uplearn fission and fusion

Identify Einstein’s famous equation.

E=mc²

Identify all the interpretations of E=mc²

mass is a form of energy

energy has mass

definition of the rest mass

the rest mass is the mass of an object or particle when it is stationary

definition of the mass defect

The mass defect is the difference between the mass of a nucleus and the sum of the masses of its nucleons if they were completely separated

definition of the binding energy of the nucleus

The minimum energy required to separate the nucleus into its constituent protons and neutrons

Identify the correct statement about binding energy

The higher the binding energy, the more tightly bound the nucleus is, so it will take more energy to split the nucleus up

Identify the correct statement about binding energy

When protons and neutrons become more tightly bound, the binding energy increases, and energy is released

The mass defect

The mass defect is defined as the difference between the mass of a nucleus and the sum of the mass of its nucleons if they were completely separated

Identify the correct binding energy per nucleon versus nucleon number graph from the options below.

Correct answersYour answers

D

The graph of binding energy per nucleon versus nucleon number is shown below.

Identify the labelled point on the graph above that corresponds to the element iron

C

Nuclear fission occurs when…

Nuclear fission occurs when a large nucleus splits into two smaller nuclei

The sum of the binding energies of the smaller nuclei is greater than the binding energy of the larger nucleus

true

Fusion

Fusion is when two smaller nuclei join together to form one larger nucleus

Identify the statement that correctly gives the ratio of uranium isotopes on Earth

The ratio of uranium isotopes on Earth is 0.70% uranium-235: 99.3% uranium-238

Slow neutrons

also called thermal neutrons

chain reactions

initial neutrons in a fission reaction cause exponential increase in neutrons, which causes an exponential growth in the rate of fission reactions

Identify the option that correctly identifies the number of neutrons N produced after n generations of a nuclear fission reaction. You can assume that every produced neutron creates a further fission reaction

N=3ⁿ

Identify whether the statements below about the nuclear decay of uranium-235 are true

The total binding energy after the fission reaction is greater than the total binding energy before the fission reaction

Energy is released during a fission reaction. Which of the following is the energy released as?

Gamma rays

Neutrinos

Kinetic energy of neutrons

Kinetic energy of daughter nuclei

Slow neutrons

those with a mean kinetic energy equal to the thermal energy of particles in reactor core

Fuel rods:

Made of enriched uranium

Moderator:

A substance in a fission reactor that slows down fast neutrons so that they can be absorbed by Uranium-235 to continue the nuclear reaction. Often made from graphite or water

Control rods:

Absorb neutrons and can control the rate of the reactions or stop them altogether. They are made of boron-coated steel

Coolant:

A substance that is heated by energy from fission reactions and removes the thermal energy from the reactor core

How many fast neutrons are usually produced in each fission?

3

How many slow neutrons should the control rods allow to continue?

1

Which of the following is a waste product of the fission process?

Plutonium-239

Which of the following are advantages of generating electricity from nuclear fission?

A small amount of fuel is needed to produce a lot of electricity

Clean (no CO2​ produced)

Why is it important to consider safe, long-term storage of nuclear waste?

Waste is highly radioactive and has a very long half-life

Nuclear fusion is a reaction that takes place in the core of stars like the Sun.
Identify all the conditions required for fusion to take place.

High pressure is required

The temperature needs to be greater than 100 million Kelvin

The proton-proton chain is a series of fusion reactions. In the first step two protons fuse to make a deuterium nucleus.

Identify the equation for this reaction

¹1p+¹₁p—>²₁H+⁰₊₁e+electron neutrino

During the second step of the proton-proton chain, a helium nucleus is formed.
Identify the equation of the second step of the proton-proton chain.

1/1P+2/1H—>3/2He

During the third step of the proton-proton chain, a helium-4 nucleus is formed.
Identify the equation of the third step of the proton-proton chain

3/2He+3/2He—>4/2He+2 1/1p

Rest mass

mass of an object or particle when it is stationary

Mass defect

the difference between the mass of a nucleus and the sum of the masses of its nucleons if they were completely separated

Binding energy

 the minimum energy required to separate a nucleus into its constituent protons or neutrons

Fission

when a large nucleus splits into two smaller nuclei after absorbing a neutron

Fusion

fusion is when two smaller nuclei join together to form one larger nucleus

Thermal neutrons

a neutron in a fission reaction that has a mean kinetic energy approximately equal to the thermal energy of the particles in the reactor core. Also called a slow neutron

Reactor core

a concrete-steel encasement around a the core of a nuclear reactor