Nuclear fission and fusion

what is nuclear fission

The splitting of a large, unstable nucleus into two smaller daughter nuclei

which two isotopes undergo fission and are used as fuel in nuclear power stations

uranium and plutonium

During fission, when a _______ collides with an unstable nucleus, the nucleus splits into two smaller ________ as well as two or three neutrons

neutron

daughter nuclei

In a fission reaction energy transferred is from _______ potential energy to kinetic energy

nuclear

why is induced fission more common than spontaneous fission and how does it work

Because it is rare for nuclei to undergo fission without additional energy being put into the nucleus, as nuclear fission requires lots of energy

Usually, for fission to occur the unstable nucleus must first absorb a neutron.

This makes the isotope very unstable and splits by nuclear fission almost immediately. So energy is readily available and often radioactive isotopes take millions of years to decay so induced fission is useful here

What is a chain reaction?

When the emitted neutrons from the fission reaction collide with other unstable nuclei and cause further fission reactions

where do controlled chain reactions occur

in a nuclear reactor, as chain reactions are needed to keep the reactor running

where do uncontrolled chain reactions occur

A nuclear weapon uses an uncontrolled chain reaction to release a huge amount of energy in a short period of time as an explosion

why are uncontrolled chain reactions dangerous

Because each new fission reaction releases energy, uncontrolled chain reactions can be dangerous

The number of neutrons available increases quickly, so the number of reactions does too

what is nuclear fusion

When two light nuclei join to form a heavier nucleus

why is nuclear fusion hard to reproduce on earth

because it requires extremely high temperatures to maintain, fusion is more expensive than fission

where does nuclear fusion happen naturally

Nuclear fusion takes place in the centres of stars

Hydrogen nuclei fuse into helium nuclei and release a large amount of energy

describe the process of nuclear fission inside a reactor

neutron absorbed by a uranium nucleus

nucleus splits into two parts

and (2 / 3) neutrons (are released)

and gamma rays (are emitted)

explain how the process of nuclear fusion leads to the release of energy

lighter nuclei join to form heavier nuclei some of the mass (of the nuclei) is converted to energy ( in the form of radiation

explain the process of nuclear fusion and outline the conditions required for it to take place

nuclear fusion is the process of joining two lighter nuclei to create one large nucleus and this releases radiation if the form of EM radiation.

it requires really high temperatures to provide energy to bring the nuclei together

it requires high pressure as the nuclei must be forced together to increase the chances of fusion