Introduction to Nuclear Energy
Jacopo Buongiorno
Associa t e Pr of essor of Nuc l ear Science and Engineering
Image by MIT OpenCourseWare.
U-235 has 2.5 million times more energy per pound than coal: 37 tons of fuel ( 3%-enriched uranium ) p er 1000 MW e reactor per yea r
Nuclear provides an emission-fre e hea t source that can be converted into multiple products
Electricity (worldwide)
Steam for industry (done in Switzerland, Russia, Japan, not in the U.S.)
Hydrogen (future with development of technology)
Nuclear com p ared to fossil fuels
Fuel energy content
Coal (C): C + O 2 CO 2 + 4 eV
Natural Gas (CH 4 ): CH 4 + O 2 CO 2 + 2H 2 O + 8 eV
Nuclear (U): 235 U + n 93 Rb + 141 Cs + 2n + 200 MeV
Fuel Consumption, 1000 MW e Power Plant (=10 6 homes)
Coal (40% ef ficiency):
10 9 /(0.4x4x1.6x10 -19 ) 3.9x10 27 C/sec (=6750 ton/day) Natural Gas ( 50% ef ficienc y) :
10 9 /(0.5x8x1.6x10 -19 ) 1.6x10 27 CH 4 /sec (=64 m 3 /sec) Nuclear (33% ef ficiency):
10 9 /(0.33x200x1.6x10 -13 ) 1.0x10 20 U/sec (=3 kg/day)
1 eV = 1.6x10 -19 J
U ore Y e llow cake F uel assembl y
Fuel pin
Pellets
Boiling W ater Reactor (BWR)
Public domain image from wikipedia.
Rankine Cycle
Reacto r
Image removed due to copyright restrictions.
Tu r b i n e - generator
turns heat into work, then electricity
Pressurized W ater Reactor (PWR)
Public domain image from wikipedia.
PWR P rimary System
Courtesy of Westinghouse. Used with permission.
PWR
Reactor V e ssel Showing internal Structures and Fuel Assemblies
Public domain image from wikipedia.
Heat Discharge in Nuclear Plants (2 nd law of thermodynamics)
Nuclear Ener gy in the US , toda y
104 US reactors, 100 GWe is 13% of US installed ca p acit y but p rovides about 20% of electricit y .
In 2007 nuclear energy production in the US was the highest ever .
US plants have run at 90.5% capacity in 2009 , up from 56% in 1980 .
3 . 5 GWe o f uprates were permitted i n t he last decade .
3.5 GWe are expected by 2014 and more by 2020 .
59 reactor licenses extended, from 40 years to 60 years of operation, 20 more reactors in process.
Electricity production costs of nuclear are the lowest in US ( 1 - 2 ¢ /kWh)
Calver t Cliffs - M D
Robinson - SC
Indian Point - N Y
Diablo Canyon - CA
Prairie Island site - M N Surr y - V A
The MIT Research Reactor
- 5 MW power
- Located near NW12 on Albany St.
- Operated by MIT students
- Just turned 50!
Nuclear Ener gy in the W o rld T o da y
Courtesy of MIT student. Used with permission.
About 440 W orld r e actors in 30 countries, 14% of global electricity pr oduced.
6 0 new reactors are in various stages of constructio n
Olkiluoto – Finland
Lungmen – T aiwan Kudankulam – I ndia
Fl amanv ill e – F rance
Rostov – R ussia
Shin kori – S . Korea
Shimane – Japan
Sanmen – C hina
3 on g oin g in the US!
V ogtle, G eor gia Summer , South C arolina
W atts Bar , T ennessee
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The Case for New Nuclear Plants in the US
Concerns for climate change…
S o u r c e s o f E m i s s i o n - F r e e E l e c t r i c i t y 2 0 0 8
S o l a r , W i n d & G e o t h e r m a l 6 . 1 %
H y d r o 2 1 . 7 %
Athabasca Glacier, Jasper National Park, Alberta, Canad a
Photo provided by the National Snow and Ice Data Center
Courtesy of National Snow and Ice Data Center. Used with permission.
U S d a t a
N u c l e a r 7 2 . 3 %
Image by MIT OpenCourseWare.
