NUCLEAR POWER PLANTS

USMAN IQBAL

Reg# BME01083045

Nuclear Power Today

Provides almost 20% of world’s electricity (8% in U.S)

69% of U.S. non-carbon electricity generation

More than 100 plants in U.S. None built since the 1970s

200+ plants in the Europe Leader is France

About 80% of its power from nuclear

Countries Generating Most Nuclear Power Countries Total (MW) USA 99,784 France 58,493 Japan 38,875 Germany 22,657 Russia 19,843 Canada 15,755 Ukraine 12,679 United Kingdom 11,720 Sweden 10,002 South korea 8,170

History of Nuclear Power

Origins

After World War II, development of civilian nuclear program

Atlantic Energy Act of 1946 1954: first commercial nuclear

power program

History

1938- Scientists study nucleus of uranium

1941- Manhattan project 1942- Controlled nuclear chain

reaction 1945- U.S use two atomic bombs on

Japan 1949- Soviet develop atomic bomb 1952- U.S test hydrogen bomb 1955- First U.S nuclear submarine

Early Beginnings Atomic Energy Commission (AEC) established

by Congress in 1946 as part of the Atomic Energy Act

AEC authorized the construction of Experimental Breeder Reactor I ( EBR-1) at a site in Idaho in 1949

in August of 1951, criticality (a controlled, self-sustained, chain reaction) was reached using uranium

A football sized core was created and kept at low power for four months until December 20, 1951

Early Beginnings power was gradually increased until the first usable

amount of electricity was generated, lighting four light bulbs and introducing nuclear generated power for the first time

In 1953, the EBR-1 was creating one new atom of nuclear fuel for every atom burned, thus the reactor could sustain its own operation

With this creation of new cores, enough energy was created to fuel additional reactors

A few years later, the town of Arco, Idaho became the world's first community to get its entire power supply from a nuclear reactor

This was achieved by temporarily attaching the town’s power grid to the reactor’s turbines

Working principle The conversion to electrical energy take place

indirectly, as in conventional thermal power plants; the heat is produce by fission in a nuclear reactor(in a coal power plant it would correspond to the boiler) and given to a heat transfer fluid- usually water(for a stander type light water reactor).

Directly or indirectly water vapor-steam is produce. The pressurized steam is then usually fed to a multi-stage steam turbine.

Steam turbines in western nuclear power plants are among the largest steam turbine ever. After the steam turbine has expanded and partially condensed the steam, the remaining vapor is condensed in a condenser.

Working principle

The condenser is a heat exchanger which is connected to secondary side such as a river or a cooling tower. The water then pumped back to the nuclear reactor and cycle begins again.

The water steam cycle is corresponds to the Rankine Cycle

Working principle

Nuclear reactorsA nuclear reactor is a device to initiate and

control a sustained nuclear chain reaction. The most common use of reactors is for the electric generation and for the propulsion of ships.

The nuclear reactor is the heart of the plant. In its central part, the reactor cores heat is generated by controlled nuclear fission.

With this heat, a coolant is heated as it is pumped through the reactor and thereby removes the energy from the reactor.

Heat from nuclear fission is used to raise steam, which runs through turbine, which is turn power either ship’s propeller or electrical generator.

Note Since nuclear fission creates radioactivity,

the reactor core is protected by a protective shield.

This containment absorbs radiations and prevent radioactive material from being released into the environment.

In addition, many reactors are equipped with a dome of concrete to protect the reactor against external impacts.

In nuclear power plants, different types of reactors, nuclear fuels, and cooling circuits and moderators are sometime used.

Nuclear Fission from Slow Neutrons and Water Moderator

Inside a Nuclear Reactor

Steam outlet

Fuel Rods

Control Rods

Steam turbine The object of the steam turbine is to

convert the heat contained in steam into rotational energy.

The engine house with the steam turbine is usually structurally separated from the main reactor building.

Energy Taken out by Steam Turbine

Safety valve The pressure in the reactor pressure

reactive vessel at an incident, to limit upward, two independent valves are available.

The pressure relief prevents the bursting of pipes or reactor.

The valves in their capacity designed so that they can drive all of the supplied flow rates with little increase in pressure.

Nuclear proliferationMany technologies and materials with the

creation of nuclear power program have a dual-use capability in that they can use to make nuclear weapons if a country is chose to do so.

When this happen the nuclear power program become route leading to the atomic bomb or public annex to a secret bomb program.

The crisis over Iran’s nuclear activities is case in point.

Uranium Mining

There are three main methods:

Underground mining

Open pit mining

In Situ Leaching (ISL)

Underground Mining

The Case of the Olympic Dam Mine

Underground Mining Olympic Dam mine is

located in South Australia

Most of the mine’s profit actually comes from the copper that they mine as well

Tunnels are dug into the earth, where ore is extracted

The ore is crushed into a powder, then soaked in a lake. The impurities precipitate and the rest is dried by heat.

Ya Got Trouble….

The Western Mining Corporation (WMC) is owned by BP

Lake uses an intense amount of water

Rabbit popluation has crashed as a result of drinking from the lake

In Situ Leaching Wells are drilled into aquifers, the

water is removed, and a solvent, such as hydrogen peroxide, is pumped in

The peroxide dissolves the uranium, and the solution is pumped back up

An ion exchange system causes the uranium to precipitate in the form of UO42H2O (uranium peroxide)

In Situ Leaching

ISL has its woes Ground water supply has radioactive

residues

There are ISL mines in Texas, Wyoming, and Nebraska that share the same aquifers as residents

Nucleons more tightly bound in Fission Product Nuclei – Gives 200 Mev Energy per Fission

Three Mile Isle

Nuclear Plant Future The countries of the world are each

planning their own course of nuclear plant development or decline

Nuclear power is competitive with natural gas

It is non-polluting It does not contribute to global

warming Obtaining the fuel only takes 5% of

the energy output Plant licenses have been extended

from 20 years to an additional 20 years

Nuclear Plant Future Newer designs are being sought to make

them more economical and safer Preapproval of a few designs will hasten

development Disposal of high level radioactive waste still

being studied, but scientists believe deep burial would work

Because they are have large electrical output, their cost at $2 billion is hard to obtain and guarantee with banks

Replacing plants may be cheaper using the same sites and containment vessels

ADVANTAGES Nuclear power generation does emit

relatively low amounts of carbon dioxide (CO2). The emissions of green house gases and therefore the contribution of nuclear power plants to global warming is therefore relatively little.

This technology is readily available, it does not have to be developed first.

It is possible to generate a high amount of electrical energy in one single plant

DISADVANTAGES The problem of radioactive waste is

still an unsolved one. High risks: It is technically impossible

to build a plant with 100% security. The energy source for nuclear energy

is Uranium. Uranium is a scarce resource, its supply is estimated to last only for the next 30 to 60 years depending on the actual demand.