nuclear power summer 2010

Nuclear Power:a Global Look

Roppon PichaThailand Institute of Nuclear Technology

Nuclear power is currently our most potentenergy source.

& a clean energy solution for today andtomorrow.

Basic human needs:

Food,air,water,energy

How much energy?

The Earth is approximately 4.5 billion years old. (fromradiometric dating of mineral samples.)

2,000 years ago, there are 10 million people.

1,000 years later: 300 millions

Today: 6.7 billions.

(data: United Nations, U.S. Census Bureau)

(OECD/IEA World Energy Outlook 2004)

Nuclear energy is due to two important discoveries: neutron byJames Chadwick in 1932 and uranium in 1789 by MartinHeinrich Klaproth.

Fission reaction

n + 235U → X + Y + n’s

Fission

In 1939, Hahn, Strassmann, Meitner, and Frisch discoveredthat neutron can split uranium.

92 → 56

Fission coined.

Energy release ' 200 MeV per reaction.

Fission

∼ 70 years after it was discovered, nuclear fission is nowresponsible for 1/6 the total energy produced around the world.

Mochovce power plant, Slovakia

First nuclear reactor

In 1942, Enrico Fermi and histeam built the World’s firstnuclear fission reactor in asquash court of University ofChicago.

The atomic pile was calledChicago Pile No. 1.

Enrico Fermi(1901–1954)

The first man-made self-sustaining chain reactions went on for28 minutes on 2 Dec 1942 (3:25–3:53 p.m.).

The pile consisted of uraniumpellets as fuel, and graphiteblocks as moderator.

Cadmium coated rods wereused to absorb extra neutrons,dampening the reaction.

Chicago Pile 1

The energy of the atom’s nucleus was first unleashed.

Fuel choices

U-235 is fissileFermi: U-238 is fertile → breed Pu-239 (fissile) at fast nenergies → EBR-I (Experimental Breeder Reactor-I)

U-233 is also fissile. Can be bred from Th-232.

First four nuclear bulbs (@ EBR-I, Idaho Falls, USA, Dec 1951)

USS Nautilus: first nuclear submarine (1953)

Research: generate neutrons from fission. Low power level(1–10 MW). Neutron flux is in the order of 1013 n/cm2/s.

Research reactor at TINT, in Bangkok, Thailand

Power: generate electricity from kinetic energy of fissionfragments

Power reactor in Leibstadt, Switzerland

The world needs electricity for development.

Only 2% of African ruralpeople have access tonational power grid.

1.6 billion people are without access toelectricity

(24.4%)

(IEA, World Energy Outlook 2006)

Carbon Mitigation Initiative

Collaboration between Princeton University, BP, and Ford MotorCompany

Mission: To find solutions to the greenhouse gas problem.

CMI’s 4 strategies

1. Increase the energy efficiency of our cars, homes, andpower plants while lowering our consumption by adjusting ourthermostats and driving fewer miles.

CMI’s 4 strategies

2. Capture the carbon emitted by power plants and store itunderground.

CMI’s 4 strategies

3. Halt deforestation andsoil degradation worldwide,while reforesting moreareas.

CO2+H2O → 16

C6H12O6+O2

(photosynthesis)

CMI’s 4 strategies

4. Produce more energy from nuclear and renewablefuelssolar, wind, hydroelectric, and bio-fuels.

Bellville NPP, France [ c©Areva]

Coming Clean: The Truth and Future of Coal in the Asia-Pacific (World WildFund for Nature)

“Estimated radiation doses ingestedby people living near the coal plants wereequal to or higher than doses for peopleliving around the nuclear facilities.”

Hvistendahl, M. (2007). Coal Ash Is More Radioactive than NuclearWaste. Retrieved October 14, 2009, from Scientific American Web site:

http://www.scientificamerican.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste

McBride, J. P. et al. (1978). Radiological Impact of Airborne Effluents of

Coal and Nuclear Plants. Science, 202(4372), 1045–1050.

ash = bottom ash + fly ashfly ash (U, Th) → escapes to environment

Asia:

countries operating NPP’s under constructionPakistan 2 1

China 11 21India 18 5

S. Korea 20 6Japan 54 1

(data: IAEA, Feb 2010)

Japan: 54

That’s third most in the world.