Ab ou t 700 , 000 , 000 t on o f CO2 em i ss i ons avo id e d every year in the US
The Case for New Nuclear Plants in the US (2)
…and growing fossil fuel imports and consumption
T o t a l U . S . E n e r g y C o n s u m p t i o n
O i l 4 0 %
C o a l 2 3 %
G a s 2 2 %
N u c l e a r 8 %
R e n e w a b l e s 6 % ( P r i m a r i l y H y d r o )
T o tal U . S. Ener g y Consumption
↑
Low C arbon
↓
Image by MIT OpenCourseWare.
Oil is the Challenge
U.S. data from EIA, Annual Energy Outl ook 2008 Early Release, years 2006 and 2030; world data from I EA, World Energy Outlook 20 07, years 2005 and 2030
C an nuc l ear di sp l ace coa l?
Y e s, as they are both used for baseload electricity generation.
What about oil?
Oil Is Used for Transportation.
What Are the Other Transport Fuel Options?
Plug-in hybrid electric vehicles (PHEVs)
Liquid f uels from fossil s ources (oil , natural gas and coal)
Liquid fuels from biomass
Hydrogen
Long term option
Depends upon hydrogen on-board-vehicle storage b rea k t h roug h
PHEVs: Recharge Batteries from the Electric Grid Plus Use of Gasoline
Electric car limitations
Limited range
Recharge time (Gasoline/Diesel refueling r ate i s ~ 10 MW)
Plug-in hybrid electric vehicle
Images removed due to copyright restrictions .
Electric drive for short trips
Recharge battery overnight to avoid rapid recharge requirement
Hybrid engine with gasoline or d i ese l e n g in e f o r l o n ge r t ri ps
Connects cars and light trucks to the electrical grid
Courtesy of the Electric Power Research Institute
PHEVs: Annual Gasoline Consum p tion
Substituting Electricity for Gasoline
900
Annual Gasoline Consumption (gallons)
800
700
600
500
400
300
200
100
0
100
-
A nnu
Compact sedan Midsize sedan Midsize SUV Fullsize SUV
Conventional vehicle
Plug-in HE V , 20 mile EV range
Plug-in HE V , 60 mile EV range
"No-Plug" Hybrid
Image by MIT OpenCourseWare.
Need 150 to 200 Nuclear Plants Each Producing 1000 MW( e)
Refineries Consume ~7% of the Total U.S. Energy Demand
G ases (Propane, etc.)
Cool
Heater
Energ y inp u ts
C
Cool
Condense Distillate
Primarily heat at 550 C
Petrocoke
Resid
Distillation Thermal
Column
Cracker
il Some hydrogen
rude Condense Light O
Oil Gasoline
Distillat
e Hi g h-tem p erature ga s reactor s could suppl y hea t and hydrogen
Market size equals existing nuclear
T r aditional Refining
enterprise
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25
Bio mass: 1.3 Billion Tons per Yea r
Available Biomass without Significantly Impacting
U.S. Food, Fiber, and Timber
Agricultural Residues
Logging Residues
Urban Residues
Energy Crops
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C o n v e r s i o n o f B i o m a s s t o L i q u i d
F u e l s R e q u i r e s E n e r g y
B i o m a s s
A t m o s p h e r i c
C a r b o n D i o x i d e
F u e l F a c t o r y
C a r s , T r u c k s , a n d P l a n e s
E n e r g y
L i q u i d F u e l s
C x H y + ( X + Y ) O 2
4
C O 2 + ( Y ) H 2 O
2
26
Image by MIT OpenCourseWare.
