Enrichment & Reprocessing technologies B.M.Suri Why Enrichment ? • All naturally existing uranium is not fissile. • Natural uranium has 0.7% 235 isotope which is fissile • For generating nuclear power minimum 3% Uranium 235 is required • Weapons require more than 90 % uranium 235 • Similarly other isotopes like Uranium 233 and Plutonium 239 are fissile and require certain isotopic composition • There are many other isotopes of different elements which are useful for medical or other applications • Each isotopic composition requirement of different elements have different level of difficulty as well as techniques employed • Technology of enrichment is secret both for reasons of commerce and proliferation
Transcript
Enrichment &
Reprocessing
technologiesB.M.Suri
Why Enrichment ?
• All naturally existing uranium is not fissile.
• Natural uranium has 0.7% 235 isotope which is fissile
• For generating nuclear power minimum 3% Uranium 235 is required
• Weapons require more than 90 % uranium 235
• Similarly other isotopes like Uranium 233 and Plutonium 239 are fissile and require certain isotopic composition
• There are many other isotopes of different elements which are useful for medical or other applications
• Each isotopic composition requirement of different elements havedifferent level of difficulty as well as techniques employed
• Technology of enrichment is secret both for reasons of commerce and proliferation
• Gaseous Diffusion (only technique 1950-1970, presently being
phased out)
• Calutrons (employed in Manhattan Project but presently not
in use)
• Ultra-centrifuge (employed commercially)
• Aerodynamic (nozzle)
• Plasma
• Laser based (AVLIS, MLIS and SILEX)
Schematic of Gaseous Centrifuge
Schematic of Gaseous Diffusion Stage
Schematic : Molecular Laser Isotope Separation
Cross Section of Separation Nozzle
Plasma Separation Process
Conceptual AVLIS Process
Separative Work Unit
• Standard measure of capacity of Uranium Enrichment Plants and Standard measure of capacity of Uranium Enrichment Plants and Standard measure of capacity of Uranium Enrichment Plants and Standard measure of capacity of Uranium Enrichment Plants and
amount of enrichment required for particular Taskamount of enrichment required for particular Taskamount of enrichment required for particular Taskamount of enrichment required for particular Task
• For Example 4 SWU required to produce 1 Kg of 3% enriched
uranium (starting from 0.7%) with 0.25% tails
• 200 SWU’s required to produce 90% enriched uranium from natural
uranium
• 1 million SWU/yr plant : 250,000Kg of 3% or 5000 Kg of 90%
enriched
• $ per SWU is cost of enrichment
Gaseous Diffusion
• Developed during Manhattan Project for manufacture of nuclear weDeveloped during Manhattan Project for manufacture of nuclear weDeveloped during Manhattan Project for manufacture of nuclear weDeveloped during Manhattan Project for manufacture of nuclear weaponsaponsaponsapons
• Plants at Oak Ridge, Tennesse, Paducah, Kentucky and Portsmouth USA
produced most of enriched uranium for long time
• USA had virtual monopoly in international Market place
• One enrichment site occupied 44 acres
Manhattan Project employed two such plants for one nuclear weapManhattan Project employed two such plants for one nuclear weapManhattan Project employed two such plants for one nuclear weapManhattan Project employed two such plants for one nuclear weaponononon
Because of ease of implementation many other countries soon followed (UK,
USSR, France and China) - proliferation!
• Kind of ultraKind of ultraKind of ultraKind of ultra----filtration using uranium hexafluoride ; but technology highly filtration using uranium hexafluoride ; but technology highly filtration using uranium hexafluoride ; but technology highly filtration using uranium hexafluoride ; but technology highly
• Many of Diffusion based enrichment plants close to end of their life
• Highly energy intensive Highly energy intensive Highly energy intensive Highly energy intensive (80% of operation cost) and inefficient
Latest plant installed in France in seventies with about 11000 Latest plant installed in France in seventies with about 11000 Latest plant installed in France in seventies with about 11000 Latest plant installed in France in seventies with about 11000 tonnes of tonnes of tonnes of tonnes of
SWU/year capacity (Eurodiff). It has 1400 enrichment stages.SWU/year capacity (Eurodiff). It has 1400 enrichment stages.SWU/year capacity (Eurodiff). It has 1400 enrichment stages.SWU/year capacity (Eurodiff). It has 1400 enrichment stages.
