P6

Question 1

How do control rods reduce the number of reactions in a nuclear reactor .
Why is a graphite core used ?

Answer 1

control rods absorb neutrons
so fewer neutrons left to react
Graphite core used to slow down neutrons so they can be absorbed

Question 2

Describe how the neutrons released in nuclear fission are used to produce a
controlled chain reaction in a nuclear reactor.

Answer 2

A slow moving neutron collides with a nuclei . this causes the nuclei to become unstable and the nuclei splits into daughter nuclei . this releases more neutrons and more energy . Neutron needs to be slow moving and number of neutrons in reactor can be controlled by control rods - this is to ensure the reaction happens safely .

Question 3

What is the meaning of stable

Answer 3

It is not radioactive

Question 4

Describe the conditions for nuclear fusion

Answer 4

High temperature
high pressure

It is these because high temperature means high KE and this can overcome the force of repulsion

Pressure because higher pressure means higher chance of a reaction

Question 5

Compare fission of beryllium with uranium

Answer 5

Both produce daughter nuclei
Both release energy

Uranium daughters are different however beryllium daughters are the same
Uranium daughters are heavier than beryllium daughters

Question 6

Describe the process of β− emission

Answer 6

The nuclei decays and the neutrons turns into a proton plus an electron (fast moving electron)

Question 7

Describe how radioactive materials can be used in the diagnosis and treatment
of some illnesses.

Answer 7

Radioactive trackers can be used in the body to check systems in body are working properly .
Trackers are isotopes with short half lives that are put in body .

Use gamma rays in radiotherapy . Aimed at tumours to destroy them using multiple beams of gamma rays - this may cause damage to normal body cells

Question 8

Describe the similarities and differences of nuclear fusion and nuclear fission

Answer 8

They both involve particles colliding
energy released in both
can cause explosions

FUSION is the joining of small nuclei
to form a larger nucleus
this occurs in stars

FISSION is the splitting of a nuclei
by a slow moving neutron
its a chain reaction

Question 9

Describe the process of β+ decay

Answer 9

A proton becomes a neutron plus a positron