Sunday, June 19, 2016

Srilanka's potential for nuclear energy


Sri lanka's potential for nuclear energy.......................................................


since 1954 when the first nuclear plant of the world was generating electricity for power gird, the percentage that is produced by nuclear power is significantly increased up to 16% all over the world. As of 2015 there are about 430 nuclear plants  in the world which of majority is located in US about 110 units, France 61 units,Russia 31 units and Japan 58 units. In nuclear plant, fission reaction of heavy elements such as Uranium or Plutonium is used to produce heat.Such of heavy element is bombarded by pulse of neutrons which results multi collision of neutrons make a chain of fission in which heat is controlled by nu tron absorbing agents such as water , zirconium, graphite, liquid metals,molten salts or gas.When neutron pulses split nuclei of heavy metals produce gamma rays and more neutrons.In addition to existing reactors there are more units under construction in Russia (7), China(6),India(5) and Nordic countries.In construction of nuclear reactor takes 7-10 years for licensing and environmental assessment and average working life time of nuclear reactor is about 60 years today.



The first reactors constructed in 1950-1960 are called early prototypes reactors which are also called generation 1 reactors.Commercial reactors are called generation 2 reactors which are still working today while more advanced reactors than generation 2 is designed incorporated more advanced features to generation 2 reactors those are still producing electricity with their lower generation's partners are called generation 3 nuclear plants.Those are more advanced of their nuclear fuel technology, passive safety systems and standardized designs and currently under research and development in their theoretical aspects.The Generation IV International Forum (GIF) defined eight goals for these systems in four key areas: economics; safety and reliability; sustainability and proliferation resistance and physical protection.




Thorium- 232 is not fissile but it is fertile that mean it can produce Uranium- 233 which is useful in fission.Thorium -232 isotope cannot be undergone if bombarded from neutron pulse but irradiating process of Thorium make Uranium.This was widely discussed topic in 1950-1960 decades , In Srilanka around the areas of Panadura,Beruwala,pulmudai,Katukurunda,Induruwa,Aluthgam Kikawala,Ahungalla,Galle,Thirukkowil,Kalaoya,Galgamuwa,Udawalawe,Rakwana,Passara,potuvil,Kalmunai,Polonnaruwa,Mahaoya are rich of granular sediments and sedimentary rocks of jurassic age which posses Thorium bearing minerals such as Thorianite,thorite,allenite and monazite.However only at certain locations that these occurances are sufficiently concentrated for economic exploitation. Of these occurrences, Monazite sands are known to occur fairly along the coastal stretch covering Authgama – Beruwala - Induruwa in SW sector and Kudiramalai in NW sector of the island.    - Notable amounts of Thotianite sands are also reported in beach sands along Beruwala – Induruwa  areas.  - In addition, Monazite and Thorianite sands are reported to occur in lesser concentrations within Pulmuddai, Thirukkowil and Galle mineral occurrence.
 According to historical records, Thorianite was first discovered in Sri Lanka in 1904 by Dr. Ananda Coomaraswamy. during this period several tons of Thorianate were exported to Japan. Concentrations of Monazite in beach sands around Beruwala were exploited using a small experimental plant during the period of 1918 to 1922. About 450 tons of Monazite were reported to be recovered from approximately 3000 tons of raw sand during this period.  In 1956, a separation plant was fixed at Katukurunda area near Kalutara by the GSMB as a pilot plant to process mineral sands.  According to available records, an average of 1000 tons of sand per year with Monazite concentrations of 6 – 8% were processed at the plant and exported to Japan. In early eighties, the separation plant had to be abandoned due to various reasons.
 Gamma ray spectrometry analysis shows nearly 1.1% of Monazite concentration consists in coastal area of Panadura and Kalutara costal area related to Kalu river, Benthota river and Bolgoda lake.In near show Geo-physical survey of such areas , 11 potential granular resource sites were identified with surface areas between  0.5-27km2 and more than 2m thick dredge able sediments.According to this research 170 million granular sediments are found in top 2 M depth.



