The Fires of Nuclear Fission
Instalasi tenaga nuklir adalah instalasi yang
dijalankan berdasarkan konsep reaksi fisi :
Yaitu proses pemecahan suatu inti menjadi inti
yang lebih kecil, yang biasanya dilakukan dengan cara
penembakan terhadap target inti dengan neutron .
Produk yang dihasilkan dari reaksi inti adalah
inti dengan massa yang lebih rendah
.
Reaksi fisi antara inti uranium (235 U ) dengan neutron
REAKSI FISI
235
92
U  n
1
0
141
56
Ba  Kr  3 n
92
36
1
0
Jika jumlah massa sebelum reaksi
sama dengan massa sesudah reaksi,
dari mana asal energi ?
Hukum Kekekalan massa dan energi
REAKSI FISI
235
92
U  n
1
0
141
56
Ba  Kr  3 n
92
36
1
0
Massa atom U-235 adalah 235.043924 amu.
Massa neutron 1.00866 amu
Total reaktan massanya adalah 236.052584 amu
Massa atom Kr-92 adalah 91.926156 amu.
Massa atom Ba-141 adalah 140.914412 amu.
Massa 3 inti neutron adalah 3.02598 amu
Total produk adalah 235.866548 amu
Massa yang hilang adalah 0.186036 amu yang dirubah
menjadi energi
Massa dapat dirubah menjadi energi berdasarkan
persamaan Einstein :
E = mc2
E = Energi
m = massa
c = kecepatan cahaya
1 Joule = 1 kg m2/s2
c2 = (3.0 x 108 m/s)2 = 9.0 x 1016 m2/s2
m=1g
E = (10-3)(9.0 x 1016) kg m2/s2
E = 9.0 x 1013 kg m2/s2 = 9.0 x 1013 Joule
Small changes in mass make for HUGE changes in
energy.
Energi yang dihasilkan oleh massa 1 gram uranium
E = 9.0 x 1013 kg m2/s2 = 9.0 x 1010 kJoule
Energi ini setara dengan energi yang dilepaskan
oleh 22 metrik kilo ton dari bom TNT
Jenis Bahan Bakar
Kapasitas Panas ( kJ /g)
Antracite (coal)
Bituminous (coal)
Sub-bituminous (coal)
Lignite (brown coal)
30.5
30.7
24.0
16,2
Kayu
14.1
Hitung berapa jumlah bahan bakar coal atau kayu yang dibutukan untuk
Menghasilkan sejumlah energi yang setara dengan energi yang dihasilkan
oleh 1 gram uranium ?
A typical Light-Water-Moderated and Cooled Nuclear Power Plant with Water
Reactor.
SISTIM DALAM PUSAT LISTRIK TENAGA NUKLIR
 Sistim Reaktor
 Sistim Turbine dan Generator Listrik
 Sistim Pendingin Air
Proses Pembangkit Listrik dlm Reaktor Nuklir
 Superheated water turns into steam
 Steam passed through turbine
 Physical motion of the turbine is converted into
electrical energy
Sistim Reaktor dlm Pusat Listrik Tenaga Nuklir
(i)
(ii)
Ada 2 sistim : (i) sistim reaksi fisi atau reaksi nuklir
(ii) sistim pembentukan superheat steam
(iii) sistim control reaktor
Sistim Turbin dan Pendingin
di Pusat Listrik Tenaga Nuklir
(i)
(ii)
(i) sistim turbin
dan
(ii) sistim pendingin
Sistim Pendingin di Pusat Listrik Tenaga Nuklir
 Superheated water setelah dari turbin masuk ke pendingin
(condenser) .
 Pendinginan dengan menggunakan pendingin air
( Pipes with the hot water are circulated through a
container filled with cold water , heat is exchanged.
Hot water is either discharged into river, ocean… or
vented into the atmosphere as steam )
Sistim Reaktor di Pusat Listrik Tenaga Nuklir
Ada 3 komponen : (i) bahan bakar nuklir,
(ii) sumber neutron
(iii) sistim pengontrol reaksi nulear
Bahan bakar Nuklir
(left) Nuclear fuel pellets
that are ready for fuel
assembly completion.
(right) A typical
nuclear fuel pellet.
Bahan bakar Nuklir
 Made from uranium core
 Enriched to 3% of radioactive isotope U-235.
 Made into pellets, size of pencil, energy
equivalent to 1 ton of coal.
 Pellets are packed into large pipes-fuel rods.
 Rods are grouped together into fuel
assemblies, these assemblies are placed into
reactor core
Kontrol Reaksi Nuklir
 Control rods placed between rods.
 Control rods moved in and out of the assemblies,
absorbing neutrons which trigger the chain reaction.
 Water circulates through the assemblies, removing
the heat, keeping the rods from melting.
Light water reactors
 85% of world’s nuclear generated electricity
 (100% in US).
 High inefficient in terms of energy conversion
 (up to 83% lost as waste heat).
There are three varieties of light water reactors :
 The pressurized water reactor (PWR),
 The boiling water reactor (BWR), and
 The supercritical water reactor (SCWR).
Spent Fuel rods
 After about 3-4 years of use, the Fuel rods become
spent-level of fission drops beneath a certain level.
 Rods are taken out of reactor stored nearby in water filled
pools or dry casks.
 Stored until they cool down enough to be shipped for
permanent storage or to be recycled.
These storage facilities are next to the reactor plants,
vulnerable to terrorist attack or accidents
Spent Fuel Reprocessing
The spent fuel rods are sent to a facility which separates
plutonium from spent fuel for further use as a new generation
of fuel or as material used to make atomic weapons.
1. First the fuel is chopped up, by remote control, behind
heavy lead shielding.
2. These chopped-up pieces are then dissolved in boiling
nitric acid, releasing radioactive gases in the process.
3. The plutonium is separated from the acid solution by
chemical means, leaving large quantities of high-level
radioactive liquid waste and sludge behind.
4. After it has cooled down for several years, this liquid
waste will have to be solidified for ultimate disposal, while
the separated plutonium is fabricated into nuclear fuel or
nuclear weapons.
Nuclear Fuel Cycle
Decommissioning of
reactor
Fuel assemblies
Enrichment
of UF6
Conversion of
U3O8
to UF6
Reactor
Fuel fabrication
(conversion of enriched UF6 to
UO to UO2 and fabrication of
fuel assemblies)
Temporary storage of spent
fuel assemblies
underwater or in dry casks
Spent fuel
reprocessing
Low-level radiation with
long half-life
Geologic disposal of
moderate- and highlevel radioactive wastes
Open fuel cycle today
Recycling of nuclear fuel
Worst Commercial Nuclear Power Plant Accident in
the U.S.
Three Mile Island
 March 29, 1979.
 Near Harrisburg, PA, U.S.
 Nuclear reactor lost its coolant.
 Led to a partial uncovering and melting of the
radioactive core.
 Unknown amounts of radioactivity escaped.
 People fled the area.
 Increased public concerns for safet
 Led to improved safety regulations in the U.S.
Worst Nuclear Power Plant Accident in the World
Chernobyl
 April 26, 1986.
 In Chernobyl, Ukraine.
 Series of explosions caused the roof of a reactor
building to blow off.
 Partial meltdown and fire for 10 days.
 Huge radioactive cloud spread over many countries and
eventually the world.
 350,000 people left their homes.
 Effects on human health, water supply, and agriculture.
Remains of a Nuclear Reactor at the Chernobyl Nuclear
Power Plant.
Aerial view of the damaged core on May 3, 1986. Roof of the turbine hall is
damaged (image center). Roof of the adjacent reactor 3 (image lower left)
shows minor fire damage.
The nuclear reactor after the disaster. Reactor 4 (center). Turbine
building (lower left). Reactor 3 (center right).
The abandoned city of Pripyat with Chernobyl plant in the distance
HUMAN CASUALTIES
 56 people lost their lives as direct result of radiation poisoning or fire
 Thyroid cancer From drinking Milk 10-12 thousand
Recent Nuclear Power Plant Accident in The World
Fukushima
 March 11, 2011.
 In Fukushima, Japan.
 A series of ongoing equipment failures and releases of
radioactive materials at the Fukushima I Nuclear Power
Plant, following the 9.0 magnitude Tohoku earthquake
and tsunami on 11 March 2011. Partial meltdown and
fire for 10 days.
 Experts consider it to be the second largest nuclear
accident after the Chernobyl disaster, but more complex
as multiple reactors are involved.
Recent Nuclear Power Plant Accident in The World
Unit 1 of Fukushima Reactors before the explosion. The join can be seen between
the lower concrete building and upper lighter cladding which was blown away in
the explosion. The trees and lamp posts indicate its size.
Satellite image on 16 March of the four damaged reactor buildings.
Reactor unit 3 (right) and unit 4 (left) on 16 March
.
Fukushima I Power Plant; Series of destruction.
KEUNTUNGAN
 Dampak lingkungannya rendah
 Resiko atas terjadinya kecelakaan relatif rendah
KERUGIAN
 Biaya tinggi
 Effisiensi biaya bersihnya adalah rendah
 Adanya limbah radioaktif dengan umur yang lama
 Mudah untuk disabotase dan resikonya tinggi
 Sumber yang potensial untuk penyebaran senjata
nuklir
Conventional Nuclear Fuel Cycle
Advantages
Disadvantages
Large fuel supply
Ample supply of uranium
Low environmental impact
(without accidents)
Low net energy yield
Emits 1/6 as much
CO2 as coal
Moderate land disruption
and water pollution
(without accidents)
Moderate land use
Low risk of accidents
because of multiple safety
systems (except for
Chernobyl-type reactors)
Low air pollution
Low CO2 emissions
Much lower land
disruption from surface
mining
Moderate land use
High cost (even with
huge subsidies)
Coal Energy vs Nuclear Energy
Coal
Ample supply
High net energy yield
Nuclear
Ample supply of uranium
Low net energy yield
Very high air pollution
Low air pollution
High CO2 emissions
Low CO2 emissions
High land disruption from
surface mining
High land use
Low cost
(with huge subsidies)
Much lower land disruption
from surface mining
Moderate land use
High cost
(even with huge subsidies)
Nuclear Power Plants Are Vulnerable to Terrorists
Acts
 Explosions or meltdowns possible at the power
plants.
 Storage pools and casks are more vulnerable to
attack.
 60 countries have or have the ability to build
nuclear weapons.
Dealing with Radioactive Wastes Produced by
Nuclear Power Is a Difficult Problem
High-level radioactive wastes
Must be stored safely for 10,000–240,000 years.
Where to store it?
Deep burial: safest and cheapest option.
Transportation concerns.
Would any method of burial last long enough?
There is still no facility: NIMBY scenario.
Can the harmful isotopes be changed into
harmless isotopes? (working on it, $$$).
Can Nuclear Power Lessen Dependence on Imported
Oil, Reduce Global Warming?
Nuclear power plants: no CO2 emission.
Nuclear fuel cycle: emits CO2.
Opposing views on nuclear power and global warming:
Nuclear power advocates.
2003 : study by MIT researchers.
2007: Oxford Research Group.
Proponents of nuclear power:
Fund more research and development.
Pilot-plant testing of potentially cheaper and safer reactors.
Test breeder fission and nuclear fusion.
Opponents of nuclear power:
Fund rapid development of energy efficient and renewable
energy resources.
“ Is the power of the future and always will be”.
Still in the laboratory phase after 50 years of research
and $34 billion dollars.
2006 : U.S., China, Russia, Japan, South Korea, and
European Union;
Will build a large-scale experimental nuclear
fusion reactor by 2040.
Decommission or retire the power plant.
Some options:
 Dismantle the plant and safely store the radioactive
materials.
 Enclose the plant behind a physical barrier with full-time
security until a storage facility has been built.
 Enclose the plant in a tomb and monitor this for thousands
of years.
What is going on to The Nuclear Power Plant
Slowest-growing energy source and expected to decline
more. Why?
 Economics.
 Poor management.
 Low net yield of energy of the nuclear fuel cycle.
 Safety concerns.
 Need for greater government subsidies.
 Concerns of transporting uranium.
APAKAH PUSAT LISTRIK
TENAGA NUKLIR
ADALAH
SUMBER ENERGI MASA DEPAN
ATAU
SUMBER ENERGI
DUNIA YANG LESTARI ?
1. What are the steps to using nuclear fission to
generate electricity ?
2. Advantages and disadvantages of using nuclear
fission as a power source?
3. Why are Japan’s reactors in trouble?
4. Compare Chernobyl to Japan’s current situation!