Turning Rocks into Gold(Electric gold, that is)

A miracle of modern alchemy

Presented at Seminar on Canada’s Nuclear TechnologyUniversity of Ontario institute of Technology

October 15, 2009

Society

Potential Energy in the Universe • Hydrogen fusion (as well as other nuclei)

– in our sun and all visible stars

• Uranium fissionUranium fission– both natural and man-madeboth natural and man-made

• Radioactive decay– energy from our primordial “big bang” via supernovae

• Gravitation– drop a pencil, release some energy. Pick it up, store some

energy (that energy came from the sun via your food)

Environment

Uranium?• It is radioactive

– Uranium-238 decays by alpha particle emission to thorium-234; it eventually transforms into lead-206

• Uranium-238 also splits by spontaneous fissionUranium-238 also splits by spontaneous fission– 2 or 3 neutrons are released by the fission fragments2 or 3 neutrons are released by the fission fragments

• The fission and decay of natural uranium, thorium The fission and decay of natural uranium, thorium and potassium releases (in the whole earth) about and potassium releases (in the whole earth) about 38 million megawatts38 million megawatts– This radioactivity heats the core of the earth

• geothermal energy leaving the earth’s surface comes almost entirely from this radioactive decay

Science

The First Fission Reactors(1.7 Billion years ago in Gabon, West Africa – 15 discovered)

Steam

SteamSteam

Steam

Water

Water

Uranium-Bearing Zone

ScienceCross section of Geological Strata

Nuclear Fission• When two light nuclei fuse (join), mass is converted to

energy• This happens in the sun

• When a heavy nucleus fissions (splits), mass is converted to energy• This happens in a nuclear reactorThis happens in a nuclear reactor

• When gasoline burns, mass is converted to energy• This happens in your car’s engine

E = mc2

Science

What are some uses for Uranium?• We use heat from fission to make steam for a We use heat from fission to make steam for a

steam turbinesteam turbine– more than half Ontario’s electricity comes from uranium

• We have used it to make nuclear bombs– and nations have formed a strong international and nations have formed a strong international

organization (IAEA) to guard against use for weaponsorganization (IAEA) to guard against use for weapons• We have used it to make attractive glass

– until recently some glass-makers added uranium to glass. Such uses are now banned, to protect our health

• We use it as ballast in B747 aircraft

Technology, society

and environment

Energy of Fission• It could be called “Femtopower” a nucleus is very small

– uranium nucleus diameter is 16 femtometers (10-15 meters)

• It takes 31 billion fission reactions to release one watt-second (one joule) of energy.– Fission is sustained at a constant rate by neutrons emitted

during earlier fissions, in a chain reactionchain reaction– The fragments (fission products) are at first highly radioactive,

then rapidly decay to stable elements– Most of the energy appears as heat in the fuel pellets. It is this

energy that we use to boil water boil water at high temperature and pressure

Science

Energy Flows

Thermal energy (fuel)

Thermal energy (water)

Mechanical Energy (turbine)

Cond

uctio

n

Boili

ng

Fiss

ion

Potential Energy in the atomic

nucleus

Electrical energy (generator)

Induction

Your lights,toaster, stove

Tran

smis

sion

Loss

es to

envi

ronm

ent

Technology, society

and environment

Losses toenvironment

Engineering

Nuclear Fuel(pellet)

• Uranium dioxide – ceramic, melting point 2800 C– It is slightly radioactive– One fuel pellet releases enough energy to make 2 slices One fuel pellet releases enough energy to make 2 slices

of toast every minute for a year (about 1 million slices)of toast every minute for a year (about 1 million slices)

• Over 6 million fuel pellets are loaded in each Darlington reactor, in 5760 fuel bundles– Darlington produces 3524 megawatts of electricity from 4

reactors

• The world’s supply of nuclear fuel is inexhaustible

EngineeringTechnology

Energy in the atomic nucleus

Thermal energy (fuel)