• This can fuel ninety 1000 MW LWRThis can fuel ninety 1000 MW LWRThis can fuel ninety 1000 MW LWRThis can fuel ninety 1000 MW LWR’’’’s with 3.7% enriched uraniums with 3.7% enriched uraniums with 3.7% enriched uraniums with 3.7% enriched uranium
• Diffusion Technology ruled for several decades. Presently considered Presently considered Presently considered Presently considered
highly inefficient and costly highly inefficient and costly highly inefficient and costly highly inefficient and costly as new technologies emerged
• What was developed in response to War was harnessed for power
through the famous plan of “Atoms for Peace”
Gas Centrifuge
• Jesse Beams (1934) specialist in fast rotating machinery using carbon tetrachloride separated chlorine 35 and 37 isotopes using steel rotor 28 cm loseparated chlorine 35 and 37 isotopes using steel rotor 28 cm loseparated chlorine 35 and 37 isotopes using steel rotor 28 cm loseparated chlorine 35 and 37 isotopes using steel rotor 28 cm long ng ng ng and 8 cm diaand 8 cm diaand 8 cm diaand 8 cm dia
• In 1939 Otto Hann et.al. demonstrated U-235 was fissile. USA persuaded alll non USA persuaded alll non USA persuaded alll non USA persuaded alll non ----German researchers to block their publications in this area tillGerman researchers to block their publications in this area tillGerman researchers to block their publications in this area tillGerman researchers to block their publications in this area till war ended (aimed war ended (aimed war ended (aimed war ended (aimed at excluding Hitlerat excluding Hitlerat excluding Hitlerat excluding Hitler’’’’s scientists out)s scientists out)s scientists out)s scientists out)
• Manhattan project hotly pursued direction of Beams research on centrifuge. At that time it lost out the race to diffusion technology of the day
• Gernot Zippe working in USSR employed for the first time a vertical cylinder on vertical cylinder on vertical cylinder on vertical cylinder on magnetic bearing facilitating high speeds and larger isotope sepmagnetic bearing facilitating high speeds and larger isotope sepmagnetic bearing facilitating high speeds and larger isotope sepmagnetic bearing facilitating high speeds and larger isotope separation factorsaration factorsaration factorsaration factors. Zippe was allowed to migrate and then he worked with Beams in USA.
• Initially Zippe’s latest design was not secret till 1960. Germany, Holland and UK Germany, Holland and UK Germany, Holland and UK Germany, Holland and UK joined hands developed it further. USA once again persuaded themjoined hands developed it further. USA once again persuaded themjoined hands developed it further. USA once again persuaded themjoined hands developed it further. USA once again persuaded them to stop to stop to stop to stop publishing. Nobody knew of A.Q.Khan!publishing. Nobody knew of A.Q.Khan!publishing. Nobody knew of A.Q.Khan!publishing. Nobody knew of A.Q.Khan!
• In 1970 these three countries signed treaty of Almelo pledging to collaborate for commercial exploitation of gas centrifuge with 5% as upper limit . URENCO was born
• Separative power of centrifuge increases as fourth power of peripheral speed of rotor
Growth of Centrifuge
Technology• In 1971 Dutch development was based on aluminium rotors,
German on stronger maraging steel (used in aircrafts) and UK
on glass fibre reinforced plastic rotor. Finally carbon fibre
reinforcement was the winner
• The final design was pooled by three countries and centrifuge final design was pooled by three countries and centrifuge final design was pooled by three countries and centrifuge final design was pooled by three countries and centrifuge
TC 12 based on two decades of development work emergedTC 12 based on two decades of development work emergedTC 12 based on two decades of development work emergedTC 12 based on two decades of development work emerged
• The same designs were set up in Pakistan and also sold to
Iran, N.Korea and Libya.
• Americans knowing the market potential and limits on
capacity of their gaseous diffusion plants were working on
centrifuge. By mid 70By mid 70By mid 70By mid 70’’’’s Jumbo centrifuges (10 meters tall) with s Jumbo centrifuges (10 meters tall) with s Jumbo centrifuges (10 meters tall) with s Jumbo centrifuges (10 meters tall) with
capacity five times that of URENCO were builtcapacity five times that of URENCO were builtcapacity five times that of URENCO were builtcapacity five times that of URENCO were built
• In 1980, after a comparative study of two huge public investmentIn 1980, after a comparative study of two huge public investmentIn 1980, after a comparative study of two huge public investmentIn 1980, after a comparative study of two huge public investments in s in s in s in uranium enrichment, USA abruptly ended centrifuge funding in fauranium enrichment, USA abruptly ended centrifuge funding in fauranium enrichment, USA abruptly ended centrifuge funding in fauranium enrichment, USA abruptly ended centrifuge funding in favour of vour of vour of vour of Laser Isotope separationLaser Isotope separationLaser Isotope separationLaser Isotope separation
• In 1989 URENCO launched study to compare centrifuge and Laser baIn 1989 URENCO launched study to compare centrifuge and Laser baIn 1989 URENCO launched study to compare centrifuge and Laser baIn 1989 URENCO launched study to compare centrifuge and Laser based sed sed sed technologies and concluded in favour of centrifuge by 1995. Fivetechnologies and concluded in favour of centrifuge by 1995. Fivetechnologies and concluded in favour of centrifuge by 1995. Fivetechnologies and concluded in favour of centrifuge by 1995. Five years later years later years later years later USA too followed suit very abruptly USA too followed suit very abruptly USA too followed suit very abruptly USA too followed suit very abruptly –––– More to it than meets the eye.More to it than meets the eye.More to it than meets the eye.More to it than meets the eye.
