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Flashcards in General Deck (22):

What cladding is used in AGRs (Advanced gas cooled reactor)

Stainless steel


What gas is used as the coolant is AGRs

Carbon dioxide


What is the order of temperature magnitude for the coolant, fuel and cladding along a cooling channel

Fuel > Cladding > coolant


Equation for total power generated in cooling channel

P = mdot c (Tco - Tci)

co coolant out
ci coolant in


Form of non dimensional temperature equation in terms of Tci Tco and T

θ = 2 ((T - Tci)/(Tco- Tci)) - 1


Coolant temperature at mid channel equation

Tc1/2 = 1/2(Tci + Tco)


For what shape does the minimum volume bare core occur



Flux equation for spherical geometry

Flux = A/r sin Br


Assumptions used in the reactor kinetics equations (for the lumped models of the behaviour of a source free reactor)

No spatial variation in behaviour
In real life the reactor core is highly heterogenous

Only one type of precursor
In real life there are a large number of them with varying production rates and half lives


Any potted in in hour equation graph

P = -λ

ρ = Λp + β


What does the prompt jump approximation assume

That the neutron population remains in equilibrium with the precursor population


Why is restart impossible impossible for a period after shutdown

As the Xe population will rise, peak then fall. For a period it will be sufficiently high that peak activity loss to axe poisoning will be greater than the excess reactivity available (from the control rods)


Fuel utilisation equation for M batch cycle

B = MTm where Tm = steady state batch time


What ICRP stands for

International commission on Radiological Protection


3 criteria laid down by ICRP

Don’t adopt practice unless risks are outweighed by the benefits

Exposures kept as low as reasonably achievable

Dose equivalents to individuals can’t exceed certain values


Methods of protection against external radiation (3)

Time, distance, shielding


Purpose of dose limits

To prevent: short term effects (burns), long term effects (cancers) and genetic effects.


What is the dose limit for registered radiation workers

20 mSv/yr


Assumptions on which dose limits are based

No threshold dose exists and any dose involves a proportionate risk of cancer

Doses received on separate occasions act cumulatively


Equation for the shield flux (flux at the edge of shielding)

φ’ = φ e^[-αd)

Φ unshielded flux
α attenuation coefficient
d distance


Equation that helps you find the criticality condition

α^2 + β^2 = Bm^2

Alpha and beta found by solving each variable in the differential equation.


How to derive the in hour equation

Take Laplace transforms (variable p) of both the reactor kinetics equations, substitute for co and substitute for c bar to get a an equation just in n

Then to take inverse transforms need to reduce to partial fraction form, which means setting denominator to zero, then equation pops out with density on one side.