Week 7 Nuclear Fission Part 2 & Nuclear Fusion Part 1

Question 1

what are the 6 key parts of a fission reactor

Answer 1

fuel
moderator
coolant
control system
reflector
containment system

Question 2

what are the two types of fission reactor

Answer 2

pressurised water reactor

boiling water reactor

Question 3

describe the two ways to enrich nuclear fuel

Answer 3

gas diffusion - difference in diffusion rate due to size

gas centrifuge - centrifugal force leads to radial separation in rotating column

Question 4

why is the moderator important

Answer 4

it is needed to achieve thermal neutrons

Question 5

give 2 of the 5 key properties of an ideal moderator

Answer 5

low atomic mass
minimal neutron capture cross section 
high density
chemically stable
cheap & abundant

Question 6

what are two common moderators

Answer 6

water and heavy water (D2O)

Question 7

what is often required of a coolant

Answer 7

large heat capacity

Question 8

what do control rods do

Answer 8

stop or slow down the reaction

Question 9

what is the carnot heat engine efficiency equation

Answer 9

η = W/Q = 1 - Tcondensor/Tcore

Question 10

what is the general concept of fusion

Answer 10

two light nuclei fuse together to form a larger nuclei releasing energy in the process

Question 11

what two things can reduce the energy threshold for a fusion reaction

Answer 11

quantum tunneling

distribution of energy for a specific temperature

Question 12

which fusion reaction produces the most energy

Answer 12

reactions that lead to the production of an alpha particle

Question 13

what is the reaction rate of a fusion reaction

Answer 13

R = n1n2

Question 14

what are the 4 parts of a fusion reaction

Answer 14

require a minimum of energy to start
produce a lot of energy
have a large reaction rate
easy to produce

Question 15

what is conservation of energy and Q equation

Answer 15

1/2mava^2 = Q / (1 + ma/mb)

Question 16

what does the fusion conservation equations suggest

Answer 16

most of the energy goes with the neutron

Question 17

what is the fusion gain factor equation

Answer 17

Q = Pfusion / Pheating

Question 18

what are three fusion gain factor scenarios

Answer 18

Q = 1 break point - net energy neutral
Q = ∞ Ignition point - no longer need external power
Q = 10-20 Feasible reactor

Question 19

define Lawson criterion and give its equation

Answer 19

Lawson criterion - condition for output power to exceed input power
nτE > 12kT/Qα = f(T)
Qα is the energy per reaction of an alpha particle
τE is the energy confinement time

Question 20

what are the two types of confinement for a fusion reactor

Answer 20

magnetic confinement

inertial confinement