• Russia had independently developed centrifuge technology and till recently its capacity was 40% of world capacity
• URENCO has plants operational in UK, Netherland and Germany and building one in USA.
• Japan (JNC and JNFL) operate small plants, China has two imported from Russia (erstwhile USSR) and has developed its own.
Present Status
• French plant operated by Areva at 3 billion Euro is expected to reach capacity of 7.5 million SWU/year in 2018
• $1.5 billion National Enrichment Facility in New Mexico, USA will use URENCO technology with 3 million SWU/yr in 2013
• USEC is building American centrifuge plant at Piketon USA around 4billion $ and 4 million SWU/yr. plans for 10% uranium 235 for sake of advanced reactors.
• Centrifuges rotate at very high speeds separating U-238 towards the edge of cylinder and U-235 close to centre.
• Safe operation requires special skills.
• Capacity of a single centrifuge is much smaller than that of Capacity of a single centrifuge is much smaller than that of Capacity of a single centrifuge is much smaller than that of Capacity of a single centrifuge is much smaller than that of diffusion stage but capability to separate is much greater.diffusion stage but capability to separate is much greater.diffusion stage but capability to separate is much greater.diffusion stage but capability to separate is much greater.
• For 10For 10For 10For 10----20 stages of centrifuge corresponds to about 1000 or 20 stages of centrifuge corresponds to about 1000 or 20 stages of centrifuge corresponds to about 1000 or 20 stages of centrifuge corresponds to about 1000 or more stages of diffusion plantmore stages of diffusion plantmore stages of diffusion plantmore stages of diffusion plant
Laser Isotope Separation
• This method uses a powerful specialised laser beam/s to separate isotopes of uranium by selectively ionising (or dissociating) them, to be followed by collection.
• There are several variations of this method. Feed is either uranium metal vapor or uranium hexafluoride. Correspondingly the lasers used are either tunable dye lasers (in visible) or infra-red.
• For quite some time there has been competition between centrifuge and laser based atomic vapor laser isotope separation methods.
• The parallel growth of these technologies in USA is depicted
• In 1985 Department of Energy judged the LLNL design of AVLIS to In 1985 Department of Energy judged the LLNL design of AVLIS to In 1985 Department of Energy judged the LLNL design of AVLIS to In 1985 Department of Energy judged the LLNL design of AVLIS to be more be more be more be more competitivecompetitivecompetitivecompetitive
• Like USA, those countries in nuclear power bussiness started work on these techniques.
• French CEA invested in their program called SILVA. This was carrFrench CEA invested in their program called SILVA. This was carrFrench CEA invested in their program called SILVA. This was carrFrench CEA invested in their program called SILVA. This was carried out in close ied out in close ied out in close ied out in close collaboration with COGEMA. This was aimed at building industrialcollaboration with COGEMA. This was aimed at building industrialcollaboration with COGEMA. This was aimed at building industrialcollaboration with COGEMA. This was aimed at building industrial facility for facility for facility for facility for fuelling LWRfuelling LWRfuelling LWRfuelling LWR’’’’s.s.s.s.
• CEA scientists could successfully demonstrate alteration of 0.2%CEA scientists could successfully demonstrate alteration of 0.2%CEA scientists could successfully demonstrate alteration of 0.2%CEA scientists could successfully demonstrate alteration of 0.2% tails to 0.13% of tails to 0.13% of tails to 0.13% of tails to 0.13% of UUUU----235. They could also enrich 200Kg of 2.5% U235. They could also enrich 200Kg of 2.5% U235. They could also enrich 200Kg of 2.5% U235. They could also enrich 200Kg of 2.5% U----235235235235
Types of LIS methods
• Laser Isotope separation was based on emergence of Laser Isotope separation was based on emergence of Laser Isotope separation was based on emergence of Laser Isotope separation was based on emergence of
technology of tunable Laserstechnology of tunable Laserstechnology of tunable Laserstechnology of tunable Lasers.
• AVLIS is atomic Vapor Laser Isotope Separation based on use of AVLIS is atomic Vapor Laser Isotope Separation based on use of AVLIS is atomic Vapor Laser Isotope Separation based on use of AVLIS is atomic Vapor Laser Isotope Separation based on use of
Uranium metal as feed and visible dye lasersUranium metal as feed and visible dye lasersUranium metal as feed and visible dye lasersUranium metal as feed and visible dye lasers
• MLIS and SILEX are based on uranium hexafluoride as feed and MLIS and SILEX are based on uranium hexafluoride as feed and MLIS and SILEX are based on uranium hexafluoride as feed and MLIS and SILEX are based on uranium hexafluoride as feed and
use of infrause of infrause of infrause of infra----red tunable lasers.red tunable lasers.red tunable lasers.red tunable lasers.