The Magnitude of the Hazard VariesH

AZ

AR

D O

F N

UC

LE

AR

FU

EL

BEFORELOADING REACTOR

OPERATION

USED FUEL COOLDOWN

Ab

ou

t 7-

8 o

rder

s o

f m

agn

itu

de

Ab

ou

t 30

0 ye

ars

Science,

environment• Used fuel decays rapidly at Used fuel decays rapidly at

first, then more slowlyfirst, then more slowly• The “last nucleus” does not The “last nucleus” does not

decay for a very long timedecay for a very long time• Radioactive hazard returns Radioactive hazard returns

to the original level after to the original level after about 300 yearsabout 300 years

Making Electricity• Heat energy is pumped in high

pressure water to the boilers• Water is then boiled to produce

steam to drive a steam turbine• Induction transforms mechanical

energy into electrical energy• Electricity is transmitted to you, Electricity is transmitted to you,

the customer, all within less than the customer, all within less than 30 seconds after fission30 seconds after fission

• About 70% of the total fission energy is lost to the environment

Thermal energy (water)

Mechanical energy(turbine)

Electrical energy(generator)

Loss

es to

envi

ronm

ent

Engineering

Nuclear Reactor Designs• Most of today’s Nuclear Plants (436) use Water Reactors

– Pressurized water reactor (PWR)– Boiling water reactor (BWR)– Pressurized heavy water reactor (PHWR)

• These designs are being modified as technology improves– Under construction: 50– On order or planned: 137– Proposed: 295

• Future designs are known as “Generation 3 or 4”– Some of these power plants will use fast reactors (FBR)

Engineering

Society

A Canadian Dream for the FutureAround the year 2100?

DUPIC Plant

CANDUCANDUPWRBWR

Oxide FabricationPlant

Reprocessing Plant

U + Pu + f.p. DisposalU238

PuU/Th

WasteFreshFuel

FreshFuel

FBRFBR

REPROC. +FAB. PLANT

Fission products

U

CANDUCANDU

CANDUPHWR

Storage

Society

Storing Electricity? – Transform It!

Base Load

IntermediateLoad

Intermediate - reservoir limited

Tops

PeakFrequencyControl

Engineering

Nuclear energy supply range

Daily EnergyStorage

Fuel -- A Small Part of Electricity Cost*• Today, the uranium price is about $90 per kilogram

– At this price we have enough to fuel 6000 thermal reactors for > 40 yearsAt this price we have enough to fuel 6000 thermal reactors for > 40 years– As market price increases the amount of “ore” (at a lower grade) increasesAs market price increases the amount of “ore” (at a lower grade) increases– The uranium fuel contribution to electricity cost is negligible today– If the uranium price were half the price of gold, the price of electricity from

thermal reactors would double– If the uranium price were half the price of gold, it would be very profitable to

extract uranium from seawater– Seawater is known to contain enough uranium to supply 100% of the world’s

energy for 4000 years using thermal reactors (PWR, BWR, PHWR) or at least 4000 years using thermal reactors (PWR, BWR, PHWR) or at least 600,000 years using fast reactors (FBR)600,000 years using fast reactors (FBR)

– Thorium Thorium (another potential fuel) is more abundant is more abundant than uranium in the earth’s crust

* D.Lightfoot et al, “Nuclear Fission Energy is Inexhaustible”, Proceedings of the first Climate Change Technology Conference, Engineering Institute of Canada, Ottawa, May 2006

Science

It’s Not all Sweetness and Light• Fission must be controlled at a constant rate• High pressure pipes must hold water• Heat losses must not damage the environment• Radiation must be contained• Fission products Fission products (the ashes of fission) must be safely must be safely

stored in the long termstored in the long term• Electricity must be affordable

Technology

Today, we only use 1% of theToday, we only use 1% of the energy in the fuel energy in the fuel

Nuclear Energy is:

AvailableAvailableSafeSafe

InexhaustibleInexhaustible