for uranium is predicted to increase 10 fold by 2020. India will need about 8000 tonnes  of uranium annually , according to Jagadeep Ghai finance director at NPCIL (nuclear power corporation of India).   A

Needing additional 1500-2000 tonnes of uranium each year to raise the share of nuclear energy, India nuclear market has been projected to grow around 40 billion dollars by 2020.

Currently India produces only about 450 tonnes of uranium from Jharkhand state from six mines.

Beside Jharkhand in 2005 and 2006 plans were announced to invest almost 7000 million dollars to open further mines the state of Meghalaya at Domiasiat- Mawthabah  and Andhra Pradesh at Lambapur- Peddagutta. In Andhra Pradesh there are three kinds of uranium mineralization in Cuddapah basin, and related deposits in north of it.

Now India has flourishing and largely indigenous nuclear power program and expects to have 20,000 MW nuclear energy capacity on line by 2020. It aims to supply 25 per cent of its electricity from nuclear power by 2050

Due to trade bans and lack of indigenous uranium India has uniquely been developing a nuclear fuel to exploit its reserves of thorium.

Now foreign technology and fuel are  expected to boost India’s  nuclear power plans considerably. All plants will have high indigenous engineering content.

India has vision of becoming a world leader in nuclear technology due to its expertise in the fast reactors and thorium fuel cycles.

Electricity demand in India  is increased rapidly as 830 billion Kilo watt hours produced in 2008 and was triple the 1990 out put. Though still represented only some 700kwh per ca-pita in India for year, with transmission losses, this result in only 591 billion kwh consumption. Coal provides 68 per cent of electricity at present, but reserves are limited . Gas provides 8 per cent and hydro provides 14 percent electricity in total power production. The per ca-pita electricity consumption figure is expected to double by 2020,with 63 percent annual growth and reach 5000-6000 kwh  by 2050

Nuclear power supplied 15.8 billion Kwh (2.5 per cent) of India electricity in 2007 from 3.7 Gwe (110GWE  total )capacity and dip in 2008-2009 this will increase steadily as imported uranium become available and now plants  come online. In the year March  2010, 22 billion Kwh was forecast and for the year 2010-2011, 32 billion Kwh is now forecast. Some 300 reactor -years of operation, had been achieved by mid 2009. India fuel situation, with short of fossil fuels, is driving nuclear investment for electricity as 25 per cent nuclear contribution fore seen by 2050. When 1094 Gwe of base load capacity to be required . At most  as much investment with grid system as power plants is necessary.

India plan to invest 150 billion U.S. dollars on power infrastructure over five years including transmission and distribution . It said that T&D  were 30-40 percent worth more than 6 billion dollars per year . Actual average India T&D loses are about 22 per cent at present.

The target to provide nuclear power 20,000 MW by 2020. The prime Minster 2007 referred to this  as  a modest and capable being doubled with opening up international co-operation. However target can achieved  if we get substantial quantity of uranium.

Following constraints for achieving targeted nuclear power

The signing of convention on supplementary compensation for nuclear damage (CSC0 by India  wrapped up last leg of its commitment arising from nuclear partnership with U.S. Last few years  have been spent in mostly sorting out legal formalities and procedures issues relating governing this partnership.

The inking of CSC broadly set ball rolling for U.S. nuclear vendors to commence actual engagement in India. However U.S. vendors like  Westinghouse  (Toshiba )  and GE- Hitachi yet to start negotiations . NPCIL should lead in solving problems relating to  nuclear liability bill.

NPCIL speed up Jaithapur  nuclear project as environmental clearance has been received, since AREVA has signed  agreement to set up 2 reactors of 1600 MW each . Necessary clarifications regarding nuclear liability bill and arrangement of finances  to be sorted out early start of this project construction.

India to speed up construction of  2 nos of VVER -1000 reactors (light water )  with RUSSIA assistance in KUNDANKKULAM  as these supplies are not associated with India latest nuclear liability bill.

India  to sign nuclear agreement with Japan since  JAPAN  vendors Toshiba and Hitachi are associated with supply reactors with Westinghouse and GE.

Long  term supply of enriched uranium supply  along with nuclear reactor supply should be negotiated with vendors for availability enriched uranium as most plants proposed are based on  light water reactors technology.

NPCIL to convince Russia to set up more reactors  at proposed sight ( west Bengal or Haryana)  after convincing or renegotiating nuclear liability bill as Russia as  shown little interest in setting up new nuclear power projects.

NPCIL should convince Toshiba and GE  to set up at proposed sites in India after clarifying on nuke liability bill.

NPCIL should increase share of nuclear power   from heavy water reactors (Pressurized heavy water reactors) as  2800 MW  of nuclear power expected to be added by 2020.

GE-Hitache ESBWR technology and safety design parametres

GE-Hitachi ESBWR  technology and safety design parameters

GE-Hitachi nuclear energy

Based    in Wilmington N.C. GE -Hitachi nuclear energy (GEH) is world leading provider of advanced  reactors alliance created by GE and Hitachi to serve the global nuclear industries . The nuclear alliance executes a single, strategic vision to create a broader port folio of solutions expanding its capabilities for new reactor and serve opportunities. The alliance offers customers around world the technologies , leadership required to effectively enhance reactor performance power out put and safety.

GE -Hitachi nuclear energy announced recently its next generation reactor model, the economic simplified boiling water reactor (ESBWR) has  passed a crucial safety review performed by advising committee for  U.S. nuclear regulatory commission (NRC). Completion of this view clear a key hurdle in the company’s bid for design certification of ESBWR , which now begins the federal rule making process. This sets the stage for final NRC certification by 2011.

In October 2010 letter to public, the NRC ’s independent advisory committee on reactor safeguards (ACRS) issued its safety recommendation for ESBWR design which is required before a new reactor technology can achieve  final certification. From this point the process takes approximately one calendar year to complete, this keeping to NRC schedule. As  a result GEH technology is on target to become a certified “Generation 111+ “ reactor model. GE submitted the ESBWR to NRC in 2005.