• All of them depend on Laser Spectroscopy for efficient and All of them depend on Laser Spectroscopy for efficient and All of them depend on Laser Spectroscopy for efficient and All of them depend on Laser Spectroscopy for efficient and
• AVLIS is useful for large range of elementsAVLIS is useful for large range of elementsAVLIS is useful for large range of elementsAVLIS is useful for large range of elements
Progress of AVLIS in USA
• Using refractory metal oven to produce Uranium vapor, Morehouse experiment produced milligram of enriched uraniummilligram of enriched uraniummilligram of enriched uraniummilligram of enriched uranium, verfying physics of AVLIS at LLNL (1974).
• Using electron beam to vaporize uranium, gram scale gram scale gram scale gram scale enriched uranium at few percent was obtained (1980)
• By 1984, meteric tonnes of uranium were processed, By 1984, meteric tonnes of uranium were processed, By 1984, meteric tonnes of uranium were processed, By 1984, meteric tonnes of uranium were processed, Plutonium isotopes were attempted for converting reactor Plutonium isotopes were attempted for converting reactor Plutonium isotopes were attempted for converting reactor Plutonium isotopes were attempted for converting reactor grade Pu to weapon grade Pu. Lasers were scaled up in power. grade Pu to weapon grade Pu. Lasers were scaled up in power. grade Pu to weapon grade Pu. Lasers were scaled up in power. grade Pu to weapon grade Pu. Lasers were scaled up in power.
• By 1985198519851985 DOE decided in favour of Uin favour of Uin favour of Uin favour of U----AVLIS on basis of lower AVLIS on basis of lower AVLIS on basis of lower AVLIS on basis of lower capital costs, operating costs as well as adherence to recent capital costs, operating costs as well as adherence to recent capital costs, operating costs as well as adherence to recent capital costs, operating costs as well as adherence to recent environmental requirementenvironmental requirementenvironmental requirementenvironmental requirement
• By 1992 Uranium Demonstration system and Laser By 1992 Uranium Demonstration system and Laser By 1992 Uranium Demonstration system and Laser By 1992 Uranium Demonstration system and Laser Demonstration Facility were constructed to test plant scale Demonstration Facility were constructed to test plant scale Demonstration Facility were constructed to test plant scale Demonstration Facility were constructed to test plant scale operation and suboperation and suboperation and suboperation and sub----system qualification.system qualification.system qualification.system qualification.
• Congressional action decided to privatise enrichment -created US Enrichment Corporation.
• .
• There was parallel growth of Pu AVLIS program. By mid 80parallel growth of Pu AVLIS program. By mid 80parallel growth of Pu AVLIS program. By mid 80parallel growth of Pu AVLIS program. By mid 80’’’’s shortage of Pu s shortage of Pu s shortage of Pu s shortage of Pu for weapons was serious. The tasks given were completed before 1for weapons was serious. The tasks given were completed before 1for weapons was serious. The tasks given were completed before 1for weapons was serious. The tasks given were completed before 1990. But 990. But 990. But 990. But end of cold war also ended the need for WG Pu. Further Plant proend of cold war also ended the need for WG Pu. Further Plant proend of cold war also ended the need for WG Pu. Further Plant proend of cold war also ended the need for WG Pu. Further Plant production duction duction duction was halted but recognising LLNL expertise, in 1996, Strategic Mawas halted but recognising LLNL expertise, in 1996, Strategic Mawas halted but recognising LLNL expertise, in 1996, Strategic Mawas halted but recognising LLNL expertise, in 1996, Strategic Materials terials terials terials Application program was created.Application program was created.Application program was created.Application program was created.
• This program was engaged in developing technologies for processing, in developing technologies for processing, in developing technologies for processing, in developing technologies for processing, manufacturing and storing nuclear materials related to weapons pmanufacturing and storing nuclear materials related to weapons pmanufacturing and storing nuclear materials related to weapons pmanufacturing and storing nuclear materials related to weapons program. rogram. rogram. rogram.
