A nuclear reactor contains and controls sustained nuclear chain reactions to generate electricity, power naval vessels, produce medical isotopes, and conduct research. The reactor core contains fuel rods that split atoms when hit by neutrons, releasing energy as heat. This heat is transferred by coolant like water to power turbines and generators. Key reactor components include fuel pins bundled in fuel assemblies, control assemblies, and the reactor vessel. Common reactor types are pressurized water reactors, where coolant is contained in a pressurized primary loop, and boiling water reactors, where the same water acts as coolant and steam source. Nuclear reactors have important applications in power generation, nuclear weapons reduction, scientific research, and medicine.

1. Nuclear Reactor
PRESENTED BY MD. AMINUL ISLAM
DEPARTMENT OF PHYSICS
JESSORE UNIVERSITY OF SCIENCE AND TECHNOLOGY-JUST.

2. What is Nuclear Reactor?
 A nuclear reactor is a system that contains and controls sustained nuclear chain reactions.
 Reactors are used for generating electricity, moving aircraft carriers and submarines,
producing medical isotopes for imaging and cancer treatment, and for conducting research.
 Fuel, made up of heavy atoms that split when they absorb neutrons, is placed into the reactor
vessel (basically a large tank) along with a small neutron source. The neutrons start a chain
reaction where each atom that splits releases more neutrons that cause other atoms to split .
 Each time an atom splits, it releases large amounts of energy in the form of heat. The heat is
carried out of the reactor by coolant, which is most commonly just plain water. The coolant
heats up and goes off to a turbine to spin a generator or drive shaft. Nuclear reactors are just
exotic heat sources.

3. Reactor Components
 A nuclear reactor heating up water and spinning a generator to produce electricity. It captures
the essence of the system well. The water coming into the condenser and then going right back
out would be water from a river, lake, or ocean. It goes out the cooling towers. As you can see,
this water does not go near the radioactivity, which is in the reactor vessel.
 The smallest unit of the reactor is the fuel pin. These are typically uranium-oxide (UO2), but
can take on other forms, including thorium-bearing material. They are often surrounded by a
metal tube (called the cladding) to keep fission products from escaping into the coolant.
 Fuel assemblies are bundles of fuel pins. Fuel is put in and taken out of the reactor in
assemblies. The assemblies have some structural material to keep the pins close but not
touching, so that there’s room for coolant.
 A full core, made up of several hundred assemblies. Some assemblies are control assemblies.
Various fuel assemblies around the core have different fuel in them. They vary in
enrichment and age, among other parameters. The assemblies may also vary with height, with
different enrichments at the top of the core from those at the bottom.

4. A Complete Nuclear Reactor Diagram

5. Types of Nuclear Reactors
 Pressurized water reactor
 Boiling water reactor
 Canada deuterium-uranium reactor
 Sodium cooled fast reactor
 Molten salt reactor
 High temperature gas cooled reactor

6. Pressurized Water Reactor

7. Pressurized Water Reactor
 In pressurized water reactor (PWR), the water which passes over the reactor core to act
as moderator and coolant does not flow to the turbine, but is contained in a pressurized
primary loop.
 The primary loop water produces steam in the secondary loop which drives the turbine.
 A fuel leak in the core would not pass any radioactive contaminants to the turbine and
condenser.
 PWR can operate at higher pressure and temperature, about 160 atmospheres and about
315 C.
 It provides a higher Carnot efficiency than the BWR, but the reactor is more complicated
and more costly to construct. Most of the U.S. reactors are pressurized water reactors.

8. Boiling Water Reactor

9. Boiling Water Reactor
 In the boiling water reactor the same water loop serves as moderator, coolant for the core,
and steam source for the turbine.
 In the boiling water reactor (BWR), the water which passes over the reactor core to act
as moderator and coolant is also the steam source for the turbine.
 a fuel leak might make the water radioactive and that radioactivity would reach the turbine
and the rest of the loop.
 A typical operating pressure for such reactors is about 70 atmospheres at which pressure
the water boils at about 285¡C.
 This operating temperature gives a Carnot efficiency of only 42% with a practical
operating efficiency of around 32%, somewhat less than the PWR .

10. Uses of Nuclear Reactors
 Powering up industries and houses.
 Using up nuclear weapons.
 Nuclear research.
 Nuclear medicine.

11. ThankYou