‘The ( ESBWR) design is robust and there is reasonable assurance that it can be built and operated  without undue risk to health risk to the health and safety of public “ ACRS chairman written in the agency’s  safety recommendation .

The 1520-megawatt (MW) ESBWR offers what GE believe is the world most advanced passive safety features, simplified construction and operation and lowest core damage frequency on the market today. In addition the ESBWR ’s innovative digital instrumentation and control design and development process are rigorously complaint to nuclear regulation and globally recognized standards.

“ Our team has been successful in keeping the ESBWR on track to become the first reactor with the extent of passive safety features and reliance on natural circulation cooling yet to be certified “ said  Caroline Roda, president of CEO of GEH. “ The team  has done a great job demonstrating that this technology is safe and reliable. This independent recommendation from ACRS, along with expanding GEHs’ global supply chain and nuclear foot print  shown the commitment of GEH to long -term nuclear projects”.


GEH and Michigan utility DTE energy are collaborating on a potential ESBWR project adjacent to its Fermi . 2 nuclear plant, 35 miles south of Detroit . NRC is currently reviewing the utility license application for the proposed  “ Fermi unit 3 “ DTE energy ,which operates Detroit Edition, Michigan’s largest electric utility, has not yet made a decision to proceed with construction of the new reactor. GEH offers utility customers what it believes is most complete portfolio of NRC-Certified reactor models. The ESBWR is an evolutionary based on GEH s 1350-Mwe advanced boiling water reactor (ABWR ) the first and only generation 111+ reactor to be fully certified by NRC (in 1997). GEH intends to renew its ABWR certification for an additional 15 years beyond 2012.

Safety enhancement features in ESBWR

The ESBWR is direct cycle, natural circulation BWR and has passive safety features to cope up with range of design basis accidents (DBAs). Within the containment structure are the isolation condensers (IC) to be elevated gravity driven cooling systems (GDCS) water pools, a passive containment cooling system (PCCS) and an elevated suppression pool. These systems can remove decay heat under all conditions. The ESBWR standard design includes a reactor building that surrounds the containment, as well as building dedicated exclusively or primary to housing related systems and equipment.

The limiting ESBWR DBA is an  main steam line break (MSLB). In this DBA water and steam are initially discharged from break into dry well. As the dry well pressure increases the horizontal vents between dry well and wet well clear. Subsequently , a steam water mixture from break flows through the vents into wet  well  suppression pool, where steam is condensed and water is cooled to the pool temperature. As primary system pressure fall to the dry well pressure, water makes up  to the reactor vessel is provided by actuation of GDCS I.e.GDCS squib valves open and water flows by gravity head into the vessel from GDCS pools. This occurs ten minutes after the initiation of accidents. The reactor core is never uncovered during the limiting of DBA . The steam condensation in the suppression pool and pressure equilibrium between dry well and wet well through the vacuum breakers reduce the dry well pressure causing the horizontal vents to close. The remaining non-condensable gases and steam in dry well then follow up through the POCS heat exchanger. The steam is condensed as it passes thorough the PCCS tubes. Water condensate is collected and return to GDCS pools and the non condesable  gases flow into  the wet well gas space .This establishes a passive long term recirculation cooling mode for over 72 hours-non safety related recalculating fans are credited after 72 hours and result in further reduction in containment pressure. However calculations show that even in purely passive mode the containment pressure remains below design pressure for over 30 days.

Probabilistic risk assessment

The ESBWR design certificate included a PRA ( probabilistic risk assessment) in according with regulatory requirements. The ESBWR PRA is level 3 PRA covers full power operation and shut down conditions. The scope of initiating  events include internal events and assessment of internal plant fires and floods. The only quantified external events are high winds and tornadoes. A seismic margin analysis was performed, but risk from seismic events and other possible external events was not quantified. Although many of the analysis elements are consistent with AS ME-RA-Sb-2005 capability  2 standard, those attributes were not consistently achieved at this stage of the PRA development. For example some aspects of human performance, models for equipment lasting and maintenance and details of fire and flood damage cannot be anal sized in the absence of physical plant, procedures and operating staff.

In these cases surrogate analysis were performed and assumptions were  applied to encompass potential plant configuration, operations and maintenance program mes and organization . In addition any analysis requiring site specific characteristics were  treated in a generic manner.

Over view found that this PRA was acceptable for design certification purposes. The estimated frequencies of core damage and large releases provide confidence that ESBWR design achieves NRC staff expectations for advanced plants. The PRA was an integral part of the ESBWR design process, and risk unsightly influenced a number of design changes though the review. The integrated risk perfectibility was an important contribution to achieving the estimated low -risk.

The ESBWR design is robust and there is reasonable assurance that it can be built and operated without undue risk to the health and safety of the public

ACR- 1000 nuclear reactor

ACR-Nuclear  reactors

After several decades of slow growth of nuclear power capacity, governments  and public are again thinking seriously thinking about new nuclear power plants (NPPs) as a source of clean, safe economic base load electricity. During  this period Atomic Energy of Canada Limited ( AECL)continued to build CANDU plants around the world and recent new  build CANDU 6 projects have shown have shown record delivery performance, allowing the industry to over come public perception that nuclear power projects often exceed their budget and  schedule.

CANDU nuclear reactors currently produce about 16 per cent of Canada’s electricity and more than 50 per cent of province of Ontario’s electricity generation mix. Canada has abundant supplies of uranium ,a strong nuclear power industry  and high-performing , home grown reactor technology in the form of the successful CANDU  power reactor and a new product the advanced CANDU  reactor ACR-1000 can meet demands for safe , clean electricity in Canada and other countries

ACR - 1000 advanced CANDU  reactor

AECL is developing the advanced CANDU reactor (ACR) to meet customer requirements for emerging nuclear market over 20 years of sale. The ACR -1000 is an evolution generation 111+, 1200 Mwe class heavy water reactor designed to meet industry and public expectations for safe reliable, environmentally friendly, low cost nuclear power generation . The ACR-1000 the only generation 111+ reactor in the world to have completed phase 2 of the Canadian nuclear safety commission (CNSC) pre license review. In September 2009 CNSC released the results of this review and concluded that there were no fundamental barriers to licensing the ACR-1000 for new build construction in Canada .

