Additional - Topic 2.5 and 2.6 - Radiation Flashcards
Both nuclear fission and nuclear fusion release thermal energy. Describe how the thermal energy released could be converted into electrical energy in a power station. (3)
Thermal energy used to create steam / boil water(1) (Steam used to drive) turbine (1) (Turbine used to turn) generator (1)
Scientists and engineers are still trying to build a practical and economic nuclear fusion reactor. They have not been able to sustain the extreme conditions needed for controlled nuclear fusion. Explain what these conditions are and why they are needed. (6)
Description of the problem - Nuclei have positive charge - Repel each other - Reduces possibility of suitable collisions - Rate of fusion too small to be useful Description of how this can be overcome o Very high temperature ( of fuel) o Very high KE / speed of nuclei o High KE can overcome repulsion o Very high density / pressure o Increases possibility of suitable collisions
(i) Use the graph to find the half-life of cobalt-60.
(2)
half-life = …………………………………. years
(ii) The cobalt-60 has to be replaced when its activity has fallen below 1000 Bq. Estimate how long it takes for the activity to fall from 8000 Bq to 1000 Bq.
(1)
time taken = …………………………………. years
i) From the graph Time taken to fall (from 8000) to 4000 (1) = 5.3 (years) (1) ii) 3 x 5.3 (= 15.9 years)
When it is time to replace the cobalt-60 rods there are two options.
The rods can be disposed of.
The rods can be transported to a nuclear reactor to turn more of the
cobalt-59 into cobalt-60 so that they can be used again.
Discuss the hazards in these two options.
(6)
A discussion which includes description of the hazards (H)
and / or possible precautions (P) to reduce risks arising from
them such as
In either option.
o Rods are radioactive (H)
o Gamma radiation is highly penetrating / ionising
(H)
o Radiation from them can cause cancer / damage
to organisms / people / environment (H)
o Need for shielding (P)
o Security to prevent public access (P)
Transportation / reprocessing
o Danger of accident during transport (H)
o Need to be suitably protected against damage.
(P)
o Danger of interception/high-jacking/terrorists
(H)
o Need security (P)
o Workers could be exposed to radiation (H)
o Special facilities required (P)
Disposal
o Can damage environment if not properly
contained (H)
o Special disposal facilities, not landfill (P)
o Remain radioactive for some time (H)
o Need to be kept secure while decaying to safe
levels. (P)
o Relatively short half-life means that very long
term storage is not necessary. (P)
(i) State the name of particle X.
(1)
(ii) State the name of particle Y.
(1)
i) Proton
ii) Electron
There are plans to build more nuclear power stations to supply electricity to the
National Grid.
Discuss the advantages and disadvantages of using nuclear power to generate
electricity.
(6)
A discussion including some of the following points
Advantages
- (currently) large resources of fuel/ fuel (reserves) will last
a long time
- (Produces) large amount of (electrical) energy/electricity
- Does not produce (much/any) carbon dioxide
- Does not produce (much/any) sulphur dioxide
- Does not add to global warming/climate change
- Good safety record (under normal operating conditions)
- Only small amount of fuel needed to produce large amount
of energy/electricity
- Reliable supply/provides continuous supply of electricity
(for a long time)
- Reduces dependence on foreign supplies of energy
- Conserves fossil fuel supplies
- (Spent) fuel can be processed (to produce fuel for other
reactors)
- Provides employment/jobs
Disadvantages
- Produces nuclear/radioactive {waste/materials}
- nuclear/radioactive waste/materials can cause
mutations in
DNA/cells/people/animals
- Non- renewable (energy source)
- Difficulties in transporting nuclear/radioactive
waste/material
- Difficulty in (safely) storing/disposing nuclear
waste/material
- Nuclear accidents (can) pollute large areas
- Nuclear accidents pollute for a long time
- Accept named example of accidents eg Fukishima,
Chernobyl, 3-mile island
- Mining and processing fuel both produce large
amounts of carbon dioxide
- Expensive to build and/or decommission (nuclear
power stations)
- Reference to target for terrorist attacks
- Produces material which can be used to develop
nuclear weapons/by terrorists
- Negative public perception OWTTE
ignore references such as unsightly, large area needed, noisy as
true for most large buildings. Ignore cost of generation or
restating stem ie generates electricity or supplies electricity to
homes etc.