Starch
( corn, potatoes, etc. )
Steam
Natural gas
Steam
Ethanol plant
Steam plant
Nuclear reactor
Ethanol plant
Animal protein
Ethanol
Electricity
Animal protein
Ethanol
Natural gas/biomass
Nuclear/biomass
Fossil energy input 70% of energy content of ethanol
50% Decrease in CO 2 Emissions/Gallon ethanol 50% reduction in steam cost
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5 Advanced Reactor Designs Considered for New Construction in the US
Gen III+ Plants: Improved Versions of Existing Plant Designs
ABWR (GE-Hitachi) US- A PWR (Mitsubishi)
US-EPR (ARE V A )
A P1000 ( T oshiba: W estinghouse) ESBWR (GE-Hitachi)
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Nuclear Reactor Timeline
Advanced Reactors (Gen III+) that initiated design certification process with the NRC
Design |
Applicant |
T y pe |
Design Certification Status |
AP1000 |
W e stinghouse- To s h i b a |
Advanced Passive PWR 1 100 MW e |
Certified, Amendment under review |
ABWR |
G E-Hitachi |
A dvanced BWR 1350 MW e |
Certified, Constructed in Japan/ T aiwan |
ESBWR |
GE - Hitachi |
Advanced Passive BWR 1550 MW e |
Under review |
US-EPR |
ARE V A |
A dvanced PWR 1600 MW e |
Applied in 2007 |
US-APWR |
M itsubishi |
A dvanced PWR 1700 MW e |
Applied in 2007 |
U . S . u tiliti es h ave su b m itt e d 18 li cens i ng app li ca ti ons (total 28 units)
Mission/Goals f or Gen III+
Improved economics. Targets:
- Increased plant design life ( 60 years)
- Shorter construction schedule (36 months*)
- Low overnight capital cost ( $1000/kWe** for NOAK p l an t)
- Low O&M cost of electricity ( 1¢/kWh)
* First concrete to fuel loading (does not include site excavation and pre - service testing)
** Unrealistic target set in early 2000s . Current contracts in Europe, China and US have overnight capital costs
>$3000/kWe
Improved safety and reliability
- R e d uce d nee d f or opera t or ac ti on
- Expected to beat NRC goal of CDF<10 -4 /yr
- Reduced lar g e release p robabilit y
- More redundancy or passive safety
31
Nuclear Safet y Prime r
Hazard: fission products are highly
radioactive
Aggravating factor: nuclear fuel can never be completely shut down ( decay heat)
Objective: prevent release of radioactivity into environment
Safety Pillars:
- Defense - in - depth : multiple, independent physical barriers (i.e., fuel pin + vessel + containment)
- Safety systems : prevent overheating of the core when normal coolant is lost
Some interesting s afety - related features of the Gen III+ reactors…
Hi g her redundanc y ( US-EPR ECCS )
Four identical diesel-driven trains, each 100%, provide redundancy for maintenance or sin g le-failure criterion (N+2)
Physical s eparation against internal hazards (e.g. fire)
Hi g her redunda nc y ( US-EPR Containment )
Inner wall pre-stressed concrete w i t h stee l li ner
Outer wall reinforced concrete
Protection a gainst airplane crash
Protection against external explosions
Annulus sub-atmospheric and filtered to reduce radioisotope release
Passive safet y s y stems ( AP1000 ECCS )
http://ww w .ap1000.westinghousenuclear .com/ap1000_psrs_pccs.html
Courtesy of Westinghouse. Used with permission.
Passive safet y s y stems ( ESBWR ECCS and PCCS )
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S e v e r e accidents m i t i g a t i o n ( E P R c o r e catcher)
IR WST
Corium Spreading Area
E x - vessel core catcher concept (passive)
- Molten core is assumed to breach vessel
- Molten core flows into spreading area and is cooled by IRWST water
- H ydrogen recombiners ensure no detonation within container
Nuclear energy economics
Nuclear Ener gy Economics
Financial risk for new plants is high
Initial investement is lar g e ( $3,480/kW G$/unit )
Fear of delays during construction (like in 70s and 80s)
p r e m i u m
R i s k
9
c o a l / g a s
o v e r
L e v e l i z e d c o s t o f e l e c t r i c i t y , c / k W h
8 $ 2 5 / t C O 2
7
6
5
4
3
2
1
0
$ 2 5 / t C O 2
N u c l e a r C o a l G a s
C a p i t a l O & M F u e l
Image by MIT OpenCourseWare.