ACR -1000 designed to meet market needs

. Evolutionary design
. Competitive economics
. Short construction duration
. Low and stable operating cost.
. Passive safety
. Hardened against external threats
. Enhanced  performance and operatability
. Clear , straight  forward  licensing
. Combined best aspects  of  CANDU  and light water reactor (LWR) technology

Evolved on experience of decades of successful CANDU  nuclear technology operation, AECL developed , ACR -1000 on principles and characteristics of proven  CANDU design but several enhancements.

ACR -1000 enhance include

. A compact core design with improved stability and higher out put.

. Light water coolant, which reduces heavy water inventory by two-thirds

. CANFLEX-ACR fuel bundles that use low-enriched uranium (LEU fuel to achieve higher burn up and negative void reactivity.
\
. Improved passive safety

. Superior accident resistance and core damage prevention features, including steel -lined hardened containment.

. Optimized plant layout

. Designed in operatability and maintainability

 Improved operation ,performance and economics

Reduction  in heavy water  inventory by approximately  60 per cent over traditional CANDU  reactors, cutting costs and improving environmental  performance and occupational safety.

. Ability to burn alternative fuel, such as  mixed oxides (MOX) and thorium

. Less  re fuel's and lower spent fuel volume Mwh ,through use of  low -enriched  uranium in a complex-ACR  fuel bundles, as a result increased burn up.

. Simplified reactor control resulting from reduced pressure tube lattice pitch and use 0f LEU fuel for high stable, more compact core. Further simplification achieved with mechanical zone control rods and eliminating the liquid zone control systems.
.
 . Improved on -power maintenance and testing, additional redundancy in actuating signals for tripped channels, reduced risk of spurious trips and overall increased reliability, though use of quadrant-based layout for safety and heat sink system.

. Enhanced power maneuvering ability due to  lower xenon load after shut down than traditional CANDU plants.

. Higher overall thermal cycle efficiency, resulting from increased coolant and steam supply pressure and temperature

The basic design and ACR -1000 program is in full project mode AECL ’s commercial operation group. The  basic features- including a modular, horizontal core with fuel channels, simple fuel bundle design , separate low -temperature and low pressure heavy water moderator and passive safety features-are retained and innovations enhance safety, performance  and economics.

Major changes to the design include using light water (instead of heavy water ) as a  coolant and introduction of low-enrich (instead of natural uranium fuel, in advanced ‘CANFLEX ‘ bundles. However 80 per cent of plant features, equipment and specification are still based on candu 6 reference plant, giving high degree of confidence that initial new build project will be completed successfully.

ACR-1000 evolving and enhancing safety

In ACR -1000 designs have increased safety and operating margins, enhanced accident resistance and core damage prevention features , provided a thicker steel -lined containment and improved fire protection. The thicker containment is designed to with stand external events such as earth quakes, tornadoes, floods, air craft crashes and malevolent acts. Each corner of reactor auxiliary building houses redundant safety equipment in a four quadrant design, with quadrant separated by three-hour fire barriers.

The ACR -1000 design combines CANDU s  passive safety features with engineered safety -technology. Central to the safety system are two fast acting, fully capable ,diverse and separate shutter down systems. These are physically and functionally dependent of each other and also from reactor regulating systems and are optimized for reliability.

Additional defense in depth is derived from the inherent passive safety of CANDU core including heat sink redundancy for potential accident conditions. These passive features have been enhanced still further in the ACR-1000 design to mitigate, prevent or significantly delay severe accidents. As well as  the ACR-1000 core is designed for a  the ACR -1000 core is designed for a small negative void coefficient.  This provides inherent protection against transients with any inadvertent   increase in power.

ACR -1000 meeting grid requirements

A focused effort was also made to ensure the ACR-1000 flexible enough to meet grid requirements. The ACR-1000’s enhanced power maneuvering capability simplifies reactor operation and  makes the reactor inherently more responsive to grid.

China -Westing house AP 1000 reactor

China -Westinghouse AP 1000

The China will build four AP 1000 beginning in 2011. AP 1000 has passed all the steps for compliance with European utility requirement and the AP1000 only generation 111+  plant to receive design certification by U.S. nuclear regulatory commission (NRC) . With many utilities already having selected the AP 1000 as their technology as a choice.

Westinghouse nuclear technology will help to provide future generation with safe, clean and reliable electricity.

Westinghouse Electric Co ( now owned by Toshiba) and its consortium partner, the Shaw group signed land mark contracts with China’s state nuclear technology corporation  limited  (SNPTC), Sanmen nuclear power company ltd , Shandong nuclear power company, and China national technical import & export corporation to provide four AP1000 nuclear power plants in China. These are first order ever placed for generation 111+ reactors, with potential to take china into nuclear technology leadership role over coming years.

Assuming these first AP1000 projects go well the prospects for more look good particularly with Chinese governments stated aim of  perusing nuclear  power more actively SNPTC has been set up specially to establish the AP 1000 in china, including technologies transfers while CGNPC ( China Guangdong nuclear power holding company, a subsidiary of China  Guangdong nuclear power group ( CGNPG) has said it has  under” preparation  “  of construct of five or six AP 1000 units, as result of those earlier agreements, preliminary design, engineering and long-lead procurement work was already under way.

The four plants are to be constructed in pairs at Sanmen ( Zhejiang ) and Haiyang (Shandong) sites. Construction begins now with first plant becoming operational in 2013. The remaining three plants are expected to come on line in 2014 and 2015.

Under sub contract with Westinghouse , Doosan of Korea ( which involved with heavy components for country’s generation 111 offering the AP 1400 ) will supply reactor vessels, steam generators and integrated head assemblies for Chinese AP 1000 reactors.

The original plan had been to place two of AP 1000 units at the CGNPC/CGNPG Yagjiang site ( Dongping town, western Guangdong ) rather than Haiyang .