Nuclear fusion can occur if a deuterium and a tritium nucleus can be brought
close enough to each other.
This fusion produces a helium nucleus and releases a neutron.
(i) Compare the charges of a helium nucleus and a neutron.
(2)
Helium (nucleus has) positive/+
(charge) (1)
Neutron has no/zero/0 (charge)
(1)
Nuclear fusion is an important process.
Scientists have said ‘without nuclear fusion, there would be no life on Earth’.
Explain why nuclear fusion is important to life on Earth.
(2)
(Nuclear fusion/it) occurs in the
Sun (1)
(The Sun / Fusion provides)
energy/heat/light (needed for life
on Earth) (1)
Neutrons are also released during nuclear fission.
Describe how the neutrons released in nuclear fission are used to produce a
controlled chain reaction in a nuclear reactor.
(6)
A description including some of the following points
Stages involved in a chain reaction:
o (neutrons released go on to) collide with other
nuclei
o causes nuclei to become unstable
o (nuclei) split/fission (into daughter nuclei)
o releases more neutrons
o releases energy
Control:
-Action of the moderator
o neutrons need to be slowed down/turned into
thermal neutrons
o to increase chance of collision
o this is achieved with a moderator
o carbon/graphite/water/heavy water can be used
-Action of control rods
o number of neutrons available for collision needs to
be controlled
o so that reaction proceeds at a steady rate / does
not increase
o this is achieved by control rods absorbing neutrons
o boron / silver/indium/cadmium can be used.
Many candidates repeat parts of the question Do
NOT give credit for these statements eg neutrons
are released during fission
A scientist investigates an old wooden comb.
The activity of the carbon-14 in it is 0.55 Bq.
The estimated age of the comb is 11 400 years.
The half-life of carbon-14 is 5700 years.
(i) Calculate the activity of the carbon-14 in the comb when it was new.
Idea of 2 half-lives (1)
11 400 = 2 × 5700
Idea of halving activity twice (1)
0.55 × 2 × 2
Calculation (1)
2.2 (Bq)
The scientist takes several readings of background radiation.
Explain why this is necessary to improve the accuracy of the investigation.
(2)
Explanation linking two of:
• Background radiation
affects the measurement
(1)
• Needs to be subtracted
from readings (1)
• Background radiation is
variable (1)
• Background radiation
needs to be averaged (1)
Alpha, beta and gamma are types of ionising radiation.
(a) State two ways in which gamma radiation is different from alpha radiation.
(2)
Any two of:
Gamma is a wave (1)
Alpha is a helium nucleus (1)
Alpha is charged (1)
Alpha has a mass (1)
Gamma penetrates further/
highly (1)
Gamma weakly ionising (1)
Gamma travels faster (1)
Explain how an atom becomes ionised by radiation.
(2)
An explanation linking:
electron(s) (1)
is/are lost/gained (1)
Nuclear fission is the reaction that happens in a nuclear power station.
Explain what happens when nuclear fission occurs.
(2)
An explanation linking any two of
the following points
- a neutron(s)(1)
- hits nucleus/nuclei (1)
- uranium/nucleus splits (1)
- (producing) neutrons
/daughter nuclei/ energy /
Kr and Ba (1)
Control rods are used in the nuclear reactor.
Explain how these rods stop the nuclear reaction from getting out of control.
(2)
An explanation linking two of the
following points
- absorb (1)
- neutrons (1)
- (influences) chain reaction /
rate of reaction (1)
