Nuclear Energy - University of Notre Dame

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Nuclear Energy - University of Notre Dame

Energy

and

Society


Nuclear Energy

Can we reach for a sustainable

and attainable energy Future?

Chapter 7 + handouts

Thursday September 27, 2012


OECD countries

The mission of the Organization for Economic Co-operation

and Development (OECD) is to promote policies that will

improve the economic and social well-being of people around

the world.

Assignment for Tuesday Oct. 2, 2012


Nuclear Power or Nuclear Energy

Worldwide Excitement about Nuclear Science


“As a zero-carbon energy

source, nuclear power must

be part of our energy mix as

we work toward energy

independence and meeting

the challenge of global

warming.”

— Nobel physicist Steven

Chu, U.S. Secretary of

Energy - May 6, 2009


Complicated

Related to Nuclear Weapons…. Atoms for Peace program

Fear/Emotion

Lack of understanding/knowledge

Expensive

Radioactive Waste

http://www.maniacworld.com/Tsar-Nuclear-Explosion.html


http://www.maniacworld.com/Tsar-Nuclear-Explosion.html


"Atoms for Peace" was the title of a speech delivered by U.S.

President Dwight D. Eisenhower to the UN General Assembly in

New York City on December 8, 1953.

• "It is with the book of history, and not with isolated

pages, that the United States will ever wish to be

identified. My country wants to be constructive, not

destructive. It wants agreement, not wars, among nations.

It wants itself to live in freedom, and in the confidence

that the people of every other nation enjoy equally the

right of choosing their own way of life."

• "To the making of these fateful decisions, the United

States pledges before you--and therefore before the

world--its determination to help solve the fearful atomic

dilemma--to devote its entire heart and mind to find the

way by which the miraculous inventiveness of man shall not

be dedicated to his death, but consecrated to his life."


Isotopes for the Nation’s Future

Ani Aprahamian

University of Notre Dame


Background

Isotopes are vital to the science and technology

base of the US economy.

medicine

biology

physics

chemistry

environmental sciences

material studies

new resource development – petrochemical, nuclear, bio-fuels

homeland security

Atoms for Peace program……1954

US Department of Energy …..Office of Nuclear Energy


Isotopes used as environmental tracers.

For example:

• As-73 is needed to understand As contamination

and transport.

• Na-22, Sr-87, and other solute reactive isotopes

are needed to understand flowpaths for

geochemical and hydrologic modeling.

• Al-26 is needed to understand the impacts of acid

rain.

• Si-32 is needed for oceanographic tracing, which

contributes to a better understanding of climate

change and its effects.


Nuclear Physics Applications

Energy

ADS systems

Fusion confinement

Nuclear Waste

Nuclear Data

Life Science

Medical Diagnostics

Medical Therapy

Radiobiology

Biomedical tracers

Nuclear Forensics

Homeland Security

Risk Assessments

Nuclear Trafficking

Proliferation

Material Analysis

Ion Implantation

Material Structure

Geology & Climate

Environment

Art & Archaeology

Nuclear Defense

Weapon Analysis

Functionality Simulation

Long-Term Storage


Nuclear Imaging

Blood flow with radiopharmaceuticals

Imaging software and analysis

Gamma Camera

SPEC & PEP

Tumor mapping & visualization by radioactive

isotope accumulation.

Imaging system development


Radiation Treatment

Brachytherapy

Gamma therapy

Neutron therapy

Heavy ion therapy


Fission/Fusion Reactors for the Future

The Tokomak approach ITER

The laser approach NIF

Magnet field confined plasma fusion

Laser ignition fusion


Nuclear Energy

From nuclear power plants

Accelerator Driven Systems (ADS) for

operating sub-critical reactors

1GeV accelerator

development (~10 15 n/s)

ADS for nuclear waste management

to nuclear pace makers

Beam optics &

irradiation system

development

Incineration strategies


Material Treatment and Analysis of Artifacts

Implantation and irradiation

from silicon chips to solar sails

Dating real and false mummies


homeland security

Nuclear Forensics

Trafficking of nuclear materials &

material loss assessments

Border control & radiation exposure

(instrumentation)

Provenance of radioactive material

by isotope composition or material

structure analysis

Signature identification,

Detector array development

Sensitivity analysis


Nuclear Energy Facts

Do not use Fossil Fuels

Energy from fission of Uranium

Or

New International program ITER in France….180 country international project!!