Passive safety

AP 1000 features safety systems to a greater extent than any other commercial available power reactors. In particular systems are used for core cooling, containment isolation and containment cooling, and maintenance of main control room emergency habitability . The passive systems are sufficient to automatically establish and maintain core cooling and containment integrity indefinitely following a design basis events, with no operator action and no-on site or off site power AC power sources.

The passive core cooling systems performs safety injection and reactor coolant make up tanks, accumulations and the containment refueling water storage tank (IRWST) . It also provides residual heat removal by means of passive heat exchanger and IRWST.

Another example of passive systems is the use of natural circulation for removing heat from containment vessels following an accident .The flow of air driven by chimney effect of air heated in the shield containment vessel annulus rising and finally exhausting up through the central opening in the shield building roof. If needed this can be supplemented by water evaporation  on the outside of containment shell using water drained  by gravity from tank on the top of containment shield building.

Westinghouse describes the AP 1000 as “ the safest, most advanced, yet proven  nuclear power plant currently available in world wide market place .“   The core damage frequency is put at 5x 10-7 (events per year).
It is also highly modularized , in design facilitating rapid construction, and high quality and according to Westinghouse , uses less concrete and steel and fewer components and systems than completing design-meaning , there is less to install , inspection and maintenance.

A remarkably  short construction schedule 36 months ( from concrete to fuel loading) is claimed .

The passive safety systems are significantly simpler than the traditional PWRs  safety systems, they make use of gravity, natural circulation and compressed gas. No pumps,fans,diesel ,chillers or other rotating machinery ,are used in passive safety sub-systems.

They don’t require large net work of safety support systems needed in a typical nuclear power plants such as  AC power , HVAC, cooling water systems and seismic buildings to house these components. Simplification  of plant systems, combined with increased plant operating margins,reduces,the action required by operator . The AP 1000 also has 50 % fewer valves, 83 % less piping,87 % less control cable,35 % fewer pumps and 50 % less seismic building volume than conventional plant of similar installed capacity. These reduces  in equipment and bulk quantities lead to a  major savings in plant cost and construction schedule.

The AP 1000 NSSS plant configuration  consists of two delta-125 steam generators each connected to reactor pressure  vessel by a simple hot leg and two cold legs. There are four reactor coolant pumps  that provide circulation  of reactor coolant for heat removal. A pressurizer  is connected to one of hot leg pipes to maintain sub cooling in reactor coolant system.

Major component changes in corporate into AP 1000 design include  a taller reactor vessel, larger steam generators (delta -125) , a larger pressurizer, slightly taller covered reactor coolant pumps wither reactor coolant flows. These designs for these reactor components are based on components that are used in operating PWRs , says Westinghouse .

AP 1000 fuel design is based on 17x17 XL (14 foot) design used successfully at plants in U.S. and Europe . As with AP600 studies have shown that AP 1000 can operate with full core loading of mixed oxide fuel.

Certification and revision

The AP 1000 has received design certification from U.S. Nuclear regulatory Commission and has been selected as preferred technology for  a dozen proposed plants being considered for construction over  next 10 to 12  years.

AP 1000 is only one of four reactor designs recently submitted to U.K. nuclear installations inspectorate  to be considered in its new generic design assessment process, the other being Arevas  EPR, Ge's ESBWR and AECLs ACR -1000.

It is suggested NPCIL (NUCLEAR POWER CORPORATION OF INDIA ) should renegotiate with Westinghouse as per earlier  their proposal to build AP 1000 reactor in INDIA and using  this latest nuclear technology.

who will beleive Chiranjeevi?

Who will believe Chiranjeevi

On Sunday praja  rajyam  party(PRP)  president K.Chiranjeevi announced the unconditional merger of his 30 month  old party  with congress .  Formal merger  on February 14 likely to happen in the presence of AICC general secretary Rahul Gandhi at a program  in city.

Addressing the media outside 10 Jan path in New Delhi after 55 minute meeting with congress president Sonia Gandhi, Chiranjeevi said he was convinced that congress alone would help him take forward his plank of social justice.

PRP has 17 MLAs and merger would give Kiran Kumar Reddy government some elbow room to tackle the threat from Jagan  Mohan Reddy. But analysts warned against premature celebrations in congress as Jagan remained potential force who could still wean away PRP MLAs.

Chiranjeevi says he is not aspiring any post or cabinet berth . Chiranjeevi said on Sunday “ we have demanded adequate social justice measures for OB C and minorities, women reservations, national status for Polavaram  - Pranihate -Chevella projects, better financial package for farmers, more incentives to artisans and more funds for SC and Sts.

“ Congress recent actions on 2G scam given an impression that the congress Party is clean and dedicated to the welfare of people of country. “ Chiranjeevi added

On Chiranjeevi joining congress,CPI state president Mr. Narayana said all PRP MLAs should resign and contest fresh election on congress symbol .

Venkiah Naidu BJP leader said on Chiranjeevi merging PRP with congress , “ leaders are changing parties as if just like changing the buses for selfish goals.”

Chiranjeevi says as personally  he prefers for united Andhra state and even  in any injustice done people of state  he will point out without hesitation at congress high command.

Chandra Babu Naidu said “ present congress position in the state is  now weak and hence congress some how forced PRP to merger with it.”

Actually Chiranjeevi started PRP in 2008 with plank of social justice and with slogan of self respect of Telugu  pride and taking corruption against congress party and failed get majority in assembly and got elected 18 MLAs with 80 lakh voters voted for PRP.

Before going to meet  Sonia  Gandhi Chiranjeeve speaking to news channel he said he abide by the decision of Sri Krishna committee on bifurcation of state.

..   When united Andhra movement is going  on in coastal and in Rayalaseema Chiranjeevi supported and given statement in favor of united Andhra .

But now Chiranjeevi found a way to become a cabinet minister or some other important position in central cabinet or in congress, after meeting Congress president he changed his version,Chiranjeevi said he will abide decision of congress high command on separate state issue it implies that he did not mind bifurcation of Andhra Pradesh

Gandhi just using Chiranjeevi to cut influence of Jagan Mohan Reddi in Coastal Andhra and Rayalaseema and to get support of Kapus as there no leader from this community at present.