Nuclear production costs are lowest of all energy sources
U . S . E l e c t r i c i t y P r o d u c t i o n C o s t s
1 9 9 5 - 2 0 0 8 , I n 2 0 0 8 c e n t s p e r k i l o w a t t - h o u r
1 8 , 0
1 6 , 0
1 4 , 0
1 2 , 0
P e t r o l e u m - 1 7 . 2 6
1 0 , 0
8 , 0
G a s - 8 . 0 9
C o a l - 2 . 7 5
N u c l e a r - 1 . 8 7
6 , 0
4 , 0
2 , 0
0 , 0
1 9 9 5 1 9 9 6 1 9 9 7 1 9 9 8 1 9 9 9 2 0 0 0 2 0 0 1 2 0 0 2 2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 6 2 0 0 7 2 0 0 8
Image by MIT OpenCourseWare.
Production Costs = Operations and Maintenance Costs + Fuel Costs. Production costs do no t include indirect costs and are base d o n FERC Form 1 filings submitted by regulated utilities. Production costs are modeled for utilities that are not regulated.
Source: Ventyx Velocity Suite Updated: 5/09
Nuclear Fuel - Com p act & Economic
Nuclear fuel cycle has made up less than 15% of the cost of nuclear electricity . In 2006 that was about 6
$/MWhr, out of a total electricity cost of 50 $/MWhr
This covers the following steps
Uranium ore extraction and conversion to U 3 O 8, at $48/kg
Enrichment in U235, typically by centrifugal forces spinning gaseous UF 6 , to about 4% (Japan Rakashu plant in side pictures)
Manufacturing of UO 2 pellets, and placing them in Zr tubes (cladding) thus p roducin g fuel rods. The rods (or pins) are arranged in square lattices called assemblies.
Removal of spent fuel assemblies to temporary storage in fuel pools, th en t o i n t er i m d ry s t orage
1 $/MWhr for spent fuel disposal fees
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Nuclear fuel cycle
Fuel Cycle Scenarios ( 1 )
Once-through ( US current )
Mining |
||||||
& |
Fuel |
Light Water |
Interim |
Waste |
||
Milling |
Conversion |
Enrichment |
Fabrication |
Thermal Reactor |
Storage |
Disposal |
Image by MIT OpenCourseWare.
Milling & Mining Process
1MT ore = 2-3 lb uranium
End product is U 3 O 8 powder (“yellowcake”)
Major suppliers:
Canada
Australia
Kazakhstan
Africa
Former Soviet Union [FSU]
Large secondary (“already mined”) market dominates supplies
Bellezane , France S ite ( open pit mine)
Bellezane Site: After Reclaimation
Kazakhstan K A TCO ( In situ leachin g)
Conversion Process
U 3 O 8 converted to UF 6 for enrichment process
UF 6 : only form of uranium that is gaseous at temperatures
Gaseous at 133 ° F ( 5 6 . 1 ° C)
In solid form at room temperature
“ industrial ”
Uranium Enrichment
Two m ajor commercial p rocesses:
Gaseous Diffusion
Gas C entrifuging
Can also blend down weapons-grade HEU
U.S.-Russian HEU A g reement ( “Me g atons to Megawatts”) - ~50% of U.S. fuel supply
Upward price pressure driven by demand Priced in Separative Work Units (SWU)
Enrichment: Gaseous Diffusion
Enriched
• The UF 6 gas dif f uses across a membrane (filter):
Feed
Exit
U 238 F 6
U 235 F 6
molecules a re smalle r ,
faster: they cross the membrane more often, statistically
Thi s ga s i s enriche d i n U 235
U 238 F 6 molecules are bigger , slower: they cross the membrane less often, statistically
Thi s ga s i s deplete d i n U 23 5
Me m b r a n e
Depleted Exit
U 235 F 6
Gaseous Diffusion E nrichment Facility
Tricastin Site: EURODIF Gas Diffusion Enrichment Plant
Enrichment: Gas C entrifuging
F eed
• The U F 6
gas i s centrifuged:
De pleted Exit
Enric h ed E x it
U 235 F 6 molecules are lighter and move preferentially toward the center of the rotor
Re d Bale/Ga s enriche d i n U 235
U 238 F 6 molecules are heavier and move p referentiall y toward the periphery of the rotor
Y e llo w Bale/Ga s deplete d i n U 235
Gas C entrifuge Enrichment Facility
Fuel Fabrication Proce s s
« D e-Conversion »
UF 6 UO 2
1 Powder Production 2 Pressing or pelletizing 3 Sintering
4 Grinding 5 Rod cladding
Light water reactor fuel rod
6 Assembly fabrication
Fabricator Consolidations
Toshiba
Westinghouse (PWR)
A BB-CE (PWR, BWR)
Nuclear Fuel Industries, Ltd. (PWR, BWR) AREVA NP
Framatome Cogema Fuels (PWR)
Siemens Nuclear (PWR, BWR) GNF (Global Nuclear Fuels)
GE Nuclear Fuel (BWR)
JNF: Hitachi/Toshiba (BWR)
Spent Fuel Management (waste disposal)
In the US all spent fuel is currently stored at the plants
2
In the s p ent fuel stora g e p ools for about 10 years …
… then transferred to sealed dry casks; cooled by air; heavily shielded; internal temp and press monitored; can last for decades with minimal maintenance and cost .