• Developing advanced techniques for safe and secure disposition of excess nuclear materials from DOE’s inventory
• SMAP is also working with Los Alamos National Lab to develop Advanced Recovery and Integrated Extraction System to recover Pu from retired or excess nuclear weapons
Design & Operation parameters
of Enrichment Plant • Separation factor per unit separator
• Cascade Potential
• Feed inventory
• Residence time
• Capital cost
• Running cost
• Running skills
• Energy Consumption
• Floor space requirements
LIS programs in other
countries• There were programs on Laser Isotope separation in 20 countries There were programs on Laser Isotope separation in 20 countries There were programs on Laser Isotope separation in 20 countries There were programs on Laser Isotope separation in 20 countries ––––
Argentina, Australia, Brazil, Britain, China, France, Germany, IArgentina, Australia, Brazil, Britain, China, France, Germany, IArgentina, Australia, Brazil, Britain, China, France, Germany, IArgentina, Australia, Brazil, Britain, China, France, Germany, India, Iraq, ndia, Iraq, ndia, Iraq, ndia, Iraq, Israel, Iran, Italy, Japan, Netherlands, Pakistan, Romania, RussIsrael, Iran, Italy, Japan, Netherlands, Pakistan, Romania, RussIsrael, Iran, Italy, Japan, Netherlands, Pakistan, Romania, RussIsrael, Iran, Italy, Japan, Netherlands, Pakistan, Romania, Russia, South ia, South ia, South ia, South Africa, Spain, Sweden, Switzerland, United States and YugoslaviaAfrica, Spain, Sweden, Switzerland, United States and YugoslaviaAfrica, Spain, Sweden, Switzerland, United States and YugoslaviaAfrica, Spain, Sweden, Switzerland, United States and Yugoslavia
• Most nations in lab stage except Britain, France and USA which went to Pre-Industrial stage
• No country operating commerciallyNo country operating commerciallyNo country operating commerciallyNo country operating commercially
• United States was on verge of commercialising, when USEC decidedUnited States was on verge of commercialising, when USEC decidedUnited States was on verge of commercialising, when USEC decidedUnited States was on verge of commercialising, when USEC decided in in in in June 1999 to cancel its AVLIS program. It had spent around $ 100June 1999 to cancel its AVLIS program. It had spent around $ 100June 1999 to cancel its AVLIS program. It had spent around $ 100June 1999 to cancel its AVLIS program. It had spent around $ 100 million million million million on AVLIS in a year since its privatisation. US AVLIS program invon AVLIS in a year since its privatisation. US AVLIS program invon AVLIS in a year since its privatisation. US AVLIS program invon AVLIS in a year since its privatisation. US AVLIS program involved 27 olved 27 olved 27 olved 27 years of research and development and an investment of $ 2 billiyears of research and development and an investment of $ 2 billiyears of research and development and an investment of $ 2 billiyears of research and development and an investment of $ 2 billion. on. on. on. Publicly the reason given was soaring of cost estimates.Publicly the reason given was soaring of cost estimates.Publicly the reason given was soaring of cost estimates.Publicly the reason given was soaring of cost estimates.
• There was another technique based on Lasers which was on radar oThere was another technique based on Lasers which was on radar oThere was another technique based on Lasers which was on radar oThere was another technique based on Lasers which was on radar of f f f USEC. This technique called SILEX was purchased in several billiUSEC. This technique called SILEX was purchased in several billiUSEC. This technique called SILEX was purchased in several billiUSEC. This technique called SILEX was purchased in several billion dollars on dollars on dollars on dollars from an Australian company. from an Australian company. from an Australian company. from an Australian company.
• US and Australian Govts declared this to be Classified(2001). OnUS and Australian Govts declared this to be Classified(2001). OnUS and Australian Govts declared this to be Classified(2001). OnUS and Australian Govts declared this to be Classified(2001). On April April April April 2003 USEC terminated funding of SILEX. This was transferred to a2003 USEC terminated funding of SILEX. This was transferred to a2003 USEC terminated funding of SILEX. This was transferred to a2003 USEC terminated funding of SILEX. This was transferred to aSyndicate of General Electric and Hitachi. Syndicate of General Electric and Hitachi. Syndicate of General Electric and Hitachi. Syndicate of General Electric and Hitachi.
Mystery of SILEX Process
• Transfer of SILEX uranium Enrichment project to GE’s
Wilmington, North Carolina nuclear fuel plant was completed
early 2007. This included equipment used in prior work and 12
key SILEX staff
• GE-Hitachi signed letter of intent for uranium enrichment with
Exelon and Entergy –two largest nuclear power utilities in USA
• Global Laser enrichment formed as subsidary of GEGlobal Laser enrichment formed as subsidary of GEGlobal Laser enrichment formed as subsidary of GEGlobal Laser enrichment formed as subsidary of GE----Hitachi to Hitachi to Hitachi to Hitachi to
• GLE got approval license from US Nuclear regulatory
Commission for operation
• GE Hitachi Nuclear Energy (GEH) and Cameco Corp World’s
largest uranium producer will be co-owners Cameco paid US $
124 million for 24% stake.
