Week 8

Question 1

Advantages of nuclear reactors

Answer 1

-Produces large amounts of energy from small amounts of fuel
-No pollutants
-Less waste
-Reliable resource

Question 2

Disadvantages of nuclear reactors

Answer 2

-Radioactive waste-must be disposed carefully
-Lot of money spent on safety-if something goes wrong can cause major disaster
-More expensive than coal/gas-higher maintenance cost

Question 3

Are nuclear reactors renewable

Answer 3

Uranium-no
Artificial fuels- yes

Question 4

Amu meaning

Answer 4

Atomics mass unit- 1/12 mass of carbon-12

Question 5

Isotope definition

Answer 5

Same number of protons different number of neutrons

Question 6

What is mass defect

Answer 6

Mass of nucleus is less than total mass of individual nucleons. Caused because of binding energy.

Question 7

What is binding energy?

Answer 7

Amount of energy needed to separate nucleons. Holds nucleus together against repulsion of protons

Question 8

What is fusion

Answer 8

Small nuclei join to form heavier nucleus

Question 9

What is fission

Answer 9

Heavy nucleus splits into two smaller nuclei (used in atomic bombs)

Question 10

What are the conservation laws

Answer 10

All must be conserved:
1) Nucleon number
2)Charge
3) Momentum
4) Mass/energy

Question 11

What do unstable atoms emit

Answer 11

Alpha, beta or gamma radiation

Question 12

What is alpha particle

Answer 12

same as helium.
Mass number 4
Proton number 2
Emitted when atom is too big

Question 13

What is beta particle

Answer 13

Same as electron
-1 charge.
Mass number stays constant- neutron converts into proton and emits an electron
Happens when nucleus has too many neutrons.

Question 14

What is a breeding reaction

Answer 14

Amount of fuel produced is greater than amount of fuel required for reaction (Can be removed to fuel other processes)

Question 15

How does pressurised water reactor work

Answer 15

primary and secondary circuits, both use water.
Primary moderates (slows) neutrons and remove heat.
Secondary raises steam
Operating conditions- 320 degrees Celsius and 160 bars

Question 16

how does boiler water reactor work

Answer 16

primary circuit only. Water used to moderate neutrons to remove heat and raise steam.
Operating conditions- 300 C and 70 bar

Question 17

how does pressurised heavy water reactor work

Answer 17

primary and secondary circuit and calandria (heavy water)
Calandria used to moderate neutrons.
Primary circuit (heavy or light water) to remove heat
Secondary circuit to raise steam
Operating conditions: 325 C and 120 bar

Question 18

how does gas cooler reactor work

Answer 18

primary and secondary circuit.
Primary uses graphite to moderate neutrons and CO2 to remove heat.
Secondary circuit uses water to raise steam.
Operating conditions: 380 C and 7-27 bar

Question 19

how does advanced gas cooler reactor work

Answer 19

primary and secondary circuit.
Primary uses graphite to moderate neutrons and CO2 to remove heat.
Secondary uses water to raise steam.
Operating conditions: 650 C and 40 bar

Question 20

Advantages of advanced fuel cycles and deadtors

Answer 20

• fuel recycling extends raw material resources
• move to purely fast reactors would extend resources