How can any body support or believe Chiranjeevi ?

design and safety of nuclear reactor core melting

Design and Safety of nuclear reactor core melting

In 1950 attention turned to harness power of atom in a controlled way, as demonstrated at Chicago in 1942 and subsequently for military research, and applying the steady heat yield to generate electricity. This naturally gave rise to concern about accidents and their possible effects. In particular the scenario of loss of cooling which resulted in melting of nuclear reactor core motivated studies on both physical and chemical possibilities and biological effects of any dispersed radio activity.

Those responsible for nuclear power technology in the west devoted extra -ordinary effort to ensuring that melt down of reactor core would not takes place, since it was assumed that melt down of core would create major public hazard, and if contained, a tragic accident with likely fat abilities.

In avoiding such accidents the industry has been outstanding successful. In over 14,000 cumulative reactor -years of commercial operation in 32 countries, there have been only two major accidents to nuclear power plants  - three Mile Island and Chernobyl , latter being of little relevance outside the old Soviet bloc .

It was not until late 1970 that detailed analysis and large scale testing, followed by 1979 melt down of three Mile Island reactor, began to make clear that even the worst possible accident in conventional western nuclear power plant or its fuel could not cause dramatic public harm. The industry still works hard to minimize the probability of melt down accident , but it is now clear that  no-one need fear a potential public health Catastrophe .

It is laws of physics and properties of materials that preclude disaster, not required actions by safety equipment or personnel. In fact licensing approval now requires that effects of any core melt accident must be confined to plant it self, without need to evacuate nearby residents . It should be emphasized that commercial type power reactor  simple cannot under any circumstances explode like a nuclear bomb.

The international Atomic Energy Agency (IAEA) was set up by United Nations in 1957. One of its function was to act as a auditor of world nuclear safety. It prescribes safety procedures and reporting of even minor accidents and its role strengthened in 1996. Every country which operates nuclear power plants has a nuclear safety inspectorate  and all these work closely  with IAEA.

While nuclear power plants are designed to be safe in the event of any mal function or accident , no industrial activity can be represented as entire risk free. However a nuclear accident a western type reactor is now understood to have severe financial consequences for the owner but will give rise to minimal off site consequences.

Achieving safety

Operational safety is prime concern for those working in nuclear power plants. Radiation doses are controlled by the use of remote handling equipment for many operations in the core of reactor. Other controls include physical shielding and limiting the time of workers spend in the areas with significant radiation levels. These are supported by continuous monitoring of individual doses and of the work environment to ensure very low radiation exposure compared to other industries.

Concerning possible accidents, up to early 1970, some extreme assumptions were made about the possible chain of consequences. They gave rise to genre of dramatic fiction (e.g. China Syndrome) in public domain and also some solid engineering including containment structures (at least western reactor design ) in the industry itself. Licensing regulations were framed accordingly.

One mandated safety indicator is calculated probable frequency of degraded core or core melt accidents. The U.S. Nuclear regularity commission (NRC) specifies that reactor designs must meet a 1 in 10,000 year core damage frequency, but modern designs exceed this. U.S. utility requirements are 1 in 100,000 year the best currently operating plants are about 1 in million and those likely to built in next decade are almost 1in 10million.
Even months after  the three Mile Island accident in 1979 it was assumed that there had been no core melt because there were no indications of severe radioactive release even inside the containment . It turned out to be fact about half of core melted . This remains the only core melt in a reactor confirming to NRC safe criteria ,and the effects were contained designed without radiological harm to any one.

However apart from this accident and Chernobyl disaster they have been about 10 core melt accidents-mostly in military or experimental reactors. None resulted in any hazard due to burning fuel in hot graphite ( similar to Chernobyl but small scale.

Regularity requirements today are that the effects of any core melt must to be confined to plant itself, without need to evacuate nearby residents.

The main safety concern has always been the possibility of an uncontrolled release of radio active materials leading to  contamination and consequent radiation exposure off site. Earlier assumption were this would be likely in the event  of major loss of cooling accident (LOCA) which resulted in a core melt. Experience has proved otherwise in any circumstances relevant to western reactor designs. In the light of better understanding of physics and chemistry of material in a reactor core under extreme conditions it became evident that even a severe core melt coupled with breach of containment could not in fact create a major radiological disaster from any western reactor design studies of post accident situation at three Mile Island ( where there was no breach of containment supported this.

An OECD / NEA report in 2010 pointed out that the  theoretically -calculated frequency for a larger release of radioactivity from severe nuclear power plant accident has reduced by a factor of 1600 between the early generation 1 reactors as originally built, and generation 111/ 111+ plants being built today. Earlier designs however have been progressively up graded through their operating lives.

It has been asserted that nuclear reactor accidents are epitome of low -probability but high consequences risks. Understandingly , with  this in mind some people were  declined to accept the risk however low probability  . However physics and chemistry of reactor core, coupled with but not wholly depending on the engineering, mean that the consequences of an accident are likely in fact be much less severe than those from other industrial and energy sources. Experience bear this out.

The use of nuclear energy for electricity generation can be considered extremely safe. Every year severe thousand people die in coal mines to provide this widely used fuel for  electricity . There  are also significant health and environmental effects arising from fossil fuel use.

Achieving optimum nuclear safety

To achieve optimum safety, nuclear power plants in western world operate using a defensive-in depth approach with multiple safety systems supplementing  the natural features of reactor core. Key aspects of approach are

. High quality  design and construction
. Equipment which prevents operational disturbances or human failures, errors developing into problem.
. comprehensive monitoring and regular testing to detect equipment or operator failures.
. Redundant and diverse systems to control damage to the fuel and prevent significance radioactive releases.
. Provision to confine the effects of severe fuel damage (or any other problem ) to plant it self.

These can be summoned by prevention, monitoring and action to mitigate consequences of failures.   

Areva - nuclear reactor technology

Areva -nuclear technology

Areva is a world leading company in nuclear energy . It is only company with presence each industrial activity liked to nuclear energy, mining , chemistry ,enrichment , combustibles, services, engineering nuclear population and reactors, treatment, recycling , stabilization and dismantling. Areva also claims to offer technological solutions for co2 free energy, and produces earth leakage circuit breaker technologies.