Korea

Seoul during Korean War (1950)

At the end of WWII (1945), power generation capacity in Korea:North 88.5%, South 11.5%. Korean War (1950–1953) put

Korea in total destruction.

(eryoni@flickr)

First nuclear power in South Korea: 20 July 1978 (Kori-1reactor). Today (Mar 2010) nuclear electricity is almost 40% of

total.

UraniumUranium is one of the most abundant elements found in theEarth’s crust. It can be found almost everywhere in soil androck, in rivers and oceans.

235U

is the only natural isotope which is fissionable by thermalneutrons.

World’s largest high-graded uranium deposit: McArthur River, Canada.World’s known uranium is estimated to be about 5.5 Mt (source: OECD NEA

& IAEA, Uranium 2007: Resources, Production, and Demand)

Another important source of fuel is the nuclear weaponstockpiles in the USA and countries of the former SovietRussia. These weapons contain highly enriched uranium.

Future reprocessing technology will further increase uraniumusage efficiency.

Uranium deposits

(Uranium 2005: Resources, Production and Demand, OECD/IAEA)

Uranium

Samples from drilling duringuranium exploration

( c©: Cameco)

Yellowcake

Yellowcake is the uranium compound mostly consisting oftriuranium octaoxide (U3O8), and some uranium dioxide (UO2)and uranium trioxide (UO3).

n + U → U∗

Neutron cross section

Uranium enrichment

Only 0.7% of natural uranium is 235U, the fissile isotope. Higherconcentration (of around 3–5%) is required in a nuclear reactor.There are mainly two enrichment processes, both using UF6.

1. gaseous diffusion2. gas centrifuge

under development: laser enrichment(photoexcitation of isotopes)

Fuel and spent fuel

Level of enrichment of reactor fuelis much less than that of nuclearweapon (over 85% enriched).

They serve different purposes.

Highly enriched uranium billet(US DoE)

Fuel pelletsUF6 is typically converted back to UO2 solid, compressed intopellets.

Fuel

A typical pellet of uranium weighs about 7 grams. It cangenerate energy equivalent to 3.5 barrels of oil, 480 m3 ofnatural gas, or 800 kg of coal.

Fuel

The uranium is encased in ceramic. The fissile isotopes mustbe densely packed so that the chain reaction can sustain itself.

Fuel pellets are packed inside zirconium tubes (resistant toradiation, heat, and corrosion). The rods are bundled togetherinto an assembly.

For most reactors, high energy neutrons are moderated bywater.

Capture, Excitation, Deformation

U-235 mass split:heavy/light ∼ 1.4

where does the Energy come from?

Kinetic energy of fission fragments heat up the water.

Conversion reactors

Converters or conversion reactors are designed to convertmaterial that is not fissionable (but “fertile”) with thermalneutrons to one that is.

238U + n → 239U 23 min−−−−→ 239Np + β− + ν̄

239Np 2.3 d−−−→ 239Pu + β− + ν̄

232Th + n → 233Th 22min−−−→ 233Pa + β− + ν̄

233Pa 27 d−−→ 233U + β− + ν̄

Fast breeder reactors

Current reactors

(Nuclear Engineering International

Handbook 2007)

Most power reactors usenormal water as moderatorand coolant.

Control room

Reactor operators must go through intensive certificationprocess.

Operators must be trained andlicensed:

• reactor theory• thermodynamics• plant components• design and operation• emergency response

Each reactor type (PWR, BWR,and others) has a differenttraining program.

Interactions

Ranked by characteristic length: γ ∼ n > e− > hcp

Characteristic energy deposition of hcp: Bragg’s peak

Coulomb forces lead to continuous excitation and ionization ofmedium. Neutrons and gamma can penetrate far due to lack ofelectric charge.

Shielding

Penetration of radiation depends on its stopping power (specificenergy loss).

S = −dEdx

For charged particles, S increases as velocity decreases.Bragg curve.

Shielding

Even in air, the energetic alphas can travel for only several cm.

R (cm) = 0.56E (MeV) for E < 4 MeVR (cm) = 1.24E − 2.62 (MeV) for 4 < E < 8 MeV

For medium of mass number A,

R (mg/cm2) = 0.56A1/3Rair

(Cember, H., Introduction to Health Physics, McGraw-Hill, 1996)

α’s and β’s are easy to protect against.

Just paper or plastic is fine.

