2023 MCQ Flashcards
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?
At the core mid-plane.
At what axial location in the core of an idealised cylindrical reactor does the cladding temperature reach a maximum?
Between the midplane and core exit.
Order the following in ascending order of typical thermal efficiency:
Combined cycle gas turbine plant
Very modern coal fired power station
AGR
PWR
PWR
AGR
Coal
Gas
What is the number density of U235 atoms?
3.42E26 atoms per cubic metre
True or false:
Uranium minerals are scarce and therefore increased demand will soon consume economically viable uranium sources.
False
What is the coolant and pressure in a PWR?
Light water at 150 bar
What material property increases as a result of exposure to high energy neutron flux?
Yield Stress
How is the thermal efficiency of an AGR plant influenced by using fuel with a higher enrichment?
Little changed
What does a microscopic cross section describe?
The properties of an individual nucleus
What happened to the reactor core in the Three Mile Island accident?
Central region of core melted.
Formed a pool which drained partly down to the bottom of the vessel.
What is the unit for neutron flux?
neutrons per square metre per second
How to calculate binding energy?
Calculate difference in mass (total mass - mass of nucleons)
Calculate E=mc2
Which nuclear project is making use CDF as a financing mechanism?
Hinkley Point C
How to calculate macroscopic absorption?
microscopic x neutron density
How to calculate K_effective?
K_infinity x fastfissionfactor x resonance escape probability
Which generation of reactor is an AGR?
Gen II
As of 2021, nuclear power provides approximately what proportion of global electricity?
10%
U238 can, in principle, undergo which of the following sequence of decay processes to become U234?
alpha, beta, beta
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 ?
12.5 g
The average lifetime of a neutron in a nuclear reactor is approximately
1E-3 secs
Approximately what proportion of neutrons produced by fission are ‘prompt’?
99.3 %
What does nvSigma_fv tell you?
local source rate of neutrons
What is the Reynolds number equation for mass flow rate?
Re = ((m/A) * d) / dynamic viscosity
In the event of a LOCA, the emergency core cooling system (ECCS) in a PWR, refloods the core in approximately
4 minutes
The Safety Authority of which country requires a risk-based justification?
UK
What does a level 2 Probability Safety Assessment find?
the frequency of different radioactive release categories
The radionuclides which have the most significant effects on human health as a consequence of a severe accident are
I-131 and Cs-137
The average UK background radiation dose is approximately
2 mSv/yr
The most common forms of ‘fast’ reactor in operation are
Sodium cooled
True or false: Irradiation of a high atomic mass materials with alpha particles causes Bremsstrahlung radiation
False
True or false: ILW wastes do not require shielding
False
How is the thermal performance of fuel affected by the presence of fission products?
Degraded