Four main subsidiaries of Areva
. Areva NP ( formerly Framatome ANP-nuclear power : develops and builds nuclear reactors Siemens has 34 per cent stake in Areva NP
. Areva NC ( formerly Cogema) nuclear cycle : covers the whole nuclear fuel cycle from mining to waste disposal
. Areva TA ( formerly Technicatome )  : develops and builds nuclear reactors and reactors for naval population .
. Areva T&D transmission and distribution  ;  It is in power transmission and distribution. It was bought from Alstom on 9th January 2004, currently Areva has entered  into exclusive negotiations with ALSTOM and Schneider Electronics for selling T&D drives .

Major partner of Areva include Euriware, STMicro electronics, Eramel  and Safron .

Areva is part of global energy partnership (GNEP)with Japan atomic energy agency (JAEA), Washington group international BMX. GNEP is plan initiated in 2006 for international partnership to reprocess spent fuel in a way that renders Plutonium in it usable for nuclear fuel but not for nuclear weapons.

European pressurized reactor EPR design

Frame tome (present Areva )and  Siemens in co-operation with E.D.F. and major German utilities  active since in 1992, in the development of European pressurized water reactor also known as Evolutionary pressurized water reactor (EPR).

Main objectives assigned to EPR were two fold. After a careful evolution of specific passive features, it was decided to design the EPR following an evolution approach  ; the advantage of funding an advanced design on operational from approximately 100 nuclear power plants. Constructed by Frame tome and Siemens was deemed by designs to be quiet important.

-As important as evolutionary feature was the objective to assure the competitiveness of nuclear power generation with any alternative energy sources . EPR was intended to provide significant improvement in terms of power generation cost as compared to most modern nuclear power plants and to large gas power plants with combined cycles.  To match this objective, a large unit power size was selected I.e. 1600MWe range.

Evolutionary design  : French and German safety authorities recommendations

In compliance with the rules established by French and German nuclear safety authorities for next generation of PWRs, and EPRs follows the following principals.

An evolutionary design to achieve maximum benefit from accumulated experience in designing and operating PWR units now in operation in France and Germany and in country’s where from Frame tome and Siemens exported their technologies (Belgium , Brazil ,China , Korea , South Africa , Spain, Switzerland ).  EPR design specially based on French N4 and German KONVOI experience.

An enhanced safety level .

 On the other hand ,decreased core melt probability has been achieved by improving availability of safety systems. On the other design features have been incorporated to limit radiological consequences in case of severe accident. For accidents without core melt, the architecture of peripheral buildings as well as the associated ventilation systems eliminate the necessity of protective measures for people living near damaged NPP unit. In the highly improbable but nevertheless envisaged situation of core melt accident at low pressure, the reinforced reactor building and specific palliative devices will limit radioactive releases. Only a few limited protective measures would be required. Lastly reactor design and confinement concept eliminate situations that could head to a large early releases.

With EPR  the probability of an accident leading to core melt, already extremely small with provision-generation reactors, becomes infinitesimal .

- Taking potential operating problems  into account very early  design effort, in depth work has been done during basic design phase to reduce to minimum collective personnel radiation exposure. Equipment maintenance  has been enhanced by good accessibility . Finally the human factor was integrated into the design to minimize the potential for human error in operation of EPR units.

Main design and operating data

Potential thermal NSSS power    from 4300 to 4600 Mwth
Rated electrical power          ------ 1650 MW(depend upon site conditions)

Reactor cooling system

Number of loop           --- 4
Operating pressure --------155 bars
Total flow/ loop     -------- 28000m3/ h
Main steam pressure ------ 78 bars

Core

Number of fuel assemblies ------- 241
Number of RCCA ------------------89
Fuel assembly array ---------------- 47X17
Active weight ------------------------420 cm

Areva lighter water reactor technologies

More than three quarters of fleet of nuclear power plants in operation across world used one of the two types of light water reactors.

Boiling water reactor (BWR)

On BWR the water is boiled and turn into steam inside vessel it self. Recirculation pumps force water that has not evoparized to return to the core, accelerating movement of natural circulation. The steam that is produced is transported directly turbine generator via steam pipe. Reactor containment prevent radio active products from dispersing in the event of damage to core.

. Areva has been active in the development of boiling water reactor (BWR) technology since early 1990 through its German subsidiary  Areva  GMBH.

. Areva offer a new 1250MWe boiling water reactor the “KERENA ‘ TM , it has developed at the request of German electric utilities in co-operation with other European countries . This generation 111 + reactor will provide the highest level of operation safety.

Pressurized water reactor (PWR)

In PWR a pressurized maintains the water at a pressure high enough to prevent it from boiling and kept in liquid form. This water referred to as primary coolant is not sent directly to the turbine. It circulates in a closed circuit between the core and the steam generator (SG) . This enables the heat from the&  uot primary coolant & uot to be transferred to the feed water which boils as its pressure is much lower. It is steam produced by feed water that is transported to the turbine generator .

PWR are most used across the globe (66 % of the current fleet in installed capacity) and equip the entire French nuclear power fleet. This biggest in world in terms of national electrical production (around 80 %) adopting single reactor give it a very homogeneous character . It benefits from continuous improvements   supported by the exceptional feed back of experience acquired by Areva from 58 reactors in operation.

. Areva therefore has 40 years of experience in the development of this reactor technologies and related services
. EPR  reactor developed by Areva is a 1650mwe  pressurized water reactor . This generation 111 reactor benefits from technological advances which makes it an advanced reactor . It provides increased level  competitiveness and safety while reducing impact on environment.

Areva signed agreement with India for setting up  1600 Mwe capacity   two European pressurized nuclear reactors for NPCIL (NUCLEAR POWER CORPORATION OF INDIA coming up Jaithapur  in Maharashtra state. Environmental approval has been given by environmental ministry recently.