Shielding

The concerns of radiation are mostly related to highlypenetrating radiation such as gamma rays and neutrons.

Gamma rays are electromagnetic wave. Its interaction strengthdepends on the charge number (Z ) of the material.

Neutrons are neutral. Must be slowed down via direct collisions.

Shielding

High-Z materials can be used to effectively shield γ-rays. Maininteractions are

• Photoelectric absorption• Compton scattering• Pair production

Absorption coefficient in PbH. A. Enge Introduction to nuclear physics (1966)

High-Z materials are good for shielding γ-rays.

Neutrons cross sections are very energy dependent.

Hydrogen-rich medium can be used to slow down neutrons.Then thermal neutrons can be absorbed by materials with highneutron capture cross section such as boron or cadmium.

Storage pool in an interimstorage facility at Oskarshamn,Sweden(Image: SKB; Photographer:Curt-Robert Lindqvist)

Vitrification into borosilicate glass (mixture of SiO2 and B2O3) isused to contain high-level waste from nuclear reactors.

Pictured is the amount of high-level waste due to nuclearelectricity generation in one person’s lifetime.

A knife can cut, can decorate, can kill.

Fire can cook, can warm, can burn.

First X-ray image (1895)

Frau Roentgen’s hand

Any use for radioactive stuff from the nuclear reactor?

Reactor isotopes

• iodine-131 (t1/2 = 8.0 d) and iodine-132 (t1/2 = 2.3 h): thyroidcancer treatment and diagnosis

• iridium-192 (74 d): internal radiotherapy, gamma radiography

• molybdenum-99 (66 h): used as source of technetium-99m (6 h)

• cobalt-60 (5.3 y): external radiotherapy, industrial radiography

• dysprosium-165 (2 h): treatment of arthritis

Radiotherapy @ Cancer Hospital, Kostanai, Kazakhstan ( c©Samuel C. Blackman)

How do people respond to nuclear for therapy?

Waterford, Ireland (2006)

Mini break

Who discoveredthe proton?

Operating reactors

(IAEA, Feb 2010)

∼ 76% of electricity in France comes from nuclear (year2008, IAEA)

56 new reactors are being constructed (Feb 2010).

Advanced designs

Generation 3+ reactors are being built around the world. Theyhave simpler designs, are more fuel efficient, produce lesswaste, and have enhanced safety.

Some of these are:

• Advanced Boiling Water Reactor (ABWR), by GeneralElectrics (GE) Nuclear Energy (approved May 1997)

• System 80+, by Westinghouse (May 1997). Not activelymarketed.

• AP600, by Westinghouse (Dec 1999) and AP1000, byWestinghouse (Dec 2005)

• EPR, by Areva NP

EPR

Olkiluoto 3: First Gen-3+ reactor built

PBMR

PBMR fuel pebbles

PBMR

PBMR uses He coolant and graphite moderator.

Fusion

From n + 235U to D + T .

Fusion

More difficult due to Coulomb repulsion. High temperatureenvironment is required.

exercise: Estimate potential energy between two hydrogennuclei at distance 10 fm apart.

Fusion

D + T → α + n

Q = 17.6 MeV: α (3.5) + n (14.1)

other reactions (much lower cross sections):

D + D → 3He + n (Q = 3.3 MeV)→ T + H (4.0 MeV)

D +3 He → 4He + H (18.3 MeV)

Various power sources are used to spark the gas anddischarge it into plasma. Must know how to control plasmaslong enough for fusion to break even.

Plasma discharge in ASDEX tokamak (Germany)

Magnetically confined plasma:

National Spherical Torus Experiment (NSTX) in Princeton

NSTX: Princeton PlasmaPhysics Lab, Oak Ridge Lab,Columbia U., U. of Washingtonat Seattle

D+D fusion

First plasma: 12 Feb 1999

ITER: Gas heated to over 100 million K. Plasma density ∼ 1020 m−3. 500MW of fusion power (non-electricity).

ITER: Future tokamak

Location: Cadarache, FranceExpecting first plasma by 2016

Conceptual fusion power plant (EFDA)

International collaborations

GNEP: Global Nuclear Energy Partnership

International collaborations

International collaborations

For countries without a nuclear power plant, thefirst step is the hardest step. People must havestrong determination and responsibilities.

Once an NPP is built, the country will developmore. Everybody starts from zero.

Thanks.