No carbon emissions to the atmosphere

CO 2 , SO 2 , CO (what renewables??)

20% of US energy needs met by nuclear power plants…most of them old!

None built over 30 yrs….


Location of Projected New Nuclear Power Reactors

http://www.nrc.gov/reactors/new-reactors/col/new-reactor-map.html


There are currently 104 licensed to operate nuclear power plants in the United States

(69 PWRs and 35 BWRs), which generate about 20% of our nation's electrical use.

Pressurized Water Reactors (PWRs)

Boiling Water Reactors (BWRs)


.

E=mc 2

Each fission releases more than 1 neutron


Uranium has two isotopes

235 (0.7%) and 238 (99.3%)

The amount of free energy contained in nuclear fuel is millions of times

the amount of free energy contained in a similar mass of chemical fuel

such as gasoline, making nuclear fission a very tempting source of energy;

however, the products of nuclear fission are radioactive and remain so for

significant amounts of time, giving rise to a nuclear waste problem.

Concerns over nuclear waste accumulation and over the destructive

potential of nuclear weapons may counterbalance the desirable qualities

of fission as an energy source, and give rise to ongoing political debate

over nuclear power.


History

Univ. of Chicago…Enrico Fermi

Manhattan Project….Oppenheimer led

Atoms for Peace- 1953

President Eisenhower to United Nations

1954 –Atomic Energy Act


Periodic Table of the Elements


The Nuclear Chart

Proton: 2 up, 1 down quark

Neutron: 2 down, one up quark

Gluons: quark antiquark


Atomic Number = number of protons

Atomic Mass = number of protons + number of neutrons

What is Atomic Weight?

Chart of Nuclides


Where is the Energy coming from??????

Splitting the Uranium Atom:

Uranium is the principle element used in nuclear reactors

and in certain types of atomic bombs. The specific isotope

used is 235 U. When a stray neutron strikes a 235 U nucleus,

it is at first absorbed into it. This creates 236 U. 236 U is

unstable and this causes the atom to fission.

• 235 U + 1 neutron

• 235 U + 1 neutron

2 neutrons + 92 Kr + 142 Ba + ENERGY

2 neutrons + 92 Sr + 140 Xe + ENERGY


Radioactivity

Americium -241: Used in many smoke detectors for homes and business...

Cadmium -109: Used to analyze metal alloys for checking stock, sorting scrap.

Calcium - 47: Important aid to biomedical researchers studying the cell function and

bone formation of mammals.

Californium - 252: Used to inspect airline luggage for hidden explosives...to gauge the

moisture content of soil in the road construction and building industries...and to measure

the moisture of materials stored in silos.

Carbon - 14: Helps in research to ensure that potential new drugs are metabolized without

forming harmful by-products.

Cesium - 137: Used to treat cancers...

Chromium - 51: Used in research in red blood cell survival studies.

Cobalt - 57: Used in nuclear medicine to help physicians interpret diagnosis scans of

patients' organs, and to diagnose pernicious anemia.

Cobalt - 60 : Used to sterilize surgical instruments...spices/fruits

Copper - 67: cancer


Radioactivity

Alpha decay

Beta decay

Electron capture

Gamma Decay

Half-life

very short

very long- longer than age of earth….billions of yrs

14

C 5730 yrs


Alpha Decay


Beta Decay


Gamma Decay


Half-lives are very often used to describe quantities undergoing

exponential decay—for example radioactive decay—where the half-life is

constant over the whole life of the decay.