However larger EPR built by AREVA yet see performance approval as non of its bigger EPR 1600 capacity in operation any where in world. 

nuclear energy industry

 Nuclear energy industry

There are now 439 nuclear reactors in operation in around world in over 30 countries, providing almost 16 per cent of world electricity. The first commercial reactors came to operation during late 1950s, but industry really took off in1970s,when concern over energy security and fossil fuel prices prompted  many governments and power companies to consider nuclear plants. Over 200 reactors came into operation during 1980s, but by end of decades there had been a marked slow down of orders prompted by  a range of economic and public acceptance issues . In the period since many commentators began writing off industry, expecting slow death  with plant decommissioning expected to be only buoyant activity.

By turn of 21st century, however there were already signs of sharp revival of fortunes. The key to this was undoubtedly improved  operating performance of the reactors already in place. With the realization that they could earn significant benefits to their owners, even in liberalized  markets. It is now generally expected  that most of its achieve extensions to their previously operating lives, while many are experiencing power out put up-rates up to 20 per cent. In addition many years of safe operation of Chernobyl accident in 1986 have eased public acceptance concerns, while volatile fossil prices and energy security concerns have prompted consideration of all alternative generation options. But perhaps the most significant factor that has prompted discussion of nuclear renaissance in the increased global attention placed on climate change. Nuclear power plants emits only minor amount of green house gases and is attracting a significant amount renew attention along with alternative low -carbon energy sources such as renewable.  

New reactor  programs are currently being led by Asian countries , particularly China and India but many of the countries with more established nuclear sectors, such as United States, the U.K. and Russia are seriously planning new build. They have been joined by many more countries now considering nuclear reactors first time  such as Indonesia, Vietnam , Malaysia , Thailand and several middle east countries.

A complex industry can be conveniently  divided into several sections. A huge R&D work goes into reactor designs, a sector that has now consolidated in to small number of players who can sell thought the world. Capital cost of nuclear power plants relatively high by comparison with rival technologies and building on time and budget is essential. This involves mainly local sub contractors but there are  a number of major international companies involved in this area . The  nuclear fuel cycle from uranium mining to waste disposal has number of specialist activities, each which are carried out by limited number of companies world wide. More in back are a number  of technology, equipment and service companies who provide a ranges of specialized products and services to all areas of industry . Finally there is a group of electricity utilities for whom nuclear power plants represent significance  share of their generating capacity.

Nuclear reactors

The new reactors being offered today are essentially evolutionary developments of well proven design having with stood the tests of time since in 1950. Reactor design commonly discussed in terms of generation and today models are referred to generation 111. These offer several improvements on previous generation 11 design, on economy of construction, safety and operating cost. There is also currently a significant amount of international R&D work going on into so called generation iv designs, but these are unlikely to become commercialized before until 2020 at the earliest

Nearly 90 per cent existing reactors are light water reactors (LWRs) of which there are two main groups  Pressurized Water Reactors (PWRs)and Boiling Water Reactors (BWRs)  . All of the operating 104 U.S. reactors for example of these two types. The most significant alternative design is Pressurized Heavy Water Reactors (PHWRs) of which CANDU design is best known. With exception , all of new reactors being offered today fall into these types. Other reactors models currently in operation such as the British gas cooled reactors  and some remaining RBMK reactors in former Soviet Union are being gradually phase out and will not form basis for any new design. All of latest model mentioned are large reactors (1000 MWe and above) but there are some high temperature gas cooled reactors (HGRs) now being developed by China and South Africa (the PBMR)which are much smaller at 200 Mwe . Those may be particularly suitable for developing countries without strong power grids but are unlikely to be commercialized before 2020.

The superb safety record achieved by current generation reactors has clearly increase in confidence  in them forming basis for a renewed nuclear build program .Many initiatives taken after math of mile Island Chernobyl accident to improve a strong safety culture thought the world industry lead IAEA and world association of nuclear operators (WANO).

The marketing of new major reactors has to day concentrated in a few major companies but with some smaller players also capable of undertaking alternative projects. Areva, GE-Hitachi and Westinghouse -Toshiba are the three majors and at the centre of the proposals to build new reactors both in U.S. and U.K., Atomstroyexport of Russia , AECL of Canada and  KOPEC  of Korea are also competing major reactor contractors having established reputation with nuclear programs in their own countries.

Nuclear fuel developments

Nuclear fuel is loaded into new nuclear reactors in the form of fuel assemblies, long, thin zirconium tubes containing  pallets of uranium. Those will stay in reactors for 3 years until reactivity declines to the extent that replacement is warranted. LWRs comprising 90 per cent today reactors were traditional shut down once per year (an outage) when one third of fuel would be replaced, but many reactors today have longer operating cycles with outages only every 18 or 24 months. After discharge from reactor used nuclear fuel cooled for several years in large ponds of water. There after they are essentially two options- either reprocessing used fuel to separate uranium and plutonium which may re introduced into nuclear fuel cycle or storing the used fuel for longer before sending it to deep geological repository .

The front end of the nuclear fuel cycle comprises the stages up to fuel fabrication where fuel assemblies are prepared . The “back end “ is the route followed by used fuel, which can include reprocessed uranium and plutonium -reentering the front end. The uranium production is starting point for  front end and it goes through stages of conversion and enrichment (at least LWRs-PHWRs run on natural uranium) before fuel fabrication.

Uranium is not scarce in any geological sense and over million tons have been mined since the drawn nuclear age in 1940s . Identified resources, exists many politically stable countries more than adequate fuel any  conceivable expansion of nuclear power for this century. The world uranium market has been characterized by periods of extreme boom to bust, caused initially by the demands of military program  and latterly by the one -off civil nuclear plans. The period from 1980 to 2003 San long depression in uranium prices at leveling insufficient to allow any but efficient producers to survive many years , 40 percent reactor requirements were fulfilled by secondary supplies rather than primary production sourced from either commercial inventories build up in boom periods or former military uranium reaching civil market . Since 2003 however uranium prices have risen sharply, encouraging an up surge in exploitation by up to 400 junior uranium companies, adding to the establishment market participants such as  Cameco, Rico T into , Areva, BHP Billiton and Kazatomfrom . Few of these will enter into production phase ,but some such as Palatial  uranium , one are already doing so and will participate in likely production boom over next few years .

