uranium fuel cycle 1. 2 conventional mining: underground/open pit ranger, australia, northern...
TRANSCRIPT
Uranium Fuel Cycle
1
2
Conventional Mining: Underground/Open Pit
Ranger, Australia, Northern Territories
Olympic Dam, South Australia
3
ISR: Drilling – Well Construction
4
ISR: Minimum Disturbance of Environment
5
ISR Plant – Schematic
6
ISR Plant – Beverley, South Australia
7
Ion Exchange Resins
Beverley Plant – Impressions
IX columns Filtration units
Yellowcake Sampling The product
9
BACKUP
General Atomics Proprietary Data10
SiC-SiC Composite Cladding has Potential to Significantly Improve Safety of Light Water Reactors
0.0
0.5
1.0
1.5
2.0
0 1 2
m3
H2
gene
rate
d/m
2ro
d su
rfac
e
reaction time (days)
Zircaloy 100% consumed
SiCβ <1% consumed
1400oC
1100oC
1400oC
1100oC
Zr + 2H2O ZrO2 + 2H2
For Zircaloy, destruction by steam reaction occurs at lower temp than fuel melt
FukushimaDaiichi
Eliminate hydrogen explosions
SiC + 4H2O SiO2 + CO2 + 4H2
For SiC/SiC, structural failure occurs at lower temp than steam reaction
At higher temps (~1400oC) Zircaloy reaction heat exceeds decay heat
General Atomics Proprietary Data
Comparison of EM2 vs Fukushima Plant To Earthquake & Tsunami9.0 magnitude earth quake/tsunami: reactor vessels and containments are intact but all electrical
power is severed
Fukushima
• Without power, cooling systems are inoperable
• Fuel heats up causing high pressure and hydrogen producing reactions from zircalloy clad
• External means of cooling is needed until power to cooling systems is restored
• Reactor cooling by natural convection – no power needed
• Silicon-carbide clad does not react with helium coolant at high temperature
• Walk-away safe – no external intervention needed
air draft heat exchanger
Grade levelEM2
Redundant shutdown cooling
Reactor
Turbine-generator
Leak-tight, below-grade containment
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Fuel Resources for Electric Power Generation in the U.S.A.
Depleted uranium (DU)/Used nuclear fuel (UNF)
inventories
Depleted uranium (DU)/Used nuclear fuel (UNF)
inventories
8 TBbl Depleted Uranium
1 TBbl Used Nuclear Fuel
Energy supplyfor > 300 years electric power generation
Energy supplyfor > 300 years electric power generation
U.S. Energy Reserves(Trillion Bbls Oil Energy
Equivalent)
General Atomics Proprietary Data13
Graphitereflector
BeOreflector
B4C neutron Shield
Core support
floor 316L
StarterConversion
Control drum location
Starter FertileLEU: ~ 12% Low- enriched uranium
DU: Depleted uranium
TRU: Transuranics
UNF: Used nuclear fuel
MOX: Mixed U/Pu oxides
NU: Natural uranium
Recycled EM2 discharge
30% 232Th70% 238U
“Convert & Burn” reactor achieves a 30-year fuel life by converting 238U to 239Pu and burning in situ
General Atomics Proprietary Data
LWR Waste Disposal EM2 Waste Disposal
• Deep geologic repository
• Million year life
• Large storage capacity
• Long term heat
• Long term radioactivity
•Above ground storage
• 400 year life
•Small storage capacity
•Short term heat
•Short term radioactivity
EM2 Changes the Game Relative to Nuclear Waste
0
20
40
60
80
100
LWR EM2
Was
te m
ass,
ton
nes
EM2 vs LWR Wastebased on 5000 GWe/days production
Uranium
Plutonium
Fission Products
3.4
Only 0.1% are long lived fission products
(e.g. Tc-99 and I-129)0
20
40
60
80
100
LWR EM2
Was
te m
ass,
ton
nes
EM2 vs LWR Wastebased on 5000 GWe/days production
Uranium
Plutonium
Fission Products
3.4
Only 0.1% are long lived fission products
(e.g. Tc-99 and I-129)
General Atomics Proprietary Data15
BACKUP 2
16
ISR Mining Process
• Groundwater pumped to surface (at start-up)• Small amount of acid and oxidant added• Water pumped back into aquifer• Uranium leached• Water pumped to surface• Uranium recovered by ion exchange (IX)• Water recycled
[up to 100 recycles (pore volume exchanges)]
17
Leaching Chemistry
• Uranium ore– Uranium as U(IV) fixed in minerals,
e.g. pitchblende UO2, coffinite USiO4
• Mobilization of uranium by oxidation and complexation– Uranium needs to be oxidized to U(VI) to form soluble
uranyl ions UO22-
• Leaching methods– Alkaline (carbonate) leaching:
UO2(CO3)22- and higher-order complexes
– Acidic (sulfuric acid) leaching: UO2(SO4)2
2- and higher-order complexes– Application of oxidants: O2, H2O2
18
Uranium Recovery
• Mining solution contains anionic uranyl complexes like UO2(CO3)2
2- or UO2(SO4)22-
• Recovery from mining solution by ion-exchange (IX)– Resin (in form of beads at 0.5-1 mm diameter)– Resin beds in big columns (about 2-4 m diameter, 3-10 m
height)– Mining fluid passes IX columns and recycles to wellfields– Uranium is adsorbed on the resin
• Strip of uranium from IX resin by highly-ionic solution, e.g. salt solutions (NaCl)
• Further processing includes precipitation of uranium as uranium oxide, thickening, de-watering, drying, packaging
19
ISR – Hydrogeology
For ISR mining, ore body must have following properties:– Ore body must be in an aquifer (sedimentary formation)– Aquifer sediments must be permeable– Aquifer should be vertically confined (above and below) by
impermeable layers
20
Beverley ISR Mine – Processing Plant