• SILEX process SILEX process SILEX process SILEX process –––– full technical details are highly guarded full technical details are highly guarded full technical details are highly guarded full technical details are highly guarded secret but is based on Uranium hexafluoride feedstock secret but is based on Uranium hexafluoride feedstock secret but is based on Uranium hexafluoride feedstock secret but is based on Uranium hexafluoride feedstock and is described as low overall capital costs and very and is described as low overall capital costs and very and is described as low overall capital costs and very and is described as low overall capital costs and very low energy consumption. This can also be applied for low energy consumption. This can also be applied for low energy consumption. This can also be applied for low energy consumption. This can also be applied for enrichment of other isotopes such as carbon, silicon, enrichment of other isotopes such as carbon, silicon, enrichment of other isotopes such as carbon, silicon, enrichment of other isotopes such as carbon, silicon, molybdenum, boron, zirconium, xenon, palladium, molybdenum, boron, zirconium, xenon, palladium, molybdenum, boron, zirconium, xenon, palladium, molybdenum, boron, zirconium, xenon, palladium, thallium, gadolinium, zinc etc. providing breakthroughs thallium, gadolinium, zinc etc. providing breakthroughs thallium, gadolinium, zinc etc. providing breakthroughs thallium, gadolinium, zinc etc. providing breakthroughs in several fields but at the risk of making uranium in several fields but at the risk of making uranium in several fields but at the risk of making uranium in several fields but at the risk of making uranium enrichment for nuclear weapons cheaper and easier. enrichment for nuclear weapons cheaper and easier. enrichment for nuclear weapons cheaper and easier. enrichment for nuclear weapons cheaper and easier. Legal and political detail on how SILEX plan to prevent Legal and political detail on how SILEX plan to prevent Legal and political detail on how SILEX plan to prevent Legal and political detail on how SILEX plan to prevent military use is unknownmilitary use is unknownmilitary use is unknownmilitary use is unknown
• In 2012 SILEX has been given the environment related clearance In 2012 SILEX has been given the environment related clearance In 2012 SILEX has been given the environment related clearance In 2012 SILEX has been given the environment related clearance ––––the final hurdlethe final hurdlethe final hurdlethe final hurdle.
• USEC has exclusive rights (purchased from Australian company SILUSEC has exclusive rights (purchased from Australian company SILUSEC has exclusive rights (purchased from Australian company SILUSEC has exclusive rights (purchased from Australian company SILEX) on R&DEX) on R&DEX) on R&DEX) on R&D
Mystery of SILEX Process
• Transfer of SILEX uranium Enrichment project to GE’s Wilmington, North Carolina nuclear fuel plant was completed early 2007. This included equipment used in prior work and 12 key SILEX staff
• GEGEGEGE----Hitachi signed letter of intent for uranium enrichment with Hitachi signed letter of intent for uranium enrichment with Hitachi signed letter of intent for uranium enrichment with Hitachi signed letter of intent for uranium enrichment with Exelon and Entergy Exelon and Entergy Exelon and Entergy Exelon and Entergy ––––two largest nuclear power utilities in USAtwo largest nuclear power utilities in USAtwo largest nuclear power utilities in USAtwo largest nuclear power utilities in USA
• Global Laser enrichment formed as subsidary of GEGlobal Laser enrichment formed as subsidary of GEGlobal Laser enrichment formed as subsidary of GEGlobal Laser enrichment formed as subsidary of GE----Hitachi to Hitachi to Hitachi to Hitachi to commercialise SILEXcommercialise SILEXcommercialise SILEXcommercialise SILEX
• GLE got approval license from US Nuclear regulatory Commission for operation
• GE Hitachi Nuclear Energy (GEH) and Cameco Corp WorldGE Hitachi Nuclear Energy (GEH) and Cameco Corp WorldGE Hitachi Nuclear Energy (GEH) and Cameco Corp WorldGE Hitachi Nuclear Energy (GEH) and Cameco Corp World’’’’s s s s largest uranium producer will be colargest uranium producer will be colargest uranium producer will be colargest uranium producer will be co----owners Cameco paid US $ owners Cameco paid US $ owners Cameco paid US $ owners Cameco paid US $ 124 million for 24% stake.124 million for 24% stake.124 million for 24% stake.124 million for 24% stake.
Supply & Demand of Enrichment ServicesSupply & Demand of Enrichment ServicesSupply & Demand of Enrichment ServicesSupply & Demand of Enrichment Services
Enrichment of fissile isotopes for
N-Power and Weapons• Fissile isotopes (UFissile isotopes (UFissile isotopes (UFissile isotopes (U----235 in LWR or PWR ; Pu235 in LWR or PWR ; Pu235 in LWR or PWR ; Pu235 in LWR or PWR ; Pu----239 in Fast Breeder 239 in Fast Breeder 239 in Fast Breeder 239 in Fast Breeder
reactors; Ureactors; Ureactors; Ureactors; U----233 in Thorium based reactors 233 in Thorium based reactors 233 in Thorium based reactors 233 in Thorium based reactors –––– proposed AHWR proposed AHWR proposed AHWR proposed AHWR
etc.)etc.)etc.)etc.)