Conversion is an immediate step in the nuclear fuel cycle, where uranium is converted from oxide to fluoride form for the enrichment stage ( which requires uranium to be gaseous form ). It is carried out in a few specialized plants thought the world. LWRs require U-235 isotope of uranium to be increased from natural 0.7 to 3.5 %. This is a major technical complex, step in cycle historically accounted  for slightly more fuel cost than uranium supply it self . Large gaseous diffusion enrichment plants owned by USEC in U.S. and AREVA in France are now gradually been replaced by new centrifuge enrichment facilities a technology mastered by Uren co in Europe and by Russian . This is much less  energy intensive than gas diffusion and capacity can be added on modular basis. Upwards of 10 billion dollars will be invested in a new centrifuge facilities over next 5-10 years.

Fuel fabrication is specialized service to reactor operators, rather than homogeneous commodity like uranium, conversion and enrichment. As such it takes place at greater number suppliers world wide in many cases national suppliers close to reactor location.

Let us hope nuclear industry will boom in next decade  since number of countries are coming forward investing in  nuclear power  to reduce green house gases.        

small nuclear power reactors

Small nuclear power reactors

There is revival of interest in small and simpler units for generating electricity from nuclear power, and process heat. This interest in small and medium nuclear reactors is driven by a desire to reduce capital cost and provide power away from large grid systems. The technologies involved are very diverse. As nuclear power generation has become established since 1960, the size of reactor units has grown from 60 Mwe  to more than 1600 Mwe ,with corresponding economies of scale in operation. At the same time there have been many hundreds of smaller reactors built both for naval use (up to 100 MW thermal )and neutron sources, yielding enormous expertise in the engineering small units .

The international Atomic Energy Agency (IAEA) defines small as under 300 MWe and up to 700MWe as medium-including managing operational units from 20th century . Together they are now referred to as small and medium reactors (SMRs). This power focus an advanced designs in small category, those now being built for the first time or still on drawing board.

Today due to party high capital cost of larger power reactors generating electricity via steam cycle and party to need to service small electricity grids about 4 Gwe there is move to develop smaller units. These may be built independently or as modules in large complex with capacity added incrementally as required. Economics of scale are provided by number produced. There also moves to develop small units for remote sites. Generally modern small reactors for power generation are expected to have greater simplicity of designs, economy of mass production, and reduce site costs. Most are also designed for a high level passive or inherent safety in the event of malfunction.

A 2010 report by special committee convened by American nuclear society showed that many safety provisions necessary or at least prudent in large reactors are not necessary in small designs forth coming.

A 2009 assessment by IAEA under its innovative nuclear power reactors & fuel cycles (NPRO)program concluded that there could be 96 smaller modular reactors (SMRs) in operation around the world by 2030 in its high case, and 43 units in low case none of them in U.S.

The most advanced modular projects in China, where Chinery is preparing to build the 210 Mwe HTR-PM which consists of twin 250 Mwt reactors. In South Africa Pebble Bed Modular Reactor (pty) Limited  and Eskom had been developing the Pebble bed modular reactor (PBMR) of 200 Mwt  (80MWe ) but funding to this project has been stopped. A U.S. led by General Atomic is developing another design-the gas turbine modular helium reactor (GT-MHR )-with 600 G wt(285MWe ) modules driving a gas turbine directly, using helium as coolant and operating at very high temperatures. All three models are high temperature gas cooled reactors (HTRs) while build an experience of several innovative reactors in the 1960 and 1970.

Another significant line of development  is in very small fast reactors of under 50MWe . Some are conceived for areas away from transmission grids and with small loads, others are designed to operate in clusters in competition with larger units. Already  a operating in a remote corner of Siberia are four small units at the Bilibino co-generation plant. These four 62 Mwt (thermal ) units are an unusual graphite modulated boiling water design with water/steam channel though the moderator . They produce steam for district heating and 11MWe (net) electricity each . They have performed well since 1976, much more cheaply than fossil fuel alternatives in Arctic region.

Also in the small reactor category  are the Indian 220 Mwe  pressurized heavy water reactors (PHWRs) based Canadian technology and Chinese 300-325 Mwe , PWR such as built at Qinshan phase -1 at Chashma in Pakistan , and now called CNP-300 . These design are detailed in this paper simply because they are well established. The Nuclear Power Corporation of India (NPCIL ) is now focusing on 540 MWe and 700 MWe version of its PHWR and is offering both 220 and 540MWe  version internationally. These small established design are relevant to situations required small to medium units though they are not state of art technology.

U.S. president Obama   approved 54.5 billion dollars stimulus for industry saying that nuclear power “ A necessary step “  in eliminating our dependence on fossil fuels. But there are more than green backs fully this nuclear renaissance . Small modular reactors (SMRs)  are dissipating nuclear fears  and renewing interest in the 30 year stagnant industry.

That because SMRs may success-ed when older nuclear design fall short. From utility perspective  SMRs are less capital insensitive and easier to install. Instead of adding 1+GW all at once to grid base generation, SMRs add manageable 30MW to 300 MW. But utilities don’t have to stop at one SMR,they can chain this together on the same plant. The Babcock and Wilcox company’s  m power of reactor for example can chain 10 or more SMRs together on the same site, giving them the power of bigger reactor with advantages of smaller ones.

Utilities and their regulators however are not only people developing a taste for SMRs. Many Americans are becoming aware of their increased safety measures. The m power light water reactors (LWR) for instance has ability to perform passively safe power  down -which means no more Chernobyl’s. Melt  down theoretically occur when loss of coolants triggers an uncontrollable reaction. This reactor however is designed  to slow down the fission rate without  a coolant or even  action by human agent.

In addition to safety the newer reactors are also tacking problem of waste . The Unites States has up word  of 77,000 tons of it. This waste however has 90 per cent of its potential nuclear energy  still locked inside. Hoping to take advantage of these remains, General Atomic is designing the energy multiplier module breeder reactor that uses some that left over energy. Nuclear waste  may be a reality for now, but at least newer reactors are getting more out of it.