Nuclear EnergyNuclear Energy

By: Elisa FatilaBy: Elisa Fatila

April 6, 2006April 6, 2006

The History of Nuclear PowerThe History of Nuclear Power First reactor built operational in 1942 by Enrico FermiFirst reactor built operational in 1942 by Enrico Fermi11

First commercial reactor in Obininsk, First commercial reactor in Obininsk, USSRUSSR US Patent held by US Patent held by Enrico FermiEnrico Fermi and and Leo Szilard Leo Szilard 11

Patent number 2,708,656 in 1955Patent number 2,708,656 in 195511

235235UU and and 239239PuPu fuels fuels

1. Argonne National Laboratory. http://www.anl.gov/Media_Center/News/History/news960518.html

Enrico Fermi

UraniumUranium Uranium as abundant asUranium as abundant as Zn Zn and and SnSn Half-lifeHalf-life 238238UU is 4.5 billion yearsis 4.5 billion years 99.3% is 99.3% is 238238UU a and nd ~ 0.7% ~ 0.7% 235235UU

Show chart of abundance in different countriesShow chart of abundance in different countries

Figure 2: Reserves of uranium worldwide

Uranium as FuelUranium as Fuel

1 lb1 lb of of 235235U = U = 1 million gallons1 million gallons of gasoline of gasoline Price of uranium ~$33/lb USDPrice of uranium ~$33/lb USD

All time high of $43/lb in 1979All time high of $43/lb in 197922

Cost comes from Cost comes from labourlabour and and technologytechnology required for required for power plants and power plants and enrichmentenrichment

Briefing papers. www.uic.com Figure 1: The price of uranium in the US US$/lb U3O8 (2)

The Nuclear Fuel CycleThe Nuclear Fuel Cycle

Mining and milling

Fuel preparation

Energy production

Spent fuel reprocessing

Waste disposal

Pitchblende U3O8 UF6 UO2

Chemical Conversion of UOChemical Conversion of UO22 to UF to UF66

UOUO22 + 4HF + 4HF UF UF44 +2H +2H22OO

3UF3UF44 +2ClF +2ClF33 3 3UFUF66 + Cl + Cl2 2

Fluoridating agents: BrFFluoridating agents: BrF55, F, F22

UFUF66 low vapour pressure low vapour pressure

Enrichment of UFEnrichment of UF66

UFUF66 gaseous diffusiongaseous diffusion UOUO22 powder powder

oror

gas centrifugegas centrifugeConverted to UOConverted to UO22 by ammonium diuranate precipitation by ammonium diuranate precipitation

~3% ~3% 235235U suitable for most reactor typesU suitable for most reactor types

Figure : Gas centrifuge cascades at Ohio diffusion plant

Reactor TypesReactor Types

Two major types:Two major types:

fast Slow (thermal)

Breeder type Light water Heavy water

Boiling water reactors

Pressurized water reactors

Neutron = 2 MeV (fast)

Breeder ReactorsBreeder Reactors

Requires Requires 15% - 30%15% - 30% enrichment enrichment Generate Generate 239239PuPu as product as product Liquid metal (Liquid metal (K, NaK, Na) as coolant) as coolant

Formation of Formation of 239239PuPu ( (ββ-emission-emission))

238238U + U + 11n n 239239U + U + νν + e + e 239239Np + Np + νν + e + e 239239PuPu

Heavy Water ReactorsHeavy Water Reactors CANDUCANDU reactors reactors

Heavy water acts as Heavy water acts as moderatormoderator and and coolantcoolant Cost of DCost of D22O offset by lowered enrichment costO offset by lowered enrichment cost Heavy water more effective at Heavy water more effective at moderating neutronsmoderating neutrons so less so less

enriched U is required (2)enriched U is required (2) Controlled substanceControlled substance

Light Water ReactorsLight Water Reactors Require about Require about 3% - 5%3% - 5% enrichment enrichment Light water as Light water as coolantcoolant and and moderatormoderator Common and Common and inexpensiveinexpensive pressurizedpressurized or or boiling waterboiling water (1) (1) USUS

Pebble Bed ReactorsPebble Bed Reactors

Researched in China and IndiaResearched in China and India Use Use 235235UU and and 232232ThTh Generate more U than consumedGenerate more U than consumed Use inert gases as coolant (COUse inert gases as coolant (CO2, N, N22, Ar), Ar)

Other Reactors TypesOther Reactors Types

Gas-cooled (fast or thermal) Gas-cooled (fast or thermal) ThoriumThorium reactors absorbs slow neutrons reactors absorbs slow neutrons

232232Th + n Th + n 223223Th Th 233233Pa + e + v Pa + e + v 233233U + e + vU + e + v 232232Th relatively abundantTh relatively abundant

Important Reactor ComponentsImportant Reactor ComponentsHeavy Heavy WaterWater

Light Light WaterWater

Liquid Liquid MetalMetal

Pebble Pebble BedBed

CladdingCladding ZrZr ZrZr Mg-Al Mg-Al alloyalloy

ModeratorModerator DD22OO graphitegraphite N/AN/A graphitegraphite

Control Control RodsRods

Cd, B Cd, B steelsteel

Cd, HfCd, Hf Cd, HfCd, Hf N/AN/A

CoolantsCoolants DD22OO HH22OO NaNa COCO22, He, He

Problems with Nuclear EnergyProblems with Nuclear Energy Terrorist concernsTerrorist concerns

Disposal concerns (Yucca Mountain)Disposal concerns (Yucca Mountain)

Wastes produced at each step of fuel cycleWastes produced at each step of fuel cycle

Accidents (Three Mile Island, Chernobyl)Accidents (Three Mile Island, Chernobyl)

Why Nuclear Energy Increasingly Why Nuclear Energy Increasingly ImportantImportant

Increase in populations in Increase in populations in ChinaChina and and IndiaIndia Wildly fluctuating prices in oilWildly fluctuating prices in oil New, safer technologyNew, safer technology Chronologically farther away from accidentsChronologically farther away from accidents

ConclusionConclusion

Nuclear fuel cycleNuclear fuel cycle

Economic effectsEconomic effects

Political falloutPolitical fallout

Spent fuel ReprocessingSpent fuel Reprocessing Resource poor Japan and FranceResource poor Japan and France Cost comparison: Cost comparison: ~$30/lb~$30/lb extract extract $400/lb$400/lb reprocess reprocess PUREXPUREX separation of separation of 239239Pu, Pu, 235235U and fission productsU and fission products Sensitive and dangerousSensitive and dangerous Kilograms of Kilograms of 239239Pu Pu criticalitycriticality risk risk

Irradiated fuel elements

Solution of UO22+ Pu (IV) + fission

products

7 M HNO3 TBP

FP

PuO2 and UO2

Waste DisposalWaste Disposal

Classification of wastes:Classification of wastes: Low level wastes: Low level wastes: mill tailingsmill tailings

High level wastes:High level wastes: