The Fires of Nuclear Fission

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

nKrBanU 10

9236

14156

10

23592 3

REAKSI FISI

Jika jumlah massa sebelum reaksi sama dengan massa sesudah reaksi, dari mana asal energi ?

Hukum Kekekalan massa dan energi

nKrBanU 10

9236

14156

10

23592 3

REAKSI FISI

Massa atom U-235 adalah 235.043924 amu.Massa neutron 1.00866 amuTotal 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 amuTotal 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 1 Joule = 1 kg m2/s2

m = massac = kecepatan cahaya

c2 = (3.0 x 108 m/s)2 = 9.0 x 1016 m2/s2

m = 1 g 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 kJouleEnergi ini setara dengan energi yang dilepaskan oleh 22 metrik kilo ton dari bom TNT

Jenis Bahan Bakar Kapasitas Panas ( kJ /g)

Antracite (coal) 30.5

Bituminous (coal) 30.7

Sub-bituminous (coal) 24.0

Lignite (brown coal) 16,2

Kayu 14.1Hitung 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

Ada 2 sistim : (i) sistim reaksi fisi atau reaksi nuklir (ii) sistim pembentukan superheat steam

(iii) sistim control reaktor

(i) (ii)

Sistim Turbin dan Pendingin di Pusat Listrik Tenaga Nuklir

(ii)

(i)

(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

(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

Bahan bakar 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.

Kontrol Reaksi Nuklir

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

Fuel assemblies Decommissioning of reactor

Enrichment of UF6

ReactorFuel fabrication

(conversion of enriched UF6 to UO to UO2 and fabrication of fuel assemblies)

Temporary storage of spent fuel assemblies

underwater or in dry casksConversion of U3O8 to UF6

Spent fuel reprocessing

Low-level radiation with long half-life

Geologic disposal of moderate- and high-level 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 WorldWorst 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 WorldRecent 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 WorldRecent 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

Large fuel supplyAdvantages

Low environmental impact (without accidents)

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)

DisadvantagesAmple supply of uranium

Low net energy yield

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

High land use

CoalAmple supply

High net energy yield

Very high air pollution

High CO2 emissions

High land disruption from surface mining

Low cost (with huge subsidies)

NuclearAmple supply of uranium

Low net energy yield

Low air pollution

Low CO2 emissions

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!