2023 MCQ

Question 1

At what axial location in the core of an idealised cylindrical reactor does the difference between the cladding temperature and bulk coolant temperature reach a maximum?

Answer 1

At the core mid-plane.

Question 2

At what axial location in the core of an idealised cylindrical reactor does the cladding temperature reach a maximum?

Answer 2

Between the midplane and core exit.

Question 3

Order the following in ascending order of typical thermal efficiency:
Combined cycle gas turbine plant
Very modern coal fired power station
AGR
PWR

Answer 3

PWR
AGR
Coal
Gas

Question 4

What is the number density of U235 atoms?

Answer 4

3.42E26 atoms per cubic metre

Question 5

True or false:
Uranium minerals are scarce and therefore increased demand will soon consume economically viable uranium sources.

Answer 5

False

Question 6

What is the coolant and pressure in a PWR?

Answer 6

Light water at 150 bar

Question 7

What material property increases as a result of exposure to high energy neutron flux?

Answer 7

Yield Stress

Question 8

How is the thermal efficiency of an AGR plant influenced by using fuel with a higher enrichment?

Answer 8

Little changed

Question 9

What does a microscopic cross section describe?

Answer 9

The properties of an individual nucleus

Question 10

What happened to the reactor core in the Three Mile Island accident?

Answer 10

Central region of core melted.
Formed a pool which drained partly down to the bottom of the vessel.

Question 11

What is the unit for neutron flux?

Answer 11

neutrons per square metre per second

Question 12

How to calculate binding energy?

Answer 12

Calculate difference in mass (total mass - mass of nucleons)
Calculate E=mc2

Question 13

Which nuclear project is making use CDF as a financing mechanism?

Answer 13

Hinkley Point C

Question 14

How to calculate macroscopic absorption?

Answer 14

microscopic x neutron density

Question 15

How to calculate K_effective?

Answer 15

K_infinity x fastfissionfactor x resonance escape probability

Question 16

Which generation of reactor is an AGR?

Answer 16

Gen II

Question 17

As of 2021, nuclear power provides approximately what proportion of global electricity?

Answer 17

10%

Question 18

U238 can, in principle, undergo which of the following sequence of decay processes to become U234?

Answer 18

alpha, beta, beta

Question 19

A fresh 100g sample of a radioactive isotope has a half-life of
5 days. How many grams of the radioactive isotope will remain after 15 days ?

Answer 19

12.5 g

Question 20

The average lifetime of a neutron in a nuclear reactor is approximately

Answer 20

1E-3 secs

Question 21

Approximately what proportion of neutrons produced by fission are ‘prompt’?

Answer 21

99.3 %

Question 22

What does nvSigma_fv tell you?

Answer 22

local source rate of neutrons

Question 23

What is the Reynolds number equation for mass flow rate?

Answer 23

Re = ((m/A) * d) / dynamic viscosity

Question 24

In the event of a LOCA, the emergency core cooling system (ECCS) in a PWR, refloods the core in approximately

Answer 24

4 minutes

Question 25

The Safety Authority of which country requires a risk-based justification?

Answer 25

UK

Question 26

What does a level 2 Probability Safety Assessment find?

Answer 26

the frequency of different radioactive release categories

Question 27

The radionuclides which have the most significant effects on human health as a consequence of a severe accident are

Answer 27

I-131 and Cs-137

Question 28

The average UK background radiation dose is approximately

Answer 28

2 mSv/yr

Question 29

The most common forms of ‘fast’ reactor in operation are

Answer 29

Sodium cooled

Question 30

True or false: Irradiation of a high atomic mass materials with alpha particles causes Bremsstrahlung radiation

Answer 30

False

Question 31

True or false: ILW wastes do not require shielding

Answer 31

False

Question 32

How is the thermal performance of fuel affected by the presence of fission products?

Answer 32

Degraded