IB Physics HL E.4 Fission Question Bank

Practise IB Physics HL E.4 by analysing fission chains, binding-energy changes, reactor physics and extended nuclear evidence.

Exam points

Calculate mass defect and binding-energy changes across fission products and parent nuclei.
Model chain reactions, multiplication, control mechanisms and energy transfer in reactor systems.
Evaluate fission data, isotope selection, radiation risk and uncertainty in extended HL evidence.

Covered syllabus points

E.4.1—Fission energy release E.4.2—Chain reactions E.4.3—Nuclear power plant roles E.4.4—Fission products and waste

[Maximum number: 4]

(a)

A nuclear power station uses U-235 as fuel. Assume that every fission reaction of U-235 gives rise to 180 MeV of energy.

[ 4 ]

(i)

Estimate, in $\mathrm{Jkg}^{-1}$ , the specific energy of U-235.

[ 2 ]

see «energy = » $180 \times 10^{6} \times 1.60 \times 10^{-19}$ AND «mass =» $235 \times 1.66 \times 10^{-27}$ $7.4 \times 10^{13} \ll \mathrm{~J} \mathrm{~kg}^{-1} \gg$

(ii)

The power station has a useful power output of 1.2 GW and an efficiency of 36 %. Determine the mass of U-235 that undergoes fission in one day.

[ 2 ]

$\text { energy produced in one day }=\frac{1.2 \times 10^{9} \times 24 \times 3600}{0.36}=2.9 \times 10^{14} \ll \mathrm{~J}>\text { }$

[Maximum number: 5]

(a)

Outline the reason why fuel enrichment is necessary for the fuel used in a commercial nuclear reactor.

[ 3 ]

(b)

The solar energy in (c) is used to heat the water directly, whereas the nuclear energy must first be converted into electrical energy in the nuclear power station. Outline the energy transformations that take place within the nuclear power station in the production of electrical power.

[ 2 ]

[Maximum number: 5]

This question is about energy sources.

A small island is situated in the Arctic. The islanders require an electricity supply but have no fossil fuels on the island. It is suggested that wind generators should be used in combination with power stations using either oil or nuclear fuel.

(a)

Any nuclear fuel available to the islanders must be enriched before it can be used.

Outline why fuel enrichment is needed.

[ 2 ]

(b)

A nuclear reactor requires both control rods and a moderator to operate. Outline, with reference to neutrons, one similarity and two differences in the function of each of these components.

[ 3 ]

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Covered syllabus points

E.4 Fission question 1

Question (a)

Question (i)

Question (ii)

E.4 Fission question 2

Question (a)

Question (b)

E.4 Fission question 3

Question (a)

Question (b)