• UUUU----235235235235 is 0.7% abundance in natural uranium and requires
enrichment for efficient fuel utilisation
• Pu Pu Pu Pu ----239 and U239 and U239 and U239 and U----233 233 233 233 are bye-products of reprocessing
• 1950-1970 Gaseous Diffusion (USA) supplied most of fuel of
free world
• Post 1970 new techniques started emerging and fuel supply
and demand was matching reasonably and proliferation was
thought to be under control (NPT)
• Pokharan I (1974) and Oil embargo (1979) increased fears
about energy security and proliferation.
Fluctuations in Demands on
Enrichment • Global Warming Global Warming Global Warming Global Warming
• Nuclear Accidents Nuclear Accidents Nuclear Accidents Nuclear Accidents (Three Mile Island, Chernobyl and Later Fukushima) affect Public Perception
• Americans willing to privatise Enrichment
• Watch on sidelines about R&D in novel techniques based on Lasersetc.
• Soviet weapon grade HEU becomes available for N-Power (1990)
• Lawrence Livermore Lab successful in converting RG Pu to WG Pu using AVLIS (~1992)
• Americans sense Proliferation Potential sense Proliferation Potential sense Proliferation Potential sense Proliferation Potential in view of Pokharan II and the aftermath (1998)
• Emergence of Thorium Cycle will reduce demand on enrichment Emergence of Thorium Cycle will reduce demand on enrichment Emergence of Thorium Cycle will reduce demand on enrichment Emergence of Thorium Cycle will reduce demand on enrichment required for Nrequired for Nrequired for Nrequired for N----PowerPowerPowerPower
• After a nuclear reactor (research or power) has operated for some time or burnt its fuel it becomes a storehouse of new isotopes (elements) because of nuclear reactions happening inside nuclear reactor
• For renewed operation of reactor this spent fuel has to be taken out.
• As Plutonium is inevitably produced in reactor As Plutonium is inevitably produced in reactor As Plutonium is inevitably produced in reactor As Plutonium is inevitably produced in reactor –––– so the problem is not so the problem is not so the problem is not so the problem is not how to avoid production but how to manage spent fuel consistent how to avoid production but how to manage spent fuel consistent how to avoid production but how to manage spent fuel consistent how to avoid production but how to manage spent fuel consistent with with with with ecoecoecoeco----politics and proliferation resistancepolitics and proliferation resistancepolitics and proliferation resistancepolitics and proliferation resistance
• Two choices are : either to process spent fuel elements followed by storage of separated plutonium or recycling of separated plutonium in thermal or fast breeder reactors, the second choice being to leave plutonium in spent fuel without reprocessing and store it as such with an option to reprocess it later or vitrify and put it in waste repository.
Criticality Hazards in
reprocessing• While reprocessing solutions with large volumes with very littleWhile reprocessing solutions with large volumes with very littleWhile reprocessing solutions with large volumes with very littleWhile reprocessing solutions with large volumes with very little
neutron absorbers have to be dealt withneutron absorbers have to be dealt withneutron absorbers have to be dealt withneutron absorbers have to be dealt with
• This can frequently result in local criticality accidents
• Large number of accidents Large number of accidents Large number of accidents Large number of accidents have happened in various countries
which have given lot of valuable lessons particularly in PUREX
• Storage and Postponed Decision (wait and watch)Storage and Postponed Decision (wait and watch)Storage and Postponed Decision (wait and watch)Storage and Postponed Decision (wait and watch)
• Reprocessing and Recycle (France, Japan, Russia and India) Reprocessing and Recycle (France, Japan, Russia and India) Reprocessing and Recycle (France, Japan, Russia and India) Reprocessing and Recycle (France, Japan, Russia and India) ----
also called Closed Fuel Cyclealso called Closed Fuel Cyclealso called Closed Fuel Cyclealso called Closed Fuel Cycle
Actinides Half-life Fission products
244Cm 241Puƒƒƒƒ 250Cf 227Ac№ 10–22 y medium
mmmm is
meta
85Kr 113mCd₡
232Uƒƒƒƒ 238Pu 243Cmƒƒƒƒ 29–90 y 137Cs 90Sr 151Sm₡₡₡₡ 121mSn
ƒƒƒƒ for
fissile
249Cfƒƒƒƒ 242mAmƒƒƒƒ 251Cfƒƒƒƒ[23]
140 y –
1.6 ky
No fission products
have a half-life in the
range of 91 y – 210 ky
241Am 226Ra№[24] 247Bk
240Pu 229Th 246Cm 243Am 5–7 ky
4n 245Cmƒƒƒƒ 250Cm 239Puƒƒƒƒ 8–24 ky
236Npƒƒƒƒ 233Uƒƒƒƒ 230Th№ 231Pa№ 32–160 ky
248Cm 4n+1 234U№ 211–348 ky 99Tc ₡₡₡₡ can capture 126Sn 79Se
236U 237Np 242Pu 247Cmƒƒƒƒ 0.37–23 My 135Cs₡ 93Zr 107Pd 129I long
• Covert diversion Covert diversion Covert diversion Covert diversion : safeguarding a reprocessing plant or MOX
fuel fabrication plant
• Direct diversion from reprocessing plant is reactor grade