Number of

half-lives

elapsed

Fraction

remaining

0 1

/ 1 100

1 1

/ 2 50

2 1

/ 4 25

Percentage

remaining

3 1

/ 8 12 .5

4 1

/ 16 6 .25

5 1

/ 32 3 .125

6 1

/ 64 1 .563

7 1

/ 128 0 .781

... ... ...

n 1/2 n 100(1/2 n )


A quantity is said to be subject to exponential decay

if it decreases at a rate proportional to its value. Symbolically,

this can be expressed as the following differential equation,

where N is the quantity and λ is a positive number called the

decay constant.

The solution to this equation is:

Here N(t) is the quantity at time t, and N 0

= N(0) is the initial

quantity, i.e. the quantity at time t = 0.


.

Half-life:time required for the decaying quantity to fall to one half of its initial

value

This time is called the half-life, and often denoted by the symbol t 1 / 2

.

The half-life can be written in terms of the decay constant, or the mean lifetime,

as:

Example: 14 C…..0.693/5730 yrs =1.21 x10 -4 /yr

or l=ln2/t 1/2

Example: How old is an object whose 14C content is 10% of what it is in living

organisms today?


Environmental and safety aspects of nuclear energy

Not in My Back Yucca

What are our alternatives for storing

radioactive waste?

By Brendan I. Koerner

Posted Tuesday, April 15, 2008, at 8:11 AM ET

Environmental Statement on Nuclear

Energy and Global Warming

June 2005

Too expensive – power plants…

Too dangerous- terrorist groups

Too polluting- radioactive waste


Thorium: Is It the Better Nuclear Fuel?

What is special about thorium?

(1) Weapons-grade fissionable material (uranium 233 ) is harder to retrieve safely

and clandestinely from the thorium reactor than plutonium is from the

uranium breeder reactor.

(2) Thorium produces 10 to 10,000 times less long-lived radioactive waste than

uranium or plutonium reactors.

(3) Thorium comes out of the ground as a 100% pure, usable isotope, which does

not require enrichment, whereas natural uranium contains only 0.7%

fissionable U 235 .

(4) Because thorium does not sustain chain reaction, fission stops by default if

we stop priming it, and a runaway chain reaction accident is improbable.


Here is the thorium sequence in the Rubbia reactor: A neutron is captured by

90Th 232 , which makes it 90 Th 233 .

90Th 232 + 0n 1 -> 90Th 233 [1]

Thorium-233 spontaneously emits a beta particle (an electron from the nucleus, see

p 173), leaving behind one additional proton, and one fewer neutron. ("...Nuclear

Energy" p134) This is called "beta decay."

90Th 233 -> 91Pa 233 + ß [2]

The element with 91 protons is Protactinium (Pa). The isotope 91 PA 233 also

undergoes beta decay,

91Pa 233 -> 92U 233 + ß [3]

The U 233 isotope that is produced in step [3] is fissionable, but has fewer neutrons

than its heavier cousin, Uranium-235, and its fission releases only 2 neutrons, not 3.

92U 233 + 0n 1 -> fission fragments + 2 0 n 1 [4]


Fusion Energy (how the sun gets its energy)

In a fusion reaction, two light atomic nuclei fuse together to form

heavier ones, as is shown in the figure. The fusion process releases a

large amount of energy, which is the energy source of the sun and the

stars.

Proton + neutron=deuterium

Proton + 2 neutrons=tritium


D+ T= 4 He +n + 17.6 MeV

2

H+ 3 H= 4 He


Fusion energy


Fusion Inside the Stars

• Fusion in the core of stars is reached when

the density and temperature are high

enough. There are different fusion cycles

that occur in different phases of the life

of a star. These different cycles make the

different elements we know. The first

fusion cycle is the fusion of hydrogen into

Helium. This is the stage that our Sun is in.


The long-term objective of

fusion research is to harness

the nuclear energy provided

by the fusion of light atoms to

help meet mankind´s future

energy needs.

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