The primary source of the world’s thorium is the rare-earth and thorium phosphate mineral, monazite. In the United States, thorium has been a by product of refining monazite for its rare-earth content. Monazite itself is recovered as a by product of processing heavy-mineral sands for titanium and zirconium minerals. Without demand for the rare earths, monazite would probably not be recovered for its thorium content. Other ore minerals with higher thorium contents, such as Thorite, would be more likely source.
The most important geological environments in which thorium are enriched include: Alkaline complexes and their pegmatite, Granitic pegmatite, Carbonatites and Heavy mineral sand.On a global level heavy mineral sands or beach sands are host for valuable minerals such as Zircorn( zirconium silicate/Zr sio4), garnet and heavy metals such as Titanium(Ti),cerium(Ce) and Thorium(Th).Such of Thorium deposits have significant size and amounts in srilanka either in granulated forms or metamorphosed sands.The potential production of thorium concentrate from the resources will depend on the grain-size of thorium enriched minerals. Thorium occurs predominantly in the mineral monazite, but occurs also in other minerals, especially in REE minerals.
The front end of the thorium fuel cycle comprises thorium ore processing, production of thorium metal or oxide and fuel fabrication.The processing of Thorium consisting ore to above Thorium metal or oxide conclude several steps such as mining, extraction of Thorium bearing minerals, refining to remove impurities such as neutron absorbing agents(granite,metal salts,others) and production of Thorium containing oxide or metal.This purity is obtained industrially by solvent extraction, by ion exchange, or by direct chemical precipitation.In 1970-1980 decades Thorium is very popular as the source of nuclear elements because it's capability to use any type of existing reactors.The accelerator driven system (ADS) which is developed by European atomic energy community(UAEC)which couples an accelerator, a spallation source and sub - critical reactor but presently this concept is focused on high level of waste transmutation than on energy production.E.O Lawrence in 1950 the ADS system was found and he got noble prize for his new invention of this ADS system.


 Mainly as a method to produce fissile materials by neutron transmutation. Later, the concept was extended to "burn" nuclear waste. In 1993, another Nobel Prize laureate, Carlo Rubbia, revived the idea by proposing an ADS that could produce energy at the same time as it destroys both its own waste and waste from other reactors.This concept was called energy amplifier(EA)when compared with critical reactors accelerator driven system is technologically well designed and minimize the risk at emergency.
Any potential nuclear power in Srilanka has to accede to all IAEA recommended safety measures and more legal measures that internationally introduced., such as IAEA safety standards for Radiation protection, Nuclear safety, Activities that can produce radiation producing substances (e.g., mining) and waste handling and storage.Srilanka should participate every of international projects related to this subject in research as well as it's competency with neighboring India in nuclear wastes managements and environmental measures in nuclear power should be encouraged in participating joined group works.However to compete with European new nuclear era , Srilanka must have a regular plan in nuclear sciences and nuclear engineering field which consists of increasing staff in universities related to nuclear science and allocate more investments to researches in improving nuclear applications to Phd or other higher education fields.




37 countries have already taken to nuclear power production where more than 50 countries had stated that they have already taken decisions to move into that area. India has made considerable progress in the utilization of thorium for the provision of nuclear energy on the basis of current analysis and that by the middle of this century, the uranium reserves would in terms of the potential increase of nuclear power generation plants, rarely would meet those needs. By the end of this century there would be a steep increase in the price of uranium. So the Srilanka have to take a decision whether  to go into that process.


 Thorium in a situation in which there is recycling to uranium, there is a possibility of making the uranium resources of the world to stretch further. But there is a limit for that too. But if thorium can supplement the uranium, it can be then taken further because thorium also has the advantage that the plutonium did in the fuel cycle. But it is much better to use thorium for production of further uranium.The cost of fossil fuel is increasingly going up and carbon dioxide emission due to burn of fissile fuel already made a huge environmental trauma recently such as green house gas effect. The importance of non gas emitting nuclear technologies comes forward in such a situation.If nuclear wastes are managed effectively and efficiently in a recycling manner, nuclear power plants are precious resource for a country.




The next of article is about nuclear waste management and protection measures related to nuclear power plant.I personally expect Hon Prime minister and Hon president of Sri lanka would keep their keen attention on potential for nuclear power generation to the next generation of the country.




Anuradha Senarathna(Bsc, Pg dip in socio, dip in psy)--youths for good politics/ sera idea blogspot.com







1 comment:

  1. I'm Sukhitha Lakwan. I'm a huge follower of Liquid Fluoride Thorium Reactor Technology and this blog is a useful source of information. There are more than two believers in this technology in Sri Lanka. I'd like to work with someone who willingly researches in LFTRs although I'm still attending school.
    Lastly, I'd like to keep in touch with you.

    ReplyDelete