plutonium (74% Pu-239 and 24% Pu-240). Normally not
considered suitable for weapon but innovative weapon
designs can overcome this problem
Drivers for Closed Fuel Cycle
• Conservation of Natural Resources
• Efficient Fuel Cycle economics
• Minimisation of Waste and optimisation of disposal
• Proliferation Resistance
• Environmental Impact
• Inventory of radioactive materials
• Choice & Capacity of repositories
• Public (political) support for N-Energy
Futuristic Reprocessing
• Sustained interest in Nuclear energy because of global
warming is motivating force
• Reduced consumption of Uranium per unit of enrgy produced
• Reduce long term radioactivity of HLW
• Ability to burn long lived minor actinides and fission products
which are not useful
• Adaptable to new reactor types and fuel cycles
• Amenable to co-location and co-processing for efficient
safeguarding
Schematic of Future Fuel Reprocessing System
Schematic : Advanced Fuel Cycle
Schematic Pyrochemical Fuel Reprocessing for Metallic
Fast Reactor Fuel
Group Actinide Extraction Concept
Decay Heat versus time for various components
Reprocessing Issues related to Thorium CycleReprocessing Issues related to Thorium CycleReprocessing Issues related to Thorium CycleReprocessing Issues related to Thorium Cycle
Issues to be resolved for
Thorium Fuel Cycle• Issues and challenges for both open and closed fuel cycle
variations for Thorium fuel cycle to be commercialised
• Learn about inventories of radionuclides in spent Thorium
based fuels for various fertle/fissile fuel combinations like :
Th 232/U235/U238 ; Th232/Pu239 ;
Th232/U233/U238.
For each case burnup has to be optimised for efficient
power production
• Residual heat for sake of repositories
• Radiotoxicity
• Thorium cycle does not produce much of Pu, Np, Am and Cm at
least for first recycle but Protoactinium 231, Thorium 229 and
U231. They have their own radiological impact
• No experience for case of optimum burnup
• Transmutation of long lived actinides and fission products to short
lived or stable isotopes.
• Thorex fuel processing uses HF with attendant disadvantages
• Possibility of production of high purity UPossibility of production of high purity UPossibility of production of high purity UPossibility of production of high purity U----233 with associated 233 with associated 233 with associated 233 with associated
Pa233• Irradiated thorium produces protoactinium 233 (decay life 27
days). For its full conversion to U233 (fissile component)
waiting period of about an year is required
• While reprocessing some Pa233 inevitably goes into fission
product (waste) stream where later on it produces fissile
U233
• Both above problems are features of present Thorium
reprocessing technique - THOREX
• U-232 is inevitably produced as part of decay chain from U233 and
Pa233
• U232 as part of its decay chain produces some products like Tl20U232 as part of its decay chain produces some products like Tl20U232 as part of its decay chain produces some products like Tl20U232 as part of its decay chain produces some products like Tl208 8 8 8
and Bi212 which produces dangerously radioactive gamma radiationand Bi212 which produces dangerously radioactive gamma radiationand Bi212 which produces dangerously radioactive gamma radiationand Bi212 which produces dangerously radioactive gamma radiation
• U232 and U233 cannot be separated!
• For closed fuel cycle case U233 fuel fabrication becomes extremeFor closed fuel cycle case U233 fuel fabrication becomes extremeFor closed fuel cycle case U233 fuel fabrication becomes extremeFor closed fuel cycle case U233 fuel fabrication becomes extremely ly ly ly
complicated because of presence of U232 requiring a hot cellcomplicated because of presence of U232 requiring a hot cellcomplicated because of presence of U232 requiring a hot cellcomplicated because of presence of U232 requiring a hot cell
• Production rate of U232 in a reactor is dependent on neutron
energy (fast or slow), irradiation time (or burnup) and location of
thorium bundle from core fissile fuel bundle
• For commercial use high burnup is must which inevitably produces
more U232 (from 1000ppm to 5000ppm depending upon the
reactor type)
• But in many reactors low concentration of U232 could be achievedBut in many reactors low concentration of U232 could be achievedBut in many reactors low concentration of U232 could be achievedBut in many reactors low concentration of U232 could be achieved
(< 5ppm). At these concentration fuel can be handled outside hot(< 5ppm). At these concentration fuel can be handled outside hot(< 5ppm). At these concentration fuel can be handled outside hot(< 5ppm). At these concentration fuel can be handled outside hot
cellcellcellcell
Schematic AHWR Fuel Reprocessing
Thank You
Acknowledgemets and
References• International Atomic Agency Report, IAEA – TECDOC 1450
• International Atomic Agency Report IAEA – TECDOC 1587
• On Spent Fuel Reprocessing : Idaho National Lab, Dr. Terry
