General

Question 1

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

Answer 1

Stainless steel

Question 2

What gas is used as the coolant is AGRs

Answer 2

Carbon dioxide

Question 3

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

Answer 3

Fuel > Cladding > coolant

Question 4

Equation for total power generated in cooling channel

Answer 4

P = mdot c (Tco - Tci)

co coolant out
ci coolant in

Question 5

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

Answer 5

θ = 2 ((T - Tci)/(Tco- Tci)) - 1

Question 6

Coolant temperature at mid channel equation

Answer 6

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

Question 7

For what shape does the minimum volume bare core occur

Answer 7

Spherical

Question 8

Flux equation for spherical geometry

Answer 8

Flux = A/r sin Br

Question 9

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

Answer 9

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

Question 10

Any potted in in hour equation graph

Answer 10

P = -λ

ρ = Λp + β

Question 11

What does the prompt jump approximation assume

Answer 11

That the neutron population remains in equilibrium with the precursor population

Question 12

Why is restart impossible impossible for a period after shutdown

Answer 12

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)

Question 13

Fuel utilisation equation for M batch cycle

Answer 13

B = MTm where Tm = steady state batch time

Question 14

What ICRP stands for

Answer 14

International commission on Radiological Protection

Question 15

3 criteria laid down by ICRP

Answer 15

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

Question 16

Methods of protection against external radiation (3)

Answer 16

Time, distance, shielding

Question 17

Purpose of dose limits

Answer 17

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

Question 18

What is the dose limit for registered radiation workers

Answer 18

20 mSv/yr

Question 19

Assumptions on which dose limits are based

Answer 19

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

Doses received on separate occasions act cumulatively

Question 20

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

Answer 20

φ’ = φ e^[-αd)

Φ unshielded flux
α attenuation coefficient
d distance

Question 21

Equation that helps you find the criticality condition

Answer 21

α^2 + β^2 = Bm^2

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

Question 22

How to derive the in hour equation

Answer 22

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.