A 1000-MW reactor requires about 80 dry casks for all the spent fuel it produces in 60 years fo operation (about 3 acres of land).
Dry cask storing of all US nuclear fleet spent fuel would r equire only 300 acres of land. (The volumes are small !!!)
Spent Fuel Management (waste disposal) (2)
In the long-term the spent fuel can be stored in deep geological repository
- The Y u cca Mountain site was selected for the US, authorized by then-President Bush, the license application received by NRC in 2008
- The project is strongly opposed by the State of Nevada
The current administration intends to shut down the Y u cca Mountain project and search for alternatives solutions (yet to be defined…)
The Y u cca Mountain Spent Nuclear Fuel Repository
Fuel Cycle Scenarios (2)
Thermal Reactor Recycle (France, German y , Switzerland,
Belgium and Japan current , soon in the U S)
Image by MIT OpenCourseWare.
MOX fuel
Pu
Fuel U Spent Fuel Fabrication Reprocessing
Fuel Cycle Scenarios
3. Fast Reactor Recycle (demonstration stage in Japan and Russia)
Image by MIT OpenCourseWare.
Wa s t e Disposal
Fuel Fabrication
U
TRU
Spent Fuel Reprocessing
Fast Neutron Reactor
Spent fuel management (recycling)
Spent fuel from L WRs is reprocessed and:
- Separated Pu is recycled in L W Rs (MOX approach, done in France and Japan)
- Pu+U recycled in (sodium-cooled) fast reactors
(being reconsidered in Russia , US under GNEP umbrella)
Japan ,
France and
96% of a u sed fuel assembly is recyclable
Composition o f u sed light water r eactor fuel
1 L W R fuel assembly = 500 kg uranium before irradiation in the reactor
Recyclable materials Wa s t e
After i rradiation *
U 475 to 480 kg
(94 to 96 % )
Pu 5 kg
(1 %)
FP 15 to 20 kg
(3 to 5 % )
RECYCLING RECYCLING FINAL W A STE
* Percen ta g e s may vary base d on fuel burnu p
The Main Stages in Recycling
T r eatment operations
(shea r ing - d issolution - separa t ion - purification)
R ecy c l e d F ue l
Fuel elements
U
Pu
Unloading Interim stora g e
Vit r ifi e d res id ue s
(CSD-V)
Hulls Compa c t e d
(CSD-C)
and end-pieces res id ues
Ultimate Wa s t e
At each stage, nuclear material accounting under EUR A T O M and IAEA safeguards
Standard p acka g in g for lon g -term mana g ement
Compacted waste V itrified waste
Proliferation R isk
Some technical characteristics of the fuel cycle (high burnup, no Pu separation, use of Th) can alleviate (but not completely eliminate) the proliferation risk
For the US the problem is minimal, as the fuel cycle is well safeguarded
For developing countries it is mostly a
political problem , perhaps b est handled
through multilateral and/or bilateral ins p ections ( successful exam p le: Brazil/Argentina)
Conclusions
Nuclear produces 20% of US electricity today
Renewed interest in nuclear stems f rom c oncerns over climate change and fossil fuel imports
Nuclear can displace coal in electricity sector and a lot of oil in transportation secto r
New reactor technologies offer superior level of safety achieved via increased redundancy and/or passive safety systems
Various nuclear fuel cycle options are a vailable
Challenge is capital cost of new plants (not safety… and not waste)
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22.06 Engineering of Nuclear Systems
Fall 20 10
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